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Full text of "Anatomy of the human skeleton"

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MORRIS'S 

TREATISE OX ANATOMY 

fourtb fi&ition 

BY ENGLISH AND AMERICAN WRITERS 

PART 1 



-»•. 



MORRIS'S ANATOMY 
m FIVE PARTS. EACH PART SOLD SEPARATELY 

PART I. Morphogenesis. Osteology. Articulations. Index. $1.50. 

PART II. Muscles. Organs of Circulation, Including Lymphatics. Index. $2.00. 

PART III. Nervous System. Cleans of Special Sense. Index. $1.50. 

PART IV. Organs of Digestion; of \'oice and Respiration. Urinarj' and Reproduc- 
tive Organs. Ductless Glands. Skin and Mammary Glands. 
Index. $1.50. 

PART V. Surgical and Topographical Anatomy. Index. $1.00. 

THIS BOOK IS ALSO PUBLISHED IN ONE HANDSOME OCTAVO VOLUME. 

Cloth, $6.00. Sheep or Half Morocco, $7.00, net. 



CONTRIBUTORS TO FOURTH EDITION 



HENRY MORRIS, F.R.C.S., London. 
R. J. TERRY, Washington University, 
St. Louis. 



J. PLAYFAIR McMURRICH, Univer- 
sity of Michigan. 

ABRAM T. KERR, Cornell Univereitv. 

TiU''°'"^°''' ""'"*'' '^'"'''' CHARLES R. BARDEEX, Universiiy 



London. , 

IRVING HARDESTY, University of of W iscon^in. 

California. 

G. CARL HUBER, University of Jlich- 
igan. 



FLORENCE R. SABIN, Johns Hop- 
kins University. 

R. MARCUS GUNN, F.R.C.S., London. 



W. H. A. JACOBSON, F.R.C.S.. Guy's Hospital, London. 



For arrangement of subjects and authors see page v. 



MORRIS'S 



HUMAN ANATOMY 



A COMPLETE SYSTEMATIC TREATISE 
BY ENGLISH AND AMERICAN AUTHORS 



EDITED BY 

HENRY j^RIS, M.A. and M.B. Lond., F.R.C.S. Eng. 

PNESIDBNT OF THE RO'^AC'^LLECI Of SVHGSONS (It BMQLAND ^ CONSULTING SURGEON TO MIDDLESBX HOSPITAL, LOHDOH: 

HONORARV MGMBBH OF THB MEDICAL SOCIHTV OF THE COUNTy OF HBW VOHK^ PORMEKLV CKAIKMAN 

OP THB COURT OF KXAMINFRS OF THE MOVAl COLLKCK OF SURCBONS ; BXAMINBR 

IK AHATUMV IN TKB tlNIVF.RSlTY OP DCHKAM, AND SXAUIKBH IN 

SURGRKV i;i THE UNIVHHSITV OF LONDON 

AND 

J. PLAYFAIR McMURRICH. A.M., PH.D. 

PROFESSOR OF AHATOHV. tlHlVBRSITV OF MICHIGAN^ MEMDER ASSOCIATION OF AHBKICAN ANATOUISTS : KBHBRR OP 
ADVISORY BOARD. WTSTAR IHSTITUTB OF ANATOMY, ETC, 



TEN HUNDRED AND TWENTY-FIVE ILLUSTRATIONS 
THREE HUNDRED AND NINETEEN PRINTED IN COLORS 



FOURTH EDITION, REVISED AND ENLARGED 



IN FIVE PARTS 

PART 1 

General morphogeny. Osteology. Articulations 



PHILADELPHIA 

P. BLAKISTON'S SON & CO. 

lOI 2 WALNUT STREET 
1907 



Copyright. 1907, by P. Bi^hi^ton's .Son & Co. 



Registebed at Stationers' Hai.l. London, Engi.ajid. 



WU. r. FELL COMPANY 

ElElTTB.-IVrSllS *VD PK1MK»S 
■ 11.--^ iA^f.'M StREII 

PHinrFLrHi*, Pt. 



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ARRANGEMENT OF SUBJECTS AND AUTHORS. 



The names of those who originally wrote articles and those who revised and 
wrote for previous editions have been retained in the following list of contents, in 
order that due credit should be given them for the work done and for their share 
in the great success which Morris's "Anatomy" has achieved throughout England 
and America. 

MORPHOGEIfESIS. (The Development of Structure.) By J. Playfair 
McMuRRiCH, A.M., Ph.D., Professor of Anatomy, University of Michigan; Member 
Association of American Anatomists; Memljer of Advisory Board, Wistar Institute 
of Anatomy; Member of Editorial Board of "American Journal of Anatomy;" 
Author of "The Development of the Human Body." 

OSTEOLOGY. Revised and largely rewritten for Third and Fourth Editions 
by Peter Thompson, M.D., Professor of Anatomy, King's College, London; Member 
of Anatomical Society of Great Britain. This article was originally written by J. 
Bland Sutton, F.R.C.S., formerly Examiner in Anatomy in Royal College of Sur- 
geons. 

ARTICULATIONS. By Henhy Morris, A.M. and M.B., London, President of 
the Ro>*al College of Surgeons of England; Consulting Surgeon to, and formerly 
Lecturer on Surgery and Anatomy at, Middlesex Hospital, London; and Examiner 
in Anatomy, University of Dunham, etc. 

MUSCLES. Rewritten by Charles R. Bahdeen, A.B., M.D.. Professor of 
Anatomy in the University of Wisconsin; Member Association of American Anato- 
mists; Member of Editorial Board of "American Journal of Anatomy." Originally 
written by the late J. N. C. Davies-Colley, F.R.C.S., formerly Lecturer on Anatomy, 
Guy's Hospital, London. 

HEART, BLOOD-VESSELS, AND LYMPHATICS. Revised and in part re- 
written by Florence R. Sahix, B.S.. M.D., Associate Professor of Anatomy in 
the Johns Hopkins University; Member Association of American Anatomists. 
The section on Blood-vessels was originally written by the late William J. Walsham, 
F.R.C.S., formerly Lecturer on Anatomy, St. Bartholomew's Hospital, London. 
The section on the Heart in previous editions was written by the late Arthur Hens- 
man, F.R.C.S., and revised by Arthur Robinson, M.D., Professor of Anatomy, Uni- 
versity of Birmingham. 

NERVOUS SYSTEM. Revised and largely rewritten by Irving Hardesty, 
A.B., Ph.D., Assistant Professor of Anatomy, University of California; Meml^er 
Association of American Anatomists. This section was originally written by the 
late H. St. John Brooks, M.D., formerly Chief Demonstrator of Anatomy, Uni- 
versity of Dublin, and revised for the S^'cond and Third Editions by Arthur Robin- 
son, M.D.. Profe-SRor of Anatomy, Lniversity of Birmingham. 

V 



vi ARRANGEMENT OF SUBJECTS AND AUTHORS. 

ORGANS OF SPECUL SENSE. Eye.— By R. Marcus Gunn, F.R.C.S., 
Senior Surgeon, Royal London Ophthalmic Hospital (Moorfields); Sui^on to the 
Western Ophthalmic Hospital and to the National Hospital for the Paralysed and 
Epileptic. Ear, Nose, Tongue.— By Abram T. Kerr, B.S., M.U., Professor of 
Anatomy, Cornell University; Member Association of American Anatomists. The 
sections on Ear, Nose, Tongue in previous editions were written by the late Arthur 
Hensman, F.R.C.S., and revised by Arthur Robinson, M.D., Professor of Anatomy. 
University of Birmingham. 

ORGANS OF DIGESTION. Revised by G. Carl Huber, M.D., Professor of 
Histology and Embryology in the University of Michigan; Secretary Associati»n 
of American .Anatomists; Memljer of Advisory Board, Wistar Institute of Anatomy; 
Member of Editorial Board of "American Journal of Anatomy." This article was 
originally written by Sir Frederick Treves, K.C.V.O., F.R.C.S. 

ORGANS OF VOICE, RESPIRATION, INCLUDING THE MEDIASTINA. 
By R. J. Terrv, A.B., M.D., Professor of Anatomy, Washington University, St. 
Louis: Member Association of American Anatomists. These sections in previous 
editions were written by the late Arthur Hensman, F.R.C.S., and revised by 
Arthur Robinson, M.D., Professor of Anatomy, University of Birmingham. 

URINARY AND GENERATIVE ORGANS. Revised by J. Plavfair McMur- 
RicH, A.M., Ph.D., Professor of Anatomy. University of Michigan; Member 
.Association of American Anatomists. This section includes "The Perineum," by 
Peter Thompson, M.D. These articles were originally written by the late William 
Anderson, F.R.C.S., formerly Vice-President Anatomical Society of Great Britain. 

THE DUCTLESS GLANDS, INCLUDING THE THYREOID GLAND. By 
G. Carl Huber, M.D., Professor of Hi.stoloticy and Embryology in the University 
of Michigan; Secretary .Association of American Anatomist.s. 

THE SKm AND MAMMARY GLAND. By Abram T. Kerr, B.S.. M.D., Pro- 
fessor of Anatomy, Cornell University; Meml)er Association of American Anato- 
mists, etc. This article wa.f oricinally written by the late William Anderson, 
F.R.C.S., formerly Vice-President Anatomical Society of Great Britain. 

SURGICAL AND TOPOGRAPHICAL ANATOMY. By W. H. A. Jacorson, 
F.R.C.S., Consulting Surgeon to Guy's Hospital; formerly Lecturer on Anatomy, 
Guy's Hospital Medical School; .Author of "The Operations of Surgery," etc. 



PUBLISHERS' NOTE TO FOURTH EDITION 



The very favorable reception accorded the previous editions of this work in 
America suggested the desirability of making the present (fourth) edition interna- 
tional in its character, by placing it largely in the hands of an American editor and 
by securing the ser\'ice!j of American Anatomists in the revision or rewriting of 
certain of the sections. 

The entire work has undergone a complete revision, and some sections, such as 
those on the Muscles, the Lymphatics, the Central Nervous System, certain of the 
Sense Organs, the Perineum, and the Skin, have been entirely rewritten and, in sev- 
eral instances, considerably enlarged; the text has been brought thoroughly up 
to date by the inclusion of the results of recent investigations, and represents, accu- 
rately, the present state of Anatomy. -Many illustrations which appeared in pre- 
vious editions have Ijeen omitted, a large numljer of new figures have been made from 
specially prepared drawings, and pictures from other books have been included 
where they sen'ed the desired purpose. 

Due credit has been given throughout the book wherever illustrations have been 
taken, or modified, from other works. Special acknowledgment should be made of 
our indebtedness to Toldt's "Atlas of Anatomy," Poirier and Charpy, Henle, and 
Spalteholz. 

The same mode of describing illustrations used in previous editions has been 
carried out as far as practicable. It consists in printing the descriptions in different 
types at the end of the pointers. Thus, the muscles, fasciee, and ligaments are in one 
kind of type; arteries, veins, and lymphatics in another; bones and special organs 
in a third; ner\-e structures in a fourth. 

Special attention should be directed to the use throughout the volume of the 
nomenclature adopted by the German Anatomical Society and generally known 
as the Basle nomenclature, or BN.\. In employing this nomenclature the editors 
have been guided by a desire to assist in the unification of anatomical terminology, 
seeing in such unification an earnest of the thorough internationalization of the 
science of anatomy and more rapid progress in its development. The modifica- 
tions of the accepted English nomenclature necessitated by the adoption of the 
BNA are comparatively few, and where they are radical, the more familiar terms 
have been added in parentheses. The slight inconvenience which the present gen- 
eration may .suffer from a partisdly duplicated nomenclature will, it is expected, be 
more than compensated for by the broader outlook gained by future students in 
having access, through the new terminology, to the best text-books and atlases of 
foreign liinds. Whilst this is the first text-book of .\natomy in English to adopt 
the BNA in its entirety, there are a number of books and papers on Embryology, 
Histology, and Biology in which it is used; its general adoption in the future, it 

vii 



viii PUBLISHERS' NOTE TO FOURTH EDITION 

may be confidently expected, will be assured. In this connection, reference should 
be made to a new book by Prof. Llewellys F. Barker, of Johns Hopkins University, 
in which a complete list of the terms used in the BNA is given and in which the ob- 
ject, system, and practicability of the nomenclature is explained. 

Each author is alone responsible for the subject-matter of the article following 
his name. Care has been exercised on the part of the editors, however, to make the 
whole uniform, complete, and systematic. 

It would be ungenerous on our part as publishers not to acknowledge our appre- 
ciation of the great labor involved on the part of the editors, writers, and artists, in 
the production of a work of such importance. Only those who have been intimately 
concerned in the making of a book of this character can have any conception of the 
mass of detail through which the editors must thread their way, or understand the 
great amount of thoughtful and painstaking care which the writers must exercise 
in reducing their knowledge to the clear, exact, and concise form so necessary to the 
understanding of the student. 

P. BLAKISTON'S SON & CO. 



Note. — For the convenience of those who prefer the 
book in that form it ia also issued in One Octavo 
Volume with One Complete Index. 



EDITOR'S PREFACE TO THE FIRST EDITION. 



This treatise on Human Anatomy is designed for the use of Students preparing 
for the Conjoint Board of the Royal Colleges of Physicians and Surgeons, for the 
Fellowship of the Royal College of Surgeons, and for the Examinations in Anatomy 
at the various Universities. 

It aims at being a complete and systematic description of every part and organ 
of the human body so far as it is studied in the dissecting room. 

Histology and development — except the mode and dates of development of 
the bones, and in a few other instances — are not included, as it is felt that these 
subjects are more appropriately dealt with in books on Physiology than they can 
conveniently be in works on Anatomy, 

The different sections have been written by separate authors, who are known 
to have devoted special attention to the subjects allotted to them. To these gentle- 
men my best thanks are due for their generoui= assistance and able cooperation. 

Whilst each author is alone responsible for the subject-matter of the article 
which follows his name, the proof-sheets of other articles besides his own have in 
certain cases been submitted to him, so that several of the articles may be consid- 
ered to have received the approval and endorsement of two, three, or more authors. 
This has been partiicularly the case with the sections on Osteology, Arthrology, 
Myology, and Neurology. There is. therefore, reason to believe that such impor- 
tant points as the attachments of ligaments and of muscles, and the nerv-e-supply 
of muscles, etc., will be found to be in perfect accord in the various sections in which 
they are referred to or descriljed. 

In the illustrations of the bones, the origins of muscles are indicated by red Hnes, 
the insertions by blue lines, and the attachments of ligaments by dotted black 
lines. 

A feature of the book which, it is confidently hoped, will facilitate the work of 
students, is the mode of describing the illustrations. 

This plan was decided upon at a conference of all the Authors and one of the 
artists. It consists in printing the descriptions in different types at the end of the 
pointers. Thus it will be found that muscles, fasciee; and ligaments are in one kind 
of type; arteries, veins, and lymphatics in another; bones in a third; and ner\'e- 
structures in a fourth. The names of special organs — such as the liver, lungs, etc. 
— are printed in the same type as the bones, so as to avoid too great a variety of 
lettering. 

Several of the illustrations are repeated in different parts of the book, with the 
object of sparing the reader the trouble of referring from one section to another when 
reference is made to the letterpres.s in such figures. 

As much uniformity as possible has been observed in the size and general style 

ix 



X EDITOR'S PREFACE TO THE FIRST EDITION. 

of the drawings; but exceptions will be found in the section on Surgical and Topo- 
graphical Anatomy, for which many of the illustrations have been borrowed from 
another work, published by Messrs. J. and A. Churchill, namely, Bellamy's 'Sur- 
gical Anatomy.' 

I have to Ewiknowledge with grateful thanks the assistance I have received from 
Mr. Gordon Brodik, who made several dissections from which drawings were 
taken; from Mr. J. Bland Sutton and Mr. Frank Steele in reading over proof- 
sheets; from Mr. Burghahd for the care with which he has drawn up the Index and 
Tables of Contents; and from all the artists named on the title-page. 

Mr. Berjeau and Mr. Balcomu have drawn a very large proportion of the fig- 
ures; and, with Mr. Smit and Mr. Parker, have shown a degree of interest in and 
given an amount of time and trouble to the illustrations for which they merit the 
fullest recognition. 

The beautiful anatomical dissections in the Hunterian Museum which have 
been, by permission, copied for this Treatise are from the hand of Mr. William 
Pearson, to whose great skill in dissecting I have much pleasure in referring. 

Too much praise cannot be given to all engaged in the actual printing of the 
book for the painstaking care they have devoted to it; especially to the difficult 
and precise work of properly 'registering' and printing the coloured illustrations. 

I need only say, in conclusion, that I shall not consider my prolonged and labo- 
rious task has been in vain if it be found that the Treatise adequately meets the 
requirements of Students, for whom it is written. 

Henry Morris. 

8 Cavendish Square. 



CONTENTS OF PART I 



Intboductiok. 



VAOt 

1 



By J. Platfair McMurricr, A,M., Pa,D. 



SECTION I 



GENERAL MORPHOGENY 
By J, PiM.YFAm McMuRRicH, A.M., Ph.D 



PAGE 

Structural Units 3 

Germinal Layers 4 

Metamerism 5 



PA OB 

Branchioraerism 7 

Viscera 9 

Limbs 1 1 



SECTION II 



The Skeleton 


13 


I. The Axial Skeleton 


Ifi 


A . The Vertebral Column 


16 


The Cer\-ical Vertebrae 


18 


The Thoracic or Dorsal Verte- 






23 


The Lumbar Vertebne 


23 


The Sacrum 


?7 


The Coccygeal Vertebne 

The Vertebral Column as a 


29 


Whole 


30 


B. Boneg of ihe SkuU . 


S9 


The Occipital 


^*i 


The Parietal 


45 


The Frontal 


47 


The Sphenoid 


,V1 


The Sphenoidal Concha (Tur- 






Ftii 


The Epipteric and Wormian 




Bones 


57 


The Temporal Bone 


57 


The Tympanum or Middle 




Ear 


m 


The Osseous Labyrinth 


69 


The Ethmoid 


71 


The Inferior Nasal Concha 




(Inferior Turbinate Bone). . 


74 


The Lachrymal Bone 


75 


The Vomer 


75 


The Nasal Bones 


-fi 


The Maxilla or Upper Jaw, . . 


77 


The Palate Bone 


81 


The Zygomatic or Malar Bone 
The Mandible or Lower Jaw, , 


83 


85 


The Hvoid Bone 


89 



OSTEOLOGY 

OaioiNALLT Written by J. Bland SdtT0!i 

Revised and Largely Rbwhitten for Fouhth Edition by Peteb Thompson, M.D. 

The Skull as a Whole 90 

The Orbits 100 

The Nasal Fossoa 101 

The Interior of the Skull 104 

The Teeth 109 

The Morphology of the Skull . 112 

C. The Thorax 120 

The Ribs 120 

The Sternum 127 

The Thorax as a Whole 132 

11. The Appendicular Skeleton 133 

-■1. Bones of the Upper Extremity. 133 

The Clavicle 133 

The Scapula 135 

The Humerus 140 

The Radius 146 

The Uhia 150 

The Carpus 153 

The Metacarpals 159 

The Phalanges 162 

B. Bones of the Lower Extremity .. . 164 
The Coxal Bone (Os Innomi- 

natum) 164 

The Peh-is 170 

The Femur or Thigh Bone. , , 172 

The Patella 179 

The Tibia 180 

Tlie Fibula 185 

The Tarsus 186 

The Metatarsus 196 

The Phalanges 199 

The Bones of the Foot as a 

Whole 202 

Homology of the Bones of the 

Extremities 10,1 



XI 



xu 



CONTENTS OF PART I 



SECTION in 

THE ARTICULATIONS 
By Henry Morris 



Structures entering into the formation of 

Joints 207 

The various kinds of Articulations 208 

The various movements of Joints 209 

The Articulations of the Skull 210 

The Temporo-mandibuiar Articulation. 210 
The Ligamonts and Joints between the 

SkuIIand Sijinal Column 213 

The Articulations of Atlas with Occi- 
put. ,. ; 213 

The Articulations between Atlas and 

Axis 215 

The Ligaments uniting the Occiput 

and Axis 218 

The Articulations of the Trunk 220 

1. The Articulations of the Verte- 

bral Column 221 

The Articulations of the Bod- 
ies of the Vertebne 221 

The Ligaments connecting the 
Articular Processes 225 

The Ligaments uniting the 
Lamms 225 

The Ligaments connecting the 
Spinous Processes 226 

The Ligaments connecting the 

Transverse Processes 227 

2. The Sacro-vertebral Articula- 

tions, or the Articulations 

of the Pelvis with the Spine 229 

3. The Articulations of the Pelvis 231 

a. Sacro-iliac Articulation and 

Sacro-iliac Ligaments . . . 231 

b. Sacro-coccygeaT Articula- 

tion 234 

e. Intercoccygcal Joints 236 

d. Symphysis Pubis 236 

4. The ArticuUtions of the Ribs 

with the Vertebra 238 

a. The Capitular or Costo- 

central Articulation 239 

b. The Cos to-transverse Ar- 

ticulation. 241 

5. The Articulations at the Front 

of the Thorax 242 

a. The Interstemal Joints ... 242 

b. The Costo-chondral Joints 243 

c. The Stemo-castal Articu- 

lation.s 243 

d. The Intcrehondral Articu- 

lations 244 

Movements of the Thorax as a 

Whole 245 

The Articulations of the Upper Extrem- 

itjr 246 

1. The Ste mo-cos to-clavicular Ar- 

ticulation 246 

2. The Acromio-cla^'icular Union, 249 

a. The Acromio-clavicular 

Joint 250 

b. The Coraco-clavicular 

Union 250 

c. The Proper Scapular Lig- 

aments 252 

3. The Shoulder-joint 252 

4. The Elbow-joint . 25S 

5. The Union of the Radius with 

the Ubia 260 



PAO& 

a. The oupenor Radio-ulnar 

Joint 260 

b. The Mid-radio-ulnar Un- 

ion 261 

c. The Inferior Radio-ulnar 

Joint 262 

6. The Radio-carpal Articulation. 264 

7. The Carpal Joints 268 

a. The Union of the First 

Row of Carpal Bones. ... 268 
Union of the Pisiform Bone 
with the Triquetral 268 

b. The Union of the Second 

Row of Carpal Bones. ... 268 

c. The Medio-carpal Joint .... 269 

8. The Carpo-m eta carpal Joints .. 271 

a. The Four Inner Carpo- 

metacarpal Joints 271 

b. The Carpo -metacarpal 

Joint of the Thumb 273 

9. The Intermetacarpal Articula- 

tions 273 

10. The Metacarpo- phalangeal 

Joints 274 

a. The Metacarpo-phalangeal 
Joints of the Four Inner 

Fingers 274 

6. The Metacarpo-phalangeal 

Joint of the Thumb 276 

11. The Interphalangeal Articula- 

tions 276 

The Articulations of the Lower Limb . . . 277 

1. The Hip-joint 277 

2. The Knee-joint 285 

3. The Tibio-fibular Union 294 

a. The Superior Tibio-fibular 

Joint 295 

6. The Middle Tibio-fibular 

Union 295 

c. The Inferior Tibio-fibular 

Articulation 296 

4. The Ankle-joint 297 

5. The Tarsal Joints 300 

a. The Talo-calcaneal Union . 300 

t. The Posterior Talo- 
calcaneal Joint. . . 300 
ii. The Anterior Talo- 
calcaneal Joint. . . 301 

b. The Articulations of the 

Anterior Part of the Tar- 
sus 302 

t. The Cuhoideo -navic- 
ular Union 303 

ii. The Naviculari - cu- 
neiform Articula- 
tion 3a3 

Hi. The Intercuneiform 

Articulations 303 

iv. The Cuneo -cuboid 

Articulations 303 

c. The Mcdio-tarsal or Trans- 

verse Tarsal Joints 304 

1. The Talo-navicular 

Articulation .... 304 
ii. The Cat can co-cu- 
boid Articulation 305 

6. The Tarso-metatarsal Articula- 

tions 308 



CONTENTS OF PART I 



xiu 



PA OB 

a. The Internal Tareo-meta- 

tarsal Joint 308 

b. The Middle Tareo-meta- 

tarsal Joint 308 

c. The Cubo-metatarsal Joint 309 
The Intermetatarsal Articula- 
tions 310 

Union of the Heads of the 

Metatarsal Bones 310 



8. The Metatarso-phalangeal Ar- 

ticulations 310 

a. The Metatarso-phalanseal 

Joints of Four Outer Toes 310 
ft. The Metatarso-phalangeal 

Joint of the Great Toe .. . 311 

9. The Interphalangeal Joints. .. . 311 
Morphology of the LigamentG 312 



The mode of descriMnp illustrations which has heen farried out as far as 
pmcticable consists in printing the desi-riptions In different typos at the end of 
the pointers. Thus, the auaoiM, nnaia, ^Dd UBananu are in one kind of typt> ; arierut, reiiu. 
umi ii/mphaiiei in another ; bohes *iio sPEC(»i oHOAHs in a third ; .vA'flix sTRrrrcREs in a fourth. 



INTRODUCTION 

By J. PLAYFAIH McMURRlCH, A.M., Fh.D., 

i-NurnMun up AXATom at tut unithuutt op hicdioas 



ANATOMY, fls the temi in usually employe<l,denotee the stutly of (he structure 
of the human bndy. Properly, however, it has u much wider significance, 
including within iti^ ficope not man alone, but all animal foniw, and, indeed, 

It forms as well, ho tluit, wlieii iIh u|)pliualitjri m limited to man. it should be 
by the mljcctivc human. Human Anatomy, then, la the ttturly of the 
ire of the human body, itnd stands in pontmst to, or rather In eorrelntion 
with. Human Physioiogif, which treala of the functions of the human body, the 
two sciences, Anatomy and i^hysiolt^jy, including the cum|^ele study of man's 
organization and functional activlticii. 

In the early histon' of the sriences these terms sufSced for all pnirtioal needs, 
but an knowledge grew, specialization of nPL'ossity resultftl and new term.s were 
from time to time intro«iuced to de-«iiinate gjiecial lines of anatomical or pliysiological 
inquirj'. With the inipnn-ement of the luicroscojie u iil'w field of aiiatr)my was 
opened up and the science of Histology came into existence, assuming control over 
that portion of .'Vnatoiny which dealt with the minuter details of wlructure. So, 
tflo, the study of the development of the various orpma gradually assumed the 
dignity of a more or less independent stud}- known a.<( Emiirijologij, and the study 
of the structural changes due to disefise were included in the science of PaOioioy;/, 
so that the tertn .\ji8toDiy caino to be limited to the study of the macroscopic 
structure of normal adult orpaniams. 

It is clear, however, that the lines of separation lietween Anatomy, Hi.'*t«lo{f>', 
Embni'ology, and Parhnlogj' are entirely arbitrary-. Microscopic anatomy nctes- 
sarily grades off into macroscopic anatomy; the development of an orRanisni is a 
(jTogressivo process and the later embryonic or fetal stanes shade graduiUly into the 
adult; luid structural anomalies lead insensibly from tiie normal to the pathological 
domains. A comprehensive siudy of ,\naiomy must therefore include more or loss 
of the other sciencMS. and since an approeialion of the sipnificjince of structural 
(lelail.1 can only be obtained by combining the studios of Anatomy, includinp His- 
toIoRv and Enibrvoloey, and since, further, murh light may Ije thrown on the 
sigiiificance of ombr^'oludical stjiyes by comparative studies. Anatomy, Kmbryolog>'. 
and Comparative .Anatomy fonn u Iriuirivinito of sciences by which the structure 
nf an orjianwm, the significance of that structure, and the laws which determine ii 
are elucidated. For this combination it is convenient to have n single term, and that 
which is used is M^irphfAogy, a ^vord meaning literally the science of fonii. 

In earlier days Human Anatomy was almost entirely a descriptive sei«ice. hut 
little attention beini; paid to the si^^nificanpe of structure. ex<;ept In so fur as it could 
he correlated wth physiolosncal phenomena as they were at the time understood. 
In reeent years attention hua lieen larcely pai<l to the morphology of the human 
body and much valuable information as In the meaning of the structure and relations 
of the various organs has resulted, t^ince the structure of the body is the final 
result of a series of complicated developmental changes, it is the science of Dmbryol- 
ng>' which has principally contributed to our present knowledge of human Mor- 
pno|og\', nr<i, accordingly, a brief sketch of some of the more important phases of 
development will form a titling introduction to the study of the adult. 



SECTION I 

GENERAL MORPHOGENY 

Br J, PLAYFAin McMCRRICH, AM., Ph.D., 

raoraeok or ahatouit tn -tuk (nttvaaflirr ov WDnoAX 



THE Structural Units. — The human body consist.s of a series of structural units 
of |;railual!y ilocrea-^iii^ coinpicxily . Tlic highei^t grade of Ihiwt; uulus i:^ formal 
by rt series of Systems, such as the nervous sysietn. ihe dipesiive sysl-eni, etc., 
enrrh of which is devoted to the performanec of one priiiciiml function, and may be 
(Ufialysed into a series of lower grade units, the Organs, ihe (tifiwtive !fl,'8teni. for 
example. Ixiiiig oomjMjsed of »ucl» organ units a6 the stonuu-li. liver, paticreafi, etc. 
Each orgun. iignin. will he found to eousist of a number of Tissues, wliich form the 
next grade of units, imo Iiksuo prcfhuninaiinp. as a rule, in each orpun and k'^'I'K **> 
it its essential peculiarities; the liver, for evninplc. is compowtl mainly of hefwitie 
tifflue. hut al*<o contains siipi>ortive, va.-iirular, aiidnervou.'t tissue. Finally each tissue 
is an OBcregate of still loner unil«. which are termed Cells (fig. I ), and with the cell 
the ultimate structural unit of the body is reached. The body may be regarded. 



Flo. 1.— Skction or mz Kpiuekum or a 
PtNUtcii, niuH .\ iluuAK Emukto or 
10^ cu. 



Fio, '2.— TnB OvpM or a Nrw-tmnx CiULa, 
WITH Fuu.lC'LeCKt.L». (After MrrttinK.) 



WW 
msy 



7V> 



.OMTM- 
.JHCHS- 



then, as composed of myriads of cell units, orf^onised into unit's of Kniduftllyincreaflinj: 
coniplexil y. very much as a wcial community is composed of individuals oi^nised 
into mufiicipHlities und other more complex units. 

Kach iH^Il dig. 2} JH eomixised of u material called jmilopUigm, a viinrid 
eulwlamw, pre^^^nting u more or less granukir appeaniiiee and having an 
exceedingly complex chemical compoisiiion. It readily breaks down into simpler 
chemical compounds, whereby energy, principally in the form of hcAt und mechunicol 
energ>', i» liberate^l, and it has the power of absorbing nutritive material and of 
building this up to replace what was lost . Its deeoraposition occurs as the rf«uU of 
stimuli of v;iriou.4 kinds, and hen(5e it may lie «aid to be irritable; the mechanical 
ener£\' which it liberates is nianife,'<te<i in it« conlnictilily : it excretes the wamte 
productjn protiurcd hy it,i decomposition; and each cell has the |x>wer, under favour- 
able conditions, of reproducing it^f by di\*ision. Protoplasm presents, in short, nil 
the forms of physiol<^icaI activity inaiiifeKled by Ihe Iwly &» a whole, and, indeed, 
the actiWties of the bodv are the sum of the activities of its constituent cells. 

3 



1 GENERAL MOKl'HOOESY 

In the protoplasm of each cell a BpecJally dififcrentiniod portion occurs, formin;^ 
what is termed the nucleus (fig. 2). a structure which plays an important part in 
regulating the activities of the cfitophstn, as the general proioplawii of the cell is 
leriued. The nucleus differs from the cytuplasm both structurally and chemically, 
its most imfwrtant peculiarity Ixdng the presence in it of a tiukstaiice, rhn/nuUin, 
wliich, during the diviniuii of the cell, aggregates tn form a (leliiiite number uf iimi*ses 
termed chTonv)Soinr$. In addition to the nucleus the cytoplitsm of all actn-ely 
growing cells also contains a second important, structure, knowTi aa the ardtojiUism. 
in whoee interior a minute body, known as the eenirasonu, occurs. The arcboplaem 



Flo. 3. — DiaoraM of Sbctiox TMHorcH a 
Mammalian Owm at tub ClASX oc thb 

Seuuent^tios Stage, 




Fio. 4. — DtAOKAii or Bccrtoif or a Mam- 

MAIXAX OVUU MIUWIKG TIIS ImVER CeLL 

&tAS8. 



■'* 



(S' ^ 



Z.^^.^^ ^ ^^1 



>»■ 






^■^^ 



and ccnlrnsome arc intimatnly concerned in the process of reproduction or division 
of the cell, for an account of which reference may be made to a text-Ixwk of hitufolojo'. 
The Ifody, then, is roiii)>i>MKi of nuriada uf cell unitts of the structure briefly out- 
lined above, together with various products inanufaclured by these cells. And,, 
furtheririopc. i-vfry individunl hcpns his existence a:^ a single cell, the fcrtiliscfl 
o\nim. The prorcascs by which this ovum bccoim's the adult organism belong to the 
!*cience of embryology' and cannot l>e considered in driail here; but certain stages 
of development are m necessar>' for a proper understanding of the structure of the 
adult body that a brief account of them will be given. 



fvi. S. — Djaokam uf SBcnoN OP A Mammalian Ovvm showing thk Amniotic Cavtit akd 

TUB Embhvonic Gehuisal Layriw. 



• ■>>&J 




(CTOonv 



nDODiim 



The germinal layers.— The first Btagcs of development after fertilisation con- 
sist of the sqftnt tit/ttion of thr oiMim, that cell by a surcesstoii of <livisinn.*< giving rise 
to a spherical mass of celU (fig. 3). In tliis a ca\-ity. situated excent rically. appears, 
and the mass ia transformed into a hollow \'eacle who?e wall, thmvighout the greate*- 
part of iin extent, ij^ formed by a single layer of cells, an accumulation occurring, 
however, at one portion of the circumfercnrc and forming what w lcriue<l the iniur 
cell mass (iig. 4). In the more ftuperficial portions of this a cavity, the amninlie 
cavU>f, appears (fig. 5), and from (he cells which form its floor the embryo dovolopea. 



J 



METAMERISM 

Uio rciuaiiiin^ portion vf Lhc vehicle giving origin to t^inirturua concprticd in the 
nutrition of the unibr>'o. Coniinliifi our an«iitiiju for the prc^nt lo lhc rclbi which 
give risp to the embryo, one of the first diiTcrentiations which occui's in iheni is their 
Bepfiration into three layers, known as the germinal layers, the outerinwit of whicli. 
that is to say, tlml furiiiing the tloor of the amniotic cavity, is termed the trtodirm. 
the middle one the niffottcrm. and the innermoHt the cndodtrm <fijr. *i). 'I'liis tlif- 
fercnliution exerts an important influence in the future dcvt'ii>i»nH'nt. since definite 
orgnna take their origin from each of the (leniiinal Iflvers. 'Hius, tiie epidermis and 
the entire nervous svHteni arc developed from the ectoderm, the mucous membr&ne 
of the diRestive tract and its uppcndsgcs, such as the wilivary gUnda, pancreas, liver, 
lungs, the thymus and thyreoid bocJies, and the urinaiy bladder from the endoderm, 
and the remaining organs from the mesoderm. 

Metamerism. — Soon after the formation of the germinal layers two longitudinal 
ridges appear u^xin the ectudermal surface of llie enibr,\'onio dlac, bounding a groove 

Fto. 6.— A UuiUA' Euanro 2.5 itit.m LcKora. (After KoUmiuui.) 



"HUT 



HUIUIUIIT (KOilX 



\ ^ 



uuoDutKic town 



tiueiuui YtiH 



WntUlTOMU. 




occupying the mid-dorsal line of the embr>o. These ridges are the maiulhry 
Tvig*!» and the groove (he mtxlidhri/ ip-ootr. and as development pmceeds the summits 
of the ridges gradually approach one another and finally unite (fig. (>), (lie groove 
being thus converted into a canal, whose walls become transfonned into the central 
nervous svBtem, while lis lumen fornw the central canal of the spinal cord and the 
ventricles of the brain. At the same (ime a longitudinal median gn»ove aiipeore 
in theendfdcrm (fig, 7), whaie lips also imite, to form, however, a solid cowl of cells 
which !*p«rateM from the endodcrm to fomi an elastic rod. the nniochard. lying im- 
mediately beneath (he medullary canal. At this stage the mewxlerni tlirougiiout 
the greater [>art of the embryonic disc com^ists of two lateral portions, sefmnited 
from one another in the mid-dorad line by tlie nie<tullar\' canal and notochonl, but, 
at on early period, each portion becomes di\ided into two sheets or plates, one of 
which, the mmatic iayfr. lies immediately beneath the eetoflerm, while the other, 
the iiscentt taytr. rajtft upon the endoderm. A short distance laterally from, tKc 



6 



geaSeral morphogeny 



mwlian edpe of each fwrtion 8 longitudinal furrow appears, and gradually deepens 
until a narrow median band is separated from the more lateral or, as they will 
eventually be, the vcniral plates, except for a thin connecting band of cells, termed 
the iiUtrtmdiale cell ntass (fig. 7). Shortly after its formation the median or dorsal 
nHBodcrra becomes divided iranaverxely into a jseries of quadrangular masses, termed 
mfnod/rriiic tunnths (figs. (> and 7), so that a distinction between lUv. iU)Tva\ and 
ventral rae<oderni becomes ver\' apjiai-ent. the launr retaining its original continuous 
plate-like comlition and its two layers remaining ilialiiict and enclosing the plruro- 
peritoneal or bodtf mvity. 

The embr>'o, which is at first plate-like in form, in later stages becomes more 
cylimlrieal by the more lateral iKtrtions of the various layers bending vcnirally. 
and finally, since the jiariotai mesoderm together witli the eiTl4Hlenn is separated 
from the visceral aieaodemi and end(Kierni by the body cavity, the entire embrj'o 
may be regarded as a ilouble cylimier, an outer cylinder, the body wall, enclosing 
an umer one. the digestive tract (fig. S), A third cylinder, situated in the sub- 
stance of the IxKiy wall, may l)e recognised in the central nervous s>-stem. 

To the division of the dorsal mesoderm into a series of meaoclermie mniiteH are 
due the indicati<m.s of metameriam, tliat is to say. the arrangeiiiwil of parts in series, 
which the adult body presents. Kiich meaoderniic gomite gives rise to the body 

Fio. 7.— DiAQH-iM or Sbctiqx op a Hi'Man Eubryo. 

SriHKL MHO 



tttsoouuio auHtic 



MOIDCNOHr 



niTiuL atioEmi. ttanfui. 



/I -i-*, ».• - WTtFIWIcm QELL UUl 



•'UTItAL NltODlMI, tUUAnS UlIU 






of a vertebra, replacing a portion of the notochorrl, and also to a plate of muscle 
liraue, which extendi by the later growl jn»f the i%(uiiite fnuii the dorsal lo tin- central 
mid-line (compare figs. 7 and 8). To each vertebra and pair of nmsele plates a pair 
of spinal nervas corresponds, and, primarily, also a pair of arteries ari.siiig from the 
dorsal lunrta, so that originally all these alnictures show throughout the trunk a 
distinctly metameric arrangement. As development proceeds the metameriism 
of the muscles and arteries becomes more or less olxscureil. but that of the vertehne 
and nerves is fully retained even in the a<iuli. In the caw of tlic inascle plaies, 
from which all the voluntary musculature of the fmiik is derived, great nnvdifi- 
cations occur. TCxtensivc fusion of .imrcesisivc plates occurs, the intcn-cning connec- 
tive tissue disappearing more or Iftss completely; assiocialed with this fusion there 
is longitudinal and tangential splitting of the fomites to form indiNidual muscles: 
and portions of some of the plates may wander far fnim llicir original jxwilion. Hut 
notwithMaiiding these complicated ehanecs. indications of the primarv metameric 
arrangement of the muscle plates are abundant, and even in the most extreme cases 
of mrojificatinn the developmentnl histor)* of a muscle can It determined hy means 
of ils nerve supply, lor the fibres derived fmm each plate will retain, no matter 
what changes of independence or position they m»y unrlenro. tiieir innenation by 
tlieir originally corresponding segmental nerve, su that the occurrence in the lumlMir 



BRAXanOMEEISM 

region of the body of muscle-fibrea supplied by nerve-fibreu froni a cervical uerve 
is eviilciiro that the muscle-fibres have been derived from a cervical mcsodermic 
soriiite and liavc eubeeijueiilly iiiij:rii.lcd to llie |M»(<ition they fiiiully orcupy. 

As regards the arteries, they arisu prininrily from a kuiftitudinai stem, the aortft, 
in a strictly segmental manner, cudi nielumere having distributed tn it two pairs 
uf arteries and a aingle median one (fig. fe). Une piiir of arteries supplies the body 
wall, and these retain very distinctly their original metameric arrangement; the 
oth«?r pair paflsca to the paired viscera, such aa the lungs, kidneys. <ivarie« (or t^tes), 
so many of the paire disajipearing. however, that tlieir luetaineric ammgemcDt is 
not \*er>' evident in the adult. The unpaired vessels supply ihc digestive tract and 
its unpaired appendages, such as the liver luid pancreas, and undergo great modifi- 
cations, iliose of llie lower thnrncic and lumbar regioni» becoming nxluced by fusion 
and degeneration to three main trunks. 

Branchiomerism. — Thniughoul the trunk and neck ri-gions, (hen. a funda- 
mental nietacneric plan underlies and det^irminee the arnkngem,ent of many ports. 

Fig. 8. — DiAORAM or .\ TnANBrBnse yKcnas throcpu thk Auuuiukai. Rsgion. 
(The periiomruni is rnprmculcd by (bo blue lint'.) 



y 



OOR&AL MUSCl.£,S 



-2$M^ 



VflOSCLES 



^ MUSCLE 



KlONEV 



(MCNCV 



VKRtCBRA 



>>»Of«T^' 



S-f>LHirOIStUM 
"j» ' pARtCTAL LAVCK 



\ 



mtesTiNe. 



-MKbtNTI.«V 

■PeniTONEUM 

VISCERAL LAVtH 






In the head there \» also evident a primarv- arrangement of the parts in Bucccssion. 
but this arrangement appears to be somewhat different from that of the trunk in 
that it iiivo]vei4 (Im ventnii insteai,! of the tlorsul iii<-soiicrm and is af^ociutcd with 
the occurrence of brancliial arches rather than i\iih true ntesodemiir pomitea, and is 
consc<iuently trnn«l f/raiu-kionurifmi. Not but that there arc also indications of 
metamerism in the head, the mu;B^Ie)! of the orbit, and the majority of the extrinae 
Edusoles of the tongue, together with the nerve* supplying the«e muscles, being 
apparently metameric structures, but the metamerism of this region of the body is 
largely ovoi-shadowed by the branchinnicriBm. 

If on embryo of nlmut the third week of development (fig- ft) be examined, there 
will ho. observcij on the surface of the horly in the ph.-iriiigeiU region three or four 
linear dcpressioiu?. and section* will show that similar and corre-f ponding grooves 
also occur upon the inner surface of the phar\-ngeii| wall. These are the bninehial 
ffroorrg, and, since tlicy arc four in number in the human embryo, they mark off 
five frrandiuil archrs. the first of which lies between the tiral deprB8Pi<m ami the first 
branchial groove, while the fifth is situated behind the fourth groove. 'CtiB*fc\«*»^ 



GENERAL MORPHOGENY 

chial arches are 80 named >>C'cau9« tliey reprnteiit the arches wlxich support the Kills 
(briinchiaO in the lower vertebratee. the grooves representing the branchial slits, 
even iilihtmjih llicy do not twcome pcrforateti in the liuitian embryo. 

Hjich bmnchioinere consists of an uxiul skeletal structui?;. of niaicles which act 
on this .skelotrin. of a nerve which supplias the nuwcles und the neighlxiurinc iiitepu- 
inent and mucous membrane, and of an arterj* which carrioti blood to all these struc- 
tures. The arches, however, do not in the human embr>o retain their original 



Fia. 9.— HuHAM BuBRTo or about t«k Tfobd Wrkk ar Dkvklopukkt, bhowihg Tuhbb 

Bhaxcrial Ohouves. (Aflcr UJs.) 







urret uw 



uf soonuio Mitrn 



\ 
lOatll t-MS 



branchial function, but underijii extensive modifications. Ijeeoming adapted lo various 
functions and showing less in the adult of their orijiinally simple arrangement than 
do the metoineres. Nevertheless no matter wiiat mtKlifications the musculature of 
any arch may undetf^o. it wilt retfun its original iimervation and. to a larpe extent, 
its relBtioa'4 to the skeletal elements nf itj* arch, and even the arteries in their distribu- 
tion show clear indications of being arranged in correspondence to the various arches. 

W'itlimit ()i*<;tiic(icis in ih'liiit Itir- fnlc <if the r»noii<i ntnirliirr-it ]K*ii>iiiimft to t-arh liraiirliini 
arch, tlit'ir gcovml iuTiiti|:vtii(,-ut iii the tulull bojy loay bv alsK.'d tii the following tabic.- — 



THE VISCERA 



Ams 



SKmaroK 



JiBHbBI 



Nniva 



1st Ardi 



Mfwdible, tnalleufi 
and mcuA. 



3(1 Ard» Hyoid <l*aser cor- 

nu) am) elylotii 
aad 



3d Arrii 

4th itnd 5th Arches 



prnvoBS 

stapiM. 
Hyoiil (greatPT 

coruu). 
Thyrooiii cartilage. I'haryng«»l 
iani'iigoal. 



Mufitifatory, my* . Trigeminua. 

lotiyoid anil di- i 

gantric (ant.), 

tciuMjr tyniuasi. 
Styloliyoid. digae- Facialis. 

trip <puHt. ].»■■>«- 

ill's tif C!\|IKB- 

si ((11. ftapudiue. 
Pharyngp.-il. 



and 



Glomopharyn- 

geiia. 
Vugiw. 



Awrnn 



tulcmaJ iiuivil> 
Uiy. 



Kxtemiil maxil- 
lary. 



Lin^[\ia]. 

Superior 
reoid. 



thy- 



The viscera. — The stmotures so ffir considcnxl belong, for the most port, t« the 
body wall; it remnins to consider ihe general plan of inrangpment of tlie ■viscera. 
It has l>een pointed out that the btxiy may be regiirded uk coni)X)jetl of two cylinders, 
one of whieh constitutes the body wall and the other the digestive tract. The latter 
may l)0 rejiardcd as iH-ing primarily a straight tvOn* traversing Iciiplhwisc tho body 
cavity encloaed by the bodywall (fig. 10), and is comjwaed of an inner lining of 

FlQ. 10. — DiAQRAU OF A TkANBVEKBE SEiTI(}.<J TIIIIOt'llH THE AuOt>Ul.VAL RsaiON. 

(The peritoneum \a rrpn-sejitod by the blue Unc.) 



OOKbAL MuSCifS 



oonaAL Muscce.s 






wianEY 



KlONEV 



V. 



AOftt^ 



y^ 



-«»tlTONEUM 



leetNTERv 

-PeRITONEllM 

v'l&CERAL Li-^Yt't 



INTtOTiNE 



n 



r- v*" 



endoderm eiiclot^ed by the visceral plate of the ventral mmodertn. Tlic layers of 
both the visceral and rwimatic plates which immediately enclose tlie body cavity 
become traatformed into a charactwnstic pleuro-peritoneal membrane, ami since 
the two plates of the ventral mesoderm of each side of the btHiy are contimioup near 
the mid-doreal line, at this rejrion a vertical double plate of |>eriloneum extends 
\-entrally between the somatic (parietal) and \isceral layers of peritoneum, con- 
stituting what i.? terined the mrsmUTn. 

As <tpvelopment proceocls the digestive tract ^ows In length more rapidly than 
the ca\-ity which ront-aina it, and so gradually bccomns thrown into numerous cnila 
in the abdominal region, these changes leading to numerou-s modifications of the 
original arrangement of the mesenterj'. ITiese will be descril»ed later Qtv<,\>- VVftW,"^, 



10 



GENERAL MORPHOGENY 



Several oulgmwths also arise from the digestive tract, lo fonn important oi^ane, 
such as the lungs, the tivcr, the pancreas and the urinarj' bladder, and. with the 
exception of the bladder, each of these becomes completely invested by [leritoncum. 
In the case of the liver this original condition is practically retained, but the invest- 
ment of the pancreas later becomes a partial one on account of the moilificatioiis. 
\vhi<*h euHue in the mesentery (ji. 1 IKiJO). The bladder ha.-' only a portion of its surface 
in contact with the iwritoneiini, but the investment of Ihc lungs rcEnains complete, 
each lung, indcetl. afjprnpriatitig to itself the entire pcriioncmii of its half of the 
thornx, with the exception of a jsniall ventral portion which fomis the investment 
of the heart, l-urtherinuro. the ix)rtion« of pcriloneuni which inve«l each of the 
three organs named, the two lungs and the heart, become completely separated 
from one artolher. and since each invei^tnieiit cniu<i.stti of a viscpxa] and a parietal 
layer, each of the organs is enclosed within a double-walled sac, which in the case of 
each hmg form.'' it-i plrurn, while that of the heart is known a<i the pericardium. 
The spaces which occur within the thorax between the tliree sacs are known as the 

Kiel. II.— DtAORAM nr A TlIAV«VRRMK BrCTIDK THnOt'OH THK ThURACIC RkOION. 

{The pleura ifi fcpruseiilod in blui- uutl liio perii:anliuni in n:il.) 



-<»^- 






^^^ 



RIGHT 






LUMiJ 



LtFT 



•V 



7 



i', \^ 



HEART 



'•5c, 



ce« 



■*'e««»u"t.' 



mediastina. and the thoracic portion of the digestive tract lies in the posterior medi- 
astinum and lacks a peritoneal investment (fig. II). 

In addition t-o the viscera mentioned there are some organs, such as the spleen and 
genil-o-urinary organs, which arc developments of the mesoderai, the spleen arising 
in the mesentery which passes to the stomach and the genito-urinary urgaiia priiiLirily 
fmm the ititennediate eel] mass. Tlie morph<^ny of these structures will be con- 
sideri'd in ronncrtinn with their Rtnicture. 

Recession of the diaphragm and heart. — In the early stages of development 
the heart 'is situated far forward, in what will eventually be the phan-ngeal region 
(tig. I>). and pairing to it from the anterior IxKly wall is a liorizontal plate of connec- 
tive (issue, the scpjum iran«r(T«um. which scn'Pft for the pas-sogc of large veins from the 
anterior IwKly wall to the heart. Thi.*) septum eventually gives ri.** to the diaphragm, 
which IjecomcM a complete partition, separating the thoracic and abdominal portions 
of the bodv raWty. The dinphraem and heart are therefore originally .situated 
far bIkivc their final jMPt:ition and rci-ede in the course of ilevelopment. producing 

p-longalion of the vessels and nenT.s a'^.'^oriateil with them ami forcing downwarcl 
ich orgims !w the stomach and liver. The effects of this recession are especially 




THE Lf^fBS 



11 



noticeable in the iictvim, these passing to Ihe various cleans concerned arisinp from 
a much higher level thmi that (iccuiMwi by the organs; the nerve to ihe diaplira^m. 
for instance, comes fnmi the fourth <thini and fifth) cervical sPK'iient. lho»L' passing 
to the cardiac ami pulnionar>- plexuses from ihe cervical region, and those to the 
]jlexus in relation with the stomach, liver and adjacent organs from the thoracic 
region. 

The limbs. — I'iniilly. a.4 ruganls tlie arraneemcnt of parts in the limbs. I-Jich 
limb, at its first iipiwiarancc (lig. ti), is a flat, phite-like outgrowth from the si<le of 
the body, and consists of an axial mas.i of me»«i»ierraie tlisue from which the limb 
skeleton will develop, and. on cither side of this, a plate, also of mesodermic li&'iue, 
frctm which the muHcUw and blood-vesswls will ariutf. M the nmscles l>ecome differen- 
fi.ated nerves jrrow to them frxiin a <lefuute number of spinal segments, and each 
ner\'e us it approflchtw the limb bud dividw into two branchen, one of which panees 
to the musculature in front of the axiiil lissuc and the other In that behind (fi^. !2). 
The variouf* nerves before reaching the hmh unite with each other in form a rather 
complicate!! plexus, so that the iirrannement indicattsl almve is somewhat olwcured. 
But, it cAn nevertheless Ije perceive<l even in the adult, and there i.s consequently 
a distinction of the musculature of each Hmb into a prtp-ojtaJ and a poit-*ixuil 



Fm. 12. — DtAORAU i>v a ^;EUMKNT op 11IB Bot>T AKB LiuB. (Ait«r Kollmaiia.} 



TMUntayMlM 




Rkiteilal aiucln 



group of muscles which are supplied by oorrc^pondinK pn^uxial and posl-axial 
nerves. 

At first each limh plate in so placed that one of its surface:* looks dorsally anrl the 
other vcntrally. and one lx»^le^ is anterior (i. c.. craniad) and the other ixwterior 
(i. e„ caudad). I^ater. however, a rotation of each limb occurs Ihrou^h about ninety 
flogrccs. £o that the limbs who!% lontc axcH were at firBt at right angles to the long 
axis of the trunk come to lie [Hirallel to that axis. The nilution of each fore-timb 
takes pince in ifueh a manner that the limli revolves outward nnd backward, while 
in the lower limh the direction of tlie moven»ent is exactly the opposite, J>einK 
inwanl and forward. A.-- u result there is an apparent reversal of the surfaces in 
the two limbs, the pri'-a.vial muscles of the ann Iwinp on the surface whirli if! directed 
Bntcriorly. while in Ihe lee the conxv«jKinding muscle occupy the posterior surface. 
The dorsum of the foot and the great toe side correspond respectively to the hack 
and thumb m\c of the hand, and the tihia corre.-^ponds to the radius and the fibuJa to 
the ulna. It is to l>e noted, however, that the rotation nccura at the hip and 
shoulder joints, and coase<iuent!y. the muscles which arise from the pelvic cirdlo 
have unflerpone only a partial chance a fact which accounlH fr)r the Klutival niup- 
clns. which Iwlong to the pofi-axial group, occurring ujxin the same surface of the 
lower limb as its pne-axial flexors. 



SECTION II 

OSTEOLOGY 

Orioin.u-ly Written by J. Bland-Sutton. Revised and Largely Rewritten for the 

Third and Fourth Editions 

By peter THOMPSON, M.D., 

pnorEAMOR or asatohy in bino'b college, i.onron: exahineb in anatomy for tkk conjoint 

BOARD OF tNOLAND 



THE SKELETON 

THE skeleton forms the solid framework of the body, and is composed of 
bones, and in certain parts, of pieces of cartilage. The various bones and 
cartilages are united by means of ligaments, and are so arranged as to give 
the body definite shape, protect from injur\- the more important delicate organs, 
and afford attachment to the muscles by which the various movements are accom- 
plished. 

In its widest acceptance, the term skeleton includes all parts of the framework, 
whether internal or external, and as in many of the lower animals there are, in addi- 
tion to the deeper osseous parts, hardened structures associated with the integu- 
ment, it is convenient to refer to the two groups as endoskeleton and exoskeleton 
or dermal skeleton, respectively. All vertebrate — i. e., back-boned— animals possess 
an endoskeleton, and many of them a well-developed exoskeleton also, but in mam- 
mals, the highest group of vertebrates, the external skeleton, when it exists, plays 
a relatively subordinate part. In most of the invertebrates the endoskeleton is 
absent and the dermal skeleton alone is found. 

In man by far the greater part of the endoskeleton is formed of bone, a tissue of 
definite chemical composition, being formed mainly of a gelatine basis strongly 
impregnated with lime salts. 

The number of bones in the skeleton varies at different ages, some, which are 
originally quite independent, becoming united as age advances. They are arranged 
in an axial set, which includes the vertebral column, the skull, the ribs, and the 
sternum, and an appendicular set, belonging to the timbs. The following table 
shows the number of bones usually distinct in middle life, excluding the auditory 
ossicles : — 

Bones. 

A ■ 1 C The vertebral column 26 "^i 

«?'.,„„ ] The skull 23 > 

OKeieton ( The ribs and sternum 25 J 

Appendicular f The upper limbs 64 ) 

Skeleton (The lower limbs 62 J 

Total 200 

13 



14 



THE SKELETON 




Several of W\m skull IjoneB are compound, i. e., in the tmtnature skeleton they 
owiaist of separate elements which ultitnhtcly unite to form a single bone, hi 
order to comprehend the nature of such bones it is advantageous to study them 
in the various .'^tage^ through which tliey pa^ in the prucesti of devetopiitetit in the < 
fcetus and the cliiJd. 

It follows, therefore, that to appreciate the Morphology of the ttkeleton — 1. e., 
the history of the osieolojjical uiiita of which it is cuni|x)t^tHl — the osteogenesis or 
mode of development, of the bones must be studied, as well us their topography or 
po-sition. 

Some bones arise by ossification in membrane, others in cartilage. In the 
early embr>'o. luany porlioiui of the skeleton are represented by cartilage which 
may become infUtrated by lime salts^calcification. This earthy nialcriul is taken 
u]> ami reiie|«)sited in a ruijular manner — ossification. Puixions of ihe original 
cartilage persist at the articuiar ends of bones, and. in young bones, at the epiphysial 
lines, i. c., the lines of junction of the main part of a bone with the extremities or 
epiphyses. lx>ng bones increase in length at the epiphysial cartilages, and in- 
crease ill thickness by ossiti cation of the deeiHfr layers of the iiivesling membrane 
or periosteum. These proe&ses — intraeai'tUagiiioLs and intrariicmbranous oHsi- 
lieation— pnteeed cimcurrently in the ii;iib-boties of a young and growing manmrnl. 

There Is no bone in the humim skeleton which, though pre-formcd in cartilage. 
w perfected in this tissue. The ossi tic:ition is completetl in membrane. On the 
other hand, there are numerous instances in the skull, of bones the ossification of 
wtiich begins in, and \s jierfected by. the intrumembranous method. OsmBeatinn in 
a few instances ijonunences in membrano, but later invades tracts of rariilage; 
iiL-casiimally the process begiiia in the perichondrium and reraain-i restricted to it. 
never inva*ling the underiying cartilage, which gradually disappear;* a.« the result of 
Continued pre^ure exertefl upon it by the growing bone. The vomer and nasal 
bones are tlie best examples of this mod© of duvclopment. Details of development 
and osaiheatton are included in the description of each bone. 

The limb-bones differ In several important particulan^ from those nf the skull. 
Some of the long bi>ncs have many centres of oa-^lfication, hut these have not (he same 
significance a.s thn.« of the skull. It is convenient to group the centres into two 
sets, primary and secondary. The primary nucleus of a long bone appears before 
birth. and the main part (shaft) thus formed is calleti the diaphysis. In only three 
instanixw dtx« a secondary centre appear before birth, c. g., the lower end of the 
femur, the head of the tibia, and <n*casiona!ly the lieiul of the hurnenis. .Many 
primary oiwific nuclei api«ar after birth, e. g.. tho.*p for the carpal bones, the cunei- 
form and navicular bones of the foot, the coracoiii process of the scapula, and for the 
third, fourth, aud fifth pieces of the sternum. 

When a bone ois.sifies from one nu<!leus only, this nucleus may appear liefore 
op after birth, lixampiw: the talus Castragaluril at the seventh month of fo'tal life, 
and the le^-?cr multangular (trapezoid) at the eighth year. When a bone (wssesses 
one or more secondar\- centres, the primary nucleus, a.-- a role, apiJeans early. 
Kxaniples: the femur, humems, phalanges, and the caleancus. 

Secondary centres wliich remiun for a time distinct from the main portion of a 
bone are termed epiphyses. An epiph>*si.i may arise from a single nucleus, qh is 
the ca.se at the lower «jd of the femur, or fmm several, as at the upper end of the 
humerus. Prominences about the ends of long bones nia> be capiied by separate 
epiphyses, as illustrated at the upper end of the femur. 

Accnrdinc to Mr. P.O. P^rxona, there are at leant thrw» kindii of epiphvsfs:— (I) Thow *hi«h 
appe«r nt lliv articular cada of Icmik V-ont-s, wliich. since they tran§mil (he n-^ighl of thr l>oH[y 
from bone to bonn, may ho tormM prr-wurc epiphyses. (2) TIioM! which appciir as kiiuli-Jik*- 
prOoenM, prhprr important muaclr* sr*: atliu'hdl to honw; and ns these are conormrd wiih thr 
puU of iQiUcI'^. they iimy be di-wrilwd aa Inrtwn epiphi'se^. '3) The third kind iiirlndpji thmw 
ep(phy§M which rcpK-^cnt part^ nf th<' skeleton at one time of functional importunw Init which. 
having lort th^r function, hnvf. now become fiwod with neighhourinit bones nnd onlyaptwjira.i 
Mmrate onilcatluiis in early life. Thf-te mny l>p tenn^d aln^'ittic npiph>'sen iind tnrl>iat' sudi 
^physes u the tubcroMty of thi> i»chtuiQ. the representative of the hypbischiuin of reptllw. 

The epiphyses of hone^ .*ecra to follow certain rules, thus:^ 
I, Thfwe epiphv^ie.? whose centres of ossification appear last are the first to unite 
with the ^haft. There is one CKceptinn, however, to this statement, \\7... the upper 
end of the fibula, which is the last to unite with the shaft, although its centre 



OSSiFICATiOA\—RULE^^ OF KPIPHYSES 



15 



appears two years after that far the lower end. This mav perhaps be accounted 
for by the nidimentan' nature of the proximal end of tJic 6bula in man and 
many other mammala. 

2. The epiphysis towards which the nutrient arter>' is directed is the first to be 
united with the shaft. It is aim found (hat while the increase in length of the lung 
f>ones taken plat-e at the epiphysial cartilages, the gmwth takt-s place more rapidly 
and is conlinuc<i f(ir a longer |»erio<l at the end where the epiphysis is the liist to 
unite. It follows, therefore, that the j^hiftinR of the investing periosteum, which 
results from these iwiy factors, leads to obIi((uity of the vasi-ular caasl by drawing 
tho proximal portion of the nutrient aricry lowanls the more rapidh growing end. 

Fio. 13— Thk Tibi* amd Fiuula i« sbction to mow thk Epu-Hrs**. 



^■^^^C 



-eiMni* 



K\lt( 



BCNTRE if nssiiiUTM or cfinimi 

UimiKAL. LI II I 



m 

■An 



WUT or rWILA 



' IHVT at mn m iienoa 



■ EnMnis DF nut 



Mnreirt-er, when a bone has only one eplphj-sis, the nutrient artery will be directed 
towards the extremity which lia.s no epiphysis. 

3. The centres of ossification appear earliest in those epiphj-ws which l>car the 
lar(:est reliitive proportion to the sliafla of the bones to whit-h (hey belonc. 

I. When an cpiplij-sis ossifies fntm more than one centre, the various nuclei 
coalftwe before the shaft and epiphysis consolidate. 

f>n section, the shaft nf n f.etal hm^gu^^en to bo occupied by red marrow 
Ifidged in 1>ony cell.'* which do not fl^BH^^^Hfeite arrangement. In an adtilt 
the central portion of the vhaft Is fiwHBWBHPBumu lidd together by a delicate 



16 



THE HKELETOS 



reticulum of connective tissue, whence the space is known as the meduUacy cavity. 
The cxpaiulcKi nmts of the bones contuin u network of cancelloiu^ tissue, the intervals 
being filled with re<l nuirrow. This canceliuus tii«ue differs from that of the ftrtal 
bone in being arrun^cfl in a definite manner according to the direction of pressure 
exerted by the weight of the body, and the tension produced by the niu.-clw. The 
arrangement of the cancelli in consequence of the mechanical condition& to which 
l}oncs are subject is noticed in the description of a vertebra, the femur, and the 
humerus. 

Bones are divisible into four clEiases; — long, short, flat, and irregular. The 
long bones, found chiefly in the limbs, form a system of levers Ba'^taining the weight 
of the trunk and pro'vidlng the means of locomotion. The short bones, illustrated 
by lliofio of the carpus and tarsus, are found mainly where conipaetncsri. ela.vticity, 
and limited motion are the princijisl requirements. Flat bones confer [irotoction or 
J>rovide broad surfaces for muscular artachmenl. as in ilie rase of the crania! Imnes 
and the shoulder-blade. Lastly, the irregular or mixed bones constitute a group 
of peculiar form, often ver>' complex, which cannot be included under either of the 
preceding heads. These are the vertebra;, sacrum, coccyx, and many of the bones 
of the skull. 

The shafts of long bones at the time of !)irth are mainly cylindrical and free 
from ridKes. The majority of the Unes and ridges so conspicuous on the shafts of 
long bones in adults are due to the ossi5cution of muscle-attuchmente. The more 
ileveloped the nm.seles, the larger the ridges become. 

The surfaces of bones are variously mothfietl by environing conditions. Pressure 
at the extremities causes cnlnrccment . and movement render? them smooth. The 
two causes combined pHxluce an tirticular surface. When rnurnied and supported 
upon a constricted portion of b<me, an srticular surface is termed a head, sunieiimes 
a condyle; when depressed, a glenoid fossa. Blunt, non-articular processes are 
called tuberosities; smaller ones, tubercles; sharp projections, spines. .Sliphtly 
elevated ridges of bones arc crests; when, narrow and pronounced, lines and borders. 
.■\ shallow deprcs-sion is a fossa; when narrow and deep, a groove; a perforation is 
usually called a foramen. 

In addition to these, otlicr terms are employed which do not require any ex- 
planation, such as canal, notch or incisura, sulcus or furrow, and the like. 



/ TffE AXIAL .SKELETON 
A. THE VERTEBUAL COLUMN 

The vertebral column consists of a series of hones called vertebrse, vU 
connected by nu-an.'; of lihrous and ela.-^tic structures, which allow of a certain but 
limited amount of motion between them. In the young subject the vcrtebnr are 
thirty-three in number. Of these, the upper twenty-four remain separate through- 
out iife. and are distinguislied a^ movable or true vertebrae. The succeeding 
five vertebrin become consolidated in the adult to funn one miiss, caltetl the sacrum, 
and at I he terminal part of the column are four rudimeiitary vertebne, which also 
tend to become unitetl as age advances, to form the coccyx. The lower nine verte- 
brEB thus lose their mobility as indiWdual bones, and are accordingly knowTi as the 
fixed or false vertebrae. Of the true vortebra>, the first seven are called cervical, 
the sucreeiiine twelve thoracic or dorsal, and tlie remaining Hvp lumbar. 

Although tlic vertchrre of the different regions of the column dilTer markedly in 
many respc'^ts, each vertebra is constnicteri on a common plan, which Ls more or 
leas modified in different regions to nieel special requirements. The essential char- 
acters are well seen in the vcrtebrBp near the middle of the thoracic region, and it will 
be a«ivantflgeous In commence the study of the vertebral structures with one selected 
from this region. 

Description of a thoracic vertebra. — The \-ertehra consists of two essential 
parts — a bo<ly in fmn( and an arch behind. 

Tlie body or centrum is a solid disc of bone, somewhat heart-shaped, deeper 



THE' VEHTEBRM COLUMN 



17 



behind than in front, slightly amcave on H» superior and inferior surfAces. and 
wider iraufiverseiy ihau amero- posteriorly. The upper atnl lower surfaces aie mugh 
for the intervertebral diyiw wliirh are interjKjsed lielween llie bodiiwof tlie vertebne, 
and che marjfiiix are slightly lipfjcd. The circuinference of the IkkIv is concave from 
above do«-nwards in front, convex from side to sitle, and perforated by numerous 
vascular forajiiina. l^oaterjorly il in concave from side to tOde and pn?»*enl« one or 
two large foramina Cor the exit of veins from the cancellous tissue. On each side 

Fw. 14. — A TuuHAUic Vehtkbha. (Ride new.) 

Dim-MCIT nil HEU W KB 



■unmo* tATiciJUJi mtilut . 

nen nw tuhmoli or ui 
TMnaiincrMOiN- 



Oiwi-Mcrr to* M»a oi m 
mrexian loncuuiK ntaoEU 



of the body, at the plaec where it joins the arch, are two demi-facets placed at the 
upfier and lower borrleri*. and when two vertebrip are supeiimposed. the adjacent 
denii-facetn form a complete articular facet for the head of u rii>. 

The arch is fonne<l by two pedicleu and two lamina', and pupj)f>rt!^ 8e\'en pro- 
eetMet! — one spinous, two transverse, and four anicular. The pedicles are two 
short, constricted columns of bone, pnijwtiiip horizontally backwanls from the 

Pto. lS.-*-A TeonAic Vbiterra. 



nctr m TuitMu or m 



rmeu 
Bui-naa nn hcu of r* 



lUMmtl FBOUM 




posterior surface of the body. The conca\-it(e8 on the upper and lower Ixjrder* of 
each pedicle, of which the lower is much the deeper, are named vertebral notches, 
and when two vcrtfbra' arc in poBJIion, the notches ore convened into intervertebral 
foramina for the transmistiion of the spinal nerves and blood-vessels. 

The laminse arc two broad plates of Iwno which connect the spinoim process 
with the pedicles and complete the arch posteriorly. The superior border and the 
lower part of the anterior surface of each lamina is rough for the inpertJon ot Khsi 
2 



18 



THE SKELETOS 



lij^aiiienta flava. The upper part of ilic anmriur siirfarc i.« sinouth wlierc it forr 
tlip posterior liouiidary of the vertebnil canal. When articulated, ihe laiiiiim* in 
the thoraric region are iiul>ricatcd or sloped, one pair over the other, j^onw^vhat like 
tiles on a ronf. 

Tiie spinous process, lonji and three-sidod. projects backwards and <luwijwarda 
from the ceJitre uf tlie arch and terminates in » slifiht tubercle. It gives attach- 
ment by 'its prominent bordera to lite intcm^piiupus Ueament>i and by llt^ frc^e 
extremity to the supraHpimius ligament. Il servo; mainly as a process for muscu- 
lar attachment. 

The transverse processes are two in number and extend outwards fi-oni the 
arch at the junction uf the- pedicle* and lamina'. They are lung, thick, backivarxlly 
directed coluimis of bone tenriinatintr in a clubbed extremity, on each of which is 
an oval facet for articulation with the tubercle of a rib. fcTlic iranHverfe ]>twis;s«8, 
in addition to suppurliiiE t!ie ribs, ntTord powerful leverape lo nuisdes. 

The articular processes, two superior and two inferior, project upwards and 
•downwards opposite the attachments of the transverse proi?es.ses. The superior are 
flat and bear facets wliich are directed upwards, backwards, and outwanls, and are 
situated a little in advance of the inferior, the facets of which are oval, contjavc, 
and directed downwanls, forwards, and inwards. 

The vertebral foramen is bounded anteriorly by Ihe body, popleriorly and later- 
ally by the arch. It is nearly circular, and is smaller than in the cerncal or the 
Iumb.tr region. When the vertcbrs" are articulated, the iwries of rings constitute 
the spinal or neural canal, in which is lodged the spinal cord. 



THE CERVICAI, VERTEBR.1^ 

A typical cervical vertebra (from the thinl to the sixth inchiFive) presents the 
following characters :-*Tlie body is smaller than in other rcpons of the column and 
is of oval shape wjth the long axis trnn.'ivorse. The lateral margins of the upper 
surface are raised into piriininenl lips, .«o that the surface is concave from side to 
EJde; it is also sloped downwards in front. Ttie inferior sm'face, on the oontraxy, 
project* downwanls in fnmt and is roundetl off at the sides to receive the ooito- 
sponding lips <»f the atijacent vertebra. Tj is^concavc from front lo bark and conwt 
in an oppa-^ite direction. *'^ C^^ , 

The' pedicles are directed outwards and backwards and spring from the liody 
about miiKvay Ijetween the upper imd lower borders. Tlie superior and inferior 

Fic. 16.— A Ckkvicm. Vbktkboa. 



0nT0-IU)>3ll««l lOUMiM 



nncu 



tHHtm lanouLWl WCfM 



LUIM 



notches are nearly e^ual in depth, but Ihe inferior are usually pomewhat deep 
Tlie tamins arc long, narrow, and slender. The spinous process i.s f*hort and 
bifid at the frw extremity. 

Articular processes .^T)oth the upper and lower articular processes arc situated 
at the junction of the pedicle with the lamina and they form the upper and lower 
exfreniiticfi of a flniall eoluum of Iwiie. The arlieular surfaces are oblique and 
nearly flat, the superior looking backwanis and upwards, and the inferior [onvards 
and dnwnward.'!- 

The transverse process presents near its base a round coslo-trans verse fora- 
men for the trfiiisni!>--i')u of the vertebral artery, vein, and a plexus of sympathetic 



THE CERViCAL VERTh'HR.E 



10 



I 



nervOij. Moreover, each proeeM is deeply grooved above for a spinal nervo, and is 
bifid at its free txlreiiiity. teniunatmi; in two tubercles — anterior and posterior. 
Tlie costo-transverse foramen ia ven- characteristic of a wnical vertebra. It is 
lj<»umlod imerriiilly i>y ilii* piHiicle, [Kjsieriorly by tlie transverse pr^jee^j* (wliich 
corTft«i)ondi* to the tr:iii.4ven»e ptxtcess nf » llioracir viTlebra). aiiteriorly by the «)8tal 
process (which w»rri!S|>onds to the rib iu the th(trucic re^ijicin), ami oxtfirnally by the 
cosliMrflnsverse lamelhi. The l.iti*r is a bar of bone joining the two processes exler- 
nally and directed obhqucly upwanis and forwmxU iu the u|Jj>er vertebrte ftod 
horizontally in Uie lower. The vertebral foramen is trituifrular with rounded 
!inple,'<. and is hiffn-r than in the th<>racie or lumbar vcrlcbnc. 

Peculiarcervical vertebree.— The various cer\-ical vertebra possess distinguish- 
ing features, though, with the exception of the finft, aecomi, and seventh, which 
:ire M) ditloront «.« to nec^<iitatc sepanite de:*oription8, these are largely contined 
to tlie direction of the costo- trans verxc lainoUn, and tlie ^iw and level of the anterior 
and po-sttrrior tuiwrclea. In the tliiixl tlie anterior tubercle is hiphcr than tlie pnnti-rior 
ami the costo-lraasverse lamella is oblique; in the fonrtli tjie anterior tubi^rele is 
elongated vertically, so that its lower end is nearly on a level with the posterior, 
though the lamella still rcnmins oblique. In the fifth and sixth they arc nearly 
on^e same level, but in the latter the anterior tubercle is markedly developed to 
form the carotid tubercle (tulxrrcle of Cbastuuguae). 



The Atuvs ok FiHtiT Cebvical Vehteuha 

Thi.s vertebra is remarkable in that il has neither Ixxly nor sjiinous proeefsi. It 
has the form of an irreeulnr ring, and consLsta of two thick porriona, the lateral 
masses, unite*! in Tmnt and behind by bony arehes, T)io anterior arch joins the 
lateral uiiwses in front and constitutes alyiut one-fifth of the entire circumference 
of the rinc- On its anterior surface it presents a tubercle for the attachment of the 
fo/iy.is «>//( muscle and the anterior lonnitudinal Up;amont, and on its posteiior surfac* 
a circular facet for articulation with Hie t«iontoid process of the axu*. The upper 
and lower tmrders »erve for the attachment of ligaments uniting tho atlas to the 
occJDiial bone and axis respectively. 

The lateral masses are thick and strong, supportine the articular processe<» 
alxive and below and c.ttending outwards into the transverse processes. The isupe- 



Fm. 17.— The Kinsr Chrvical Vertebra oa A-n-Aa. 



WIDHON lUkOWtf 

lurunt ««n(iui.M Monn 

w»»«i rft>«sj 

Danii<T«vi««au raituif* 

nuwiim tciiui» 

SMWE f*l VCRTtUU 
MTDII 



IMTOIM n«nisit 




rior articular proccKscs am elongated, deeply concave, and converge in front. 
Directed upwards and inwards they receive the condyles of the occipital bone, and 
ooca-sionally each presents two oval facet.3 unite4l by an isthmus. The inferior 
articular processes are circular and aImo.st flat: they are directed downiwanis and 
inwanls and articulftte with ttie axis. The articular processes, like the superior 
articular processes of the axis, differ from those of other vertebra; in being situated 
in front of the places of exit of the spinal nerves. 

Between the upper and lower articular cnrfiurcs on the inside of the ring are two 
smooth rouniled tubercles, one on each side, to which the trans\'ersc ligamejit is 
attached, lliis ligament dindea the interior of the ring into a smaller anterior 



20 



THE SKELETOS 



part for the fuiontoid process of the axis, and a lai-grr posterior part, corrcspoiiiiing 
to the foramina of other vertebrae, for thf spinal cord and it^ mertibranes. 

The transverse processes are larKe and cxteiul farther outwards than those of 
the vertebra- imniediately below. They are flattened from above downwards and 
each ie jwrforated by a hirge costo-transverse foramen; the ext.roiniiy is not bifid, 
but, on the conlrary. Is brojwl and roufili for the attachment of numerous muscles. 
The posterior arch unites the lateral masses l»ehin(l and forms about two-fifths 
of the entire circuraferMice. It presents in the middle line a rough elevation or 
tubercle representing a nidimentAry spinous process. At its junction with the 

Fro. 18.— Ths Axis. 



ODONTOID FFIOCtW 



. norr for ihm 



DKOOVt (OK INAnrrlRBi tlMDCIlI 



' surtmaK turneuutii moctsj 



vm 



IRFERIOt UTIOUUR RUICEU 






lateral mas* on the auperior surface is a deep groove, the. mnrw atUnUin, ■ivliirli 
lodges the vertebral jiriory aiid the suiwieeipItMl (tirsi. ^ipiiial) nerve. The groove 
^Mjrresponds to the su|>crior notches of other vcrtebrit and occaiiionally it is converted 
into a foramen by a Iwny arch — ^thc oj^-iificd ol>Iii|ue Ii(fanienl of the atlas. A similar 
but much shallower notch is present on the under surface uf tlie ptisterlor arch. and. 
with a correnpondinn notch on the axis, forms an intcneriebral foramen for the 
exit of the second spinal nerve. Tlic upper and lowpr siirfacos of the arch afford 
altarhinent to iij;ameiit-s uniiine the at Ijls lo the occipital bone and the axis. 
The atla-s ^vo3 attachment to the following muscles:— 



Anterior aroh. . , 
Posterior arch - 
Transverse process. 



, U)n;;u.s colli. 

Rectus capitis posterior minor. 

. Rectus capitis anterior(minor) , rectus capitis 
lateralis. obli<^uuscupitifiinferior.obti(tuus 
capitis sujjerior. ^plcnius cervicia. levator 
scapul»\ and intertransvci'sales, anterior 
and posterior. 



The Axis. Epi.sTBoi'HKt;.s ok Skcond Cbhvical Vektebka 

The axis or epistropheus is the thickest and strongest of the hones of this region, 
and is so named frotn forming ii pivot on which the atlas mtates. carr^-ing the head. 
It is easily recognised by the rounded odontoid process or dens whidi surmountg 
the up|»er surface of (he body. This procctw. which represents the di.4plaretl body 
nf the atlas, is large, blunt, and tooth-like (proceaaus dentatus). and Iwars on i^ 
anterior surface an oval facet for iirticulation with the anterior arch of the atlas; 
posteriorly it prewnts a smooth groove wliich rcceivet* the transverse ligament. To 
the apex a thin narrow fibrous band (the apical odontoid or suspen^ry ligament) 
is attachdl. and on each side of the apex is a rough siul'aee for the attachment of the 
alar or check ligaments (lalend iKkmtoid) which connect it «'ith the owipital bone. 
Tlie enlarged part of the priK-css is -siimetimes termed the head, and tlie constricted 
ha-^rtl part the neck. The inferior .-surface of the body nvsembles that of the suc- 
ceeding vertebra' and is concave from front to back and slightly convex fnnii side 
to aide. Its anterior surface is marked by a me<lian ridge Be(>aratiiig two lateral 
depressions for the insertion of the longus afili. 

The pedicles are stout and broad; the taminee are thick and prismatic; the 



THE CERVICAL VERTEBRJi 



21 



spinous process is* I«rire an'.l ssironp. ilcoply concave on its uiwier surface, and 
markedly bifid ; the transverse processes are small, not bifurcated and not grooved. 
Tho costo-iraniivenw* fummfii is ilirecieil very obliquely upwaRls and outwards, 
and the c(x^lttl process is larger than the traiisveree. 

Fio. 19. — ^Tbe Ckrvicai. Vehtehh-c. (Anterior view.) 

TO WHIOH M leiMIU a«m 4 'NtEnTO 



, liMtQi npltla «Bl«»- 



mt \jmti ottMjut 

raiTDa 0' lonco* 
aoni 



SOlU lOD IHIIO- 



r 



m 



w 



> r\ 



, tmt i<9 THt TMini m^ 

QKCMil fKDCtMU Un 
CAiiii* }0 rxi Itiniiu 

to TM MAlonua an- 
tMtOC 



TT- 



TTf 



'V^v 



in ntlEflTMtll I) IMTO TMI UOOMC^ THIItO, MO FOURtH VUTCM't 

Tlie superior articular processes are oval, and directed upwards and nutwardri 
for articulation witli ilie atla*. They are reinarkaljlc in being supported partly by 
the body, and partly by the pedicles, and in being situated in front of the superior 
notcheti. The inferior articular processes arc ^inular in form and position to those 
of the succeeding vertebra-. 

The axis gW(^ attachment to the following nitwclcs: — 

Body Ixjn^us colli. 

Spinou.i proces-s ()Mif|uu.i capitis inferior, rectus capitis 

poi^terior major, semispinalis cer\'tcis, 

interspinalee. uiultifidus. 
IVoitsverse process Splenius cervici«. inlertrans\-crsalea. levator 

wrapula?, Innpiwiinus (tratwvenyilis) cer- 

vicis, acAlenua medius. 



The Seventh Cervical Vehtkbra 

Rituatpd at the junction of the eemcal and thnmcic regions of the vertctwal 
cotunin. the spventh (vmca! \ertebra may Ite doj;crilK'<l as n transitional verlebni 
— i. c, yiossejisintt certain features characteristic of both re^ona. 

The spinous process is longer than that of any of the other cervical vcrtehrtp. 




■pinoua proc«» *■ hiA 



thv tiPrtil of the first rib. When this is present, there U usually a well-dp%tlnj 
cerWcal rib. 

Tlio wventh cernrrnl vertebra given AttJichmenl to the foltowtng muscles: — 

IVxly I^ngus colli, 

Spinous process 'n-apexius. rliomlxiideuF minor, serratus pos- 

t prior HutK'rior,.«pleiiiui'C!i[>iti8.multifuUi8, 
interspinules, semispinalis dorsi, 

Tronirt'crsie process TntorfTans\-ersjilps, lovninr cosLn, <;oalcnua 

posterior. iliocostalU dorsi fnitisculus ac- 



TUB THORACIC VEIiT£BIi.€ 



23 



Articular pmcess. 



oessorius), scaleDus medius, semispuiBlu 

capitis (coniplpxus). 
MultKiduH, longlt9>ititu8 capitis (tracbelo- 
amMtoid) . 



Thf cvnii-ul vi'rtclira- ^-xliniil ki"!-"' vuijiilirtii in n-^nnl tn llir rtlrciiiili™ of Uir-ir K|>ii)OiM 

ftrocesw*. As a rule uiiionn Kuropt-nim, tin- WTond, tliiM, foiirtli. utid liflh vertthrif pomcsat 
■ifitl ((pinps. The aiJctli and srvi'nth cxliibh a tPinicncy to Inl'iirvaH', tlictr tip? prf^cnting two 
Ainall lateral tillM^rcle»; sonu-times Ihf sixrh ha;* a hifiJ spiiit, and iiiorr ran-ly llii- ju-vinitli |>r»- 
writa th« «anie comlition, ^.l(x•a^ioflally nil rlif ci'riicttl Rpinpc. with the txct-ptioii of tfie m.-vonil. 
are uoii-l»ifid, and even in llie axU the l)ifurc«tion h not exlcnuive. In thf> lower rncnv o( men 
thu! oervical spiuM are rplativrly shorler and mope sl.irnlod thnn in Kurojifsiiit Kf"''''ally iind. 
aa a rule, are Biinple. The only cervical vertebra wliich prwient« a liifid spini- in all rac*s is tlw 
axis; even thie nmy )»> non-l'iifid to the Nci;ra. and occasionatty in the European, (Otren, 
TumiT, Cunningham.) 

The lamin.v of the lower eer\'ic»l verlelww frerpieiilly present over the inferior articular 
procwwH di-ititict tuherrlw from which fa3ci(.>ttti of the muttifidug muscle uriee. They are 
usually confined to the sixth and seventh verlc)>rir, but arp fairly (t^uent on the fifth, and are 
Oc«89ioually se«n on the fourth. 



THE THORACIC OH DORSAL VERTEBR,E 

The Renersl chnrarters of the thoracic vertebrip have already l>een con-'idered. 
Their niu»t dititiiicuitttiinjr featua':; are the facets on thu transverse processes and 
Hides of the bodies for the tubercles utid heads of the ribs. 

Peculiar thoracic vertebrae.— St«vcral vi-rn'bra' in this scrif-s dilTer from the 
tA-pical example. The exceptional ones are—the first, ninth, tenth, eleventh, 
and twelfth. 

Tlie first thoracic vertebra is a transitional vertebra. The body in its general 
conforiuation approaches very closely Ihi; seventh cervical, in tliat the greatest 
diameter is transverse, its upper surface is concave from side to side, and itH lateral 
maririns ht^r two pn>minent lips, (hi ejich side Is an entire faeel , clns(> to ihe upiwr 
botflcr. for the head of the first rib, and a verj* small demi-facet lielnw for the head 
of the wcond rib. The spinous process i^ thick, stronfc, aStnost horizontal and 
more prominent than that of tlie seventh cer\ical. ( iciasionally the traiisvei-se 
process 'is perforated near tlie nvot. 

The ninth has demi-faects above, and usually none below; when the inferior 
demi-faceis are pre-'nait, this vertebra is mil exceptional. 

The tenth tisually has an entire coFtal facet at its upper border, on each side, 
Ijut occa*iii^nhlly only demi-faeeta. It hits no lower demi-faoels, and the facetjt on 
the traiisven*e pp'cesses are usually small. 

Tilt' eleventh has a large IxkIv resembling a lumbar vertebra. The rib faceta are 
on the pp'liclft'i and they are cnniplet« and of large size. The transverste proeesaca 
are short . whow evidence of Iwconiinc bmkea n]> into i hree parts, and have no facets 
fur the tubercles of the eleventh pair of ribs. 

In many mammals, the spines of the anterior vertebra- are directed backwards. 
and tha-wj of the posterior dircetod fonvards, whilst in the centre of the column tJicre 
is usually nnc 9j)ine vertical. l"he latter w callr-d the anti-clinal vertebra, and iiidi- 
eates the point at which the thoraeie hepin to assume the characters of lumbar 
vert^brjp. In man the eleventh thoracic is the anti-clinal vcrlcbni. 

The twelfth re>'emblcs in general cliaraetcr* the elrvoiitli, bul may he distin- 
guished from it by the facets on the inferior articular processes being conve.x and 
tume«l outwanls a.< in the hiuilmr vorlchnt^. Tltc tranpvei-se process is rudinienlan.* 
and tripartite. preHentinj; for examination three tubercles. /tupi-riiiT. inferior, and 
pxtrmal, which enrreypnnd lo the inammillary. accessory, atid transverse proces.'tes 
of the lumbar vertebra-. There is one entire facet on the pedicle for the head of the 
t'R-elfth rib. 

.\ p<^'ili«ritT. r.iore frequent tn thf Ihoradc snd lumhar than in the cen*icftl and sncTftl 
ri-it^on« of the rolitinn, ifl the pxiatencw of a hnlf-n>rl<>hm, S«4"li -tpccimenH Imve a WfKlre-ehaped 
half-ri-ntruiii, to whtoh are att.'tclwd a luininn. » f ransivirne, -luperior. and inferior arliruiar. and 
half n npinoiis procosa. A» n rule, a half-vertet>ra b ankvlosed to the vertchrs above and below. 

THE LUMBAR ^'ERTKBR.E 
The lumbar vertebrs are distinguished by their large size and by the alisencc 
of costal articular surfaces. 




34 



THE SKELETON 



The body is somewhat renifonn. with (he preatest Hiameter transverse, flat aiwve 
antl below, an^i goncrally sHphily <lcc)5er in fmni than behind. The pedicles are 
str<jnp and directed -straiKiht liaekwarris. iind thi* lower verlpbral notohcs are deep 
and large. The lamine arc- shorter and thicker than those of ihe thorjicic or 
CJervical vertebra?, and the vertebral foraraeo is triangular, wider than in the 
thoracic, but smaller than in the cervical region. The spinous process, (hiek, 
Hroad, and poniewhai ciuadrilateral. projeets horiztintally barkwards. It is thickeo* 

Fia. 21. — Pbci'liak Thokacic VehtbukjC. 



•N INKK UCET IBO't: k 

Dtvi-F*aiT lEioir. n 



'':f^ 



-?>>: 



usuiuT k KHi-Marr uan 
imitvmtt nuiit Btm- 



K' .f 



UMiltV in tumi 'KTt 

*M«r Gceuiaouit THIS 

run ON [HE nUHlVERU 
FflBOIM II UIUMIT MAIL 



AH UrTIRE f AKT U6K. NME 

e> TMNWtMi rmiaut. 

(Ml (NII-ttlKiL VCRTESnA 



X^' 



^fl' 



yi% 



.^gg^ 



; 



m utu FUi(T uon -. «a 

riCITU TIUKinUf K 

OSS IftNiS" IStWPABI ■;. 

niinnjH ufiGE. tNftnioH 

iRTlCUURMCCfULttUNN 
CH<TWtllpl Ki n (LVUBAR 

ttKtEM* 



--^-— ■--; 



MAD 



•'i. 



below than above and terminates in a rough posterior edge. The articular 
processes an> thick and t^tntnc. The siU)>rnor articular surface iK ronrave and 
directed bai-kwanls and inwards; the inferior is convex and hwiki* forwards and 
outwards. The superior pair are more widely separated than the inferior pair am! 
embrnec the inferior ari.icular processes of the vertebra alx>ve. The posterior margin 
of each superior articular process i» surmounted by the mammillary process or 
tubercle (inetapophysis) which rorre6fx>nd« tn the ^■uperio^ tuberele of the irans- 
veree process of (Jic ta»t thoracic vertebra. In man tlie tnammillar}' tul>erc]cs are 



THE LUMBAR VERTEBBM 25 

nictimcntan'. but in pome ftnimalo they altftin iRrge proportions, as in ihe kangfiroo 
ftml ftrtn.-ulillo, Tlie transverse processes are kniK. etender. KotnewhiU ypatula- 
sh«.|wd, fornpresseil from t>effire twckwards. Hnd directed outwards and a little 
backwards. They are longest in the third vertebra and diniinish in the fourth, 

Fro. 22. — A LvmAK Vbktxbka. <Si<]e view.) 

' HPFmoii Atmcuuit noccu 



.a'tJ 



HUH nun nootsi 
nmianui nociu 

WaMORT MOCfM 



.•^'. 



IHKllOR MTrOUUO PROeitB . 



second, and fifth, in this order, to the first, in which they arc shortest of all. Their 
extremities are in werios with the external tubercles of iho transverse processes of 
the twelfth thoracic vertebra itnd al«p with the rilw. With the latter Ihe so-called 
traiis\*crse ])roce!wes in the lumbiir region are homologous, and he[ice thej- are some- 

Fio. 25. — A l.uuiuR VumxhBA. 
(Showing the compound nature of the tnuuversL* process. L'l^er ^new.) 



UAUVIUMV PW4U8 - 



FKOCEla 

Msm firutxi 
reuDM 



BODY 



^.V1 



'*-i*iAije^fV"A-' 



times called the costal processes. Occasionally the costal element differentiates 
and beconicii a wcllHlcvdojxHl lumbar rib. 

Hehind the baee of each Inuinverse or costal process is a small emineui'e. directed 
downwards, which corresponds with the inferior tubercle of the lower thoracic tranf^ 
verse pnicess, ami with the transverse pnwcsscs of the ihoracic vcrtcbrre above, 



25 



THE SKELETON 



and is named the accessory process (iiniipophysis). The accessory process repns 
sents the tip nf the purtinUy snpprcsswl true tninsverw process nf a lumbar vertebra,. 
Il is weii dfvelope<l in wime of tlie lower animnl*. as in the dog and cflt. 

tiach of the five lumbar vertebne is readily recognised. The body of the first 
is deeper beliind ihau in front ; the body oi" the second is equal in depth in froni and 
behind; the bmlies of the lliinl. fourth, and tiftli an- deei>er In front than behind, 
but the third has long transverse processes and the inferior articular propcsses are 
not widely separated. The fourth has shorter transverse pmresses and the inferior 
articular proceases are placed more widely apart. The fifth lumbar vertebra dex-iates 

Fio. 24. — Vabiation* ra trr Fifth Li'mdar VeRTEnnA. {Mia Tiimtr.) 



T 



M-5^ 



in some of its features so widely from the other members of the scries that special 
proniinenee iimst now Ik- uiveii them. 

The fifth lumbar vertebra is niafsivc. and the body ir; much ttucker iu front 
than t>ehiiiil in consequence of beinsr bevelled off to fnrm with the sacrum the sGero- 
pcrtebr/il an/iir. The transverse processes nrv Hhnri.. thick, tHwiii-al. and wprinp 
from the body as well as from the pedicles. They are very strong for the attachment 
of the ilio-hinibar licaments. l^ie spinous process is ftmoller than thaT of any 
of tJie other lumbar vertebVa?: the laminae project into the vertebral foramen on 
e,nch sifle; and tlie pedicles are .st*»Ll ami llattened from nbovf downwartt. The 
inferior articular processes arc separated lo auch a depree as t^) be wider apart 
than the superior, and they articulate with the firHt sacral vertebra, 



Pre. 25.— A Vahution in the Virm Lumbar VcinxBitA, (After Tiinier.l 




mvK 



Till' pediclM of tt)i>f v^rlpbni nn- }i.ililp to tt rirmnrkiiblr d^vLitioii fmni tli«- cnnflitinn^ found 

Ih* arch imnirrlialfly l«hind tho superior ftrliciilikr pron^sKc. In Mich .■i|K-niiirHJ> tin- anterior 
pari. M tin i -lis of t\w lioilv rtirrviiiK I hi- iwilidi-jt, tr;iiii"vi-rjii' miil mipi-rior iirlw-iiiiir pKiri'^.'ii-.H; whilot 
th« poct<'ricir soKntent is coiii[)03i.-d of Hk- l«iiiin:i;, cpitiF. and inferior ttriionlar [>Toco!W"rs. The 
paxloriiir ttL-eriicnt of tin- rinc of i)iii< vf'rTclini m.'iy pvcn con^isl fif twn piw«<. Tlicro it reason lo 
LpIii'm- lh.it thi-i rilnioriiiiiiity (if tUi- fttth lumhrtr virlt-lini oci-iim in fiv*^ per will. of hU sulijent* 
fxnmiiiwi. fiir Wilii-un Turiiir. in \m ix-porl on thv )iu;ii.in -ikvlclon:* in the ('liiilIofiKpr ICpporte, 
found Htvcn *'x.im[ili-H amonc ihirly "ki'l/'iori" cxitniiniv). Tlii' sk'-lrtons in whirfi lhin orciirred 
WfTi' — ft M.ilikv. QTi AncIninniicTH-, » ('!iiiM"»f, twn iltkihinrn, iin L-Akiino, and u \rsro. Ttirner 
hfl» aho iKvn ii in tho nkelftoti of » .'^^iiulwivh iNininUTr- A Kirailnr eonditioD in occasionally met 
with either uniUlprallv or t>ititt«^raliv in tlip thoracic vcrt^hnr. 



THE SACRUM 



27 



THE SACRUM 

The five wirral vertphrn- are united in (he a<!uU to fomi the os sacrum, a laTge, 
curx-eii, trinnffular bone, firmly wedgerl between the innotninjtte Ijone-s, and coni- 
pletiii);, together wiih the coccyx, the posterior boundary of ilie true |wivic ciiuty. 
0( the five vertebra- which compose the siicruiu the uppermost is the hu-gtwt. the 
sucoeeding anve tntnimio rnpidly smaller, and Ihe hllh i» (^uite rudjrnentiin.-. In the 
creet posture the sacrum lies «bli<|uely, being directed from above downwards and 
backwards, iitid forms with the last lumbar vertebra an antpjior projection known 
as the promontory. The sacrum presents for examination a peine and a dorwd 
surface, two lateral niarpnif, a bjuie, and an apex. 

Surfaces.— The pelvic surface, directed downwards and forwards, in smooth, 
concave frnin alMJve downward** and sliglitly from side lo side. It 13 crosscrl in 
the middle by four transverse ridpes which represent the ossifie<l intervertebral 
discs and separate the bodies of the five sacral vcrtebrie. Of the bodies, tho first 
and second are nearly equal in sijte and are larger than the third, fourth, and fifth. 

Fio. 28.— The SAracu Atto Coccnc (Anterior view.) 



"^. 



■ finnrmiu 



■rniM UTDUi 

MMtE 



-oo«c>n*<M 



0«M)«ma 



-LwttWruu 



which, in vertical depth, are also nearly equal lo each other. At the extremities 
of the transverse ridijefi on each side are four opctiings, called the anterior sacral 
foramina, which cr.rre-p<ind to tlic inler>ertebr,-il foramina in other repions of ihe 
column, and (niiiHMiil the anterior fhrisions of the f'rr-t four ^ac^Ml ucrven; llur upi>er 
two are also travcrse<l by the lateral sucral arteries. The fominina are sepanite«I 
by wide proccMsiw. rvi)n'st>titinK the costal prtwesse*! of the vertebnr, whieh unite 
externally to foi-m the lateral mass. The latter is grooved for the sacnd ner\es. and 
rough oppojtite the 5CC«Mid, ihird. and fmirt,h sacral vertobne. for the origin of the 
pinformi.f muscle.- Tlie lateral pari of the 6fth sacral vertebra gives insertion lo 
fibrw of the a>cc<^[euK. 

The posterior surface is stronirly convex and roush. The middle line is oceu- 
)iieil by four eiiiim-iir<'^ re|<r<:s<'iitiri<; the suppre^si^l spinous processes. Of ditse 
the first iy the hirgest, the second and thirri may lie p*>iiflnent. and the fourth v^ 
often absent. The Ijone on each side nf the spines is slightly hollowwl an<l 1= formed 



38 



THE SKELETON 



by the uniteti laminae. In the fourth sonictimeti. but always in the fifth, thc> lEuniniv 
fail lu meet in ihe iiilddle line, teuving a fup (hiatus sacratis) M ilm termiiiatiun 
of the spinal cfinal. the lateral margins of which are piolmnptHl downwards as the 
sacral comua. Thoy roi)rcs(nit the lower articular pmcftwfts of the fifth sacral ver- 
tebra and K'^'C attachment to the posterior sacrococcyireal HEaments. Kxtenial 
to the lataiiiHf is a sectmd series nf stiiall eiiiinencos whidi represent the articular 
and manunillary processes pf the vertebne above. The first pair are large for 
the liLst liiitihar M^rtehru. tlie »ecoiul and third arc t^iuoU, uiifl the fourth and 6fth 
arc incorwpicuouH. 

Immediately extenml to the articular processes arc the posterior sacral fora- 
mina, four on eaeh side; they are stnwiler than the ant-erior. nnd give exit to the 
posterior primary divisions of the first fyur sacral iiervt-v. Kxtenial to the foraDiina 
on each side are five elevations representing the transverse processes. The liret 
pHir. !>itnated at the junetiitn of the poKieriorsurfueeMith Ihelut^ie, are lar^and eon- 
spicuoua, and serve all for the attHchment of lipamenti* and muscles. The space 
between the spinous and transverse proeesses pn-wf-nl^ a shall<)W coneaWty known as 
the sacral groove, continuous nliove with the vertebral jcroovc of the movable part of 

Fai. 27.— The SAratn. (PiiBterior view.) 



nncuuK ntsom 



MRIMUH ■»■>*«• 



y 



LailMBiiia do**l ' 

MTiouuiH niucna - 

TMRntRK ra&9En- 



ucnu rauupi . 



w ^r 



r- 



■ 8»ia9-oplmtUa 






OloMus BUtBua 



MTCH rO* ntTH tURU KERiE 



the column, and. like it. lotlping the miUUfirlvs muncle. Rridpnp aeroHs the gi-oove 
and attacheil to the sacral spines internally, and to the lower ami Imrk part of Lhe 
sacrum exl^-'mally. is the flat tendon of orijtifi of the sttcrih^piuah's (irrd/jr spina). 
'\\\(^ (fluteiix nuirimiis takes oriijin from the back uf the lower two pieces of the sacrum. 

The base or up|>er .surface of the sacrum Ijearr? coiinidentble rtweniblanee to the 
upper surface of the fifth lumbar vertebra. It present.- tn tiie middle the lx>dy, of 
a renifonii sliai*. [Mwierinr to which is the n[>i)er end of the sacral canal bounded 
by two laminic. On each .'side of the cnnal are two articular pnH'e.«f*s bearinp well- 
marked mammillari' tubercles. Tlie conjoined tr.insverse and eostal processes 
form on each oide a broad surface, the winji or ala of the «acrum, continuous with 
the iliac fossa nf the hip bone, and g^^*inp attachment to a few fibres of the ilianis. 

The lateral margins. — It' ha^ alrnuiy l>een noted that the lateral nias!> of the 
jaierutii U the part external to the foramina. It is bmad and thick above, where 
it forms the ala, but nurmwed below. The outer aspect of the upj)cr part. pre.seiit6 
in front a Inroad irrejailar surface. ro\'ere»l in the recent estate with fihro-cftrtilage. 
wliich artieulate? with the ilium and i.-* known m the auricular surface. It is 
bounded posteriorly by some rouRh depressions for the attachment of the posterior 
fiaen>-itiat; liiratiientH. Below the auricular surface, the lateral margin is rough 



THE COCCYGKAL VEHTEHR.H 



20 



for the sacro-luberoas (greater) find sarm-spinnua (leaser sacrw-sciafir) lij^a- 
monU. and t*i-minatrs in rhe projectian known as the inferior lateral angle. 
Immediately l>elo\v X\\c angle is a nolt^h, cnnvPrted iiito a foramen liy the trmi-s- 
verse pnx-ess of llie Jii>t cnccy^ffal vertebra, and a ligament connecting this with 
the infenor angle of the Burruni. 'llirouph this funtmcn paiiM>K the imlerior 
I»r;incli nf llio fifth tiacrij nerve. 

The apex i? dirorteil downwanls and fiirwanls and i-' forrned by the inferior 
asijwt <if th«body of the fifth Mirral vertebra. It is tran.svorse]y ovtil and nrtieulates 
by means of an intervertebral disc with the coccyx. In advanced life the ai>ex of 
the sacrum becumei! unitwl to the coccyx by botie. 

Fio. 28, — R\BE or Saciiom. 



MTwuui nwcin - 

UHI«1 
tMtStU. UML 



m 



.V. 



'v^-f: 



Pi 



The sacral canal i.i the continuation of the spinal canal through the ^tHcruiu. 
Uke tlie trone, it Im curvetl ami triangular in forui at the ba«c and flattened towards 
the apex. It termitiates at the hiatu.s .'tHcralLs between the .sacral eoniua, where 
the hinrma- of rho fourth and iifth sacral vertebra- are iiieoinplelR. The ranal o[)en9 
on the surface by the anterior and i«(st*'rinr sacral foramina and lo<lges the lower 
hnrntrhftit of the Cauda piiuina. the fi!un» l^crminule, and the lower extremity of the 
dura mater. The sul>dund and sub-anK^hnoid spa<*M exten<l downwards within 
the canal a.s far aa the Ixxly of the third sacral vertebra. 

IMfferences in Ihe two 5cx«s.— Tlio siwruni of the fpinalc is usually hroadflr in pmportion 
Cu lUt li*iiK^li, iLiiii-li inei (.'uni'il, liiul (Jiivct^tl iiion' ulilti|iifly ItiiokwnnU than Jii tliu mtilr. The 
^m curvamr*! of llie female sacrum Ix-loTigs chivfly lo tlw lower purl o( Ihe bon«, wttentM in IIm: 
^H m&W- it i» f|<iimlly dUtributiMl over ita wliule length; but the curvature is subjnrt to consider- 
^^V nlilc vMriiittoii in difTerent itlwclctonh. 

■ Racial diRvrences. — The humxn sucruni is cbanictvriw-d liv iu gn-at hrvadtli in coinpari- 

I finn wilh '\\a icnirlh, though in ihv lowt-r rucc^ U m reluliwly loiigiT thiin in thft high<yr. The 

I prpportion ia exprcwwl liy th« xaiml indrx — . —r . The ATcnigt; wtcral index in the 

I Rrilinh nuilv is 112, iu lUe fciuulc lUl. Sitcru iu which Ihv index us ahtvo 100 ari* plalifkirn/:. u 

t iii Kuropeans; those under 100 arc doiichohifrtc. an iu autal of the black raoc6 (8ir W. Tunior). 

■ di 



THE COCCYGEAL VERTEBR.T: 



The four coccygeal vertebne an? unitwl in the ailult to form the coccyx. ^Miilo 
four is the u.sual nunil^er oi these rudiment.-*ry vertebra*, occasioualty there an> live. 
and rarely three. In tnidille life the tirat jiicco in usually weparale, and the original 
divi<uon of the remaining portion uf the coccyx into Ihrett parts is indicated by 
transverse grooves. In advanced life the pieern of the coecy.x, ha\'iiig previously 
uml«xl t-t) forTQ one l>mc, may al.-*© become joined to the sacrum. 

Ulie first jMece of the coccyx is much broiuler than the others. It consists of a 
IxKly. transverse proccBses, and rmlimenta of a neural arch. The body proeents 
on i\s iipiKT Hurfa^-e an oval facet for articulation wilh the a|)e.x of the ssxcrum. On 
each side of the Uidy a transverse process [irt>ject8 outwanls and is joined cither 
by lignment ()r bone to the inferior lateral angle of the sjicrum. forming a foramen 
for the anterior division of rhe fifth sacral nerve. Krom the po.-Jtcrior surface of 
t^ body two long coccygeal cornua project upwards and arc connected to the 



30 



THE HKKLETOS 



.sacrbl cnrniia hy the posteinor sivrm-rorcv)?™! lijtaniipnts, enflnging on each .side an 
uperture — the last intervertebrnl foramen — for ihe exit of the (ifth sacral nerxe. 
'J'he coccvM^eal comua represent the pedicles ami superior articular processes of 
the first segment. 

The second piei^e of the ciinovx is muoh .'^mailer than Ihe first, and conpists of a 
bcidy. truce.Hof iriinsveiw! prooeKa<>s. and u neural iirch. in the form of slight luWroIes 
at the Hides ami nn the pasterior aspprt of the ho<iy. 

The third ;md fourth piece.-* of the coecyx. smaller than the aecond piece, are 
mere nodules of bone, eorref pond) tig solely to vertebral bwhes. 



Fio. 29. — Thb Coctyx. A. Postmior Hew; B. Anurior view. 
A. . a 



OOMTSUl 



nwoEu 



rM<r nn 

*fn Of 



,-*i'^ 



caoa 



Oluleu* 



I*t UII 



Ulj 






Tlie anterior surface of the rocc>'x gives attachment to the anteririr aacro- 
coccyiical ligainent and near tlie tip lu the Irmtnr uni; it is in relation m itli the pustH?- 
rior eurfiice of the st'coiul part of the rectum. 

The posterior surface of the copcy.-c is convex, and the upper three piners afford 
altachineni ro the yhiitus mnxiniiitt <m each side, and the tiwt |Mece to the iroccygeal 
portion of the gjiftitictfr ani txljruiis. 

The lateral margins are thin, anci rereive |iarts of the soero-soiatic liganients, 
of tlie coctijyci muiitles, and of the InxttorrM ani 



THE VEUTEliUAL COUJMX AS A WHOLE 

The vertebral cr>lunui is tiie central axis of the skeleton and is situated in the 
median line at the posterior aajwet of the trunk. Sujieriorly it supports the skull; 
laif-rally it gives attnehmcnt to the ribs, ihrouph which it receives the weieht of the 
Upper limb?, and inferiorly it is .siippnrlfrd l)y thr- hip hone.-!, by which the weiRht 
of the trunk i» triitisiiiitted to Ihe lower limlw. It,« length varie.-^ in different skele- 
tons, hut on an avenige it nieMMires alx>ut 70 cm. (2S in.) in the male mid about 
2'5em. (I in.) less in the female. To the eiilire length the cervical region cuiitril)- 
utes ]2'-5 em. (5 in.), tlie thontcic 27" 5 cm. (11 in.), the lumbar I"'5 cm. (7 iiv.), 
and the sacrn-coccygeal portion the reniaininj; l2'o cm. (.'» in.). The vertebral rnl- 
uinn present,^ a series of curvatures, four when viewed in profile and one when 
riewed from the front or back. Tlie former are dii-ectod alternately forwards ard 
biM-kwardj*. and are naiued. from the regions of the column in which Ihey oeciir, 
cervical, thoracic, liimhar, and sacral. The hfth cune is lateral, being in 
miwt ciiWM dirwted lnwimiH Itic riirht side. 

The cervical, thoracic anri lumbar eur\'aturcs pa.'*siin|}erceptibly into one another, 
but at the junction of ilie la.*tt lumbar vertcbm wilh the sucnirn a well-marked angle 
occurs, known as the sacro-vertebral or lumbo-sacrat :inglc, with rhc result that 
the promonton- of the Ktcruin overhang:* the cavity of the true pelvis ami forms a 
portion of the jielvic brim. 

The thnmi'ic and sacral r'ur\'es ha^T their concavities directed forwanls and are 
dcvelo[)ed during intrauterine life. They are in obvious relation to two great 
eMyJi'jca of the tnmk. thoracic and pehic. and may be regarded as primaiy or ac- 



32 



THt' SKELETON 



commodation curves, for the thoracic and pelvic viscera. The Ihoracic curve 
cxIfnilM from rhe M*c*nnd Ici tin? twelfth thiimcic vprtehm and ihe ftncnil ciirvo coin- 
cides wilh ihe BJHTum and corcyx. 

The (vrvicjil and himlxir curves have tholr cnnvexities direptcd forwards, and 
are flcvelnped during the first )*efir aft^r hirth. They are essentially eur^'cs of 
compensation, necessary far t he muintenance of the upriglit posi ure. and arc brought 
aiwiit by modifier tiuQs in the 8hii[>e of the Intervertebral dvavH. According to Balua- 
din. thp cervical curve is formed alwmt. the third month, or as soon as the infant can 
sit uiiriuht. The Kreat |XH-iiliarily of the curve is that ii ih never eonsfilidiilwl. l>einK 
present when the body is placed in the erect position tmd oblileraled by bending the 
lifa<i down upon the chest. Tlie himbar curve is dovehiiied nl>oul the end of rhe 
first yojir or when the chihJ Iwgins to walk, but is not consohdiited until adult life. 
(8yminfft<)ii.) The cervicjil curve extends from tlje athw to ttie jiecond tlionictc 
vertebra, and the iiunbar curve from tlie twelfth thoracic to the promontory of the 
sacium. 

Thelalenil curve issituatrcd in I lie U])|)er thoracic repion. and when diret'letl to the 
right is prolinhly ajMociaUid whh rhe greater iise made of ihc riglir hand. This 
curve, however, is particularly liiiblc to modificurion in different m'cnparinii.-^ iind in 
different laees. 

Mcweil from the front, the vertebral eolunin presents a series of pyramids due 
to ihe sureessive inerease and ilecrease in size of the bmlies. These become linwder 
from the axis to the first ihtirai-ic verli>bni and rlieu decrease Ui The fourth thnraeic. 
The first p>Tamid therefore includes all the oen'ieal vertebra- except the atlas, and 

Fto. 31. — A Divided Thoracic Vbbtebk.*. (After Turner.) 



I 
I 



ha6 the apex diroctwl upwards and its base downwards, wlulst the second is inverted 
and formed by the liret four Ihoniiric verlebrte. The third pyramid, much the 
longest. i.s the resxdt of the increase in size from the fourth thoracic to tlie fifth lum- 
bar vertebra, and the fourth, also inverted, is produced by the rapid contraction 
of the sacral and cocfygeal vertebne. 

Viewed from behind, the »|uiious pnicesjie.s project in the mi<ldle line, and the 
transvcfsc prt>ces.ses as two lateral rows. t»f the .spines, those of (he axis, seventh 
cervical, lirMt tlionicic, anil llie lumlmr vertebra- ap]M'ar nuwt pruminent. *.)n each 
side is the vertebral groove, the floor of wliicli i.-? formed in the L-ervical and lumbar 
region.s by the lamina' and articular procK«ea, and in the thoracic region, by the 
laminie and transverse processes. The tranH\*orse processes project laterally for a 
considerable distance in the atlas, first ihoracic, and the middle of the himbar series; 
th<n' are shortest in the third cer\ical and the twelfth thoracic. 

In Ihe lateral view, the intervortfbrai foramina apjwar ova! in shape, and are 
small in the cervical, larger in the thoracic, and largest in the lumbar rt-gion. 

Structure of a vertebra. - Tlie Uidies of the vertebne are largely composed of 
cancellous ti.ssue, with a thin outer covering of compact tis-sue. In a vertical section 
through the centrum the fibre* of the cancellous (issue are seen to bo arranged ver- 
tically and horizontally, the vertical tibres Ijeing curved with their concavities 
directed towards the centre of the bone. The horizontal fibres are slightly curved 
parallel with the upfter and hnver surfai-es, and have tl»eir wnvexi(ies towards the 
fi&nre ot the bone. They are not so well defined as the vertical set. (Wagstaffe.) 



I 



OSSfFICATlO^; OF VEHTEHR.E 



33 



Ossification.— The Tertebrie in general. -Tht^ omifieation o/ e^ch vtrt<4)rn takr»i plac« iti 
FnrtitsKo from ilirrf prim.irv jind fiv* t^M.-nndHry cptilm. T!ii? Htn-e prmi«rs' oi'iilr<^ nppi'Ar, 
ouc ill tliu tjtjily uml (m-o iii tlii; uri^li. uliout llii^wvi^nlh wvckuf iiirrn-iitcrini- lire. In (lie thor- 
ftcjc rii^Kin the niiclciu for itu- bodv itppcAT!* liral, bin in ih* cor\'ic»I roinon it i« prcc»^l«d by tJip 
c^utrv* o( the nrcit. Thi> iiiic)r<ii> lor tli»- IxhIv miOd Imwuiiic^ liilohii], luid Uiix {runililion is Mim^ 
tiuicH w |>i"ii"(iriwl (I.* Ill jtive rise lo liie appmrani'c uf Iwy di)<iiiicl inivk'i. ludcrd, the 
Diirlrua ii* iti.'inplim*'^ tinulili; iind tlif Iwo pitrbi of tlic boily may mmiin M-imniU^ tlimtigliout lifc 

Fio- 32. — A Vkhtebrai. Centhuu in aecnoN to bhow the rKEsKUHis Curveb. 



(fid- 31). The bilaitral oharacwr of the nucleus la further emiihasised by the occfiotoDol for- 
tnntion of hnlf-v^^rtpbni'. Tlio lateral centn-H arc Atr^trtinieA no-sr tho Haium of iJie atiporior 
articular pruo<HHtw hhJ fiive riiw to the petliclfn, liuiiina-, articular, au<l the g,Tea,Ua {lartu of the 
truiuiterw aiid spinous procoti!»es. 

At birth mtHi of ihc vM-t^-hra? ««n(iia( nf threo di«u«iu pi«w«i — a body and Iwo latirnL miuM4, 
wiiich couatitute the urcli, the p-irts U-ins jomnd toKuther by hyaline cartilage. Tlic Cue of 

Fio. 33.— A ViaTBiWA AT Rnmi. 



■ uriML IMU 






union of the lat^riil portions with the body Is known m (he nentTo-errOral nHfurf, and i« not act- 
Ually ulilileniteij fur twvcnii veiuv nfU-r birth. In tbi- Iboracic ref(iuo Lhv conlnd iiwiliciilicM) 
Aom uul pasa beyund the uoini with wliii'li tJut hciul uf (hu rib articulate, but Imviai a purliou 
of the Ixidy on each side toniied from tbi^ Uttral oMii beat ion. A thoracic v(*rtebru. at tnr fifth 
year shows tbnt the facets for Ww lu-juls uf tlie ribit ur\' nituatetl Ijchirid \hv iieurofvtitral tn- 
turo. whiiii is dirtxitcd obliqtiuiy backwards tuid inwards, The laminiL' unltv during the fint 

Fio. 34. — Cbrvical Vehtkbka showiku the KpiPuvaiAi. Platk on th« Urpm Sumfac-k or 

THB Body. 



I^year after birth; and by the jradiin! eTtentunri of o<<aification Into the various proce*wes. ihu 
trtelira? have attained Blmoul llieir full «w- by \ho time of puberty. RulMequently the tec- 
iidary centrw appear in the cart ilu^noiM extremities of the "T>inniiK and transvenie pmceiwra, 
id io the eartila^ on the upper and lower surfaeeti of llie lioiiett, formin); in each vrrtebra 
'^twn umm lor plate's, tbiekeflt at the circumfnynee and gradually thinning lownrds tlio central 
deficiency. Tlie epipbyes appear from the fifteenth to the tn-entielh yenr imd join with the 
vvndira by the twenty-fifth vear. 
3 



34 



THE SKELETOS 



In xRvrral vBrt«brac thv moAn of owificatioD diffen from the ticcuunt given abore — in mote 
cases wiiwWvnii^ly — and neooesitBlns Bcparatc coiuiderstion. 

Atlac. — The InU-ral maxAPA *nd posUirior arch are formwl fmtn Iwo cCTitres of oasificalion, 
wliich corrtwpomi to \he. litleral rrn[iv« of other vertehrii- ainl u|)|H*iir iibouC thcwvenih W«l<, 
TImt anterior arcli Li oMifieJ from one cvntre. vrhich. however, dots, not nppriir until a lew moittlu 

Fio. 35.— LuHBAB Vektebra at Tna Eiohtxes-tr Vkas with Secokdamy CE.vmE». 

intHYUl PUT! M f iC 



h 



- TIUIlB«tME Mlfim 



ffiFiii^iiL ruii (Ji QiJb 



'(Afterbirth. Vnion of the lateral porta occurs poet«norty in the third year, hf'mfi aometilDM 
'^ecc'dc^ by the appearand' of a iiMondary centre of oteificalion in the intervening csrtlla^ 
ftod flic imiun of the blt^nil wirlM with the ant«fior art-h occurs about the sixth year. 

All*.— Tht arch, and ibe proccosies aasDciat«d with it. are formed from two lateral centns 
vrhich appear, like those in the other vrrtebra>, about the seventh, week. The common pieM 

Flo. 30.— Upper TaoRAac Vertebra with ah KririiVBiAL Plate Kciiovbd a.nd Dbawn at 

THE SinE, 

The f^ale ^hows the characteristic deficiency in the centre. (Natural ai«c.J 



of eaxtilflfp; which pit<cede« the body and odontoid pmnw^ in ofoifiixl from four (or five^ centm, 
one (or two) for the body of the axis, in the fourth month, two. bterally disponed, for the 
odoritoiil |iro(<eiM, a few weeks later, and one. for the apfx of the process, in the second year. 
The two collateral cenlren for the main pari of the odontoid .=oon coalcw-e. eo that at birth \\m 
axis consiats of four oiweous piec4-»t— two Iat*?r&I portions whji^h con»tituto the arch, the bodyj 

FiO. 37.— iMMATCtiB Art-Afl. (Third year.) 



and the odontoid procnis. surrnnunlpd by a piece of cartil-ijEF. Durinj; the third or fourtE 
year tlt^ orlontoid proeew joiiw "itb the bodv, the line of union bi-inif iiidicAl«-d even in "'' 
vancnt life by n MwaXi disc of earlilnco. and the nn-h imiteit iu front and behind nboitl the lu 
/iffi^ i>r /t tittle }atPT. The apical nurh-un of the odontoid, whidi repruai«ts an cpiphyM-t, je 



36 



THE SKELETON 



The nftK lumbar exhibits in some cuius a Hiiecinl mode of ossification in the arch. Instead 
of t»-o centres, thtre arc four — on<! on ctt<h sid* for the pcdiclr, transverw procesa. and super- 
ior articuUr process, nnd aiinllirr on cwch xidn for th*; laminft. infmor articuuir pmcvea, and the 
tiitcral liaU of thi- Hpiuuus |jn.>c«w i^fig, 43). There may be failure of union of pedicles with 
Ihe Inminic- or of the liiminit- wilh om- iinoth*fr (fi*. 2.11. 

Sacral vertebr*. — Thw jiacnim mnirirn from ihirty-five centres, which may be classified as 
follows: — In each of lh« G^t vcrtcl^i-ii- tliiTe nn- three ^miniary iniclei — one for the bndy and two 
for the arth; in eneli of th? first ihrt'c the roiital rlement of the lateral muse on each fiide is 
forniod from « wpnrair niicteuft; afworiated with t-aeh body are two epiphymal plates; and 
on each lateral iimrijin are two irrvRiilar epiphyses, one for the Hiinciiinr surface and another 
for the rougli tnlge below. 



Fkj. 42. — OasmcATioN or tmk Firra Ldhkah Vhbtehiw. 



NivKD-ctatui lurum 

GORNUH 




The centres for the bodks appear about the ciehth or ninth week and for the neural arches 
about the sixth month. The Jirchen join the bodina at different timf-s in the (liffwent verle- 
brie. T»n)nng from the •wL'Ond year below, to the fifth or sixth year above, will union of the 
Inminii' takes pL-ice liehind wme years later, from about the ninth lb (he fiftit-nih year. 

The centrcH for Ihe costal eloncnts ai>pear oiitsiik the anterior Hurral fonmiina. from the 
fifth to the seventh month, and thes« niiit« with the bodies soniewhut later tlian the un-hen. 

The centres for the epiphysial plaiM appear about the lificenth year, and for the auricular 
opiphyHCB and the edges lietuw, fnmi the eichteenth to the twentieth j-car. 

Conaolidution be^^in^ soon nflcr puberty bv fusion of the eotilal procexM^, and thiji iti followed 
by ossification from hrluw upwnnU in the intervertebral disco, resulting in the union of the 



Fia. 43-— Sacrum at Bnrni to mhuw Ccn-tres of 0«aj«r.\Tiow. (Enlarged one-third,) 



OtiiiiO cnTm n> ihi loot of fini uani. iuiirm. mkeitm 
iHii Ml sciH IN succtsaitiH IHI cEK'm w txe mdiu of 

THE SIC010, TMlKO. FOURTH. UO nnn IHIIIU 



PNKIO CUIVll fR THt UltML VIM 




iceeif bodiw and the epiphysial platefi. the owifie union oJ the first and second bedng eom- 

„ *d by the twenty-hflh Vcat or a Utile laU-r. The murainnl •■piphvaes are aliio united to the 

uenim by the Iwnitv-fifih year. E>en in Hd^■an<.•(td life iiitLT\-eriebTsl discs pernat in ttw 
men* central parts of the bone and can be well speii in iwclionn. 

Coccygeal vertebr»,--Thc coecypeal verli-bra- are rartthiginoits at birfh and each is uminlly 
ownied from a sincii- eenin'. Ihrniph there may 1h' two for ilie (irsl piece. *)a»ification lic- 
gin* tiMon after birth in the firHt scfcment, and in the .^i-conH from the fifth to the Ii-nth venr. 
Tlic euntrcs for Ibe third and fourth sccmenis appi-«r jm! hrforp, and uftt-r, pul.prtv reepee- 
tively. A» a^ ailvatiees (he vimrtus pieces l.ii-onie unii<-ii with f^aeh otln.T. the three lower 
iiniiiiiK U'forp middle life and tin- upiwr suinewhut I.Tier. fn tulvanred life the eoccvx mav join 
mill (he •aerum. the union oecnrring carhcr arul more fre<|iienLlv in tJw male than in the fprnale. 



THE OCCIPITAL BOXH 



39 



The Ovnmtrsf prrrctaeca ofTur more tiiilicuity. They occur iu tUi? eiinpk-Kl tuna in the tlioi^ 
Bcic seriM. Hew ihcy urttciiintr wilh the tulwrclivi of the rilii". wltcncc iiip t<'nii Itibrrcular pro- 
v*Mti or Hutpopkyjifii hun ))pi:n fcivrn Ilirni {ttii- pWr uf nrtiriilniirm til Ihi- hriul uf |}i« rib 
wilb ihc vt-j-U'bni is tin- vapiliilar pri/iy-if nr panifiuphi/ihii). uiid tilt.- (niiis* «r>v pron-te iiud the 
tutck of the ril) en«1oi!ir %ti arccrml forniiuTi mimed t1if oottlo-t ntn-ivrrw forani<>n. In the eer^ 
vich) region Ihr «»lal i-U-tiwiii ( /j/<-um/«ip7i_i/si«) i'lul the trnnsvprse procww are IumhI to|t*iher, 
mmI tlip conjoint procvs*" ihuit forniod U pi^rewl Uy the c(*to-traiisven»e foniiiieii. Tlio coin- 

Cmnd niiturr of In*? procc.-w is indicated by the iact that ihc sniprior or co!iC&l jirocetuies in the 
WW c*T\ ieal vtTtfhni' art.tf (mm additionn] centre* hikI occusionally retain ihrir indc<|i<>nd- 
euce n« cvrvicjil rib.*, and in Snuropflida (birds and n?piilt*i ihe»p pr«ici«ses are rvpn-w.-nlt.'d by 
fiw ribs. In thi' Imnhar region, the compound iiaLurr of the transverse propfw? w further 
Eniirkt^d. Th*- Inn* traii.-ver* process Ls grpolly suppressed, and it* extremity is indinilnl by the 
gK!CO««orv luln-ri'lr. Antt-rior to this in tne adult vertebne a group of holes represent* ihc costo- 
Imnmente foramen, and the portion in front of this la the cofitaf cleineut. OccseionaUy U pci~ 
Bbt« iu> an independftit («sifle, the lumbar rib. 

In the SAcral M-rieA the eo^tal elemeiitK ure coaleneed in the first three vertebne lo form Ui0 
srejUoT portion irf the lateral masa for arliculatioi; with the ilium, the costo-lraiiavewe foroLminu 
beinp: eompletely ohscured. In rare imiiancea the first wicral vertebra viil Articulate with tlie 
ilium on one aide, but remain free on the ulher, i»n>l under fuch cnndstmnti the free proceM ex- 
actly resemlilea the etonsaled irwitrt'enw pruct«f of a, lumbar verfebra. The first three .lacml 
vertcbne which develop coftta! nrooeseen for articuhition with the ihura nrw termed rri«? aarral 
vertehrw, while the fourth ™nd fifth :\a> termed paruiin-xarmi. ,\ kIjuic nl lij;. 45 will nhow the 
horaolugy of the various parts uf u vertebni from tlic ctirNJcal, lliorucic, luiubur, auU lUKral n^oous. 



B. BOXES OF THE SKITLL 

The skull is the c.vpunded upper portion of the axial ski'lctoii and is supported 
on the summit of the vcriebrul eolumn. It consists of the cranium, a strong bony 
CMC enclnaitijf rh*^ brain nml iniule up of eight bones- — \'iz., occipilaf. two ;oirv<(ni, 
fronltil. iwo UmjjortU. sphvuoid, dhmoiii; and tlie bones of the face, suirouiiding 
the mouth and now, and formiuH nith the cranJum Ihe orbiiui cavity for the 
reception o( the eye. The honey of the face wre fourteen in numl>er— viz.. two 
maxilUe. two stjtjntnntie (mtiUir). two mimi, tn-ti Uicknjmai, two jmiUUc, two injerutr 
eonchtp {turbinates), the marutUik. and the vonur. All the bones enumerated above, 
with the exception of the mandible, are unit«l by suture and are therefore immov- 
able. The proportion Ijetween the faciid antl rr4ni.ni parts of the skull varies at 
tUffereiit periods of life, being in the adult about one (facial) to two (cranial), and 
in the new-bom infant about one to eight. A gnjup of movable bones, com|)ria- 
ing the hifiiid, tiiwpendeil from the basilar surface of the cranium, and tlirec small 
bones, the ineug. mnlh-us. juul «Ui/ir.-t. silvisiiet! in the miii<ile ear or tym|Kinic 
cavity, may also be included in the eoumenition of the bones of the skull. 



TKE OCCIPITAL 

The occipital bone is situated at the posterior and inferior part of the ernnium. 
In (leneral form it Ia flattened and trapezoid in shape. cur\'ed upon itself so that 
one surface is convex, and directed backwards and soraewhiit downwards, while the 
other is eoneave ami ItKiks in tlie iippn.vite ilireetion. It i.-* pierced in its lower and 
front part, by a lar^e ain-rlure, I lie foramen magnum, by wliich the vertebra] ctuial 
commtmicatts with the cavity of the cranium. 

The oecipital bone is divi.fibb into four parts, basilar, squamous (Uibutar), and 
two condylar, so arr.niiee<:l amund the forauien nmgnum that the haailar |>ar1 lies 
in fn^nl , I be condylar parts on rather side, and the squamous part above and behind. 
Speakinp ^nerally. this division corresponds to the four separate ports of wliieh the 
bone oonsisis at the rime of birth, luid which are kntwii as llie basi-occlpital, 
supra-occipital (s/juamo-oa-ipiia!) , and ex-occipital. In early Ufe these fu.-w; 
together, the lines of junction of the supni-ocripital and cx-tirripitals cxtendinR 
outwards from the posterior margin of the foramen mapnum, and those of the ex- 
occipitals and basi-tiecipital passing through the condyles near their aiilerior ex- 
tremities. It must be noted, however, that the upper (Ktrtion of the squamous 
part rn]>reseiit^' an additional bone, (he interparietal. 

Tlie squamous part fsupra-oedpitsl and iiiii!rpariet.al) presents on its oon\'ex 
posterior surface, and midway between the sui>erior angle and the jxisterior mar- 
gin of rhe fnr;imen magnum, a prominent tubercle known a* the external occipital 
protuberance, from which a vertical ridge — the external occipital crest — nun* 



40 



TffR .SKKLETO^ 



downwarrls and forn'&nls as far us the foramen. Tlie protuberance anU crest give 
tttt»<rhinciit to the Itgatticiitum iiurhu'. 

Archiiig ouiwHnln on wirli mW fmm tho extemttl ocwiMtal prtitulierancc towards 
thelatprol angkof the bone is a semieircular ridge. Ihi- superior nuchal line {ctcrved 
line), which (livitics the surface into two part.s — un upper iiiul n ]<>\\ci\ Aiiovp ihi.-* 
line, a second less distinctly marked ridge^thc highest nuchal line nr linca 
BUprenia — is usually (Wen. It is the mwt curveil of the tlirce lines on lliij4 surface 
and frivcM attii«hn»ent to the epicraniiU aponeurosu; and to a few fibres of the occipi- 
Utiis {oca pUo- frontalis) niUHcle. liplwet'ii the suptirinr and hiphCAt curved lines is a 
narrow rrcscentir nrcji in which the Ijotip is smoollicr and denwr than the rial of 
the surf.tce. whilst tho part of tho bone above the linea Buprema is convex and 
covered by the scalp. 

Fta. 47. — Thk Occipftal. (External view.) 

unaiML oociNTkL mnMUMOf 



Tiaf«iii 



8«Biiap>n*n> MP>Ua 



Ooedpllalta 






■ UKU SU*^0)i 



t-Mft-' 



KLPCRIDIt 

HI. ZhU 



'k 



flnlBKlUB . 






Dbuqu* 

Bbbhw 

oapiila 

ponUrlar 

uiiQap 



BMfu 

Mviua 

poaMrUr 

IDlBOr 

KaduB 

oarrilla 

UlarslU 



PnUtmi 



CMtn 



lamtHOi lUWUH 



'^ 



PUKlHtl 



MOCUI 



, tOHunt 



R*«iiu M|Uito •atwimr 



Lcnmvm unliu 



. AiiashaHoil ar*ii»nar CaamiBUx 
en ruryiix to vkmrjanal TiiMrau 



The lower part of the ^lurface in very uneven and .lulxliWded into an upper and 
& lower Bren by the inferior nuchal Hoe, which runs outwards from the middle of 
the crest to the jugular pn>pcss, Tlic cur^-ed lines and the areas thus mappnrl out 
between and bclon- them give attacluiicnt t« several nuwcles. To ti»e j^uperior 
curved line arc attnclieti. internally the trnpeziua. and externally lite occipititUi 
and sttTno-riifulo-mQ^toiif : the area between the superior and inferior curvetl lines 
receives the srrnixpirwlix mpHi? (complex'is) inlenmlly. ami Rpletnux cfipiti» and 
abtujnw< nupfritrr exwrtiaWy : the inferior curved line and the area l>elow it afford 
insertion lo the rtrtitn ryipitis po.ttm'or minor and mnjor. 

'D\e anterior or cerebral surface »« deeply concave and marked by two grooved 
ridgttf which cro** one ani^ther and divide the surface into fo»ir fossa- of which 
the upper two. triangular in form, lodRC the occipital lobe« of the cerebrum, and 



THE OCCIHTAL BONE 



41 



the lower two. more qiinrlrilatcral in outline, the lohos of the cerpbellum. The 

vertical ridf.'"i Mteiids from (he auperior nnple to the fornnien niajj;imm ami t!io 
transverse ridge from on* lateral angle lo the olher, the jxiint of inlerewtion b«i-inft 
indicated by ihc internal occipital protuberance. The upper part of the vertical 
ridRC 18 griMJvtfd (ur Ihf ^uiKrior f-;i|iillal {iwujitudintil) sinus and gives attach iiieiit, 
hy its marginB. to the faix cen-liri: the lower part i« tshnrji and known as the in- 
ternal occipital crest, and affords attachment to the falx cerebelli. Approach- 
ing the foramen inaj^imm the ridj^e divides, and the two parts become lost upon 
its margin. The angle of diverfience ijometimes presents a shallow fossa for the 
extremity of the vermia of the cercbellurn, and U called the vermiform fossa. 
The two parts of the transverse ridB;e are deeply grooved for the tran^vei-se 
{lateral) sinuses, and the margins of the giTiove give atiaelinient Ui the leulorium 
ecTebelli. To one side of the internal owipitid prtituhwanee is a wide space, where 
the vc-rtical jtroove Is contiime<l into one of the lateral groove* (more freijuently the 
right), and this is termed the torcular Itcrophili; it is sometimes exactly in the 
middle tine. 

FiQ. -IS. — OccinTAL Bone, Ceokboal SirurACB. 
kwmmiMiKi 






ctmiwL foiu 



■NCI 
UTOUi W«LI 

otMattufi mm • 

MOon nm Tuntmrat twui 

4VWU* mwtai _ 
Rm fnutu. 



41' 



if 



»Vii^ 



aA«l-OCCII>tTAL 



The srjuanioua portion haa three nnglM and four borders. The superior angle 
forming the .-uinniit of rhe bone is received into the space formed by the union of 
the two parietals. The lateral angles are very obtuse ai»l wm-cKjuind in .situation 
with the outer on^ls of the tran«ver>« ridges. A1h>v(! (he lateral angle on each side 
the margin is deeply serrated, forming the lambdoid or superior border which 
extends to the superior angle and articulates with the posterior border of the parietal 
in the lambdoid suture. The mastoid or inferior border extends from the lateral 
angle lo the jugular proress and arliculatest with the maj^toid jKirtion of the temporal. 

The condylar portions (ex-()ccipital8) form the lateral boundaries of the fora- 
men magnum and bear the eondyles on their inffirior Hurfaoes. The condyles are 
two oval pmecK-'eK (pf bone wiih MintHilh articular surfaces, eovered with cartilage 
tn the recent slate, ftir the superior articular processes of the atlas. They con- 
vei-gp in front, diverge behind, and are somewhat everted. Their mai^in.<t give 
attachtnent to the capsular ligaments of the occiplto-atlantal joints and on the inner 
Bide of each is a prominent tubercle for the alar or lateral mtontoid ligament. The 
anterior exlremiUes of (he eondyles extend beyond the ex-oceipitals on the basi- 
occipital portion of the bone. Tlie hypoglossal (anterior condyloid) foramen 



42 



THE SKELETON 



pcrfnrntcs the bone at the Imse nf tlin pondyie, and is tlirected from the interior of 
tlitt cranium. Juki. alH)%'e the. fnratnen tim{r"im. ouiwaniB iintl forwards; it tnins- 
niit-'! the hypogI«s,saJ nerve and n twijj of the ascpMiiins; phuryrifreal artery-. Tlie 
foramen is somptina^ double, heiiie lUviiieil tiy a finlicatf spicuic of liuiie. Vva- 
terior to oacli ooiulyle is a pit. tlie condylar fossa, whjcii receives tlit- hinder etlfje 
of the superior articular process of the at)a« when the head is extended. The lli>ur 

Flo. 49.— CBnEBBALSfftPACEoF-niBOcapiTAL, HMovtNa AN Occasional Dwpo*itio.\ ^^r 

TIIK Cma^NK-I.h, 



TonMlM 



utAkH^iiH nnu 



^f' 






of the depression is occasionally jwrforated by the condylar (posterior condyloid) 
foramen, which transmits a vein from tlu; hiieral sinus. Wojei-tinji outwards 
jippowite the condyle Is si (|Uadrilaronil jiortion uf ixmv known as l.he jugular 
process, the extremity of which is rough for articuhii inn with tlio juffular faeet 
on the potrouH portion of the temporal bone. I'p to twenty-five years the Ikhics, 
are united here by means of curtilaste ; alx^ut Ihi.-i age ossification of the cartUi 

Pio. iSO.— Tas Foit.\uE.s Maqxum at tue Sixth Year. 



--,•*. 



>J 



ri)i»nia [0iiii>|j|\ 



U^OOC^ru lO^IIDN Of tME . 

liiwuii nocisi 

■ut.oooT'TaL romoR or tat • 
GOD mi 



ip 



■ut'OedPtikL 



takes place, and the jugular process thu-s becomes fu.«ed with the petrosal. Its 
anteri'ir bonier is deeply nntchcil to form the potitviioT Umndiiry of the jugular 
foramen, atid the notcli is dire^-tly contiriu<»u5 with a ^rnntvc on the up(jer sin-faoe 
which lo<iges the tenninntion of the trunsverse ainiis. In or near (he p^wve is s< 
the inner opening of the rondyhir fornmen, The lower imrface of rhe prfveess jrivwi 
attachment to the rectut eopiiis UUtrnlia and the oblique occdpilo-atlantjvl ligament. 



thf: occrriTM bone 



43 



Occasionally the mastoid air celU extend inio this proceMS and rarely a i>roceas of 
lK>ne, ropresOntinK the paramofloiif prixrnif of rnany mammals, projects downwards 
from its under aspect and may be so long as to join or arlieuiate with I he transvprst; 
prot*SM*of tlie 'A\\as. 

Tlie basilar portion (baai-oecipital) is a quBtlrilateral plate of Tmnc projecting 
forwards and upwaniw in front of the fnrunien ninf;nuni. lis superior surface presents 
a deep groove— tlu^ basilar groove; it supiM")Tt.s the medulla oblongata and pives 
attachment lo the t-ectorial niembrnne (occipito-axial lieament). The lower surface 
pretH^nls In the middle hne a t«niall elevation known as the pharyngeal tubercle for 
the attachment of the fibrous raphd of the pharvnx, ami iinniwliaicly in fnuit of the 
tubcrelc then; is frwjuently a shalhtw fowsa - the scaphoid fossa— which originally 
received the primitive anterior extremity of the forepui. On each side of the middle 
line are impressions for the insertions of the Inngus eapUiit (rfi-tu* en-pitis aiiUrior 
nmjfir) and at/i« capitis nnlfrior (minor), the imprr(*sion for the latter tjeing nearer 
to (he condyle, and near the foramen iim(;iiuin tliis surface gives att»chment to the 
anterior occipito-atlantal ligament. Anteriorly the basilar process artieulates by 
synchondrosis with the body of the sphenoid up to twenty years uf age, after 

Fio. 51. — 1^ OccirrrAL at Birth. (Ajit«rior view.) 






THE nnvinitlAL AHo mm- 
socmiu roHt«Nt fmm ihc 
)quAw«ui rwmn cr iMt 
wit 

m OMTlUtflli 



-V 



FORAMEN 




K»0«»n*i 



whieh there is cvimplete lK>ny union. I'osteriorly it presentfl a smooth rounrlrd 
bnrfler forming ihc anterior boundary nf the foramen magnum. It fiivcs attach- 
ment to the apirrtl odontoid lijianieut. and aijovc this to the accendinj; jjortion of 
the crucial licament. In the occipital Ixine at the sixth year the latend extremities 
of this Iwrder arc enlar(|[ed to form tlic basilar jiortiou of the condyles. 'Hie lateral 
Ixmlers are rou^h below fi>r ariicuUuion with the petmus purtion of the ^.l.■JIllH^rlil 
bones, but above, on either side of the basilar groove, is a half-groove, which, with 
a Kimilar half-groove on the petrous portion of the temporal l)one, lodges the 
inferior petrosal sinus. 

The foramen magnum is oval in shape, with its long axis in asjicrittaldirerlion. 
It transmits the ni'i-tlulla oblongata and its membranes, the spinal accessor) nerves, 
the vertebral arteries, the lUiHTior and post r-rior spinal arterii's, and Itie tectorial 
membrane (ncci|>ito-axial ligament). It ia widest behind, where it transmius the me- 
dulla, and is narrower in front, where it is eneroachKl ufion by the condyles. Occa- 
sionally a facet is present on the antterior margin, forming a UUrd occipital eondylp 
for articulation with the odontoid process, between the condyles and behind the 



THE PARIETAL BOSK 



45 



• 



upper pnir arp depoftitpd in mpttiKraitP. arwl lliia part of the equamow portinn irprrtwiilG tlip intcr- 
jjiirirtfll Ijoiic o( tnniiy uitini.tln. The lower pflir. deposited in wiMilage. (orm tho tnic supni-occij^ 
iltil *-li'men(. Hiui I^lo lour p^ils nuiciify oanl^-sc*' near Hw Hitn.-ttion of llip fiitiin> (icrijntnl pn>- 
talipratice. Kur iiiutiv wtvks twu deep Utcrul fisEurct sepurutv (he inlrrpurictnl luiil fiiprtt- 
occipital portions. imH a mcinliranous spjirc cxionding from (he ecntrr of Ihc K|ii(imnii.s ]Hirtiiiii 
to tlie foramen iniiK;nvitn pnrtiiiUy aepnntiv liie Inlernl jwrfmn* of the »iipra-<nTijiittJ. Tliiji 
ftpatre U occupied laler bv a siMCuie of boue, and is of iiitcre^iC ax Uvinst llif u)kmiiii8 llirousli 
which the fomi of hemin oi the bruin and iij* tiif ninpi-s. known .■«, ocf.ipilat mcningocrle or mcopli- 
alncele, ocnm. The hiiai-iirnpitiil luid Ihe two e\-aK'ri{.iil;>U urr' otunticil riM*)) liuiii n xiciKle 
iiiicleua which !tpi<(.-.-irs in ciirtilnce from the luihtli lo I)r- tnnth wevk. 

At birth the bone consLsl* of four piirid ntiited by "iripTt of cartlburr. and in thr ^iiTiatiMKu 
portion figures ruonTiifc iti (roiti li)e ujijmt noil titl<<m] uiifcIcM an- >till notircable. The cuuvotM 
nnioii of tile Mjuainoiis uiul cx-occipitai is coiiip|<-U>d tii thu fifth year, artd tliat of tliu c\- 
occipitnU with tKe l^nsi-occipildl iK-forclUewvcnthyear. Upto the tVuntirthyi^rthebnjti-ocrip^ 
ilul w nnitiil to thv Ixidv "f tbr ii[)hi-noid liy an inlr-rvi-iirri;; piivr of eKrtiligtr, luil MlH>ut tliu-l 
date OBsific union bfjtinn and is wmplt'ted in tbi- courst- of two or tlirw yiwi-n. .Not infre- 
qucntly t^ll^ inti'qi.'tnctal portion rr-mainH :^pnnlI^ lliroushoui lifi* (fie. S2l, forrninc whdt hiu4 
|j«rfi (jtiiuhI Ihf innx Jkiiw, or it iimv !»■ rt'jtrt^^«-iil»'d by iinnii-roibi dctaclu-i) owicio or Wor- 
mian bonei. In jionif c'ai*i*' n larRi- Wormi-iii bon«. nuuied the pre-tnTirpiihi-fal. i" found, 
pftrtly lepWiiiK the intcrpanRtnl bone (fie- -Wl- A prp-inie-Tparietal lutne is found in «>nin 
inam'muh, and it hat nceiiaioniU]y liecn (ilL<ior\-ed in the bumAn foetal skull. In tig. 53 the 
boue is seen id an adult skull. 

THE PAKIKTAI. 

The two parietal bones, inti'i^HifCfl l>etwttTi the frontal before and the occipital 
bchiml, form ;i larjit- porl ion of the roof nml .sides of the craniuni. The_\- are qumlri- 
liiLcnit ill form. riDinox (•\It;ni!illy, wmnive iiitcninlly, and Pflch pres^'tils for' examina- 
tion two surfftcea, four twtrtU'rs, and four an»:les. 

The externa.1 surface is .^anootli atid [a crossed, just bclnw the middle, by two 
curvei.1 lines knou-ti us the temporal ridges. The superior ridge jrives attachment 
to the teiiijxtral fascia; the- lower, fa-quont ly the belter marked, liiiuls the origin of 
the tciiipitTrtl tiiuscle; whil'^t the narrow part of the surface eneloseii between them is 
smooth ami more |Kili.sh«l Ihim the rf.st. IrniTiediately above the ridp'-s in the mofit 
convex pan of the lH>ne. icnned the parietal eminence, lie«t marked in ymme Imnes, 
and indicating the point where ossification eiiiiimenoed. Of the two divisions on the 
outer surface marked off by the temporal ridpes, the upper i** covered by the scalp. 
and the lower, somewhat striatcii. affords attachnteiit tci the tauporul muucie, Close 
to the iipiKT bonier ami near to the posterior anple is a .small oi>e]iing— the parietal 
foramen- which transmits a vein to the superior sapittal {tnngttudinal) sinus. 

The inner surface is marked with depression*" eorrcsiMindinp lo the cerebral 
ronvohitioTis and hy numerous deep furrow.i, runninff upward^ and bnckivard-i from 
the anterior inferior .inele and the lower border, for Ihe branched' of Ihe middle 
meniiiEi'-al artery. .\ shallow depre&,siuu ruiiniiic close to the superior border forirut, 
with the one of the oppn^iie side, a channel for the superior i^icillal sinUK. at Ihe 
side of which are stiiuil irrepular pit.s for the riicchionian bodies; the pits are usually 
present in adult skulls, hut are best marked in thoweof ohi peiv^oiis. 'Hie marKins 
of the ^oove for the superior sjiRittal siau." give attachment to the fnix cerebri. 

Borders.— The sagittal or superior border, the longest and thickesit. is deeply 
serratfti t-o articulate with the opixjsite paz'ietal. with which it forni.-? the sagittal 
suture. The frontal or anterior border arlit-idalcs with the frontal to lorni the 
coronal suture. It i» d<-»'ply .serratwl mid lii'vellwi. e*> that it is overliippcd by Ihe 
fronliii almve. hut overhif*s the wifre of that Imne Iwlnw. The occipital or posterior 
border ariirulatcs with the oceijiital to form the lambdoid suture, and r^-seriibk^ 
the superitir and imterior in Iirinji markedly serrated. The squamosal or in- 
ferior border i;* divide<l into t}iree portion*; — the anterior, thin .nnd be^elleii. is 
overlapped by the tip of the great wing of the sphenoid ; the middle portion, arehetl 
and al«> lte\'ei]ei], is overlapjfed by the i^tpiamoiis part of Ihe temporal; and the 
ior puriion, tliick and aerrated, articulate? with the mastoid portion of the 
lempond lauie. 

Angles. The frontal or anterior superior^ alitwwt a right anjrle, occupies that 
part of the hone whir!) at l>irlh is memhranous and fornw part of Ihe anterior fon- 
tanelle. The sphenoidal or anterior inferior ancle is thin and prolonced down- 
wanl-^ fo articulate with the tip of the ci^al wing of the sphcnoiii, lis inner surface 
is marked by a deep (imove, .sometimes eoiivertcil into a canal for a short disljinee. 
for the anterior imiiich of the middle ineninEejd arterj*. The occipital or postehor 
superior angle is obtuse and uccufnes that part which during fa-tal life caters into 



THE FRONTAL HONE 



47 



Articulations.— The parietal ariicuUtrfl with the occipital, frontal, sphenoid, 
t«miwral. its fellow of the oppcisile side, and the epipleric bone when present. Occa- 
sionally the to]ii|>orut and epipteric bones exclude the parietal from articulation 
with the [ji'eat wing of tlie splicnoid. 

0«»ific«tion.— The pariotal OMiliM Irom a wngle niideiiii which app^an* in tin- (mfcr layw of 
thi.' tii^'tii)>raiioii!< will! of th<? aktiU nlxtut, lite iwvpiith wcvk. Th«> oenificiicinn radwh-H in eurli n 
vfiiy an to leave a Hoft .it the iippi-r piirt of tht- byne in frunl of Ihe posterior )m(;I«, the cMX of 
Ihe two .lidus tormiug & lozpiigc-^hnpcil space ocnMs rh« fui^ttal suture known an IW sagittal 

FiQ. £6. — Unusual Fonat of PAtttETAi, Kxhibitixo a Horizontal StrrcRR SsrAKATiMo thk 

itoKE tNTO IVo I'UCC«», UpPBB AMP I^WER. 



^' 



m- 



fontanelte. Tlii* is uMiallv dosed atwut the fifth month o( inlrn-utf-riiif life, hut tmwfi nwiv 
FoiiLctiiiii-^ hr mcoKnteed at the time nt hirth, and thr jwirif'tal fonuniii.i iin- li> In- rt'«:ird('d »)» 
rcrnwiiis of the interval. Acrordiiig to Dr. A. W. W. lA-a.n wtrll-dcvflopiHisuKiltiil fontain-Ui- i^t 
pWJienl in IM per cent, of intuntA ut hirth, In surh crsM:» it olnwn n-itlim the tirBi ^■wn moniha 
of lifr. Iitit lit [lEiics it iniiv rcnuun open for nt letwt vi^ht inuiilhn nfler liirlFi luid jHuoilaly loiiKi.*''. 
Itiircly tin' punrtid ln'iie i» roinjwtvd of two pienw ffiif. 5fi>. out- aliove \hf otln-r, aiicl 
Mparnrfd Uy i\n .tntero-|)03tefior sulure {Kiih-MKit'Al »iiti)rt.->. ntorc or Ir-ju paralli^l with the 
■agittid Miture. In Huch ciu«! lh<; pariftiil u owalifd from two c«nlre« of otiiiificattoa. 



THE FROXTAL 

The frontal bone closes the cranium in fr^mt and is situated alxive the skeleton 
of the face. It (•(uusist-s of two portions— n frontal (rertirnl) portion, foniun? the 
convexity of the forelicjul, ant! an orbital [borizoniut) portion, which enters into 
formalion of the rrujf of the orbit*. 

Frontal (vtrlical) portion. — 'Hie external surface is smooth and convex, and 
usually prft^eiits in the middle line hImivc the niot of ilic none some traces of the 
KUturc which in youiifr subjects traverses the bone frt>m the upixrlo the lower pan. 
Tlie suture, known as the frontal or metopic suture, indicalea the line of junction 
of the two liiter.ll halves of which the lione consL-rts at. the time of birth; in the adult 
the suture is usually (iblitcni(e«J except at it* lowest part. On each side is a rounded 
elevation, the frontal eminence, very prominent in young bones. Ijelow which is a 
shallow (rroove, the sulcus transversus, separating the frontal lanLnence from 
the superciliary arch. The liUler forma an .irch«l prtijection alK)vc the margin 
of the orbit and corresponds to an air-cavity within the bone known na the frontal 
sinus; it Rives attachment to the orhicuhritt ocuH (o. pnlpthraruwi) and the 
c^aruqtii'nr sripfrcUii. The nd^es of the two sides converge townnls the median 
line, but are separated by a smooth surface called the glabella or nasal eminence. 



4» 



THE SKKLKTOX 



licluw the arrh the bonr presents a tihurp rurvtvl nmreln, the supra-orbital 
border, forming the upper hniindnry of the circumference of the orl>it ;inil 
separating t}ie fnnital frrnii t-he ori)ilnl portion of the iKJrie. At (he junction of 
it6 internal and middle third is i\ iiolch. somefimes coiivLTted into u fonkiiicii. 
ami known a.« the supra-orbital notch or foramen; it tran.«iniU Uio KUpr;i-orl>ilui 
nerve, anerj-. ami vrin. iiiiii n( the Uitiom i)t' llii; notch is u. smiifl ojienin^ 
for a vein of the diploe which tennitiiilep in the supni-orljilal. S(»mrtiiiies, a 
second Iws marked notch i» prevent, Internal to the supra-orbital, and known 
as the frontal notch (lienle); it transmits one of the divisions of the supra- 
orbital nerve. The extremities of the ;*upra-^>rbit!i! tjorder are directed downwards 
and form the internal Mid external angular processes. The cxteniai. Ktrong 
and very prominent, iti-tieulates with the zvgoinatie lione mid rcrt-ive? superiorlv 
two well-marked liitf--* whi<*h converKP w»[iiewluit as they curve (iownwnrds and for- 
wartb across the lione. These are the superior and inferior temporal ridges, 
contimimis with the temporal ridges on the pjirietal Imne. (he upjier nivinii aHjifli- 
nienL to the temporal faseja and the lower to the tein]>firal muj'i.-Ie. Heliind the 
hilges is a slight (x>nravily which fonnsi part of the wall of the tenipond fossa and 
gives origin to the temporal muscle. The internal angular processes articidate with 

FiQ. JI7.— TwB Fkostai.. (Anterior view.) 



ii 



■MINtMCC 



-^ ; 



.tUnittC RIDQE 



07EN1X. IHIiUUUl 

Ttuxm 



miniMl UGUUR fWOU 



tnoilltt. BRNI 



the Inchrymaln and form the lateral Unfits of the nasal notch, hoinidei-1 in front b\' 
a rough, semilunar ^iirfare which ailirulates with the upper Mifis of the nasal hones 
and the frontal <na>.n]| pn»eesse» of the niaxilh-t-. In the coneJivity of llie notch lies 
the nasal portion of llie frontal, which projeclM somewhat benejdh the iia.<ttl hones 
and the nasal processes of the mii\illfl>. It is divisible into three jwirts: — u me<iian 
frontal (na^^l) spine, which de^cendif in the na^nl septum Ijutween tiie erest of the 
na/ial iHiutti in front and the vertical plale of the ethmoid iiehind. and. on tlie {hm- 
terior asiieei of the procestt. two alee, one on either Ride of the metljan ridge fn>m 
whieh the frontal (nasal) «pine ii* continuerl. Kach ala forms a small grortvwl sur- 
fnee which entei-s into the fonnntion of Ihe nvif of the nasal fossa, 

The internal surface presents in the middle line a ^■e^ti^:al groove — the sagittal 
sulcus— whieh descemls from t lie middle of I he upper miirein iuid Imlces I he siiiKrior 
KMgii.tal flongiiiuliiud) niiius. IliJow. ilie gniove is suec:ee<U^l hy the frontal crest, 
whieh terminates near t he lower margin at a small not ch . c*)tivi>rl tsl into a foramen 
by articulation with ihe ethmoid. It is called the foramen crecum.and isgcnornlly 
closed l»elow, hut wimetinies transmits a vein from the nasal fossa- to the superior 
Mfcilttil (lotigitndinal) j^inus. Tlic frcmtal crest serves for the nttachinent of the 



THE FRONTAL BO.\K 



49 



anterior \ysiTi of the falx cprchri. Orx each side of the middle line the bone i^dwply 
concavc. preacntinp tIepro«(ti»m« for tlie cerebral convolutiong ami numerrjus smnll 
■furrows which, ruiitiinc iinvanlH from th« lalt-ral mai^in. Iwicc braiivhw of tlie 
inkliili? iiieninneiil vessels. At the uj>i*er part of the surface, on either skic of the 
frontal sulcus, aro miiiK' i]r[>rft»i*ioiiw for I'arrhionian iMHliw. 

Tlu* horizontal portion coH-alRts of two somewhat trianKular plates of Ixino 
califd the- orbital plates, which. soparat«i fmni onfi Htirithpr by the ethmoidal 
notch, form tlie srcater part of the roof of each orbit, ^^■hen the bontrs ai-c articu- 
lated, the notch is filled up by tlie cribriforui plale of the ethmoid, atid the half-cells 



^^K uiicuLiTiDii %nn wu- 

^^H MIiSUl4l'(Jli WitH 

^^H mcnKrioi. 

r 



Fta. 68. — Thb Feoktai. Bone. Uafcrior view) 



,^^Z. 



UMiNt nrKHOJI 

u»(<i mis OF 



INbMIIAI tOlU 



UOIinHtl. K)tU 



OnilU. lURfKI 



tnuoiou MTOi 



on the up[)or surface of the lateral majw of (he ethmoitl are completed by the dejjres- 
Nons or half-eelM which ocTUpy the irrc^ul:ir nuirpiiis of the notch. Traversing 
thtwe edpcs trannversply arc two grooves which complete, with (lie cllnnoi<l. the 
anterior ami posterior ethmoidal canals. The anterior transmits the umerior 
ethmoidal nerve and vesftcis; the |M)8tenor transniitj^ (he fKisterior cthmoidol ner\-e 
and vowsHs. and l>oth canals open on the iiiuer wall of Die orbit . Farther forward.-*, 
on «ther wde of the nasal spine, are the openinpa of the frontal sinuses, two irregular 
cavities whicfi extend within the lione for a varialtle distance and ijivo rise to the 
superciliary arches. Kach i.s linwl liy mucous nipmlininc and wiininunicatcs with 
the naHid ^is.-^ by means of a fiassage called the infundibulum. 

Fk;. 50.— The FnoNTAL Bonk at Bihtm. 




The inferior surface of each orbital plate, smooth and concave, presenta 
inmiediatdy Ijehital the externa! ancular proccaa the lachrymal fossa, for the lach- 
ryiiiai claiul. Close to the int^^mal aneular process Li a depression ndlul the 
trochlear fossa, which pivrs attachment (o the cftrtilajrinouii pulley for the supirinr 
oblifiii tTinsr\e. Tlie superior surface of each plate h convex and slronnly marked 
bj- eminences an<l deprewions for the convolutions on tlie orbital surface of the 
cerebrum. 

Borders. — The articular Ixinler of the frontal portion forms a little more than 
a semicircle. It is thick, strongly serrated, and bevdlrd so aa to overlap tho parietal 



so 



THE SKHLKTON 



ahryvc and to be o\-erlapp«l by the edpe of thut bone below. The border is con- 
tinued inferiorly into a trianpular rouj;ii surface im cilhi-r side, which ^rticululPii 
with the great vvitiR of the sphenoid. Tlie posterior border of the orbital portion 
is thin Hnd urticutatvd with the ledger wini; of the sphenoid. 

The blood-^-essels for 1 he sup|>ly of the vertical portion art dei'Ived fmm the frntitHl 
and BUi)ni-orbiial arlenes. wliich enter on the oiitei' surface, and fn>m the middle 
and small uieiiiri^rt^iil, which enter on lln: eereliral surfiiet;. 'llie horizontal portion 
receives bninrlies from the elhnioidal, luid other bnuichta of the oiililhiihnic, as well 
as from the meninKeiJ. 

Articulations. — T\^e frontal Articulates i*iih the |>arielftl, Bphenoid. ethmoid, 
lachrymal, zyfEoniatic (malar), niMxilla, and najtJtl bones, AIsr>. -uith the epipteric 
iKines when present, and occasionally with the hqimmous portion of the temjwral, 
and with the Hplufnnidnl coneha when it reaches the orbit. 

Ouificatioa, — Tlic fnmtsl U OwiifJMl fruiii tvro miclii (lfr»<;H«it4'(l in tlir outer layer of tjie 
membruuuLU! wall of tlto cnuiJum, in the nituiilioiui ultinuirt:ly kiioMii lui tLu fruutd L^niiiicticee. 

t'lo. 6(1— rxusuAfcLV L.UIGE Fkosttal Sinfreh. 



M 



is^-ar 



These oucltfi aiinmr alioiit the eighth wtflv, tint) onsifimiinn Pon-jMlf »|iiifldy ihmuk'li tli'' itinii- 
hnine. At tiirth Ihc honc-t nrc ([iiile distirirt. I>ut (Mil>«'qiiMilly ihi-v Hrliciiliilc wilji cac-U nrlior 
in Om iiuttiiti) liitr to form l}ii> inftopji' >uturv. bi thi- riiiijuiity uf rrtM-e llii^ viitiirv U iibliUT- 
ated by cw<i-ou» union, wliidi {.-uinnifacc-j alwut tb« Mtxrnd yi-iir, UioukL iii u fvn L'oeve ifav 
boucM rrm-niii ilixtirtd. thniiighiitil lifn. 

ATtrr tlK- In'u hiibt^ i>( ihi; liotic- linvt; united, oi»i>ous mnlcrio] i» il*>pu8tt«il at (be lower 
end o( th** mi^rttpic sulur? Ui fimn the frnntal ^pin*. whirh ia one of llic dblinguishinf: foMliiros 
itf tin- liiliti.-ici I'nmtiil liuiir. The- jtpitin iipju-iir^ .itioiit tin- ttvi-l!l)i yvar, .•iikI jkihii rt>tii«tliil;ilr.« 
Willi tlw friHiliil lnirK- !iIm>vc. Al.■c^■^^aJ^y iiucli-i iiru trOtiiptmir« jwtn bi-twivii lliis buiic and Ok* 
Inchrvmal and inhv pt^i^i.tl. lu Wrtniiiiiii o^.'^iclf^. 

'rhi; frontal .niiuwr?" apjM'nr iilnn;! lIic «-vcnlh yi'HrriMpmloitKntioiiMiipwnixltirnHii thr tiiadi.-t 
itemiJiinariti nnil incri'iiM' itt :<inc up in <i1<l ai:e. .\s rlivy utotk tlicy cxiviid in t]iri-<- (liiavtiou-i. 
vit., upvritnU. nntwardft, nnil bnrku-tinU iilnri; iho orWital roof. A bony M-ptiini, ui>MBlb' 
mmplele. w^ran-n ttu? .HiniiM-?! nf tlic twii nkli^, and (hry nn- UrKer in Uh- rnaiB tliau in th»? 
female. The !»i(»TciIiarv :in-hw an; not nlloKfthri n.<lialilr Kiiid'-si as lo Ih* tuv of lh» 
i>imfa«9. sinw c\aiiipl™ are ntnm in whlrli the orchw an- low itnil rh<^ mhiimw lai-Ri^. In fig. (10 
«n e\ample of iinu>iinl!y larpt siniwca is fiRiiml, illu.ttratin(r the ^xu-naioii upwards, out- 
wards, Mid iMLckwurda. 



THK SPHEXOin 

The sphenoid is situated in the base of tlie skull and lakes [wirl in the formation 
of the iloor ni !ho anterior, middle, and [Histerictr cnitiial for^a*. nf llie temporal an<.l 
nanal fo",-;!*. and of Ilie caWty of the orbit. It is vvt\- irregular in shaiw and is 
drscribol :kt ronsi.stiti(; nf a central part, or body, two pairs of laltral e\|>ansioni* 
called the great Am] small wings, and a pair of processes which project down- 
wardly, ca|k-«l the pterygoid processes. 



THE SPHKSOtO 



fil 



Tlic body, irregularly cuboidal in shape, is hollowed out into two Innre cavities 
known as the sphenoidal sinuses, sepdrntct] by a thin sphenoidal septum ;ind 
oiwiiins in front by two large apertures xnMt the nasal iot^a-. Tlic superior sur- 
face (nT^>nts thp followint: [xiiiitf^ for extuiiiuatioii: Iti fntiil. iin seen u proniirit'nt 
spine, the ethmoidal spine, which urticuhites witli the hinder ttipe of the criliriform 
plate (if llip- cihnioi.i. Tiio surfa<H; lj*;liin(l thirf \a smooth and frciiuenlly prtvrnts 
two lonptudiiml (jrooves. one on either side of the nK-fiiim line, fur the olfactory 
hulbe; it is Uniit*^ ]Njfflt'riorly by a rid^c. the limbus sphenoidalis, wlucli forina 
the anterior border of the narrow transverse optic groove (sukus ehiastuotis), alwve 
and lH?hind which lies theojKio eonnnji^ure. Tlie gi'oovc tenninute» on each side in 
the optic foramen, which [ierforutes the natt of the mnall winji and transmits the 
optic nen'C ami the ophthalmic arten-. lichind thu optic grcHtve i^ the tuberculum 
sellte, indicating the line of junction of the two partf) of which the 1>o«ly is 
fnrinci (\^n'- and [xwl-spheuoitl) ; and still further back, a deep depression, liie 
hypophyseal fossa (^-lia turcica), which lodpeti the hypophysis cerebri. 'lliO 
fifwr of (lie fossa presents numerous foramina for b!ood-ve„'weIs. and :it liirth 
the superior orituie f)f :i narrow passage ealWI the bast- pharyngeal canal. 
The posterior IxMindari- of the fossa is fonmvi by a quiulrilateral plate nf 
bone, the dorsum sella or dorsum epbippii, the posterior surface of which is 



tarn, amo 



/ 



Fio. 61. — Thr BrHENoiD, rnou Abuvk. 

omc cwoic iTHHOiou tmt 

ivwKuuiK ituA ivmiM vtBini nawit 
rwuMta 









. f: 



1-, I 'Al 



.fHMU ItWJI 



cusno auavE ' 
PDtnson nnvBiL mecut 



MMUMIQK 

roCTWOR cuNoiD noeui 



(OMIlU VWU 

- HlUtla WINMnH 



IWMU 



slopeil in coutinualion with the basilar p'oove of fliu oeripilal I>one. The au- 
perior angles of the plate are siirmount«l by the posterior clinoid processes, 
which give attaeluneni m the tentorium eerela-lli an<i (he inierdinoid liga- 
inent«. Melow the elinoid pntce^. on each side of the dopNuni sells' (9ontttina» 
at the suture l>etwwn llie sphenoid and apex of [ictrosal), a notch is seen, couvfrteil 
into a fornnien by the dura iiiater. ftir \\w fvt-^ine nf the sixth cnmial nerve, and 
at the inft-rior an^le (he posterior petrosal process, which nrticuliues with the aj>ex 
of the |»-iMii.s jx)rti(H) of the teniponil Vwne. forminpthe inner luiutulnr^'of the fora- 
men lacerum. The dorsum sclhe Is slightly concave posteriorly (the clivus) uud 
BUi)ports the |K)nA Varolii anrl the lifwilar arterv*. 

The inferior surface present* in the niiildle line a prominent ridge known as 
the rostrum, which is received inio a deep depre^on between the ahe of the vonirr. 
On ea«'h side is thu vaginal process of the inlernfit pterygoid plat*-, (lin'cied httri- 
zontally inwanls, and with the iiUe of the vomer, nivcring the grejiter part of iht 
surfaw. The remainder is rough and clothed by the mucoufi membrane of the roof 
of the pharynx. 

Tlie anterior surface is di\-i'KI into two lateral lialvt^ by the sphenoidal 
crest, a verticrtl rndj;e of Ume confinuoite above with the etiimoidai Piiine. beloiv 
with the ro*truin. an<( iirticulaiiitc in frmt with the periH-iidicnlar plate of ihe 
ethmoid. The surface on eacli Ride prceouta a rough lateral margin for artirulo- 



52 



THE SKEL£:TO:<f 



tion with the lateral mnss nf the cthrooiH and the orbital proocRs of thp palate bone. 
Klwwherc it is smooth, and rnl<T9 into the formation of the roof of the nasal fossje, 
presentinjE Buperiorly the irreg:ular apertures of the si^enoidal sinuses. Th^ body 
is not hollowed until after the sixth year. Imt imm that time the sinuses inci-ease 
in h]ze an iwje advances. l-Ixcept for the apertures just mentioned, thev are closed 
below ami in front by the two sphenoidal conch« (turbinate Ijoneft), originally 
distinct, Imt in the adult usubIIv incorixtriited wilh the sphenoid. 

The posterior surface is unitwi to the IwiKiiar process of ihc occi|ntal, up to 

Fig. 62.— The Lr.rr Haij' or fira SAenoid. 



Umlm CtWDII MDCEH 
lUOPlI nUNDIP 'Null 

poiTiiwit olinoib noetas 



ErMMailHl SfME 
.THE IIMBVt 

luitAcuiLju inijt 

BDItSUU SItLI 
' FOR ODCIPITU 



•mt Of •muotD ■ 

ECTCM'iL mitWIO KlTt 
HMUUR FMOEN OT mCEMU. FTIHTSOia fuTi . 



the twentieth year, by a disc of hyaline cartilaji;e forming a fi>'nehondra*i«. but 
afterwards this becomes ossified and the two Iwnes then fonn one pief^c. 

TliL' lateral surface of the body ^ve^ attudnnent to the two wiugci, and its 
fore pan is free where it forms Uie inner Ixmmlary of the sujKTior orbital ti.ssure ami 
the [Kiistmor part of the inner wall of the orbit. Above rlie line of allachmenl of 
the great wing is a broad groove wliirh lodges the inieniiil carotid urinrv and ihe 
cavcmouj^ sinus, called the carotid ni- cavernous groove. It is deepest where 
it curves behind the root of the process, and this part is bounded along ilii outor 

Fin. 03.— The Sphenoid. (Antorior view.) 



MHIM. WUUiOt <Ttie M«T 

ooMu mi moHtDC nHam 



nr. nticruiarun. 



rmaoiiMTcii. 

tlMIUI.UI niDHM . 



Omo RNUVPI 



SUKMM OMlTIt^ 

nuuM 



dMlHEO KdruDMH 

-mnrMwcuu 



pitDao-riuTmE Mootrt 



margin by a elender ridge of bone named Ihe lingula, which projects backwards 
in the angle between (he body and thp great wirip. 

Tlie small or orbital wiogs are two thin, triangular plates of kine extending 
nearly horizontally outwani? on a level with the front piiD. of the upper surface of 
the body. Kach arisf-s imeniftHy by two proccsees or inots, the upixr thin and 
ilrtt, the lower thit-k and rouniled. Near the junction of the lower r<x>t ^ntli the 
body isasmall tubercle for the attachment of the common tendon of three ocular 
muscles — viz., the superior, itUemat, and upper head of i^tirunt netua — and between 



THE SPUICSOID 



53 



the two nmis u> t)ic optic foramen. Tlio outer extremity, sleiiiler and pointed, Bp- 
proachea the greut wing, but.aa h rule, <ioes not actually touch it. The RUpcrior 
jiurface, smooth and sliphtly conrave, forms the posterior jmrt of the anterior fossa of 
the criinium. The inferior surfHco constitutes a iw>rtion of the roof of each orbit 
nnd overhant^ the superior orbital or spheaoidal 6ssure, the elongated openint; 
between the small and great wines. Tlie anterior bcu-der is serruted for aniculmion 
with the orbital plate of the Ironial. and the poKtertor bonier, tiniiioth ami njundal, 
Ifi received iau> llio Sylvian litwvir*! uf liic oercbruni. Moreover, the posterior bonier 
fortiiH the boundary between the anterior and middle eraniul fossir and is prolonj^od 
at its inner extremity to fomi ihe anterior cUnoid process, which gives attflcbriiont 
to the tentorium ccrebrlli lind the interclinoid ligaments, Between the tuljerculum 
sella? and the anterior cHiioid process is a RCimcircular notch wliich represents the 
termination of the carotid groove. It is sometimes converted into a fonmien, Ihe 
carotico-cliaoid forameQ, by n s]>ieu|e of Ijone which brid^ir» across from the 
anterior cliiuiiii to the middle clinoid process; the hitter Is a .'«mall tubercle fre- 
quently sr-en on each side, in front of the hyp<^physeal fossa, and slightly posterior lo 
Inc liilMirculum sell.T; the fnranien transniitn the Internal carotid aricr*', and the 
spicule of l»one which may complete the loramcn ia fonned by oHHificatioii of the 
camlico-ulinoid ligament. 

The great or temporal wings, arising from ihe lateral surface of the body, 
extend outwards, and then upwitnls and forwards. Tlie posterior part is placed 
horizontjilly and projects backwords into the angle lietwoen the squamous and 



Fio. «.— Right IUi* of SrnENoiD. iAnterku- vidvr.) 




TwnMu. wwiioi 



•BH MMH rOtIM TKE WHU 

MUNDMT OF THt itFemOR OR- 

nib pidrntotd amael* 



nitinffi 




SNOlOIBU. SNVl 



petrous p(*rtioii8 of the temporal )xme. Fnmi the under iL?peet of its pointed 
extremity the spine projects downwards; this is grooved internally by the ehonla 
tj-miw-ni nerve (J/Uca»): it serves for the nttttchment of the sphcno-mandibuUr 
ligament and a few fibres of the tcn»or jtaluti. Kacb wing prcgenl.8 for examination 
four Hurfatnx nn<i fmir lx>n!eiv. 

Tlie cerebral nr superior surface is Hmoolli aiHl concave. It enters into the 
formation i)f the middle criiniul fussa, supports the teni|Kjri>-sphennidal lobe of the 
cerebnini. and pro-'aent.'^ several fnraminii. .\t the imterior and intenial parts is the 
foramen rotundum for the secr>inr division of the fifth nerve, and behind and 
external to this, near the [xistenor margin of the great wing, is the large foramen 
ovale, tnmHmittin^ Ihe thint divi>)tonnf the lifth. the small nieiuogeal Hrter^.aiid un 
emissary vein from the cavemoun f^tnus. Hehind and external to (be foramen ovale 
in the smidl circular foramen spinosum, sonietimes ineompleto. for the jiaasage of 
the middle meninneal vesM-ls, and the i-ecurrent branch of the third division of the 
fifth. Bftwecii the foramen ovate and (he fonimen nitundum is the inconstant 
foramen Vesalii, which transmiti! a umall emissary vein from the cavernous sinus: 
and on I lie plate of bone, behltid and internal to the foramen ovale (i^jjheno- petrosal 
lamina), a minute canal is occasionHlly seon— the canaliculus innominatus — 
through which the snxall supertictal peirasid ner\-e e-seapes from the skull. When 
the earuUicuiuK i« alxfcnt. the nerve |>n68cs through the fonunen ovale. 

Tlie anterior surface looks inwiu^ and forwards and consists of two divisions — 
a quadrilateral or orbital [Hirlion. which forms the chief part of the outer wall of 



54 



THE SKELETON 



thL> orbit, and a smaller, inferior or spheno-mazillary [Kirtion, tiituactxi iiIkivc the 
pterygoid inTocL-sa ami pcrforot«l by iht- fommon nimndum; the latter parr fonntt 
tlie jx>slPrior wall (if thf ptrrk'j;<v]itiIiitiiio f.i.-w;i. 

The external i>r squamo- zygomatic surface is dividwi by a prominent infra- 
temporai ridge into ii sujK^rior fiortion. fthtcb forms part of the temporal foesa and 
;Lllords jilinrliiuent li> tin? triiijMfral muscle, and an inferior pari, Mlii{:li \nuUs ilnwii- 
ttiirdsinto Xhv zypomnUi- fosataTnl givrtjiilliirhiru'iit iti l\tv rjicrinil ptrrifijofd muscle; 
rhe latter is continuous with ihe outer surfaee of the cxteriiiii ])tcryg(>icl plate, and 
presents the inferior orifices of the foramen ovule, foramen spinosum, and foramen 

of VftMlliU!*. 

Borders.— The posterior border extends from the body to the spine. By its 
outer third it articulate^ with tiie petrous i>orliim of the tempnral Imiie. whilct Ihc 
inner two-thinlB form the uiiteriur UiuinUiry of Ihe foraim-Ti Ificerum. Tlu- external 
border is sfTmted beliind and lievelled in front for ailiculatiiwi with the s(|U:jmnus 
portion of the temporni lionc. whilst its upper extrrmity. or summit, is bevelled on 
its inmT iu-i>Cft. for tlie anterior inferior angle of the pntietal. Inuiit-diiitely in 
front of the upper extremity is a rough, trianguliir. sutural area for the frontal, the 
sides of whieh jin* funned by tlieupjipr inar(t'm»iof thesu]K'rior. atilfrior, and ext4'rtijil 
surfaces respectively. The zygomatic or anterior border separates the orbital 
ami temporal surfaocs and articulates with the zygomatic, and by iti* lower angle, in 
many skulls, also with the maxilla. Below the anterior iitirder is a short Imrizontal 
ridge, non- articular, which separates the sphem>-niaxillary and zygi>:iiatic surfaces. 
Above niul intenisdly. where the orbital iind ceix;bnd surfaees meet. i.s the ^liarp 
interna] border, wliicli forms the li>ner tuiuiulary of the superior orbital fissure, 
ser\'ing for the passage of the third, fourth, thrw branches* of the first division of the 
fifth, and the sixth cranial nerves, (he orbital bnuieb of the middle meningeal arten-, 
A recurrent branch from the lachrymal arterj-, some twigs from the cavernous plexus 
of the sympathetic, luid one or two ophthalmic veins. Near the iniddleof the border 
is a small tubercle for the origin of the lower haul of the cxltrnal rectus muscle. 

Tin? pterygoid processes |>rojeei. down«anls from the junction of thf: iMnly and 
the pi-eiit winss. Each consist.-^ of two plate-s. one shorter and broader, the external 
pterygoid plate, the niher longer and narr<>wer, tlic internal pterygoid plate. 
Tliev are united in front, but diverge Ijeliind so as to enrlose between ibem the 
pterygoid fossa in which lie (he iiiU-rnal i<Unnjmd iind Unxor jjtiluli nuwelejf. The 
external pterysitiid plnte is tuniol a little oulwardw and by tl.-i outer .^urface, which 
looks into the ngtirnatic fossa. alTonin attachment to the rjrtcrnnl j)tfrt/rjni(f muscle, 
whilst from its inner surface the intertuil j/trrt/goid takes origin. The posterior 
border fre<|uently presentti one or more Ixmy projections, which rcpresicnt ossified 
partK of the pterygu-spinua^ ligaments, and occsii-ionally one may extend aejx>e« Lo 
the spine and eotuplete the Uniy Ixiuiidary of Ihe pterygo-s]»inuu.s foramen. The 
interna] plcrjgojd plate is piolonged below into a slender, hnok-iike or hamular 
process, smtKtth on the under a.vpeci, for the tendon cif llie tnijuir jmlali. which playw 
round it. ,Sui>erior!y. the internal pl.ife extend.? inwards on the under ^urfaec of 
the body, forming the vagtnal process, which ari-iruhites with Ihe ala of the vomer 
auil the sphenoidal prc»ce»f of the palate. The vagina] process presente. on the 
under surf aiv. a ^niall gnHive which, wilb (he sphenoidal prtM^-«i of the palate, foniw 
the pharyngeal canal for the tmnsmi!<sion of branches of the apheno-jMilatine 
vessels and ganglion, The inner surface of the internal pter\'goid plate 
fonnx |»arl ()f the outer I>oundar>- of the n.-wal io-^n. and Ilie outer surface, (he 
inner lx>und«ry of the ptcr>"goi<l fo-;!;ii. The |K>f-terior border |;]f:sents su|>eriorly 
K well-niark«l pmminenec. the pterygoid tubercle, al>o\e and to the outer fide of 
which is the pnfierior orifiw of the pterygoid canal. The latter i)terccK the Ixine 
in the sagittal direction at the root of the internal pten-goid plate and transmits 
the Vidian vr«iols and nerve. Some dbstance below the tubercle is a projection, 
called the processus tubarius, which supports the caililagc of the tuba auditiva 
{Ivustaohiaii tul)e). I'"rom the liwer thini of the jjosterior border and from the 
hamular profiv.". the HHjuTior rotiftrivfur of the phar>nx takes origin, and from the 
depression knoun ;lh ihe scaphoid fossa, siluatwl in the ujiper |«ui of the reei-ss 
between the two pterygoid |)lale!*. the truxirr /*ff/«/i* arises. 

Tn fMnf. the two jilato* are joine<i atxjve. btit iliverge below, lcfl%-ing a gap — 
the pterygoid notch— <iccupied, in ilie .'irticulate(l ttkuU, by (he pyramidal process 
of the palate. cJujH'rinrly, thev form i< in:iiiir.ilnr surface which looks into tho 



THR .SPIIKNOH) 



!>!} 



atcrj'po-palattne fossa and pre«ciit.s the nntcnor orifice of the pten-poid cimoi. Ilie 
interior bonier of tlie inwmal ptcry(i5oid plate articulates uitli thp posterior border 
>f the vertical plate of the palate. 

The sphenoid is supplied by branches of the middle and small nieriinjiea] arteries, 
'the deep temporal and other Itraiichw of the iDtenial uiu\illur>' nrtcry — viz., the 

Fio. 85.— Tub SriiKNoip at Pirth. 



\-v% 



rtixium c*iui uhuu 

Vidian and sphcno-palatine. The bo<ly of the lx>nc also receives Iwigs from the 
lintemal carotid. 

Articulations,— The sphenoid articulalejf with all the Ikuigs nf (he cniniuni 
-\iz., f>rcipit:il. pnrietn). frontal, ethmoid, teniporul, and sphenoidal turbinate. 
[AUii with tlio palate, vomer, z^'gomacic, Gpi[>leric ixino wlieii present, and oceasion- 
Jly with the maxilla. 

Flo. 66. — ^Thk Ji'npw fl^HKxniDALB. 



OBaificatfoo.^Thp Bphennid i^ divided, up to tho sj^vt-nth or fijtht.h mouth of iiitra-tilcrine 
life, in'o lui inil^Tior or pre-»phenoid iH>rf uni, itn'ludtriu fla- part of the liodv Jii froiilof tin; tiilc 
prculuiii ricWip and the small winirp, aim n po»t-sphenoid portion, llic part behind the luWrculmn 
Sf>JUf iricludiiix the wlla t)in-tc» Ami tlic iiTvn.1 wingB. Vhv two ))orttona of the bcKly Join to- 
gether lipforv liirlti, hill iti niiiriy xniiiialt ihi- ilivision is pcrsislvnl ihroUfihoMl life. 

The piv-sjihr'iHiiit portion oiwifif^ in rartilitcc (nun four wnlrw. one of which gives rlw to 
each l<is*cr winft (orblto-sphenoid^ juiri a [wir lo thtr hody of tin- pn-nphcmoiil. 

Fio. 67.— The rxDER ScKPAf-E nF PKR-sraRNoin at tiik Sixth Veab. 



I«J|U KINt 



aim fmi%a 



nC-ITHBIIM 



rmnos-Mumi goon 



■vJ 






In (1u» rortii!itto» r)f the post-pphrnoidnl ifortion Iwtli c.-.trllliuic and nn'iuhnitio l»OfU' pnr- 

tkinatfi, the |H'r>iroi(l ptaics ttriiiK forini'd in mf^mlmini*. whik rhc r^^l of the [>iirliori, loet'ihf^r 

,ffttn thf li.tniul:ir |troi>-^«t, ivmUii^ fniin i-:irtil:trt'. fKimn-tl,! At .tI«>iiI Ihc cii^lilh wwk 

centrv HpiHvirn nt ihe lnwi* of ••acU [{n.-iii<'r wiiiy (ali-sphenoid'), and hI alxmi IIk- mitic linn; 

pair of cmtrp.^ appear 'in the hoiiy ibasi-sphonoidi and tatiTonp in ^nvh hnciilji iBphenotic], 

tThc internal pttrvfroiil pinteo an- pn'-fornnii m i-MrlilaKr, In whirh a crntn- itpjH^arx for thr ham* 

luUir pn>c«<w, but tlu> re»t of Ute pUlv a fonned from iu«iubnti)v iKinr- which ii)ve«t» tliv ear- 



sa 



THE SKELETON 



UUge. The external plat« is toimtd in mcmhrAnc and the anterior mtpcrior angle of the 
ftreaUr wina is also prohabtv memUmnotis tii origin (■oi' i-jiiptiTir boiic). 

At birth tlic hnnv e'>n--Uis ot tliroejiiwvs. _T)H*nindi:iii pJwe includes thuba.M-'<iihciioid and 
iingulAT. conjoircd witli llic pre-sphonoiil, nirryjiig thfi orhiui-ripliendiii.'*. 

The two iHtomI pierrn urc itia ah-T(phctioKl», c-irryiu;c Mm iut.niul pN-rvjtwI pl.iti>fi. The 
dcKBum EdlUe is cortiuiutnoii^. A cimnl, kiiuwii an iIil- bau-pharyDK««l caoa), •■\(vnili! iuto tlie 
body from the fttlU turcic.i hihI soinctiniejt ro/ichw ils unch-r surfiicc. It mntnins u procr-w 
of (iur» tn»li^r, itnd rrprTv4rtit» llir n'trmiiiH of tlip rtiiml it) thi- haxe of thr crHiiiiiin, t.lui»ti|cli 
which ihc divgrticuluni of l^lthk« cxlrtidcil iipwunhi to form i>i»rt of thu hypophysiB. 

The great wingii atv joiiknI to the linK;u1ii> hy ciiriilneo. lint in th« coiir-w of tlio firet y«ir 
borv iiiiion l:iki<9 pt;ic*t. Altmil, (hi-n.-irrif timr lln" ftrl>itit-jinhrniitiU ini-«-t. .ind fMsr in Ihc iniil- 
dk line >o f'jnii thf juRum splienoidale, whk'li th>w cxi-liidi.'* thoiuilcnor purtnf tin: pTi-splu-noid 
fmni tlic criuiitvl wiviiy. tor stomc ywint the bodj' of the pre-sphenoicl is broiul nnti rounded 
inf«riorly ttlg. tt7J. 

THE SPHENOIDAL COXCH.E 

T\w sphenoidal conchte or sphenoidal turbinate bones (boncsof B*?rtin) maj 
be obtain(^i as itistinci ossicKs nbcmt Ihi- fiftli ycjir. ami rc-si'mhlr in shape two hollow' 
conw flatteiK^i in three planes. At this date each is wedf^ed in between the under 
surfaee of the pre-fiiliwioitl find the urbilal and n|)hfnoidal procetwes of the palate 
buiie. with the apex of the cone flin-eted backwards as far as tbe vaginal proee.ss of 
the internal pteryp)i(l plate. Of it« thn*e siirfariw, tim outer in hi reiaticm with 
the pterygo-palatiue fossa, and occasionally extends upwards between the sphenoid 

Pta. OS.— Tbk Sphrxoidil CorfcHA at thb Sixth Y&vr. 



and the lamina papyraeea of the ethmoid, (o appear on the inner wall of the orbit (fig. 
S7). The inferiin- .surfaw forms the upper boundar;' of the sph<aio-pBlatinc foramen 
and enters into formation of the posterior part of the nwf of the nasal foesa, 'ITie 
Bupc^rior surface lies flattened against the under surface of the pre-sphenoid, whilst 
the Ijaseof the cone is in contact with the lateral nia,s.s of thp ethmoid. 

The depoails of mrthy ■natt'fj' frotn whieh the sphmoidtil turi)iaete bonea am formed ap- 
peur »t Ihv fifth month. At birlh euch funua :> iiiii:i1l Innniculoi' Inniiiin in the perichuiidriuiu 
of (hp c'luiiu-voiiiiTiun pluUr ni-Jir its juniriion with iIm^ nr»>|)l)i-ni»Iii, aiid pnrtlulU' ciirlusc^ 
k sniAll rt'ct-M Iwini thii mucoiu nicmlimne of thi; not*, whicb iH-*-oin«i the sphenoidal sinim. 
By thi; third yvMr ttte lioiia hiut «urTuuiidrd thv ainuit, fortiiiiiK "n osseous cnpsulv, cuidcid in 

Fto. 69. — Tna Si^exoidal Coscnx ntoM ak Old Skdix. 



^st^:- 



mmoiMi coiiou 



■Mnini OF Bntooit 



8hi»p<-. the rircnlur oritipc which n^iHi«it<i tiic U-.im- lM-«>mlnE the sphentddnl fornmen. A? 
the wivity •■(ilni'uiii lh«' nuiii;iii wi»ll l-. :ili»jr)M:(l. «> thwl Iht- inni-r ivfiit of Ihi- »iiiti« in rvt'titiinllv 

(OTit""' *" " ■■ "' ••■' >til. 'n»L' iiiiliiiuiii' bone* un? H>ili-i>.|ii..'otly iiiikyluR«] in munv skulfs 

wird . (• ihpy .'in* oflt'ii niKsinliMl a.^ pari--* of ihsit lK>n»;. Mort- frequcinlv tlwy 

fm" iJd, [ind Xeas fri^)uciit]v with Iht painti^ bunc.<i. Aflnr thr twvlftii v"'ar 

(hfv ' t 1 ■ l» (ir Pfpikfuled (poni Ihe sknil n-iihoiii dnniiiA" In miiny dijiart iculat':^.! jk'illD thvv 
urr -' l-ni;., ri Hp ih.'K !i p(trli(Wi is fuiittil uii llip tiph<>roid, fni|{iiiontt> bn the- pnl»ii> lionc*, and 
tiu-. rtmuiiiiL-r utiachcd to llio ethmoid. Soinc^timM. dvmi in old skulls, they an reprvsuut^d 
by ft ^-ery tbin (rinngiiliir plnt<> on ii^ich side of tbe roatnim of the sphenoid t^S-'^^)- 



TUB TEMl'OHAL BOSE 



57 



THE EPIPTERIC AXI) WORMIAN* BOXES 

The epipterics are seale-Jikc Imjiu's which occupy iVn; anli'i-o-latirral fnntam'IIee. 
Each ftiiptcric burn- i.'^ wwlfitni lieiwemi the f^iiuftmri-zyRurnalic fwrlJun of the 
temporal, frontal, ^cat wing of sphenoid, and the parietJil, and is present in most 
skulls between the siecnnd ami fifteenth yfar. After that dnte it may pcrsisl as a 
M'parat*; oawiclc. or unite with the sphenoid, the frontal, or the 8quami>rypoinatic. 
The cpiptchu bone is pre-fonne<l in iiiembrane, and appeur» ati a. scrica of bony 
granulp« in the course of the first vcar. 

The Wormian bones are wnalj. irregularly ahapefl ossicles, often found in the 
sutures of the cranium, especially those in relation with the parietal bones. Thpy 
sometimes occur in jjreat numbers: as many as a hundred have been counted in one 
skull. They an; rarely present in ihe sutures of the face. 



THE TEMPORAL BOXE 

The temporal bone, ^ituateil at the side and thebawof the cranium, contains the 
organ uf heariuf; and articulates with the lower jaw. It is usually divided into 
three parts — viz.. the squamous portion, fomiinj; the anterior and au|M'riar part of 
the bone, thin and expanded and prolonged externally into the z>-g;omatic process; 
the mastoid portion, the thick conical posterior part, behind the external aperture 

Pio. 70.— Tae Tkuporal Bone at Uibtb. 



muuioM. 



Fio.71.— Tbmivhi^l Rove j*t Dnmi, (Innerww.) 



i 



■ HUTUIUHAUirUIUIt 

KU'CDvcivtnsiiwu 

WUTUI 



ransu' 



?«W 



/ 



Fio. 73.— Thb ToiroRAL Boxb at Birtb. (Out«r >-iew.) 



•quAMO^Ak 



roii><inaig twiuu - 



mruiD UIUJLU8 



' rnu-iQuMioui auioAE 



of the ear; and a p\TamidaI projection named the petrous portion, situated in a 
plane below and to thi.- inner side of the two parts already meniioncfi, and forming 
part of the base of the skull. Jloreover, when wmnidered in refererce to its nwdc 
uf develiijiinenl. the tenijKiral kme is found to be built up of three parts, which, 
however, do nnl altc^ether corrc-ifxind to the arbitrQr>' division? of the adult bone. 
The ttirec parts arc named squamosal, petrosal, and tympanic, and a knowledge 



58 



THE RKELETCS 



of their nrrBngcment in tin; early stftgcs of growth greatly faciiilaica the study of 
the fully formed bono, 

Thi! iiKirtt iiti)mrt.ant (h\iMoii of the tr-mporaJ hoxw la Iho fiRtmas [Kirliim. ]| 
is pjTamidat in sImjM'. ami wmtaiiifi the cssfnlial [wrt of the organ of henrinK. iiruuncl 
\vhi<'h It, is iievL'Iop<Hl as u cartilaginous capsuio. This is known tw the periotic 
capsule or petrosal flmn-nr , and ilj* baise ahuta on thp outrr a.-niwct of the craniiun, 
whwre il foniw a lartic |>ai-l of the so-cnU'-fJ niaxloiil [jortion of tlio terii|5onil bone. 
JJi?sidcs LijntHiniii)! \\w inti-nia) ear, it- licars on \\^ cnininl side a foramen for the 
ec'veiith and ciglith cranial nerves (intemnl auililory meatupt, imd on il« outer side 
two o|>eiiinpB — the fcnoj^tTa vewtilmli and femwtni weUIeiR (ligs. 72 Hiid 73). The 
squamosal \fi a superadded element and Ls fornuHl iM a. meinhnine Iione in the lateral 
wall of the cniniuni. It is csjwcially developed in nuin in conpefjiniiec of the large 
size of the brain, and forms the S(|uaninu» diiision of the adult hwie. and by a tri- 
angular shaped process which is prolonged behind the aperture of the ear it also 
contributes to the fnrmation of the mastoid portion. It is obvious, therefore, that 
the ma.stoid \s not. an inde|»eiident element, but beiongn in [lart to the petrous, and 
in [mn to the .-iqunmous. The tympanic portion, iilso superaddeil, is a ring of lioiic 
developed in connection with the external auditor},- meatus, and eventually forms 

Fm. 73. — HiOMT Tcmfohai, Bone at ABotrr Six Yrarj). 

Tlie tympanic plate lia-* bo«n iwpjinilCLl and (Iraun Iwlow. A portiuti of the post-auditory 

prorcA^ t>f tliB itqiniinniml l)u» Ui-en rvnmvcd to sliow llio miutofi! ajilnim. 



luiroiD tnrnuH 



\ 



^^"X j' 



t1^ 



imunw viitiivu 

UML FQB mWII nilFWK 

PKovantDirr 



tturaif fmeus 
mctiu coMux ' 



UAQTIB miU. 



HH-eainrD aou of rxi 

TWfUIIC FUTE 



nit»iiiiiit 



a plate ronptititting part of the bony wall of this pawuipe. Thew three ports ar^ 
easily ^|>anible at birth, but eventually l>eeoine (irmly unite<:l to form a single lione 
which aITon.is little trace of iti^ complex origin. Ijistly a process of l.Kjne, devclopetl 
in the ^eeoml viseeral arch, itmlesces with the under mirface of the temporal bone 
and forms the styloid process. 

The squamous portion (Bf|mimo-z>-gomatip) is flat, seale-Iike. thin, and trtms- 
luccnt. It is attached almost at right angles to the petrouR portion, fonna part 
of the aide wall of tlie !<kull and is limited above by an uneven l)OKler which describes 
alxjul two-thirds of a circle. Tlie outer surface i.** smooth, slightly convex near the 
middle, and foniLs part of the teriifKiral fo««i.. .Mjovc the externa! auditory meatus 
it prewntu a iieariy vertical groove for the middle temimral »rter\-. (.'oiincctol with 
il.t lower jwirt it a narrow projecting bar of bone known as the zygomatic process. 
.^t it^ base the process i^ broad, directed outwards, and flattened from alxivc down- 
wanU. It so<:m, however. Incomes t\»ist€d on itself and nins forwards, almost 
parallel with the stiuantous portion. ThiB part is much narrower and coniiirewwl 
jaterally m as to prcHcnl iinier and outer surfaces with upper and lower margins. 
Tlie outer surface is aubcutaneouT*; the inner looks towanls the temporal fowa 
and gives allnchment to ihe mmuttUr muscle. The lower Ivirder is concave and 
rough for fibtv-s of the same muscle, wliilst the upper border, thin and prolonged 



THE TEMPORAL HOSE 



59 



farther forwards tliitti ili« Iowpt. reoeivee the Ipinpornl fascia. The extremity of tlie 
procc»B« iri serrolwl f<ir articulation with the zypoinjitic bono. At \i» h«sp the ri'RO" 
matic pmrcss prtsonts thrw no<it,<t— antfrior, middle, itnd ixisterior. The niiterior. 
conlii\uoii.s with the lower Imrder, is ."horl., I)n>ad, cmvex, and direi-tt^t inwanls td 
terminato in Uk* articular tubercle, which is coverwl with carlilace in liie rwent 
state, for articulation wiih ihe <-inn!yle of t!ip lower jaw. 'Hie iiiiddic mot. winit*- 
tiniea very prominMnt, fi>nii« the post-glenotd process. It separates theurlicular 
porlion of the plejioid cavity from tlie exTernal auditory tiicntn-s and is .«ituat€«I 
immediately in front of the peCro-tympanic (Glaserian) fissure. The posterior 
root, prolonRerl from tlie upper l:x)rder, is wtrontjly marked and t'xtenil? hackwards 
as a ridjre ab«jve the external auditory meatus. It is called the temporal ridge 
(ftupra-mastoid crest), and marki' Hieart>itrary line of divij^iou iHMwii-n the «i|uaiiious 
and maKtoid [mrtions nf tlie adult hone. It forma part (if the posterior boundnrj' 
of the tenipnnil fr>»«a, from which, as well as from the riflfte, fihres nf the trmpnrfil 
ma^cie nnao. Wlirrc the anterior root joins the z>gr>matir process is a slipht tubercle 
— the preglenoid tubercle — for theatl.Hrlimeiitiif the temi«?rc>-mandil»ular liiiameiit. 
and between the anterior nnd middle roots is a deep oval depres&iou, forming the 

Fio. 74. — The Lstt TEin<oR.iL Bokk. (Outer view.) 



^-!i' '. ' 



4 'M- 



tguuout POATlOt 



— ciogvEfORwian.E 
tiwraRUiATEfn 



l.i^ 



HMHITIO I 



MncVlMTU>B)ClE 
bEHOlC UnTT 



_// 



nMo-rxmam nasuRl 



Tatiie*tiil rLdca 

lUIUHl 
Ol-L-i|JII«llB 

a u tana* 

iii.inlalll 

Kisiixirjiuuiii 



nvMNicruTt ■ — 

MjlO-plLMynH' 

BLylo-tkrold 



tmOIO KSCCK 



mwMrto 

uuTom nuctBS 



LooKUtlai'U 

till rota »o«Tim 

OF IIHKIUJ. 



part ofthPRlenoidfosBa for the oomlyleof iheUiwer jaw. The glenoid fu-wa isaeon- 
ifiderahlc hollow, houiidcti in front h'v the itrtieular tuherelc and behind by the tym- 
panic plate whii.-h xepamites it froni tKc extenial auditory meatus. It is illvidcd into 
two parts by a narrow slit — the petro-tympanic (Glaserian) fissure. The tui- 
teiior part, which belongs to the pqunmous jwrliun, if< ftrlicular, and. like the artitv 
ular tubercle, ia ciMite:l with cartilage. The pfwterior (wirt. formcrl by the i\-m- 
panir pl.-ite. U non-articular and lodges the glenoid Inbc nf the panHid gland. lui- 
luetliatdy in frortf of the articular tubercle i.s a small triangular surface which 
enters into the formation of the roof of the zygomatic foasa. 

'Ilic inner surface of the 8t)Uftmous jxfftiou is markwl by furrows for the con- 
volutions (if the brain and grooves for the branches of the middle meningeal artery. 
.'Vt the upi>er part of the surfaw the inner table ia deficient and the outer (able is 
prolonged ?»-imP fli^tanee upwards, forming a thin Hcale. with the Ijevelled surface 
looking inwards tn overlnp thp corresponding edge of the parietal. Aiiterinrly the 
border i.s thicker, senatwl, and slightly bpvclted on the outer side for articulation 
with the ixwlerior Ijorder of the great wing of the :*phenoid. Posteriorly it joins 
the rough serrntwl margin of the mastoid portion to form the )inrietal notch. The 
lino wpnrating iJie squamous from tlie petrouji portion is indicated fit the lower 



f.O 



THE SKELETON 



part of ihe inner surface by a aarrow cleft, thb internal petro-sqiiamous suture, 
thi; appirariince of which variw in (lifTfirnnt IxmcM HKCorriing i« the df^ree of persis* 
tcaicc of the oricinul line of division. 

The mastoid portion is rouph and convex. Tt is Ijounrlprf above by the tem- 
poral ridpe and the pnricfo-nnistoid suture; in front, by the externa! auditory 
meai:us »ud t)ic> tympano-mastoid fi&iui'e: and behind, by the suture between the 
mastoid and occipital. As ahvady jMJintecl out. it is formed l>y tlio squainoufi 
portion in fnml find by the ha.** of the pt;! rosal litihind. the line of junction of tlie two 
f!onifx>nent piii-t^ beine indicjiied on the outer surface by the estemal petro-squa- 
mous suture (sf)uaiti(>-rii!i-')toiil). The iippeiimnoc of the suture varies, being in 
some bones scarcely distinpuishable, in others, a series of irrcKular deptresj-iuiis, 
whilst occasionally it is present as a well-marked fijsiiire (fig. 75) directed obliquely 
downwards and forwards. The mastoid portion is prolongal dowiiwardH beJiitid 
the external auditory meatus into a nipplo-sha))e<l projection, the mastoid process, 
the tip of which points forwards as well us downwanls. The process is marked, on 
its inner .wrfaee, by a deep groove, the mastoid notch (digastric fossaj, for the 

FlO. 75.~-T8C Lsrr Temporal Bo.ns. (Swa fnun the iiioor side and abcnre.) 

mUMOUtrHRTIOII 



d' 



J 



a^ 



_^ 



v^?_' 



HIMIklUl. BMXrn 



rrr.»uiThe tmatH 



tWKENTIt MC»T1 

tMOIDailMVt 
HiSTOIB nUKCN 



>* 



c^ 



k\ 



HMiiiiUiiJi.ni CiCkU)* 

* 
lltllRUl. «uQfiaiiir UUIftI 






tQUXOUSTUS VEETieUU I 



attaehiiient of the liiijaMne mtiecle, and more internally by the occipital groove 
for the occipitttl artery. T^e outer surface is perforated by nuinemua furunurm. 
one, of targe size, l>eing UBimlly iiiituat<^ near the pfwterior border and called the 
mastoid foramen. It iransmiisavein to the truasver^e (lateral) sinus and the mastoid 
branch uf the ucdpital artery. Tlie mastoid ixirtion pvc« attachment extemally 
to the iiitriculoris finslcrior (rdmfu-m nurnii) and occipitalis, and. along with the 
nia'Htoid pnKH^j«, tn the HttTuo-ftuiataitl. s}iU-u\us cnpiiis, and {tmtjixuxmus atpUi* 
v{trnchtitt-nui3timl). projecting from the posterr>-su|x'rior margin nf thr external 
'.auditory tneatus there is frequently a small tulM^cle — the supra-meatal spine — 
Whind which the surface is depre»»e<) t<> form the mastoid ( supra-meatal) fossa. 
The inner aurfac' of the mastoid portion preevnta a deep curve^i sigmoid groove, 
in whieh is lodged a part of tlie tranfs^'eree sinus; the mastoid foramen is seen open- 
inji into (he gn«ive. The interior of the mastoid porlion. in tlie mlult. is usually 
ocou|)iod by cavities lined by mucous membrane and known as the mastoid air- 
cells. T1ti-se open into a smidl ohamber— the mastoid antrum which comnmni- 
aite* with the upi>er [mrt of the tympanic cavity. The mastoid cells art; arranged 



THE TEMPORAL BONE 



CI 



. 



in three groups: — (I) antero-suporior, (2) niiddle. and (3) »picul. The apiciil cells. 
Bituattxl at. tJie apex of the niaMtnid process, are small and ueiiatly rontaiii nianv^w. 

Borders. — The f*ii|Mrrior iKmlcr is bniail mul mufih for nrtiuulBlioii with the 
hinder pan of the inferior Ijorder of the ptirietal Sione. The pasterinr border, verj* 
uneven and snrrai<vi, artirvijiiros with the- inferior linrder of the orcipital bone, 
extending fruiu the lateral an^le In the juRular process. 

■ The petrous portion iti a four-«idoi.i jiynunid of very dense bone presenting for 
examination a ba^e. an apc\, four surfaces, and four bonlcrs. 'Vwo mdes of the 
pjTamid look into the cranial c»vity. the iKmturior into the (xjeteiior cranial fosea. 
and the superior into the middle pranial fiBsit. Of the two remaininp surfaces, one 
—the inferior — appears on the unrirr surface of the cnmium, and the fourth, the 
anterior or ext^^i-nal surface, foniw tlie inner and posterior walls of the cavity in the 
tcinporul bone, kIlo^^7l an the tympanum. 

Tlie posterior surface is triangular in form, liounded alwive by tlie Kuiierior 
border and below by the posterior border. Near the middle h an obliijuely directed 
foramen leading into a shorr eanal— the internal auditory meatus— at the IxHtom 
of which is a plaic of Iwne, pierced by numerous foramina, and known as the lamina 
cribrosa. The canal trao^nitri tlie facial an<l auditor^' nerx^eti, the pars intermeilia, 
ami the internal auditorj- arteri.-. Tlie bottom of the internal auditory meatus can 
t>p most iwlvuntapx)asly sfiidicii in a teni[Kind Imhic at about the time of birth. 
when the canal ia shallow and the openings relatively wide. 

Tho fuii<lu)t of tlie meatus ja diviilc*) iiy a tninsvrnc ridge of bone, ttio Iranrnvnte crett. into d 
Hiperior ami infprwr fo«wa. Of Uiwv, rlie «upvriur is tlicr smaFIcr. and prewMiie anlvriurly the 
[>cginniiis of lite facial canal (uiucduc-l nf Fallopiu-sj, which Lroni^niiLN the !>i-vrtith nerve. The 
rest of ific ^ur(tt(T tilxne tliO i-re«t in floltcii with Miiall torainiti:* (tlip «iijA-rii>r vr«lilmlar atra) 
which lrark«niit m.T\i*-lwi|pi U> llm nx-reattJi eUijilk'un (fovwi hmiit'lliplicu) and the ainpulke 
ol tlio fiUpcriur :tnd I'xUTiial suiiitVirrulur (-aiiiJ;^ (ve«tilHiliir d)vif>ion of iho uiiditort' nerve). 
Deluw III* t-nvf thpw ftiT- two Hct)re-.«iiii».i and ah o]ici»itig. (_K llic^-, an HDlerior curled Irwct 
(tin spiral vribrifumi tract) witli u. i-nitml (oruiiHtn (fonuuvn 47ontnUo eoc)tle»rc) marks the 

Fio. 76. — Thb Foramina is the Fundus op thb Leit IvTKnxAt. Avditort Mk.\tcs or a 
Child at Uikth (}). (I>iagnuiiiiiatic.) 

lurtHIM HUM 

I 

\ bxse of the cochlea; the cetitral {nnmea indic-at*w th« orifice of lliv canal of tii« inodiolUB. 

I aud tlio FtunllLT funuiiiiui trutiEmit liic cuchloir twijcs of tiie auditorj' nerve, 'llic posterior 

npcning ((oranw^i <iingul(irr) i» for the ner\'e to tlic an^pull& of the pr><lcnnr ■scmieirrulnr canal. 
Tlie iiiiddir licpnst^ifjti (^inferior vrtrtibiiUr anw) i" di>t(«"<I miIIi iiiioiitc fiir!i.rTiin:i Utt tlie nerx^C- 
Iwun^ to iJic Nicvuli.-, wIir-Ij is ludin-'i in llic- rvcuKHUtt t^|iliuTiL'UK (futeti hvinisphiiTi (.-»). The iit- 
fcrior fojwft if «ibdivided liy u low i-crti(*l crc«t.. The knvu in tronl of the ittttl in tlie faeauia 
MchUfirit, and the rccem behmil it w tlin fmtJtufa vrntAtiJaru. 

liehind and outside the meatus is a narrow fissure, the aquffiductus vestibuli, 
cover&i by a scale of bone. In the fiwure lic*< the ductus endolyinphaticus.asmall 
arteriole and venule, and u proceaa of connective tissue which imitcs the dura mater 
to the slieafh of the inicriiaj ear. Occaifionally a bru^ile can be parsed through it 
into the vestibule. Near the upper margin, and opposite a point about midway 
b^'twcen the meatus and the a<}ue<luct of the vcrttibulc. U an irrepdar openinji, the 
fossa subarctiata, the rpmain.<j of the floccular fossa, a conspicuous depression 
in the fretal bone. In the adult the dcpresi^ion usually lodges a pnicLfis of diu'a 
mater and tr:in><init.s a small vein, thoui^h in t^onie bones it is almost obliterated. 

Hie superior surface, aloping downwards an<l forwards, forum the iKick part 
of the fifKjr of thi- middle fos,fji of the cninium. It prwents the following [joints of 
Intereat, proceeding from the ai>ex towards the haae of the pyramid:— (I) a shallow 
depression for the semilunar or Gasserian ganglion of the fifth nerve; (2) two 



lupf RiOR sRamronit an 



Hicoif eaannHM mu, 




tiiiUNCi TO m fuui wu-i 



THMSmtU auT 

vnnot «f iMt CMUL ct va Ronouti 



»Mut nilKifOM tm;i 



iKFtRioi nan 



62 



THE HKELKTOS 



smaJl grooves ninninK backwards aikI (mtwanls lowanU two smnll foramina over- 
hung l>y » tliiii (»s»eou* it|>, the larger and inteniu! of which, known as tlic hiatiu. 
canalis facialis, trHa^mit:; the ^ireat Kuiwrficial i^etrwal nerve aud the petroi^ul 
bruiirii of (he tiiiddic ineningeul urtery, whilst theKniulIcr and external foramen ui 
for the Hinjill .siiiKirfieial in'tro«al tiorvc; (lil lK-hil»i ami out«irle ihKw- ij? nil eminence 
— I lie eniinentia arcuata — beat seen in young bones. c(>rrpj<pondinfr to the superior 
semicircular cjjnjil in the interior; (4) still morecxli'rnally isa thin trnnslucent plate 
of bone, roolinjj: in the tympanic caxity, and named the tegmen tympani. 

The inferior or basilar surface is ver%- irn^jrular. At the iti->ex it is rough, 
([uailnluti-ml. and gives attuchment to the tcn»or lympani, Ivvalor jkiIiiIi. ami tlie 
phnryngi'Jil a|>i>neuro*«is. Behind thiH are so>«i (he iiirj^c eircular oriBee of the 
carotid canal for the transmission of the carotid lu-tery and a plexus of Bympathotic 
nerves, and on the same level, near the jKwtt^inr border, a. small thrfo-sided depres- 
sion, the canaliculus cochtee, which transmits a sinall vein from the cochlen to 
the internal jujiular. Iteliind thes** Lwu oiK'ninp; is the livrge elliptica.1 jugular 
fossa wliieh forms theanteriorandouterpart. of tlielx>ny wall of the jugular foramen, 
in which i.s coiilainiil a dilatation mi the CiHiinK'iini'iin.'iit of ihc inti-rnal ju^uljir vein; 
on the outer wall of tlie jufoilar fossa is a minute fommen, the mastoid canalic- 
ulus, for the entrance of the auricular branch of tlic viif^ust (Arnold's nerve) into 
the interior of the bone. Uelween the inferior aperture of the carotid eamil and the 
juF^lar fossa is the sharp carotid ridge, oit which is a snudl depre.s.>^ioii, the fos- 
Eula petrosa, and at the bottom of this a minute ojMmine, tlie tympanic canal- 
iculus, for the Ivmpaiiie branch of the jrliwwo-pharyneejd or Jaeoh-snu's nerve, and 
the small tvinpanic branch from the a-sccndinf; pharynpeal artery-, Ilehind the 
fo»i«i is the nuiijli jugular surface for articulation with the juKiilar proc<^s of 
the occipital Ijone. on the' outer side of which is the |»romiiienl eyiindrical epur 
known as the styloid process with llic stylo-mastoid foramen al its base. The 
fjicial nerve, juid K<iuietiiiie3 the auricular bnmeh of the vapu-s, leave the skull, and 
the stylo-niastoid artcrj" enters it by thi.^ foramen. Hiiniiinc; backwanis from the 
foramen are the mastoid am! oecipitid frrooves already dcs'cril>ed. 

The anterior, external, or tympanic surface, forminK the inner awl jMJsterior 
walls of the tympanic cavity, is shown by removing; the tyiupaiiic pUile (lie. 73). it 
presents iie-ar the base an excavation, known a;; the tympanic or mastoid antrum, 
covered by the triangular part of the squnmou.'s below ami l>elund the ti^mporal 
line. The o|Hrniii*; of the antrum into the t.ynipanie cavity is situaleil imnie<liat4dy 
above the fenestra vestibuli, an ov.-d-shaiiol oiieninie which receive-* the bjise of the 
stapes; liclow the fenestni vestibuli is a convex projection or promontory, marked by 
grooves for the tympanic ple>:us of ner\'es and containinK the commenceuienl of 
the first turn of the cochlea. In the lower and posterior part of the proniuntoiy is 
the fenestra cochleae, closed iu the recent state- oy the secondary membrane of the 
tymiKitiuin. Ruimin); downwanls and forwards from the front of the fenestra vrsti- 
buli is a thin curve<l plate of bone, llie processus cochleariformis, !»ep»ratinK two 
KronvHS''niivcrtv-.l intocinal-s by the overlyinp t>nnpanic phitu. The lower is the 
tubaauditiva (Eustachian tube), the communicatinn piissj^e Ijctween the tym- 
pjuiimi and the phan-'ux; the upper is the canal for the (cnsvr tymjKini, and tl»> 
external apertures of both canals are vi.sible in the retiring angle, between the 
petrous and s^juamoiis jiortions of the bone. 

The apex is truncated and presents the interna! opening of the rarotid nanid. 
The latter commences on the inferior surface, and, after asccndinp for a short dis- 
tance, turns forwards and inwards, ttmnelhnfr the bone as far as the aj^x, and finally 
Q|)c[is into the upper part »{ the foramen lacenun formed lietweeii the tem[MiraI ajul 
sphenoifl bone*=. One or t\vo minute openings in the wall of the canitid canal, known 
as the carotico-tympanic canalicuH, traii.^mil cominunicatini^ twigs between the 
carotid and tympanic plexus. The upper part of the apex is joined by eartilageto 
the iKwterior pet rn«d pnx-css of the sphenoul. 

The base is Ihc |>art, of the petrous portion which appears externally at the side 
of the erauium and tukee fmrt in the fonnatioii of the mastoid portion. It is des- 
cribed with that division of tlic Imne. 

Borders. — The superior border is the longefil and separates the posterior from 
the superior surface- It is prfMivwi for the .'fujwrior petmetal sinus, gives attachment 
to the tt-ntoriurn ecrcbelli, and pn-scnls near the apex a Pcmibrnnr iinlcli u(K»n which 
the fifth cranial ncr\'e lies. Near it* inner end there is often a small projection for 



THE TEMPORAL BOSE 



63 



the attachment of the pctm-sphonoidnl liEamcnt. which arches over the inferior 
petrotyil sinus iiiid ihc .vivtli m-rvc. 'I'lii' posterior border wparHtcw the poetcriur 
from ihf bttailur aurfiio*. iiiitl when articulaterl with the ocnipiiiil. fornf Ihogrotwe 
for the inferior pf'lri>sj»I sinus, and onniplerfs the jugular foramen fnrmeri by the 
temporal in fniiU aii'l on the out+T sicit*. and hy the occipital bt-hind and on the inner 
side. The juRiilu-r foramen is divisible into three compart men ts: »n anterior fur 
the inferior pi^trnsa) i^iiius. a middle for tlie mnth. tenth, and eleventh crania] ner\'es, 
and li pfwt^rior for the intpmal jupuUir vein and some nieninpeid branches from the 
oceif>itnl nnd ascendinp pharynRenl arteiies. The anterior border is the short*^ 
and consists of two pflrt"*. one joined to the 8r|Uflmoai in the petro-»f|U(imoui* 
suture ftnd s smaJl fn* part iiitoniaily which nrlieulfttc!- with (he sphenoid. The 
inferior border runs abng the line of junction with the tjTnpainic plate and is con- 
tinui*d on Ui the nuijih an-a bi-low the apex. 

The tympanic plate is (lundrilHteral in form, hollowed out above and behind. 

Fio. 77,— TuK Lkpt Teuporal Bonk. (Inferior view.) 



- mowiiie mooiM 



Vt-'JI 



■ tHtlMLUt lUURU 



ouono tMU. ■ 

T«a»«r Ijrnpanl ' 
GIMT>aCUU.. 



Aiuui sum«E 



-PlTRD-nMHMICnSCW 

. niiMiiio run 
■itLen mtua 

' TTVrMO-ltMfTOIB HHUMl 
. IlllO-UnWft TOftUItt 

uuToo noom 

' SlluUia 

-oceiniu, ttoovE 



and neaj-Iy Hat. or somewhat coneave, in front nnd below. It forms the whole of 
the anterior nml infrrior wiills, and part of the posterior wall, of the extemnl 
auditory meatus, and is scpam-tol behind from the mastoid process by the tympano- 
mastoid (auricular) Hssure Lhroueli which the auricular branch of the vftfiu.-* may 
leave the bone. In front it is separatwl by tlu' petro-tympanic fissure from the 
Bnuarnoiis [wirtion. Through the petro-tym panic fissure the tympanic branrh 
of the int^'nlal inaxillar.' arter\' and thcso-calhfl laxator tynipani pass. The pmct*- 
siis p-afilw of the malleus i» lod[;.y! within it, and a narrow sulwhvision at its inner 
end, known as (lie canal of Huguier, tn»nsniit.s the chonla tynipani nerve. The 
tympanic plate presents for exannnation two surfaces and four Ix^rders. 

Tlie external or antero-inferior surface, directed downwanU and forwards. 
lo<lKe.'» part of the pannid sland. Near the middle it is usually very thin, ami some- 
time?! presents a small foramen (the. foramen of Hii'^ehke). which represenl.s a nnn- 
ossified portion of the plate. The iatemal or postero-superior surface looks into 



64 



THE SKELETO?>r 



the external auditor.' meatus and tympanic cft\ity. and at its inner end is a narrow 
invo^'c. tin; sulcus lympanicus, dr-ficieut aV>ovc which receives the nirnibrana 
tjnnparu. 

The outer border ik rough and everted, forming the external auditory process 
for the attachment of the cartihige of the pinna; the upper border enters into the 
fonnatjon of tin; jK'tro-tvnipaiiic fi*sur»»; the inferior border is unevt-n and pn> 
longrd into the vaginal process which surrounds the outer aspect of the base of the 
styloid process ami gives aiiaehmeut to the front part of the fascial sheath of the 
carotid vesRels; tho inner border, short and irresular, lies immediately below and 
to the outer fside of the opening of the Eustachian tube, and liceomefi continuous 
with the rough iiuadrilateral ama on the inferior aspect of the apes. 

TTie external auditory meatus is formed j>artly by the tympanic and partly by 
the wiuunnMi-s ]Kjrtion. I: i.s an elliptical bony tube leading into the tympanum, the 
entrance of which is lx)und«i IhrmRlwiut. the greater J)ar1. of its circuniferenee by the 
external auditory procL-ss of the tympanic plate. Alwve, the entrance is limited 
by the temporal ridge or posterior root of (he zygomatic process. 

The styloid process is a ^Joder, cylindrical spur of bone fused with the under 
aspect of the temporal immediately in front of the atylo-mastoid foramen. It con- 
sista of two parts, basal (1ym|winn-hyal), which in the adult lies under cover of 
the txTnpanic plate, and a projecting [xirtion (Htylo-hyal), which varies in length 
from five to fifty millimetres. When shon, it is hidden by the vaginal process, but, 
on the other hand, it may reach to the hyoitl bone. The projecting portion gives 
attachment to three musciea and two ligaments. Tl»e stifto-phari/nijcus arises near 
the base from the inner and sliglitly from tlie jKisterior awpect ; the st'jlo-hyoid from 
the postr-rior and outer aspect near the middle; and the siyto-tflosgus from the front 
near the tip. The tip is eontinumis with the stykj-hyoid ligament, which runs 
down to tho lesser comu of the hyoid bone. A band of fibrous tb«sue — (he stylo- 
mant.libular ligament — passes from thft process below the origin of the stylo-glossus 
to the angle of the lower jaw. 

The arteries supplying Ihe temporal bone arc derived from i-arious sources. The 
chief are: — 

Stylo-mastoid from [xwlerior aurifular: ii enters the atylo-mastoid foramen. 

Tympanie from internal maxillari-; it passes through the pctro-tjinpanic fiaifurc. 

Petrosal from middle meningeal: tran-'miittM by the hiatus canalis facialis. 

Tympanic from internal carotid whili^t in the carotid canal. 

Auditor^' from the basilar: it eutens the internal auditory meatus, and is distri* 
butftl to the cochlea and vtwtihule. 

Other less important twngs are furnished by the middle meningeal, the men- 
ingeal branches of the occipital, and by the ascending pha^^■ngeal art-eri,'. The 
tHiuaiuous p<irtion is fiupplicil, nn it.s internal surface, by the niiiUile nir-ningefll, and 
exlfnially h\ the branches of the deep leuiixTuI from tin- internal maxillary. 

Articulations. — Tlie temporal bone articulates with the occipital, parietal, 
sphenoid, zygomatic, and. by a movable joint, with the mandible. (>cea.sionally the 
squamous portion present* a process which articulates with the frontal. A fronto- 
squamosal suture is comioon in the nkulU of the lower racett of men, and in norma] 
in the skulls of the chimpamiee, (^rilla, and gibbon. 

OsnficatioD. — Of tlio Uiree parts which cunEtitute the tompnnil Imn^ at birth, the sqiia- 
moKtal and tympanic develop in tncmbraiic And the petrosal in cartilage, llie MjuamKLoitl is 
fomied from one centre, wKk-Ii appexre as early a^ the eighth week, and otwification extend* 
into the jij-nomatk- proposs. nhirh gn)W5 conrurrenUy witli Ihe li^iuatiioKal. At first liie tj-tn- 
[MtQic border i^ nearly fftniiglit, but af>0Q A«siimes itAVharoctenstic hon««hoo ahape. At birth 
tl»e post-glcnoul tiil)eri"le is conspicuoiM, a/id at tlie hinder end of the »<|uanic«el there ia a re- 
aem whcrv it (.■oincs into rclutiou with the ma.'<toid antniin. The cvntrp for tJie IjTinianic ele- 
ment appc&ra aboiil the tirclfth week. At Iiirtb it foniis an incomplete' ring, opcii atwvc, and 
ali^tJy ankylrwcd In the iou-er Iwirder of llie miuaniofial. The anterior extremity terminates 
in » smull tm-vular procesa. and the inner aspect prcaenta, in the lon-er luJf of jU circumfer- 
ence, a gnxnt for the reception of Wm tyni|iatiic membrane. 

Up to lite middtp of Ihe fifth month the neriotic capsule ja car tiloffi nous; it thai o«aiSee 
«o rspidlv Itiat by tho end of tlie sixth mnntn its rhief portion is ron\TrIed into poroiw bono. 
The owiinc material is deposited in four centres, or ^)up« of centres, nniiied according to 
tbdr rebitJon to the ear^ap-iile in it« pmbr>'onic ponitiou. 

'llic uuclei arc deposited in the follon-inic order: — 

I. Tho opisthotic appears at the end of the Rfth month. The oneotu malenni l« seen fint 
on the prrHDontory, and it ijuickly surrounds the fenealra cochlcfc frooi obox'e doniiuurd-. and 
fonns tlM Qoot of tlio vetitibule, the lower port of tin feneatm venlibuti, snd th« tntcmaj an- 



THE TE.MPOIt\L BOSE 



6S 



dilory mcstiut: it also invesu the cflrhlea. HiibHec|iia)ily a pluU> of hone ariMft from It to sui^ 
ruuna ll)o ititnniiil rjimu'd artt^ry and funii thr flcmr of thf tyru|i>iiiuii). 

2. 'f'lie prootic nin-leus U c1i<|m>kiii>(1 liehiiid rlic inlemal auditory nieatiu near ihe inner 
Hinb of thr MifH^rtor Hciuii-iit-ular iiinitl. ll lovi'i^ in n part of tlip rtichleu. the vestibule, and 
tlitf int»-rtiiil iiiidiion.' meuLus. complettii the tent-Mtra ventibuli, iind in%'oat6 the superior i*m;- 
virculHr ruiml. 

3. Thv pierotic niit'leiiK oxHiBeia llii> leicnieii (jnnixini aad vovara in Llio external seini-circiilar 
canal; tJii- o^ific tiialtiT Li (iral dtrij«»nii(Hj uvrr ihe outer limb of this canal. 

i. '\'hv epiotic. olten dnuMe. m the last to appear, and is first (Mon at tlie most poeterior 
part i)( ihf pf>-^i«*ri<ir acinicirrular raiml. 

At tiirlJi Uie \iciiif- is of looac luid open texture. Ihiis offering a flrikiiiK roiitrdflt lo tlio deu» 
and ivury-liitt' pvironaJ ni the atbiJt. It hIm) diHern fitim the ndult Ikiiip in several uIIkt par- 
limlarit. Thf Hocculjir fosaa i>> \^idely opfii and ixitispicuoiM. \'oltotini l»w |M>iDt«l out ilitil 
a mtuill mjial Ii'mU from the Hoor of the floi-cular fiivia luul ojiedfi fKwtcriorly on tlie mastoid 
Hurfaev f>f tin? tnjtie; it may open in the irjOKtuid aiitnini. The hiatus eanalis facinJis i" iinftospd, 
aticl ttie tytiipiinti.- rece^ ia filled willi (^flatinouH t'oniteetive tiasiK. The uiaeloid prutw^ii 
w mil. di-vcld^M^. utid the jiiffular fo^a is )i i>ha]]«vv depre^ion. 

After birth the ptartx (trow rapidly. 'Jlie tj-mpmium l)eeonieB peniieate«l with air, (hr var- 
ious Hrmeiit.s fuse, and thtt tympiuiir iinnidiu gniWK rapidly and fomia ihe lynipHtiir pinto. Dc 
vvlopiiirnt of tl»e lyuipanir'plule takes pliw-e by iin outgrowth of Ivinc from the (Octcnut) 
SHpci-t uf Ihe tympanic annuliii. This iiutj(ro«tn take* plaee iiLOnt rapidly from the (tilw-rele* 
at itK iifwxT cxtmnitiex. and in c<>iL«*<|uen<>e of the plow groivth of the loner aegitient a deep 
rnilrli i> fonned; (imduslly tlie tiihendi^ roaltswe. cxt^oriiiil to the iiotoh. so aa to enclose a fotfl- 
uiDu in Ui(! aiiteiior pail of the bonymentUH wbic-h |)er>it>tA until puberty, and vometimcx cvm 



Flo. 78. — ^TkhPOMAI. rViNK AT TBK SIXTH YeAR. 



t 



>■/■ 



/ 



ttlRHIKI IME tN Tht MHM 
WTtM 



V 

rnna-mruia riwunt 



)D the adult. In mcmt -diuJU n cMt cApahle of iw«innn the nail rttnains hetwren the tym- 
panic element nml the ma.4tuid prucvw; tlib is thf tvmpiuio-ma«toid (Itttun*. I1iv uiitcriur 
portion of (he lyinpaniv pljuc frtmis m'lh the inferior border of th/* K|unmoitiil a clrft known 
as l)ip petro-lyinpaiiic fi.viun''. nhii-h t» smlBriUM'iitly ettrrtwudiMl iit>tiri liy Uie ^niuth of ll»c 
pelroMi. As the lynipauif plule iin.Ti'a%e» in i-i*i.' it join-s the yijt«r wall of tin- curvltd canal 
an»l pre."cnl* a pr(m!in<*jit lower edge, tinnwn il* the vnginiit [irrM-enn. 

The mastoid process t)t->xiii)c< dixtiix-t nlxml the lir«t jT.ir. roincidt-nr with the ohliteratton 
of the pet«>-*]u:inir>ii» "iiture, and iiK-rea-'^" in thickiiv« l»y deposit from Uie peri<*teuui. 
AeeortliiiK to mont ft-rilcrf, the [mKN-K-t l>eriitn<'K ]ineuiniitic alioiit iIie* lime uf pulierly, but wore 
reoentJy It has been *)iown by l*nife-v«>r Yoiinp: aji<l Dr. MHliK«ti that the mH-tloid air-<-elhi 
develoji nl ii miii'h enrlier |ieri>Kl tlmn i-> uMialU' >'iipp<^iHeil. Thei^ nritert have defcrilieij sf>ecU 
luenx in which the iiir-rellH v.x're prft*enl, an iunidl pit-like diverticula fnnn the iuaiiL«>id aniruni. 
in a nine nmnrh-:' fictii'. :in<l ui nu indmt one year old. In old i^kulU ri«! aJr-ccUx may extend 
into thf." jiiRiil-'ir pmcw-* ol' ihe (iccinilal Ikinc. 

At birlJi the mastoid aniniiii i>: n'hitivelv large and Imiindeil exiemnllv hy a thin plate of 
hone belonging to the s>|>iaiii<Hal (]«>"t -auditory pruce'iHl. A^ tlio maflloid increafte!' in (liiek- 
oeKK the antrum romc* to lie a( h ETcHter tlepth frnoi the mirface and becomcM relatively xmaller. 

The styloid prucnw i» osBilied in eartiliute from two c«nln». itnu of which apjiears at the 
ba«e in the tympano-hyat liefore birth. This ••uon fouts with the temjiora] bono, and in the 
tiecand year n cwilrr^ uppoan for the ^lylo-hyal, whirh. however, remuiifi very "anall until pu- 
Wrty. Jn the adult it uvuuJIy iKM-umes finnly united with the lympau'>-hj"al, but it may re- 
main permanently lAcparalo, 
5 



66 



THE SKELETON 



THE TYMPANTM OR MIPDI-E EAR 

Thp tjrmpanum is a t-ftTity of irirpulnr fnmi in \hp tompnm] lione, situntod over 
tbe juEular fi..-i-a, Ix-tween the p<'(rnus jwrtion iiit»'rtiftl]y. and llif tyniimiiic ittid 
gqiuimous iwrtioiis exlt-niHlIy. When fully devpjoped. it is coiiipJtU'ly surrouiMiod 
by btme oxci-pt \vl»*rf il cotninuniraU's uith tlic cxlrmal auditory turatiw, jiiid 
prewiUs for pxatniiiation six wsUIsi^'xtcmal, iiitcnial. lifwlfrittr, nnU'rior, suporior 
(roof), and inferior (fl(>or). The extrrnal and intenidl whUs arc flat, hut ihr r^ 
mainder arc clI^^'od. so thsir they run into atljoining surfaces, without their limits 
U'iiiy; sharply imlicftted. 

The roof or teamen tynipani is a translucent plnte of bone, forming part of the 
suiK^ritirnuifaooofthopftrouB portion and j^parating the tympanum fmni ihi- middle 
fossa of the .■*kul!. The floor is the plate of bone wliieh foruis the roof of llie jugular 
fossa. 

The inner wall is formed by the anterior or tympanic surface of the petrous 
portion. In tlie angle between it and the roof is a horizontjil ridge which extvnda 
badovanb? a;* far as the posterior wall and then t unts downwards in thp angle between 
the inner ami posterior walls. 'Hiis m the facial (Fallopian) canal, and in oecujjied 
by the facial nerve. The other features of this surface — \-iz.. the fenestra vestib- 
ulif the fenestra cochleae, and the promontory^have previou.sIy \<vi:u liiwrilnd 
with the anfermr surface of the petrous portion of tlie temi>oraI bone. 

Tile posterior wall t»f the tympanum is ab«> fornietl by the anterior Hurface of 
the petrous portion. At the superior and Rxtemal angle of this wall an opening 

Pio. 79. — Thb Iknbr Wall of Ttmpanxu, 



OMOTIO UHtL 

V««ia<w irmpanl 
BilNlt«IIIEL<ir>Ci<ll» 

LcTXer p*l«cl 

f imuL tuw 



•TV*-«^ 



■f!^ 



stviB-vkwnra 






niERNu srHicinouuui 

■ UtttSlOJlllTIIUW 



ClKtL lOK (HOOD* ITIirwI 
KniO-MlIIIlD FOnrkUU 



leads into the mastoid antrum. Inunediately below this opening there is a small 
hollow eone, the pyramidal eminence, the cavity of which is eonttnuoms with ilie 
de-teeiidinp limb of the facial canal, t>ne or more bnny spicules often connect liie 
apex of the pjTaniid with the jinjniontory. The cavity of this cone i.s oceupictl by 
the iftniM-i{iii:t an'I the tendon of the niasele enierires al (he ajH-x. 

Tlie roof and Ihwr converge towanlM the anterior extremity of the tytupanuni, 
whieli is. in eon.s4Hinftnce. very low: it is occupied by two canals, the lower for the 
Kustachian lulie, the uppi>r for the Uiisnr tt/mjwmi muscle. These charniel-s are 
iw)metimes deserilMxl together as the canalis musculo- tubarius. In carefully 
prepared bones the upper canal is a small horizontal hollow cone (anterior pyramidl, 
12 mm. in ienglli; the apex is just in froni of the fenestra ve>ttibuli, and is perforated 
lo permit the passage of the tenilon of the muscle. As a rule, the thin walls of the 
ranal an- damaged, and represented merely by a thin ridge of Umo. The posterior 
jMjrlion of ihi-* ridge pnijeets into ihe tympanum, and i;* known as the processus 
cochlea riformis. Tlw thin .sepluni lietween Ihe canal for the tensor tympani 
ami the tube is pierced by a minute opening which transmits the small deep petrosal 
nerve. 

The outer wall is occupied mainly by the external auditor^' meatus. Tliis 
opening is closed in the nrcent fitate by the tympanic membrane. The rim of bone 
to which the membrane is attached is incomplete atjove.and the defect m known as 
Ihe tympanic notch (notch of Rlvinusl. Anterior to this notch, in the angle 
betwct^n the squamous portion and the tympanic plate, is the petro- tympanic 



THK TYMl'ANUM OH MlimLK EAR 



67 



(Glaserian) fissure, and the juimll passage which tranuniitA tho rhorda tympon] 
nerve, known as the canat of Huguier. 



Rut 



l"i» to tliU point the doi4.?tii)lii)ii rjf the middli* i-\T wmfoniift to Umt iti Ki>ii4^nil tixnca.'. Hut 
recently I'rofessor Voiii>k aJiit [)r MiIliKan tmvi* liiid .itri»M on tlifi (itet that Ihe mitUllv c«r is 
Rally A rteft. Darned by CliHii llic 'midittt-rar Hrft.' ^'hicb iiilerveiH's l)elw(VJi thp pt'riolifl cap- 
Mtlc.'on the one hand, iind iht- *rjuanio-iyEoinntic and tympanic clpinfiits of tlu- fcitiporal bone 
on th* other. This cleft, as development proceeds, ^iveu rise lo three c«viti*«' — (1) tne mastoid 
tuitruiii: (3) tv-iupuiiuin: luid (^) thv Kusturhiao \\i\m. TItcy jiouil out tlint 'tliprl«fl in primar- 
ilv «>ti(inuot», itnd however mueh it niny be alt<'refl in shape imd modified in parts to form Ibese 
tliree cjivilied. lh;it cDntuniity is never lot! ' li will be clear that the mastoid nntruni, nc- 
(.■ordiux to this vifw, is not iiii outjiruwtli from the tynipaoutu, L>ut ia Giiuply the uuler or pos 
terior exlrmiily of the iiiiddle-*ur cleft. 

TliL- tympanic cavity may bo di\idpd into three parts. The part Im'Iow the level 
r)f tlif suficrior nior^n of the I'xriTiial .auditor)- mr^atiis is thf tympanum proper; 
the portion ivbove thi.s li-vel is the epitympanic recess or attic; it r<-c<-ivr!t (he h<-ad 
of Uu' iiiHllfiis. ifii- l«nly of ihe iticu,':. atid lends i>ostmorly into the rwef* known as 
thr mastoiil antrum. The third E)art ia the downward rxtau^ion known a^ Iht- 
hypO'tyinpaiiic recess. 

The tympanic or mastoid antrum.— The air-cdls which in the adult arc found in 
the interior of the mastoid portion of the temporal Ijoneopen into a small cavity lenned 

Fto. 80. — Tb«po«ai. fiosB at DniTU disskctbd moii Annm and behikd to phow trb tiswi- 
ciRCVL.«R C'anau* and THK Mahtoii) Anthvm. (.Enlarged i-) 



oruM Htq niMNini 



MUIBID AvniJII 



MKMOIt lEIIICiltCUUUI OMIL 



tXTfMUL lEHIIURetlUiR OIN<t 



minmafi sEuicnsuuK uhul 



the mastoid antrtma. This is an air-chamber, romrnunicfllinfj with ihe nttic of the 
tympanum. :ind separated from the middle crania! fossa In- the (XKsterior jMirlion of 
the [<'erneu tyinpaiij. The Roor i." farmed by the mawtoid portion of the petrosal. 
and the outer wall by the !^iniaino,nal. helow tlie temporal ^id^e. In ehildrrn 
the oulcr wall is e\«'e<iinply thin, but in the adult it is of oonsiderabh' thickness. 
The external semicircular canal iimjncts into the antrum on its inner wall, and is 
very conspicuous in the foetus. Immediately Ijelow and in front of the canal is the 
facial iier\'e, conlmned in the facial canal. 

Tlie mastoid aninim has somewhat thp form c»F the hnlH of a retnrt {Tbaiic and Ciodlrc) 
<>oiiinfc-«ed laterally, and opoaiiitc hy il» narmwvd iierk into ihv uttiv ur vinlVTiipiinie re«eM>. 
It^ ditiimr^ioiiA varv iit diflerent pcriofU of life. ll i* well developed at Uirtli, attains ita man- 
unum Mie about 1iie third year, and dimiiiinhiv .witnrw hal up to adult lifi*. In Ihe adull 
thn pbii-' of bone whieh fnn'iia the outer wall of Ltiv anlruin in 12 tu 1^ tiiin. () to 1 in.) in 
thi<fkite»i, whereafl at birth it b about I'S mn).(,';, in.) nrlftoi. The deposition of boneextemully 
ooeurn, theripfore, at avmiito rate of nrarly 1 mm. a yt"iir in tbirkntw. In th« adult the atitnim 
is about 12 nun. () in.) from Trout to back, 9 mm. (J in.) from above downwards, and 4*5 mm. 
(lV in.) from side to side, 

\ eiinal oeeiifionally leads from thr ninxloid aniriim Ibrough llif petroiin Itono to open in 
the rwff» whieh imlicutcs ihe position of the lloccular foosii; ii u temml the pctro-mastoid 
canal, (ti ruber.) 



68 



THE SKELETON 



The facial (Fallopian) canal.— This caoal beginB at tlic ant^^rior angle of the 
8U|Kfrior fossa of Die InliTiml iiuditory iiii>alu(), and imsm^a fonviinIi> uiiij outUfLrdti 
above the vestibular portion of the iiilernal ear fur a distaticr of r5-2'0 mm. At 
thf qmXk^t Mid of this jxinion of its course it bopomrs dilatinl to accommodate the 
gfniculate ganglion, arid then turns abruptly bnckwHrds and runs in a horizontal 
ridgp on thf innvr wall of the lyrnpanuin, lying in thf angle between it and tho 
tegmen tympaiii. imaieditttely above xhv fenestra vestibuli. and extending us far bark- 
wbhIh a*) the entrance to the mastoid antrum. Hen' it ntnwn into eontael with the 
inferior aspect of the projeetion formed by the external semicirpular ronal, and 
then turns vertically downwai-^is. running in the angle l>rtwecn the inlf-mal ami 
posterior walls of the tympanum to terminate at the stylo-mastoid foramen. 

Fto. 81. — TsR BoKes or the Ear. (ModifiMl rrom Ueole.) 



•Tapca 



LEFT MaLLEU» 



mu nn wcu! 



1 



Atit or MlltUI 



. UTIKU. r«OCIH 

■ uiiRwi raostst 



Ltrr INCUS 



UTIDtrltn aURFUf FN IMIltllS 



MnriMin- 



IDNtMOCUS 



JNTIIlOt tSUI 



IcNTICMUR MOCUl 



uu- 



NiiniM txn 



.EFT STAPES 
14) & 



UK » iTirrt 



UOC 



The canal is travrrsM-d by thp facial (seventh) ner^'e. Numerous openings exist 
in the walls of this passage. At lis abrupl bend, ur genu, \\\v greater and smnlter 
aupffficial petrosal nen'es escape from, and a branch fnim the middle meninpcal 
artery enters, the canal, and in the vertical part of it* course the cavity of the pyramid 
opens into it. Tliere ia also a small orifice by which the auriciil.or bmnch of the 
vagus loins the facial, and near its tennination the iter chords posterius for thp 
clionia tynipsni nen-e U-nds fmni it into the tympanum. 

The small bones of the tympanum.— These bones, three in number, are con- 
tained in the upper part of the tympanic cavity. Together they fonn a jointed 
column of bone connecting the membrana lympani with the fenestra vestibuli. 



THE OSSEOUS LABYRINTH 



m 



The malleus. — ^This i.i the most fxlornal of the audiu>r>- ossicles, and lies in 
relatioD with the tympanic mcmbranr. Its upper portion, or head, is Io<igrHl in 
the epitympatiic recww. It in of roumI«l Hhapp. ami prpsi^nts fxiHtcrioriy an t-llip- 
tical deprpssjun for articulHlion with the incus. JJolow thc> head is u conHtrictrd 
portion or neck, from which thn^r pmccfwcs (li\-rrjr(\ The larprst is t)ii" handle 
or manubrium, which is shghtly twistt-d nnd ft.ittoncd. It forms an oblusi- angle 
with tilt? ht-ad uf the bone, and Uw h^-lwwri ttic iiirmbrana tyiiipaiii ami the mucous 
mcmbranf covcrinp its inner surface. The Ui>»or tympam tendon is. irwertctl into 
tht^ nianubriutn near iis junction with the neck on the inner sitle. 

The anterior process (prowssiw pracilis or Folii ) is a lonu. tulcnder, delicate? spicu- 
lirni of Iwno (rarely seen of full length except in the fttlus), projecting nearly at 
ri^ht andlcs to the anterior aspect of the neck, and extendingobliquely downwards. 
It Ilea in the peli-o-tympanic fissure, and in the adult usually becomes converted into 
connective tis-suc, except a small ba«il stump. The lateral process is u conical 
projection from the outer aspfct of Iho base of the maniilmuni. Its apex Is con- 
nected to the upper part of the tympanic membrane, and JCa base receives the lateral 
ligament of the malleus. The malleus also gives attachment to a superior ligament 
and an anterior Ii|ipiment, the latter of which was formerly dc-scribed as the laxator 
ttjmjxini muscle. 

The incus.— This bone is situated between the malleus externally and the 
stftjiCH internally. It prrwent^i for exaniiiiation a body and two priK^esstv;. The 
body is deeply excavated anteriorly for (he reception of the head of the malleus. 
The short process proji-cls backwards, and i.s connected by means of ligamentous 
fibres to the pnsterior wall of the tympanum, near the entrance to the mastoid 
antrum. Thn long process is slender, and din-ctwl dowiiwardy and inwani.'^, and 
lies parallel with the luanubrium of the malleus. On the inner aspect of the distal ex- 
tremity of this process is the lenticular process (rirt«cular tubercle), separate in 
early life, but subsequently joined to the process by a narrow neck. Its free surface 
articulai*^ with the head of the stapes. 

The stapes is the innermost ossicle. It has a head directed horijwnt^ly out- 
wards, capjwii at its outer extremity by a difc r<-seuiblinj; the head of the radius. 
Tht' cup-fihapt?d depression receives the lentieular process of the incus. The base 
occupiiv the fenestra vestibuli, and like this n|«'nin(r. the inferior border is straight. 
and the superior curvinl. Tlie base is conriecte<l with the hea*! by means of two 
crura, and a narrow piece of tmne called the neck. Of the two crura, the anterior 
is the shorter and straifthter. The crura with the base form a stirrup-shaped arch, 
of which the inner margin presents a groove for the reception of the membrane 
8tretehe«"l across the hollow of the stJi|je«, In the early euibno this hollow is traverswi 
by the stapedial artery. The neck is ven.' short, and receives <m its posterior border 
the tendon of the aUi^H'tiius muscle. 

Development. —The tympanic cavity reproaente the upper extremity of the Rrstendodemial 
branchiiU en>ove. whirh becomeH ocmverl^ into a blind poiii^li, th» conimunicaljon of uhirh 
with the [marynireal ca\*ily is iJic tulm iiuditiva (Eustat-hiim lubci. The thin inGiiilirane whwh 
aeparAten the enrlodennal from the ectodermal eiv>ovc beeomca the tympanic membrftnc. and 
it ift frr.'m the upper pittretnilii^ nt the sttint •kelt^totif of the limt »ti<i -lemtKi hriujrhi.'il arches, 
whieh Iwiind [lie unKwu uiilcriorly and posleriorly, ibat the autlitory o«-it'ie« urc funiicd. th« 
malleus «nd incuit beloacing to the firwt arch and the stapes to the h^coikI. Theowielcs conse- 
quently lie "rigimvliy in tlin wjtJU i»f llw ejivily. hut ihey are niirmiiiiilrKl by h Irxiw apong;}- lissiie. 
which, on the eutrunce of air into the cavity, l>ee<^iMee eoniprcsM^I. ulluwiiiK the cavity to 
finfoM the ossicles. The«e thcfcfore tire «i<'loh««l within an epitholiimi whjrh i« continuous 
intsm&lly \rit}\ thtit liiijiiiK the poxtoriDr tympniiir w&ll. lUid extemully wttli l)^nt Uning the 
ialcmal tturfaLT* uf tiw lyiiiputji'.* inniibnine. 

The mastoid relU trc out^rowihn »I t)»e esvity into the adjacent bone, and nre therefore 
lined with »n epitheUuni i->»itiniioi»i with that of the ravity. 



THF, OSSEOfS T,.\HYRINTH 

The osseous labyrinth is a e«^mpiex canly hollowed out of the petrous portion 
of Ihe temporal bone and containing the membranous lab>Tinth, the essential part 
of the orcan of hearing. It is incompletely dinded into three parts, named the 
vestibule, the semicircular canals, and the cochlea. 

The vestibule.— This is an oval eham!>er situated lietwcen the i>as<* of the in- 
ternal auditory meatus and the inner wall of the tympanum, uitii which it com- 



70 



THE SKELETO.y 



municatea by way of the fenestra vestibuli. Anteriorly, the vestibule leads into the 
cochlea, aJXii posteriorly it receives lh«^ extn-nulie* of the semicirt-uiar canals, U 
iiieasunw alxmt 'A mm. transversely, and is somewhat longer aiiter[>-posteriorly. 

Its inner wall presenLK at the anterior part a circular dt-prrasion, ttif spherical 
recess (fovea hcmispherica) , which w finally perforated for the passjipe of nerve- 
twigs. This recess is separat-f-d by a vertical ridge (the crista vestibuli) from the 
vestibular orifice of the aqusductus vestibuli, whirh passes olilirjucly backwards 
to open on the post^-rior surface of the pt't rosal. The roof contains an oval depression 
— tlie elliptical recess (forea heniielli]>tica). 

Thir semicircular canals an- three in numln-r. Arranged in different planes, 
each forms about two-thirds of a circle. One extremity of each canal is dilated to 
form an ftmpulla. 

Pto. 82. — TnE Lei^ OftflBODS I^htrinth. (After Henlc FTomacMt.) 

ltin«JOft tiaicifiauuiii WML 



nieoMiu 



(irEfwu. tuiDRCiuuit anu. 



mUTM COEHiU 






The superior canal lies trautiversely to the loof;; axis of the petrosal, and 
nearly vertical; its highest limb makes u projection on the superior surface of the 
bone. The ampulla is at the out^T end; the inner end opens into the vestibule 
conjointly with rhc superior limb of the [Kwterior canal. 

The posterior canal is nearly vertical and lies in a plane nearly parallel to the 
posterior surfare of the [>etrosal. It is the longest of the three; its upper extremity 
joins the inner limb of the superior canal, and opens in common with it into the 
vestibule. The lower ie the ampuUated end. 

"IIh! external canal i.s placed horizontally and arches outwards; itse.\temal 
limb forniK a pnimiiu'TUT in tln' niiLstoid antrum. This canal Is the shortest; its 
ampulla is at the out^-'r end near the fene.sira vestibuli. 

The cochlea. — This is a cone-shaped cavity lying with its base upon the internal 

Fio. 83.— Thb COClttXA l» SAorrTAL Sbction. (After Ilenle.) 



« 



inrrtnxtL uoTon uutus 



TMi snuL tuuii 



auditory meatus, and the ujm'X directed fonvarrls and outwards. It measiures 
about fivi- millinietr*'s in length, and the diameter of its base is aUnu the same. The 
centre of thL-( cit\-ity is oerupie^l by a column of bone— the modiolus- around which 
a canal is wound in a .spiral manner, making about two and a hnlf turns. This i» 
the spiral canal of the cochlea; its lirst turn is (he largest and forms a bulging, the 
promontory, on the inner wall of the tympanum. 

Projecting into the canal throughout its entire length there is n horisrontal. shelf- 
like lamella, the lamina spiralis, which temnnates at the apex of the cochlea in 
a hook-like process, the hamulus. The free edge of the lamina spimlis pivcs at- 
tachment to the membranous cochlea, a canal having in s^K-lion the form of a 
triangle whn!»e base is attached to th»' o«tcr wall of the ppiral canal. By this the 
spiral canal h divided into a portion above the lamina spiraLis, termed the scaU ves- 



run ETHMOID iiOXE 



71 



tibuli, which (M)tiiniuiiiciilra at its lownr end with tlit.^ ik^di'tjUH vcstibuic, and a 
portion below. t*'niuil the scala tympani, whirh jihuts Ht its lowor t-iui ii|K)n the 
ffiic5im ciwli!pa\ TIm' two ncaia' cojiiinunieaic al llu' apex of ihr <x>chlea by Ihe 
helicotrema. N>ar tlie commoncemeni of tHp scala tympani, and clc»se to the 
fciu'sUa niluiiila. is the- cochlear orifice of the canaliculus cochleae (ductus pcri- 
lymphatirxisj. In the adult this opens below, tii'iir thi* iiiidUK' of tin* ["•f^lcrior 
Hi)n|fr of Ilic petrous bone, and traiistnit^ a snialt vein fixiiu the cochlea la the 
jugular foesti, 

Meaf^rcmunbi nf the prinffipal parte ri>nnert«(l with the audilory orgaiu: — 
IiilvmHl Jiuiiilory (iiiiiilii.t .....l^tiglU r>f aiiU-rior wall. 13-14 nun 

heiiKlh of pL>s(*nor wall. 07 mm. 

Kxtfrnal uuditory meutuK U- 10 nun. (lJriilM>r,) 

Tympanum I^-tigiJi, i;i mm. 

Ilfiictit ill c«ii(iv of cavitv, 15 mm. 

Wjoih oppatJite the memliranii tympnni, 2 mm. 

Width omioitibc the tubal orifice, 3-1 mm. (\'on Trtltoch.) 

Tbc eapwlle of the owwoum laliyrinui in in leiiRth 22 mm. (.Schwulbe.) 

Supwior aeuiicirRiilnr i-anal meairiiirGa alnng iu convexity 20 mm. 

The |»J»l«ri«r aemicin-ulitr ranal mcanur^ alonR it« conwxity 22 mm. 

ITie external swiiicirciilar canal measures along it* convexity 15 mm. 

The ranul is in ilinnii'Ler l.'i mm. (Hu^chke.) 

'HiP HmfiulLi of iJic taiial. 25 mm, 

DevelDpm«Dt. — i'lie niembriuious int«i]al ear ariees as a depTeti«iou of l]ie ectodomi nf tlie 
Biirfncc of the hiwid and later lionamea a Bat-tike ravily which Mpnnites from iu nrifiina] wto- 
dtrmtiJ romiwtioni. sud ^inks deeply .into the subjacent nicsodcnn. Tin; pordona of thin latter 
linKiic which curround the auditory sac IwrotapR latpr the pctrutis portion of the lemp<»rai bonv, 
ftiid the oaspoUH labyrinth is thcrdoro merely tJiti |K>rtions of llie pctniiH whic-h enrloac the cavity 
occupied by the iticmbranouH internal car. 



THE ETHMO[D 

Tlio ethmoid i.s a hone of delicate trxturc. atuatwl at the antmor part of the 
basi' of the cmniuni. Projcclinp dnwnwanlw from bctwiN-ii the orbital plates of (he 
frontal, it enters into the formation of the orbital and na^ial fos-sa-. It iti cubical in 
form, .ind its extreme lidhtnfss and delicacy are due to an arrflnKeinent of very 
thiu plates of liuiic E^urrouuding irrc^lar spaces known as air-celU. 'HiLt ethmoid 

Fio. 84.— Sktiow TTiiiocdH thb NAaAt, Fo«ba td anow the MiixeTituoii}. 



CRUT SI tMEWiD ' 



vmyf fM <iiLw-*(ui)ffi (({wt 



'Hiaiitu iniic 



«^SRTt<"OIt 



CKEST Of rujni wot 
■PUH Of null wilt ' 



■ ORnr n huilu 



insists of four part*: the horiwnt*! or cribriform plate, two lateral masaes, and a 

perpendicular plate. 

Tlie cribrifonu plate forms pari of the anirrior cranial fossa, and in rpceivwl into 
the etlinmidal iioteli nf the frontal Um(\ It. |»re{*ent« on its upper surface, in the 
nic<iiiin line, the intra-eranial porti<m of the perpendicubir plate, knoi^-n ii3 the 
crista galli, a thick, vertical, triangular prorew with the highest point in front, and 



72 



TUB SKELETON 



a slopipg border behiiul whicli gives sttachraent to the falx cf-rebri. The anUTior 
liorditr is shon and in its lowt-r part hmadcnH out tii ruriii t\Yci alar processes which 
articulate with the froiiUl l«mr and coinpk'te ihp foramen cecum, lin' chslagalli 
is continuous behinil with a median ridg<'. and on i>ach side of the middle liny jf a 
groove which lodges the olfaciori' bulb. The cribriform plate is [Merced, on each 
side, by nuintrroua foramina, arrangMi in two or three rows, which tranHinil the fila- 
ments of the Qlfactor\' nerves <le»cendiiig from the bulb. TIiow in the middle of 
the groove are few aud are simple ]X(rforaiio[it;. through which pass the nerves to 
the roof of the nose; the iiilfrnal »nd external series an- mon> numerous and con- 
fititute thr upper eniL-s of small eaiials. whidi suhdi\-idr as they course downwards 
to tliL- upper parts of the septum and tho outer wall of the nasal fossa. At the front 
part of ilie L-ribrifonu plali* is a narrow longitudinal slit, on each side nf thi' rrisla 
galli, which traa^mita the anterior ethmoidal (nasal} branch of the ophthalmic 
division of the fifth nerve. The posterior border articulate with the ethmoidal 
spine of the sphenoid. 

The perpendicular plate Cmesethmoid) is directly continuous with the crista 
gftlli on thf umler nspcct nf tlio eribrifnrm plate, so that tlu- two plates^ cros>-i each 
other at right augh-y. The larger part of the perpendicular plate in below tin* |M>int 
of intersi'ction and forms the upper thinl of the septum of Ihe nose. It is quad- 
rangular in fonn with unequal iiiAvti. The anterior bonier articulates with .the 

Fio. 85. — 'The Ethmoid. (Side vipw.) ' 

Bin o>iu 



wnnot immrw. Mwm 






moMTf raoixu ■ 



, irifCNUIEULl. KNEHJL 
■ KlMM OUU. OaMM 



WFEMR «UU, CW«HII - 



Spine of the frontal and the creet of the nasal bones. The inferior border artici 
latos in front with tin* M'ptal eartilagi- of the noM- and behind with llie anterior 
marKiu of the vomer. The |)08teri'ir margin ia very thin and artic^ulatcs with the 
en«t of the .sphenoid. This plate, which is geniTally ileflect^'d a Hltle to one side, 
presents above a number of grof>vc8 imd miinile ciiniils which Ii-ikI from the Inner 
set of foramina in the cribriform plate and transmit the olfacton* ner^■e8 to the 
septum. 

Tlic laUTiI mas) or labyrinth \s oblong in ehape and HU»|X'ndHl from the under 
aspect of the lat4'r:d (Nirl nf the cribriform plate. It timsisiR «f two scroll-like 
pieces of l>one, the superior and middle nasal conchse (turbintitelionc;!), and 
encloses numerous invgularly shapinl b/xici-?'. known as the ethmoidal cells. Tliese 
are nrrangej in three siM-* — anlcrinr. middle, and jjix-ilerior ethnn'idal (■•■lis — and, in 
the recent state, are lined with prolongations of the nasal mucous membrane. Kx- 
lenially the lateral tiuiBS pn'sen1> a thin, smooth, ipiadrilateral plate of Ume— the 
lamina papyracea (o.-* planum)— which closes in the middle and posterior ethmoidal 
«*Il.q and forms a large purl nf the inner wall of the orbit. Hy its anterior liorder it 
nrticulated with the lachrvnu*!. and by its posterior liorder with Ihe sphenoid; the 
inferior Iwrder articulates with the inner margin of the orbital plate of the maxilla 
ati<l the orliilal proci-ss of the pnlut^' Ixine, whilst the sufwrior Itorder articulates with 
ihi' horizontal plate nf the fronlid. Two notches in-the su|>i'rior bnrder lea<l uxUi 
grtK>vc» running horizontally acniss (he laleml mass to the cribriform pUile, which 



THE BTIiMOfO BOSE 



73 



complete, with th^> rrontal bone, the ethmoidal canals. The antmor canal tnuis* 
luita tlie anterior ethoioitla! vwsfls ami (naaal) nerve; the jwstvrior transmits the 
postt'rior otliiiioidal vosstls and nerx'p and orbital branches from tlic spheno-ijalatine 
ganglion. At th^- iowt-r part of the outer surfaet; is a dt^p groove, wliicli Ix-longs to 
l.hc middle meatus of the no3f. and is lK>un(li>d below by the thiek curvinl umrcni nf 
the inferior niuial concha. Anteriorly the middle meatus receiver tlif infundibulum, 
a siriuovw pawiftge which descends fmm the frontal sinas through the aniennr part of 
the lateral miws. The anti-rior L-thmoidal. cells open into the lower part of the jtt- 
fundiliulum, and in this way conmiunitate with the now, whereas the middle 
ethmoidal celli^ 0[jen iliri'Ctly into the middle or horizontal part of the nuatu^. In 
front of thp Q8 planum are snm u few broken cells, which extend under, and are 
completed by. the lochn-'mal bone and the frontal proctss of the maxilla; fmm this 
part of the lateral mass an irrpgular lamina, known as the uncinate process,- pro- 
jects doi%-nwarda and backwarda. The iinciDate process articulates with the eth- 

Fio, 80. — Swmox tkkouom trk Hkm.^ Fosaa to show the Lateral SlABa OPTmeEmjioiD 
It sliou's also llifl outvr wall u( tlic left nitiia] fnniia. 



IDnrnON HUTVt 

UtDMC UUL 
0011 AlA 



Sirill-gR HAUL GMCM 
sou TUROlC* 



« 



Wi- 



'^^r^ 



UHC:illTE nOUU Of EI^UDIO 

iMTtnuiL ■'■itrsDiD niri - 



w 

(".•, 



? 






ItmiUMCS 



Urtiit, n On 



«au vmt 



Ufr«TMlt soiie 

M JUMtt JTMu 
IKfEXIOt MUl 

coHcm 



moidal procegj! of the inferior nasal concha and forms a stnaJl part of the inner wall 
of the ma\ilhiry t'imis. 

IntcTnnlly the lateral muss takes port in the formation of the external wall of 
the nasal fo>wa, nixt pn>sentii the superior and middle nasal conchs (turbinate 
procc*ses). continuous imteriorly. but se|>arated behind by a spare direcrt-d forwards 
from the posterior margin. This channel is the superior meatus of the nose and 
communicates with the posterior ethmoidal cells. 71ie processes, which arc a]t>a 
refeiTe<l to as the superior and middle spongy bones, arc covered in the fL-ceni 
state with mucous membrane and presr*nt numenms foramina for blood-vessels and 
gmovea for twigs of the olfactnn" nfr\Ts. I-'ach proceM has an attached upper 
bonier and a free, slightly conv(>lut<xi, lower Iwrder, and in the case of the inferior 
process, the lower margin h^^s already been noticed on the outer aspect, where it 
oveihangH the middle nieatus of the now. The ix>sterior extremity of the laby- 
rinth articulates with the anterior surface of the body of the sphenoid and is conv 
monlv united with the sphenoidal concha. 

Many of the ethmoidal cells are imperfect and arc completed by adjacent bones. 



74 



THH SKELETON 



Tliuae alojiR the superior ed^e of the lateral mass are the fronto-ethmoidal; tht«e 
at the :iiit(.Tior border, usually two in number, an." known a* lachrymo-ethmoidal. 
Thuse along the lower edge of the hwiiinii pHpyniceii. are the max illo- ethmoidal; and 
poeleriuily. are t,hc spheno- ethmoidal, euiriph-tcd by the sphemikUil cuncha. mid a 
palato-ethmoidal eell. Tlie luUerior extremity presents one or two incompletp 
cells closed by the nosiU process of the maxilla. 

Ilif ethmoid receives it-? blood-supply from the anterior and posterior ethmoidal 
arteries and from the nasal or fipheno- palatine brutich of thi* internal aiaxillary. 

Articulations. — With tlie frontal, Bphenoid, two palate Iwnes, two nuAnJs, 
vomer, twii inferiur uaniii eonchre, two »ph('iioidul ouiieli;e. iwo niaxjllie. and two 
lachrymal bones. The posterior surface of each labyrinth is in relation with the 
sphenoid on each Hide of the crest and rostrum, and helps to close in the sphenoidal 
sinus. 

Osstficatioa. — riieeitimoidlia* tlirtw centre* of oKfification. Of tliese.a nticleutt np|>eam in t)i« 
rotiriJi nioiitli of inlra-mcrinc life in carh UihyrliiUi, firet in llic Uniinii pnpyracea ana afterwiinls 
extending; into the middle concha. At btrtli caoh lateral portion in roprcsontcd by two acroll- 
Ijke bonos, very delifatu and rovereil wil.li irrt"gular depre«Mian!i, utikh give it a «onn-«ateii 
nnpeamim'. Six montiiE uftcr birtli b uucUmis iip|i«in; m Ui« ttliCEio-voiiifiriiif t-artikuic for 
the vertical plato whioh gradually extcndit into the crista galli^ and Iho rrihrifonii plalc is fomied 
by iKtiiGcBtjoD exlaadiuf! oulwartj* (ruin this irntrp. and inwards frotn Hie lntyrinLb, The 
thrae parts roaloece to funn aim pi'Hv in Uie fiftli or eixtii year 

The rtlinioiclal cpIU make liirtr appcarancD aboiir thv tbird v«iir, and Erad>ia]1y invade 
llie lateral niawes. In niarty placca llit^rc \s no iuur1i aWirplion ol Ijont- ttial Um ivIU {iprf<irat« 
tlie ethmoid in (tituattons nucrc il in uvcrlappotl by ulhvr bun«>. Alunv llii- Inwcr burdt^r, near 
iU articulation with tlic maxiltu, the abxor^ilion IcaH^ to the purlin! dcTachnient nt' a nariuw 
atrip known a* Ihc unoinatje prooruM. Somrlinn-" a m-cnntl but itnialliT hi^uk-liko pivfi-wi in 
formed, above and anu-riur to tliiit. su fnijicili] that it ix diflieidt lu prcM-rvi.- it in diKEirticnIuIod 
|}oncH. The n>lution« ni the uncinate pivicefl« ure Ixwt xtudied by removing tlie outer wull of 
tlie maxill.-iry wnn*. 



THE INTERIOR XASAL CX)NCHA OR IXFKHIOU TIRBIXATK 

The inferior nasal concha is a blender, 8eroll-like lamina, attaclied by its upper 
marRin to the lateral wall of the nasiil fossa, and hiinRing into the cavhy in such 
a way as to separate the middle fr«m the inferior meatus of the nose. It may be 
regarded as a dismerabennent of tlie lateral mass of the elhracid, uith which it is 

Fid. 87 — Thjc Isip-eiuoH Turbikatii, Adoi,t Spmiucoiuai. Tvkhinat«, amd Lachhvxal Bonih. 



TM CKS1 Bt LtCMRtML - 

THE tmirtL Biinf>4E- 
UaailUL ORMIVL I 



HMIUUUI NDCISI • 

WNCMu moctu ' 
THE UCMfniMt reiCEss - 

nc tTHweu, neeisi ' 



■ TMt SrMEKOIaiiL CDDCht ItlTH Ml 
OFlllItU PRCICfU 



HIDDK VUMI DOirCIU 



TWt HXIUMT M9CtM ■ 



rit^ 



closely reJated. It ptraeenta for examination two surfaces, two borders, and two 

extremities. 

Tlie outer surface in concave, looks towards the lateral wall of the nasal fossa, 
and is overhun? by the maxillary or auricular process. The inner surface is 
cfinvrv, piltrd with depressions, and grooved for vessels, which, for the most part, 
run lonKitudinally. The superior or attached border articulates in front with 
tbv vunchal crest of the maxilla, then a^^cnds to form t-he lachrymal process, 



THE LACHRYMAL HONE 



75 




which articulates with the lachn-mal brmr iind forms jmrt of thi> wall of the lachnTnal 
canaJ. IJehiutl this, it is turnwi downwards 1o fonu the niaxillan' proce**, already 
mcnliomHl, which ovwhangs thf orifice of the niaxillarj' einias and sen'es to fix the 
Ikmm; linnly to the outor wall cif the nasal fossa. The projection liehiiid ih<' iiiaxil- 
larv procfss is thf ethmoidal process, juitit^l in the articulat<*d hIjuII with the 
imriniitc pn»^*^s of l\xv fthinoiil acrtxss llic opening of tho niaxillan' sinus. Pos- 
teriorly tlie uppiT bortier artirtilatos with tho conchal cro«t of the pjilatc. Tlie 
inferior border i** fire, roundod, and somewhat thickcnwl. The anterior extrem- 
ity i-s blunt and flattwieU, and broader than the posterior extremity, which is 
doiiKHtcd, narrow, and |M)into(i. 

Articulations. ^With thi- inasilla, lachrymal, palate, and ctlumoid. 

OssifictttiOR. 'The inferior nntal concha ix o^ifu*d in cnrtilagc from » tingle nuclotiH which 
a.p|>eAr<t m ihe tiflli month of iiilm-utcntw liif. At tiirtii it i» a rvlalivply large bone atitl fill* 
Up the luvver part of the tuu>aJ fosai. 

THE LACHRYMAL 

Tho lachrymal bone is oxtremoly thin and delicate, qua<^lrilaterftl in ehape, 
an<l Kituati^d at the aaturior part of the inner wall of the orbit. It h the smallest 
of thi* fafiial bones. 

The outer nr orbital surface is dividnd by a vrrtical ridicr. th*- lachrymal 
crest, into twn unequal portions. The anterior, smaller portion is deeply pjooved 
to form the lachrymal sulcus, which lodges the lachrymal sac and forms the com- 
mcDcemenl of the- caiml for the naaiil duct. The portion behind the ridge is smooth, 
and forms part of the inni-r wall of the orbit. The ridge gives origin to the Icnsor larm' 
muflcle atui tonnimites infnrinrly in a hook -like proees*. the Aumu^wji. which curves 
fonvflixis to articuJiite with the l!iohr\'nittl tubercle of the maxilla and completefl 
the superior orifice of the nnsfv-Lii-lirymal canal. The inner surface is in rel/ition 
with the two anterior celts of the ethmoid (lachr\m'WthnKiidal), i«m\^ part of the 
iiU"undi!>uIiiiii, and iiiferiorly lonlts into tbo middle uioalus of llie nose. The 
superior border is short, aiKl articulates with the internal angular prore.ss of the 
frontal. The lower border jxisterior to tbo ere»t joins the inner edge of thp orbital 
plttteof the maxilla. The narrow piece, anterior to the ridge, is prolonged downwards 
as the descending process to join tho Iachr>'mal procefs of the inferior turbinate. 
The anterior border articulates with tlie po-sterior border of the frontal process 
of the imi.\illa and liic posterior border with tlu; luniinu papyrucea of the etJunoid. 

Tho vcssel-s of the lachrj'nial linne are derived from the infra-orbital, dorsal nasal 
branch of the npbthaWnic, and anterior ethmoidal artcj-tes. 

Articulations. ^The lachrymal articulates with the etlimoid, maxilla, frontal, 
and inferior nasal concha. 

QtuficAtion. — ^This Ixmo &ri!«ex in tlie m«rnbniTie overlyiiiR the cartilage of tlie fronliv-iuual 
plat*, ami in iW mode of orwification if* very variahlo, Aa » mlfl, it i« fomwd irrtm n mnelc nu- 
r-leux. which uppmirx in tlit! thiril or fiitirm tiioiith <if ititru-iiti-niie life. Not >ii(ni|iiotidy, Ihe 
hamulus is a WfxiraW clement, uhJ wviiciimnll}' Ihc l>ono l* divided |jy h hori/tiiital Heft, r pn>- 
epM of thr Immna ptipymccn projnctiag b*>iv»'PMi the two halvfls In join iJie fmnlal jiroreM of 
tlw niAxilln. Miirr) nirrly t]ic Ixinu in n'preMiiTcd liy ti p(niii|i of dvUii'lird ossirles mwrinliliiig 
Wumiiiin Ijoiiot, 

The hnmiilju- prociVK fa regarded as reprexvoting the remnina of tjin facial part of dip lach- 
rymal MMtn in lownr unirtuiL*. 

THE yOMEK 

The vomer fpIougKshare bond is an unpaire«l flat Iione. which lies in the inerlian 
plane and forms the lower part of the nasal septum. It io thin ami irregularly 
quadrilatcnU in form, and is usually bent somewhat to one side, though the deflection 
rarvly involves the posterior margin. Kacb lateral surface is covered in tho recent 
state by the mucoaH membrane of the nasal cavity, and is tniverse<l by a narrow 
but well-m.-irked groove, which lodges the naso-palatine nerve from the spbenu-pala- 
tlne gannUon. 

The superior border, by far the thiekest part of tlie bone, is expanded laterally 
into tw)i alse. The gniovelx^lwcen them receives the ro.strum of the sphenoid, and 
the margin of each a)a comes iiit-o contact with the .sphenoidal |>roce,'s«i of the. jHdate 
and tlic vaginal process of the intemtd pterygoid plate. The inferior border is 



76 



THE SKELETON 



uneven and lies in tho rtoovc formed by the ercsl« of the maxillary and palate honea 
of the two bides. Tlie anterior border slopes downwards and forwards and id 
grooveil below for the wepnU fartilafip of the nose: above It. is united »viih the |»r- 
pendiculftf plate of the ethmoid. The posterior border, smooth, rounded, and 
covered by mucous tnembraiie, separaies tiie posterior narea. The anterior and 
inferior bon.iere meet at the anlenor extremity of the bone whit-h Umiw a short 
vertical ridge tieliind the incisor crest of the maxilla?, t'ruin near the anterior 
extremity, a small projeetiim paBses duwnwaixlt; tictween the incisive foramina. 

Fig. SS.— Thb Voueh. {Ride view.) 



INFUIOR MIIODl 



mriuoti miDut 



The arterial supply of the vomer is derived from the anterior and posterior eih- 
moidal and the s|)heiio-pal.ii.inc arteries. Hmiiches arc al.^j deriveil from the 
posterior palatine through the foramen incisivum. 

Ottjfication. — 'l"ho vomer w o>.«ificci from two rcntrr* whirh apptnr aliout tho ciKhlh week 
in clie iii«:iibniiiG mvestitut ilii* vtlinio-vonivrirti- c-Hrtiltigi'. 'I lip Ini) hiiiicltH- unite b«low diu> 
inj; the tiiird montji ami foriii a HKiilkiw bony trc>t^;h in uliivEi tlir lurtiliigc Uen- ]n tlie pro- 
i-eMt of Kruwth the LunclLo: rxt^'nd upnardi und forwnrdn nnd er&dutiUy fuse tn ttinii a rcrtangll- 
lar plat« uf booe, Uie cttrlilnge ciirluxfd 1win<i-ri tlicm umlprgoin^ alMorpljtm at tbe mmdp 
timff. The alie on tlie ouperiur margiu und the lEnxpve in fruiit 4iro evidimce of the urigina.! bi- 
liiminar condition. 

TIIE \AS.\L 

The nasal are two small oblonj? bones situated nt the upper part of the faec and 

foniiin'^ the bridt^e of the nose. I'j»ch hone is tliiokcr and narrower above, thiniipr 
and broader below, ami presents for examination two gurfaces and lour bordeiD. 
The facial surface is concave from above downwards, eonvex fnmi Bi<le to side, 
and iiisir the renlro is perforated by a small foramen, which transmits u small trihu- 
tar>* to the facial vein. The piwterinr or nasal surface, rovered in the reeent state 
by mucous membrane, is concave laterally, and traverseil by » lonfritudinal groove 
for tlie anterior ethtnoidal branch of the ophthalmic division of the fifth rierx'e. The 
short superior border is thick anil seiTate<l for hrtifulation with the inner pari 
of the na.sal u'llch of the frontal. Tho inferior border is thin, and serves fur the 



Fio. 8M.— The Leit N.\*kti, BOJfE. 



aurenm MRaEH 



HCDUNMniU 



ovm loucR 

MffH* eOMCK ' 



^Jv 



unit 



attuchment of the lateral nasal cartilage- It is notched for the cutaneous branch 
of the anterii>r et hmoidal nen-e. The najwil hones of the two sides are united by their 
media] borders, fomiinjic the Intemasal suture. The contiRUous borders are pro- 
luojiod baekwanls to form a crest which rests on the fmntal spine and the anterior 
border of the jwrpwiilicular plate of the ethmoid. The outer border articulates 
with the friintttl prnress of tlic maxilla. 

Arteries are supfiliwi to ihis Ume by the nasal branch of the ophthalmic, the 
frontal, the aiitrular. and the anterior ethmoiilal arteries, 

Articulations.— With the frontal, maxilla, ethmoid, and its fellow of the opi>osttc 
Hide. 



THE MAXILLA, OR UPPER JAW 



77 



Osftilicdtioa. — Each nasad bone \a de\'«loped from a &inj;le centre which Apfienni about Uii* 
etgliUi wwk ill tits mviubmne uvprlytiijc lite froiito-Diuial cartilaxe. Ilie rArtilfiR«, wlijrh U 
conr.iniiniH nith Uih ethintnd irartiluffe above oiid ihi' lal«ml (.■artilasi' nf the noiie bclnu', ^iil>- 
fte<|iiently und^rsoea atMorpUoo aa a mult o( iho prowurc oaiL<wHl b^ tlie expanding hone. At 
birlli tlie niuiul bones are neorlv an wide ax iJiey uj« long, M-hvrvas in tho adult tlie length is 
three times greater than tlie wiuth. 



TIIE MAXILL.\. OR UPFKR JAW 

Thfi maxilla ia one of ilif larpcwt and mofit important of ilie bone* nf IliP face. 
It supportin till! niaxilliiry teeth niui takes part in the fumiatitm of the url>it. the 
harti palate, and the nasal fossa. It is divipiblc into a body and four prtK-csses. of 
whirh iwfv— the frontal and zygomatic — belong to the upper part, and the palatal 
and alveolar to the lower pnrt of tlic Ijomc. 

The body is pyminidal in !>Iijipe and hoilowecl by a Urge cavity kno^^•n uk the 
sinus maxillaris (antrum of Highmore), luied by inucou:^ nipiubrane in the rci^eut 
state, 1111(1 n[X!nin^ at the i»ji«: of t!iB pymniid into the na!<Hl cavity. The facial 
surface l<i<tUs fnrwards and outwartia and is miirkt^l nt its Imvpr part by a K>rie.s of 
eminences which indicate the positions of the fangs of the teclb. The eminence 
proJueed l»y the fang of the canine tonlh is very prominent and Repiirates two fojwffi. 
That on the inner side is the incisive fossa, and gives origin to the alar and ImtiRtrrae 
jHjrtuTiifi of the TULmHs, and just al»ovc the aicket of the hdcml incisor tooth, to a pJip 
of the orbieiUaTis oris; on the out<>r side is the canine fossa, from which the caninus 
{levaior nnguli nri.i) arises. Above the canine foswi, an(i cluHe to tiie margin of the 
orbit, 13 the infra-orbital foramen, throuRb which the terminal braochee of the infra- 
orl)itaI nerve and vessels enwirge. and from tlie ridge immediately aljove the foramen 
ihv. levator L'Aii superiorts takes origin. The inner margin of the facial surface is 
ileeply conra%'e. fonning the nasal notch, the eilge of whirh givct* attachnienl to 
the dilator uaris posterior, and is prolonged below into the anterior nasal spine. 

A ridge of bone extending up^vards from the socket of the first molar tnnili .«epa- 
rates the facial froni the infratemporal (zygomatic) surface. Thie ^^urfitce is 
convex atiJ presents near the niidtilc the orifices of the posterior alveolar 
canals, transmitting the posif-rior alveolar vessels and nen-cs. The posterior inferior 
angle, known il4 (he tuberosity, is rough and is most prumincnt lifter ervijuion of the 
wisdom tooth. It gives attachment to a few fibres of the internal pterygoid muscle 
and articulate with thtf tuberosity of t!ie palnte. 

The orbital surface is smooth, irr^ularly triangular, and forms the greater part 
of the lloor uf the orbit, .\jtteriorly, it is rounded and reaches the orbital circum- 
ference for a short distance at the root of the nnaal prttccss; cxlcmally is the rough 
surface for the jiygomiUic bone. The ptwiterinr border, simioth and rounderl, forms 
the inferior boimdar\" of the inferior orbital fisstire. The intemnl border is nearly 
straight and prcsent.4 behind the frontal procpiis, a wmootb rounded angle forming 
pu.rt of the circumference of the orbitnl orifice of the naso-lacbiyma! canal, and a 
ncit-i^h which receives the lactir\'iiml bone. The rest of the inner bonier isnmgli for 
aniculatioii with thelatninu papyracca of the etlmioid and orbital process of the 
palate bone. 

The orbital surface is traversed by tlie Infra-orbital groove, which, commencing 
at the posterior border, deepens tut it passes forwards and Cnally becomes closed in to 
fiimt the infra-orbital canal. It transmits the second division of the fifth nen'e 
iirid the iidnmrhital vessel? and terminates <)n the facitd surface unmetliiitely 
lielow the inaririn of the orbit. From the infm-orbltal. other canals — the anterior 
and middle alveolar — nm downwards in the wall of the anfnim and tran.'miit the 
.interior and middle alveolar vesseln and nerves. Kxternid to the c<i!nmcncement 
^^ uf llie hichr>'m:i| canal is a shallow depression for the origin of the injenoT obtiqne. 
^H The internal or nasal surface takes part in the fomiation of (he oute-r wall of 

^H the luLsal fossa. It presents a large irregular ajierture which lead^t into the antrum 
^H and. innnediately in front of thi^, the lachrymal groove, directed dfvn'nwartls. 
^H backivard.i, and outwards into the inferior meatus of the miwe. The groove is cnn- 
^H verted into a canal by the lachr>'mal and inferior nasal concha and tran.-imitR the 
^H natto-lachryinal duct. In front of the sroovc i^ a smooth jiurface crof^ed obliquely 
^0 by a ridge, the conchal crest, for artirulnlion with the inferior nasal concha. The 
W surface below tlie crest is («n(N»lh, concave, and belongs to the inferior meatus; the 

^^ Burfaee above the crest extends on to the lower part of the nasal pnyess and forms 



78 



THE SKELETON 



the wall of the atrium of the middle raratus. Brhind the opening nf tho antrum 
the surface i:^ roup;h for articulation with the vertiffll plate of the palate bone, and 
croBsing it obliquely is a smootli groove cuiiverttxl by the palate into the posterior 
palatine canal for the passage of the anterior palatine nerve and the descending 
palatine artery. 

The frontal process, somewhat- triangular in shape, rises vertically from the 
angle of the maxilla. It-s outer surfiicc i^ continuoiw with the fariiJ snrffti^e of the 
body, and ffivcs attarliment to the orbiaihris ocidi, the Undo oculi, and tlie 

Fto. W. — T«K I.Kn- M.UCIIXA. (UuUr view.) 



iNflu-oniTiii mtm» . 



MItL MOTCN ' 
MTWDH ttlMA Sf-iNE 



IMJa. WNQICt . 






11 "il 



1 



'•yi»»ee_, 



h 



BBRDUI 01 INIWOit OFttlTJU. (IglURt 

laKimiiioiB 

irSOWTIC lUHMCt 

.-rooHjiTic Picactss 



TUBUOSlTI 



levaior labii superinris nlcBque nasi. The interna! surface forms part of the lateral 
Imuiidan,' of the nasal fossa and is civ>s.se<] obliquely by a low ridge, known as the 
agger nasi, Uniitini;; tlie atrium of the middle meatus. The hinder part of llna gur- 
face rests on the anterior extremity of the labyrinth of the etiunold and completes 
the niaxillo-ethmoidal eells. The suixirior border urtieulatas with the fmntal; 
the anterior border artieulates with the nasal bone; the pwtcrior boirter is thick 
and vertically grooved, in continuation with the lachrymal Rfoove. and lodges the 
laclirj'mal sac. The inner margin of the groove artit-ulates with the lachnTnal 

Fio. SI.— Thb Lb?t &Uxiua. (Inner view.) 

. raaiirti ntoQiti 

lUDU fOII Iit0lll.f CONOH* Of ITHMtB 



MM 



ucmruAL ORcait 

CON SHU CHEST 






IMTtRIDIi NUtU. mME 
'IIOttVE OHDOIE 



Ixine, and the junction of its outer margin with the orbital surface is indicated by 
the lachrymal tubercle. 

1'he zygomatic process, rough and triangular, forms the summit of the prominent 
ridg« of bone -M-parating the fa^-ial and zygomatic surfaces. It articulates above 
with the zygomatic, and from it« inferior anfile a few fibrea of the ma.inrttr taltc 
origin, 'liie anterior »nd posterior surfaces are continuous with the facial and 
xygomatic surfaces of the body. 

The palate process projei^ta horizontally inwanls from the inner surface and, 
with the correiii|}ondiitg process of the opposite side, forma al>out three-fourths 



THE MAXILLA, OH. UPPEH JAW 



7U 



of the hiini palate. The superior Rurfnce is smooth, concave from side to side, nnd 
constitutes the Iflrger pan of the floor of th<- iiaaal fossa. The inferior surfare is 
vaulluJ, rough, and perforat<^ with foraniiiia for uutrient vesseU. Near it* lateral 
margin is a longitudinal groove fur the transmission of the vessels and ner\-c« which 
issue al the poeitenor palatine canal and course along the under at^pect of the palate. 
When the bon&s uf the two sides are pUiced in appiwition. a lai'ge orifice may he 
seen in the middle line immediately heliind ihc incisor teeth. This Is the incisive 
fossa, at the bottom of which are four foramina. Two are small and arr!mRc<l one 
hehiinl the other exactly in the meso-palatine suture. These are the foramina 
of Scarpa and transmit thenaso-palaliiie nerves, the left passing through the anterior 
and the right llirnugh the posterior aperture. The hiteral and larger orifices are the 
foramina of SteDson, repre^seiiting the lower apertures of two pa-ssiigca by which 
ihe noisc coiimiunicates with the mouth: they transmit nnnie terminal branches of 
the descending palatine artery to the nasal foss», and lod;jc reeejwes of the nasal 
mucous membrane and remnants of Jacobson's organs. Running outwards from 
the incisive fos.sa to tiie space lietween tlie seeoiid incisor atid catiine tooth, an indis- 
tinct fiuturc may sometimes be seen, indicating the line of junction of the uia.\illaiy 
and pre-nmxillan.' pnrtiinw uf the Iwiie. Tho premaxilla or incisive liitne is the part 
which bean* the incisor teeth and in some animals exi>;ts throughout life u.s an itulc- 
pendent element. The posterior border of the palate pro<.-es.s U rough and }*rrated 
for articulation with the honcontal plate of the palate bone which completets the hartl 
palate. Tim menial border joins with its feliow to fonu the nasal crest upon which 

Fio. 92. — SscrtON or lUxiiXJC to aiiotv Tar. Floor op thk Maxillabt Axtruu. (Reduced i.) 



BonnoGcn 



li^ 



the vomer \h received. The mom elevated imterior portion of thi.'; border is known 
as the incisor crest, iiiid is cnntinncl forwanlw into the anterior nasal spine. The 
septal cartilage of the nose resta on its nummit and the anterior extremity of the vomer 
lies immediately behind it. At the side of the incisor creet is seen the up|x*r aperture 
of the canal learling from the nose to the mouth (Stenson's canal), which in its course 
dowiiwanis het'omes a groove by a defieioncy of i(i» inner wall. Thu-s when the 
.two iKmes are articulated a fossa is formed (incisive) with the lower ends of two 
canals opening into it. 

The alveolar process is rre-scentic- in shape. spoivE>' in texture, and prcwnts 
cavities in which the teeth are liRlge*!. When cnmplete there ait eight tooth-cavil ies. 
with wide mouths, gradually narrowing as they pa-ss into the eul»stanceof the bone, 
and forming exact ini|>r(Wfiions of tht- cornjwpondiim fangs of the teeth. The pit 
for the canine tootli is the ileei)est; lho«; for the nv^ars are the %vidwt, and prewnt 
8ubdivi.*ions. -Along the outer asi>ert. of (he alveolar process the buirinatvr arises 
as far forwani.s a« the first molar tooth. 

The maxillary sinus or antrum, as the air-chamber oecnpyinK the body of the 
bone is callei-l. is somewhat pyramidal in sbape, the base being represented by the 
nasal or internal surface, and the apex corresjjonding to the zygomatic process. In 
ailditioTi it has four wall.«: the suiierior is fonnwl by (he orbital jilate. and the 
inferior by the alveolar ridge. The anterior wall corresponds to the facial surface 
of the maxilla, and the posterior is fonned by the zygomatic surface. The inner 
boundary or base presents a ver\- irregular orifice at its posterior part; this is par- 



80 



THE SKELETOX 



Unlly filled in by the vertical plate of the palate bone, the uncinate pmcess of the 
ethmoid, the maxilliin* proci'ss nf the inferior nnsnl ronrtm, and a small portion of 
the lachryinal bone. Kven when tho^c bones are. in their relative positions, the 
orifice is very irregular in shajie, and requires ttie mucous nicmljrane to (onn the 
definite roundetl aperture (ur aiwrturev. for they :u:e ufteti multiple) kuonn as the 
opening of the slaus ilu'ough which the t-nvity conununicau-A with the middle 
meatus of the iu.kge. The cavity of the sinus varies cansidenUiiy in aise and sJinpe. 

Flo. oa.^TuK Maxilla at Birth. 

raui*jiiU4i wtrtoM 



•I- 



Ovitt vltv. 



lufrrlor *lr>. 



llltllT 111' 



In the youuff, it is small and the walls are thick: as life advances it enlarges at the 
exi^nse of It* walL^, and in old iiye they are often cxta-niely thin, so that m-t'ai^ionally 
the cavity extend* even into the aubstancc of the zygomatic l>one. The floor of the 
sinud is usually verj' uneven, due to prominences corresponding to the root« of the 
molar teeth. In most csises the bone sepunitinj? the teeth from the sinus is very 
thin, and in some ra.se.s the roots project into it. The teeth which come into closest 
relationship with the sinus are the firet iind second molars, but the !*ockets of any of 

Fio. 04 — Maxill-o at the em> or tvt: Fiiwr Duxtition is norii ok which the Sl-tl-rbb 

BICTWKKK MAXU.IJI ANb l*aKiUAXU,Uk, AND l>KrwB£N TUE TWO I*Aim4 OF TUl: I'ltMIAX- 
ItXA, HAVK rKIKISTKI). 

" ■ CWiBlilAtUUUI UklU 



*-A 



tn«UIN«CUl«K UNAi WITH tSOTM 



prDaoNAiHieH 



X! 



/ 



- - OlM-MUOeiiiTHIC tiflWU 

- — VEM-aHMTHta lUTUU 



V ♦ 



y 



1 



the teeth lodged in the nin-xilla may, under diseased conditions, communicate with 
it. As a rule, the canty of tlte sinus is single, but oecasiotially specimens arc seen in 
which it is divided by bony wpta iiitw chiunbers, and it is not imcounnon t<i find 
nn^essefl separated by bony procefaes, The roof of the sinus presents near its anterior 
BspfM<t what appears to he a chick rib of bone; thw is hollow and corresponds to the 
inirH-orl-iilfit eaiiid. 

The most satisfactopi' inethoii of studyinE the relation of the bones clowng in 
tlie h&tie of the anlnun is to cut away the outer wall of tiie cavity (see Gg. 107). 



THE PALATE BONE 



SI '» 



The maxilla in a very vascular bono and \i» iirterieM aiv nuniemus and larfce. 
They are derived from the infra-orlutal. alveolar, descending palatine, spheno-piila- 
tine. eth[nni(l:il. frontal, nasal, and facial vessels. 

Articulations. — With the fmntal. nasal, lachrymal, ethmoid, palate, von»er. 
zygotmilic, inferior nasiil foncha and it,** fellow of the opposite side. Occasionaily 
it artriculates with the great winjB;, and the pteryKokl process, of tbe sphenoid. 

OBsificatimi. — The itiaxillm is developed fruiti Kverul cvtitres wliicti arc dcnoiiiUMl in nKin- 
bmoc during the Mcond mnoth of inLra-iiu>rin<> life. Several piVrrw nn rrimicu which spM-dily 
fuae. Ml Uiat ut birUi, with tbe exception nf the indaoT lUftiirv xcjiiiriitinK tlie ninxilla from the 
premaxilla. thvm is no truce of tiie ooinptwite charapter of tlie bcMie. Tlio ccntn* uf tMwiH<^tioii 
compriM— (It Ihft malar, whirli sivoB nae toUie portion of hone nut«ii)v iht- inrra-orbjtal amn]; 
('2> thv mftiultary, from h-IiuK the frealer part of Itii? txidy »iid tin- fmiitnl pmccM arc ite- 
veluped: (3> lh« paiBliji«. runniii); tlif Iiinder ll.ree-fourtlia of tho pahilal pruccse and adjoin- 
ing part of th« nawil wull: <4i Uie prcinaxillary,eivia|{ Hhc to lIlc independent premaxillnr}- 
bone (cm inciMvum), ^^'Iho-'Ii iud^na trie tnc-i'uir tcoth and cii]ii[>VlrK thr xnttTior lotirlhnf thr 
bwd pahito. In tliv early staoc* uf Krowtb tlie prcmajiilla may cooKi*! of tw^i pimmw urifitng 
from two centres o( otwihcntiiiii whirh \lbrw?ht has nnnii^d in* follows;^thr cnrfn./nofftwn, or 
iDtrnm) iliviiinn for the ruiitra] iruTiMtr, ,iiid the iif^migrinlhiun, or ext^^naldiviMfiii lor rhr liit«-ral 
iaciwr: llic n-st of llic muxilU i« iisuiied the tjinjnaihwn; (.M the |>repalaUoe, currvt^poiiditm; 
to the Infra -Toraerine centre of Ramhiiud and Renault, iunint a p^irtitm of Imnc int^rixMiNl be- 
tween th(t preiuuxiHury in fmiit aiid tlm ii.ilHlirie jiriMCM liehtnd. Il givx-ji riw to a part of tbe 
nasal Mirfare and complotci tlie mmiaJ wall of the incisive canid. 

At birth the sinu< i* narrow from Hide to aide and dooa not extend outwardx to any appre- 
ciabie extent iK-tivewn the orUt and Uie al^-euli i>f the (eetb. Durinff IJie curly vtm ol lif© 
it p-adindly I'tilargiu, hul doca nut attain iUi full growth uiilil after tlie period ol the iceDad 
deutilton. 

THE P.\LATE 

The palate bone is rectJinguKir in shape and rnmia (he posterior part of the 
harrl palate, the lateral wall of the nasal fossa between the maxilla and the internal 
pter>-Koid plate, and, by its orliita! prnres**, the hinder part nf the floor of the orbit. 
Il preseiitji for e-vaininsitinn u horizontal plate and a perpendicular plate; at their 
point nf junction is the pyramidal process, and ^uiinounting the ti>p nf the vertical 
plate are the orbital and sphenoidal proct^sacis, separated by the spheno -palatine 
notch. 

The horizontal plate resembles the palatal process of the maxilla, but is much 
shorter. The suiwrior surface is smooth, concave from side to aide, and forms the 



Flo. 95.— Pauat* QijerT) Bokb. pinner view.) 



SPHINailllLL tlOf.U 

' : !■( iSICH 
MUtK II 
I' MUtE 

i.j... .; .. .,,Lro«.tv- 

tukia HHH H^NiMUIDH 







wirtRion M»nil 

tTHVOItUl MelT 



DOItlUL CRIVT 



Imck part of the floor of the nasal foewa: the inferior «urface compleief: the hard 
palnU* behind mid presents near ita posterior border a trunsverBe ridjie which };i\'es 
attachment to the te-nnor palati muscle. The anterior border Is rough for articiJa- 
tion with the palatal procej« of the maxilla; the |->ortterior is free. fur\'ed, and .sharp, 
Kiving attai-'linicnt to the soft palate. Internally it is thick and broad for articula- 
tion with its fellow of the opposite side, formine a continuation of the crest of the 
palatal processen of the niaxilla- itnd ^-upiH»r!in)i ihe vonipr. The hinder extremity 
of the crest is the posterior nasal spine, from which the ttzygos uvulir arises. Ex- 
ternally, at it« junction with the vertical plate, it is grooved by the lower end of the 
posterior palatine canal. 
a 



S2 



THE SKELETON 



The perpendicular plate is lonser and thinner than the horizontal plate. The ex- 
ternal surface is in relation with the maxilla and is dmded into two panti 
by a vertical grtKivc which [onus with the maxilla the posterior palatine 
canal for the transmission of the unit^rior palatine nerve and the descending 
palatine artcrj'. The part of the surface in front of the groove articuhiti?;! with 
the nasal surface of the maxilla and overlaps the orifice of the antrum Ijv iht- maxil- 
lary process, a variable projection on the anterior bonier, litiliiiid the groove 
the surface is rough far articulation with tlie maxilla below and the internal 
ptioo'goid plate abo^e. 

The internal or nasal surface presents two nearly horizontal ridges separating 
three shallow depressions. Of the depreasions. the lower forms part of the inferior 
meatus of the nose, and the limiting ridge or conchel (inferior turbinate) crest 
articulates with the inferior nasal concha. Above this is the depreeaion fomiiiiji; 
part of the middle mcatas, and the rid);e or ethmoidal (superior turbinate) crest, 
con-stiiiitiiig its upfMT bdUiKlary. articulates with the middle nasal iHuielia. The 
upper groove is narrower and dcej>er tlian the other two und fonns a large part of the 
superior meatus of the nosr^. The anterior border of the vertical plate is thin and 
bears the maxillary process, a tonffuc-lil;c pieee of hone, which extends over the 
opening of the uiaxiiiary sinus from behind. This border is continuous above with 
the orbital process. The posterior bonier is rough and articulates with the anterior 
border of the internal pterygoid plate. It is eontinuous superiorly with the sphe- 
noidal process. 

Fio. 9fl.— Pacats Bonk. (Posterior viiyw.) 



DROru fitVKt 



IIUMITIO SUMMIT 

miEM-nuiniE lauittti 



wertii naan 



- tmtnoiMt nuKOi 



noon RM araBUL rtnwni . 

mon rw rrutios'i roiM 

iwwn to* imuiaK tnmva 



■ jfKt Bi tujrt 



rxBuahTY— . 



The pyramidal process nr tuberosity fits into the notch between the lower ex- 
tremities of the ptervKoid plat« and presents posteriorly thi-ee grooves. The middle. 
siu(«)lh and concave, ronif^etes the ptengoid ftwssii. and fiives orijiin to ii few fibres 
of the internal ptcryqoid; the inner and outer grooves are rough for articulation with the 
anwrior border nf the corresponding pter}'goid plate. Infrriorly, cliise to it.-* junc- 
tion nith the lioriKontJil plate, are the openings of the posterior palatine and acces- 
sory palatine canals, of which the latter are the smuller and less contilant: they 
trnnsmit the palatine nerveis. Intemidly the pyi-aniidal process gives origin to a 
few fibres of the xnftrn/ir constrictor of the phar>'nx. and extenially a small part 
appears in the zygomatic fowa between the tuberosity tif the maxilla and the pterj-- 
goid process of the «phennid. 

The sphenoidal process, the smaller of the two processes surmounting the 
vertical plate. cur\es upwards and inwards and presents three surfaces ami two 
bonlenj. The superior surface is in contact with the body of the sphenoid, and 
llic lop of the iiitenial pterygoid plate, where it coniplctos the ptery go-palatine 
canal. The internal or inferior surface forms pari of the outer w all and roof of 
the nasal fo(wa. and at its inner end touches the ala of the vomer. The external 
surface looks forwards and outwards into the pterygo-palatine (spheno-maxil- 
lary) fosaa. Of ihc two Iforden*, the posterior is thin and articulates with the 
internal pteryumd plalc; the anterior border forms the posterior bcnmdar>- of the 
spheno-palatine for»nien. 

Tlie orbital process !-« somewhat pyramidal in shape, and presents for examina- 
tion tivc surfaccH, three of which — the ptwterinr, anterior, luid interniU-are articular 



THE ZYGOMATIC HONE 



83 



And the nsl non-articular. Tlie posterior or sphenoidal surface is smnll and 
jouis tbe autcrior surface of the bmly of the spheooid; tlic mtemal or ethmoidal 
articulates with the labyrinth of tlic ethmoid; and the anterior or maxillary, which 
is continuous with the exlemal mirfaci; of the perijemlirular plate, ia joined with 
the maxilla. Of the two non-articular surfiicos. the superior or orbital, directed 
upwards and outwanls, In slightly conravc, and foniw tho posterior anpilt of tlie floor 
of the orbit; the external or zygomatic, smooth and directed outwards, looks into 
the pterygo-paJaline isphen'>iimxi]lury i and zygomatic fossK. and foniiK the anter- 
ior boundary of the J^iilifno-tmlatine foramen. The procctss ii^ UHUully hollow and 
the cavity completer one of Uie jxisterior ethmoidal cells or communicates with the 
sphenoidal sinus. 

Detwcen the orbital ami Rphenoidal processes U the spheno-patatine notch, 
converted by the body of the sphenoid, into a complete foramen. It leads from 

Fin. 07. — Maxilla ano Pai.\tii Bohis showimq How tiik btFRA-ORerrAL Gmoove Rcsa Out- 
wards ALMoflT AT Rianr Anoi.i» ruou Ttir. NEtoHBoiHiioon of tug SrtiENO-PAiATtvB 

FokAUKN AJtO lNVci|.rK>4 MOTH THK HxlK Of TIIE MaXIU.A A.M) THE OKBITAI, PkUCISBS Or 

■ma Palats. <E. Fuwcetc) 



. nfU-DMITU. tumt 



■X^ 



the pten.'go-pftlatino fossa into the back part of the na.<ial cavity close to ita roof, 
and transmits thfl inlernid branches from the spheno- palatine ganglion and llie 
!sphem>-p:ilatine vessels. 

The piiiate receiver branches from the dettcending palatine awl the5pheno-paU- 
tine arteries. 

Articulations.— With the uphenoid, maxilla, vomer, inferior nat-ul coocha* elh> 
moid, and it» fellow of the appoflit« side. 

OeclAcation. -The palate i* oMified in mMiibrarie from a ajiikIc ftntrc «hich Appmrn aliout 
Uifl rwhtii viifk »t the anglo betweea Ihe hnri/nntnl and p«rp4ri)dKriilHr plitt«^. .At hirth th« 
t«-o plu,tu» An ui'urly- (k|UiiI in ImiKLh, htiL an ihe iiuHd toeeue iui^rcjLM.- m vorticJil ilvplb, thv 
pftrpcndieiiUr pUlo i Icngthr-ned unTil it bocrutnea about twice m long m the horiionml plntc. 



THK ^vc;o:\tATic 

The zygomatic or malar bone forms the prominence known a^ the cheek and 
joiiLS llio zygomatic pHK^es-s of the leinpornl with the maxilla. It is (|Uitdraiigular 
in fonii with the anple.s directed vertically and horizontally. The malar or external 
surface is convex and presents one or two small orifiees for the transniisflion of the 
r-v^tomatico-facial nervea and vessels. It is largely covered by the orbictilaris ocult 
and near the middle U ftlightly elevated to form the mslar tuberosity, which 
gives oiigitL to the zyyotnatkus major and minor. 



84 



THE SKELETON 



Tlic temporal or internal surface is concave and looks into the temporal and 
zygomatic lossx; it is rxoludcd from the orij'it hy a prominent cun'ed plate of bone,.' 
Uie orbital process, which forms the anterior boundary of the temporal fossa. The 
upper pert gives origin to a few fibres of the temporal niusK-'lc, while at the lower [mrt 
is a lar^e rough area for artieulation with the zygomatic process of the maxilla. 

The orbital process it: plawsd at right angles to tlie reitiaiiiinff part of the hone 
and forms the anterior niirtioii of the outer wal! of the ori>it. On the orbital snrfare 
of the process are seen t lie orifices of two zygomatico-orbital canals, which traniunit 
the zvgOKiatieo-facia! and /.ygomaticn-temporal branches of the xygomatie branch 
of the fifth, together with two small arteries from the larhrymal. In some cases, 
however, the eaual is single at its commeocoment nu the orbital plat<- and bifurratea 
OS it traverses the bone. The mugh free edge of llie ]>riii-es^ articulates above 
with the zygomatic border of the great wing of the sphenoid, and below with the 
maxilla. When the orbital process is large, it exclurleis the great wing of the sphe- 
noid friMii articulation with the masilla. and the border then presentjs near the 
middle a short, non-serrated portion which closes the anterior extremity of the 
inferior orbital (spheno-niaxUlarj') fissure. 

AH the four iinglew of Uie nygninatie bone have diHtinguishing features. Ilie 
superior, forming the froDto-sphenoidal process, is tlie most pronuneut, find is 

Fm. 08,— The Ixn M.ila« Bon-s. 
A, from the outer si^le. li. from the inner aide luiti slightly from lh(.> front. 



MMTM. PROOEU 



HUM QtNtl 



nOOtnut WRWMW T«npor»I- 



IIUNTM. MOCIU 



■lIKMAtKO-ontta. 



L« Tutor In nil 
■ui-artoriA 

wuiiuini aowtn 



Sytoan ■()«»■ nitMV 
Zj><om«Uaua mator ' 






■BKCIN 



NMIfTlRIO 



■CMMitr 



HAIM TVKKOa 



umirw. rMCf ;i 

lt|(U. 

noci» 



j-J.' 



i K 



UkM TUBERUE 



vutLum* BsnDtn 



serrated for articulation with the zypomatie process of the frontal; the anterior or 
infra-orbital process, sharp and pointed, arliculate.4 with ilie inaxillH and urca^ion- 
ully ionutt the superior boundary of tlie infra-orbital foramen; the posterior or tem- 
poral process is blunt and serrated mainly on it.i inner a.spect for articulation with 
the zygomatic process of the temporal: the inferior angle, blunt and rouuded, is 
known as the malar tubercle. 

Of the four borders, the infra-orbital is (he longest and oxtondfi from the fronto- 
sphenoidal totheinfm-orbital phxthu, It is tliirli, nmiuled, and forms more than one- 
ihini of the circuniference of the orbit; tlie temporal border, extending from the. 
fronto-fiphenoidal to the temporal pnvciW, i,'? sinuously curved and gives attachment 
to tlic temp.-tral fascia. Near the frfrtital angle is seen a .sliglit elevation, the proces- 
sus marginalis, to which a :(trongslip of the faecia is attached: the masseteric bor^ 
dcr, ihiek and rough, completes the lower edge of the zygomatic areh aiul gives origin 
to the anterior fibres of the jiumdir: the maxillary border, rough and cotica^-e, is 
connectwl by suture with the maxilla, and near the margin of the orbit gives origin 
to a portion of the Icmtnr lahii »uperioH8. 

The arteries of the zygomatic arc derived from the infra-orbital, lnchi?'mal, 
IninHvcrn*' isciiil. and deep temporal arteries. 

Articulations.— With (be maxilla, fnmtal, temporal, and sphenoid. 



THE MANDIBLE, OR LOWEK J.iW 



$5 



OssifiCBtioii. — Pio zygoniRtir JK owiHed in niBiitl>riuic trom tliri'C rciitrt-tr which apptiur in 
tlio eighth week o( intrit-iitorinc li/r. Thp iJiwe piw-c-s, wliirh h»ve rt-mvod the tinincvt of prf 
rnaliir, iMiMinalitr , luid h;f[iiimalnr, tiiiil« xluiiit tUr nlUi tiirjiiOi. ( lt'i-a>juiiiilly Ihr |iririi:iry niirlci 
fail lo co.'JcM-e. aiiJ llw \x>uv w tUvii rfpnisentetl ui lln? aduli l>y two or llinjo |H.>rtio]i5jn;|Hi- 
rnlctl by wKuresi. In i-Jiows r/ww in wiiich Uio pmimlur juicl ptiAinmliir unite lUid tlio^n'^^' 
m:ilnr rem:ui» djatincL, tbe miture lit hohiontnJ; if tlie mdejwndeiit portion u Uie promuiir, 

Fw. 99. — dxcLL *nown«o the Rioht .Malar Bone nrvrnKD into Two Parth bt a Hoici- 
zoNTAL iJrrtHK, (From a tijjeL-im«u 'ui tlio Miuteuin of Uuivoreity Cullcge.) 



^ 



\ 



then the aitiire it verricnl. Tlie hipftriitA zygoniBiic hiw hc*n oba«rved In ultiills oUatnMl from 
nL leaitt u (loutn difler<>nt mixM i>f niiuikincl, Imt Iwrhmw ui tin greater frt-fpitttii'y in wiiicli it 
occurs in tJie crtuiia of the Japauow (aeveo per cenL), che name of oa Japonicum haii been 
gi\-on to ii. 



TIIE MAN'DIBLE. OR LOWER JAW 



the 




The mandible L<; the lorgntt and ntrnngcst bone of the face. It impporiji 
mandibular teeth, and by means uf ii pair of condyles, moves on the skull at the 
mandibular fotssa; of the temporal boucn. It consJi't« of a homoutol portion — tlie 
body — strongly curved, so as to somewhat resemble in shape a horseshoe, from the 
cndn of whi{^li two lirintrlim or rami aneend almost at right angles. 

Tbe horizontal portion or body is marked in the middle line in front by a faint 
groove which indicates the symphysis or place of union of the two originally wparate 
halves of the l>one. This ends below in the devation of the chin known as the 
mental protuberance, the hiwpsi part of which is slightly liepresned in the centre 
and raiswi on each siiie to form the mental tubercle. Karh half of the mandible 
present"* two surfaces and two borders. On the eitemal surface, at the shIp of 
the?<yinphysi!<. imd Iwlow the incisor teeth, isashalldw drpresrtion. the incisor fossa, 
from which the menUtUs and a slip of the orbicularis oris muscle arise; and more 
externally, opjiosite the second hicunpid tooth, and midway between the upper 
and lower margins, ia the mental foramen, which tranKniits the mental nerve 
and vessels, lielow the foriinien is the external oblique line, extending backwards 
and upwards from the mental tubercle to the anterior border of the rannis: it divkles 
the bt«lv into an upper or alveolar p»rt an<l a lower or basilar part, and affords 
attaclimont to the quadrafus labii inferioris and the trian(p.tlaris oris. 

Tli« incerual surface |in'.sciit-s nr tin- l>:ick of iho symphysis four small projec- 
tions, calltut tlie mental spines [genial tubercles), which art* arr:ingi--d in two pairs, 
one above the other: the upper comprising a pair of prominent spines, gives origin 
to the qail0-<fh»<ti, and the lower, representetl in some l>oncs by a median ridge 
or only a iUglit roughness, give origin to the genio-hjoid muscles. At the side of the 
symphysis near tbe inferior margin is an oval depression, the digastric fossa, for 



86 



THE SKELETOS 



the anterior Httachment of the digastru: muscle. Commencing below the getiini 
tubcn^tes, unci cxmiiHtn^ upwiirdH and liackvvanifi to the raitiu». w the internal 
oblique or mylo-byoid line, which befoiiies more prominent as it QpiJroachcM the 
alvoOUr border; it jrivesiittuchmcnt along it^ whole length tn xhe mylo-htjaid muscle, 
at its posterior fifth to the sitj^erior couMrictor of the pharynx, .ind at the posterior 
extremity to the ptervfio-niandibular raphe. Above this; line at the side of the 
5>TnphysiH is a stnoolli dcpre^Mon for the sublingual gland, and below it, farther 
back, is another for the >iubiiiiixilliiry gland. 

The superior border or alveolar process is hollowed out into eight fiocket«i or 
alveoli. These are conicjd in shupc and fonn an exact count-crpnrt of the roots of 
the teeth which they contain. From the extermil aspect of the alveolar process, a^s 
far forwards as tlie first niuhir tooth, the bticciiuitor muscle takes origin. 

The inferior border or base i.s thlek and rounded. In the anterior part of its 
extent it gives attachment to the jtl/itysina . iuul near its juni'tion with the mnius 
is a groo\*o for the external maxillary ;irt*rry wliich hei^ turns upwards on to the face. 

The ramus is thinner than the hocly and r|uadril:itera! in shape. The external 
surface is flat, giveji Jnsertiuu to the massHrr. and at the lower part is marked by 



Flo. 100.— Thc Mamdibi.k. {Oiil«r view.l 

TCDponJ 



COKONOIO 

niaciK 



HlNOIRUUIl 

mren 



SzMnul ^•TTtoM 



' COHDTLE 
Artlovlar 

C«|l«IllM 

' T*in|ior<>- 

Ur ll«a- 
mMtt 



.KM 



Buodualor 






BOD' 



tRl CXI* 0* 
TUIDUHOt 



<NStl 



Triaarulart* orta 



BMOVE roH Errnnmt H«xitu«t uiehi 



aevenil oblique ridges for thc attachment of tendinous bundles in the suVwtanrp 
of the miiRcle. The internal surface presents near the middle thc mandibular 
{inferior dental) foramen, leading into the mandibular {inferior dental) caxml 
which traverses tlie bone and terininjites at the lueiitiil foramen on the external 
surface of the body. From the canal, which in iih posterior tw<>-l!iinls i.s nearer to 
llie iineriml.and in its anterior third nearer to the external, surface of the mandible. 
a series of small channels pass upwanls to the isorkcts of the hinder teeth and tninRmit 
bnuichej* of thc inferior alveolar (dentall ve*»el3 and ner^'e; in front of the mental 
foramen a continuation of the canal extends forwards and conveys the \'e!!8el8 ami 
nerves to t he canine and inciisor teeth. 'ITie mandibular fnramen is Ixiunded intemallv 
by n sharj> margin forming the lingula or mandibular spine, which givas attach- 
ment to tlie f'phenii-mandibular li^iiunent. 

The posterior margin of (he ?pine is notched. This notch fonn.«» the rnmmence- 
ment of a groove, the mylo-hyoid groove, which run.? obliquely downwards and 
forwards nml lodges the inylo-hyoid n^-rve an<l arter>\ and. in the enibrj'o. Meckel"? 
cartilage. IVhiud the spine is a mugh area for the insertion of the intcrtwi 
pterygoid mti-sclo. 



THE MANDIBLH. OH UJWER JAW 



87 



Thc posterior border of the ramus is thick ami rounded, and in meeting the 
infei'ior border of the ranms forms the angle of the jaw, wliich i« rough, obtuse, 
usually evert«(i, tuid about 122° in the aiiutt: the Hiigle gives attaclunciit to the 
stylo-maudjbular ligautent. The inferior border is thick, rounded, and continuout> 
with the base. The anterior border i^ roniimious with the external oblique hne. 
whilst the upper bonier presents two processes separated by a deep c-oncavity, the 
mandibular (sigmoid) notch. Of tlie procettsca, the anterior is the coronotd; the 
poslijrinr. the condylar. 

The condylar process consists of the condyle and the narrowed portion by 
wbicli it is Hiipport^^. ttie neck. The condyle \a oval in shuj)c, with it« ioii^ a\t^ 
trftns\'erse to the upi^Mjr liunier of the nunus, but oblique with regard to the median 
•axis of the dkull, ao that tlie outer extremity, which prtwents the condylar 
tubercle for the temporo-mandibular ligament of the temporo-mandibular articula- 
tion, is a little more forward than the inner extremity. The convex surface of the 
condyle is covered with cartilage in the recent state, and rests in the glenoid fossa; 
the neck is flatt{tned from before backwards, and prciwnts, in front, a depression for 
tlie insertion of the exlrrnnl pterijijuul inviscle. 

TIic coronoid process, fliitteiied and triangular. \s continued upward.s from the 
anterior part of the ramus. Thic external .surface Ls smooth and gives attachment 









WMMULWI SMNE 

MMMUIU r3RAU» 

Mrts-hyDi4 
KtoaTO 



pMrysolil 



flIllo-masitlbuUf 



Fw. lOI.— The MAxmnLR. (Inner view.) 



TaaijMisI 




-»i.f 



MODvt re* sva> 

IJNdUU SIJ49 
DICMUtn 



mS^^^^i 



enocrr fsr tuMUiiiuirr qund 



to the tempoml niuJ man^eter muscles ; tlui intenial surface is marked by a ridge 
which descends from the tip and becomes continuous with the fmstcrior part of the 
mylo-hyoid line. On u> this ridge, on the area of bone in front of it, as well as on 
to the tip of the coronoid process, the tcmpomi muscle is inserted. The mandibu- 
lar or sigmoid notch, the ileep st^tiilunar excavation iwparating the coronoid from 
the condylar process. \s cmased by the nuLSseteric nerve and vessels. 

Comparcti with other bones, the superficial parl.t of the mandible are not so 
freely supplied with blood. The chief arter>- is (he inferior alveolar which nimi in 
the mandibular canal, and hence, a» the Iwne is exposed tfl injury and sometimes 
aetuallv laid bare in its alveolar portion, it often necroses, especially if tlie arterj' 
is involved at the same time. 



Ossification. — Tlie Diandpilc la mainly formod by omtfKatlon in tlie ni>roui listup investing 
the c.irtilat:c of ihc tirst bmnchinl nrth or Mcokel's rartilage, although a smnll portion of the 
Mtrtilnf^f ii-*lf i- (lirertly oiHivfri*-!! intn htmv. 

It IB now gcntniUy admittvJ tliiit iLc lowt-r jaw is drvoloiu'd in ii»piiit»riuie &• a "ineti* *kri- 
etal element. The cfnirc of o^.^ihcntinn /ippmr* in the otiior n--i«»cl. of Mwlidl".-' (^riiln^e and 
gj\'e« ritw <ti Uie liotiy ptato known «« tlie aenlnry. 'l'\\i» [i]me ftxtCHd-. fun* Urdu riglil tl]i t" the 



8S 



THE SKKLETOX 



mid<llc liuc in from. iLnd from [C a «tioIf xrows upwurdu Tur Hie supporl of the (ooth genns. 
M«!krl'«<'Artilflee lien IjcIow and inside the ociilrtry plftfe, tind tlic inferiiir alveolar nerve pawo* foi^ 

of clic lower juu'. Omirii'iitxui (roiu Uie priutiu'y iiui:l<^u.t iiivadtM Uic> ciuUluu «t u puiut op- 
punte tiie iiiterviLl Iwtncen (he 6nt ana second tooth K<^nna, and the ruultin^ boM eontri- 
Dtitea to the formation uC tltc alveolKr manin upponit« ihtte tiro teeUi. Behind thift point 
the cartilsge atrophies exoopC to eo fv w it bdpi to form the apheno-uuuidibular liKotnciii aud 

Fio. lOS. — Thk MANnniLE at Bikth. 



OUTER view' 



INNtfl VIEW 



.^. 



the malleus and incup. Uehiiid the ej-niphy^ii^ rhe anterior extretuity of the cuttlage does not 
enter into the (omuitioo of the jaw. hut it u.-iiia!ly norsintfl throiiglmut ttBtai life a^ one or two 
emitll, rounded, cartilnf^nouf nia^ew. Occaxiunully tliey bet'ome oi**i(icd and fpve rise to 
octeeeory oetUolea in tliL^i nituation. The Inniella of Done situated on the inner side of Meckel's 
rjirtilAf^e, rorTenpondinj; tn the distinrt .ipicnial olemont in some animalB, ariaeR ih man as an 
exteiiHion froin the dentary element. 

Fio. 103. — The Scmx op a Womas Kicktt-^hbee Ye-viw Old, to show thb ClUNOKa in 

THE M.VXU1IILE \Ha WASlLLJi.. 



/ 



/ 



»'*' 



/ 



7 



In i-niinec(iun wilfi the condyljw ami coronoid proceixt-Ji, c.'irtiliud'*oiu nuisiHe* are develojied. 
These do not, however. lEidiukto sepunite elemetili<, hul are adtiptntiwi" to the emwlh ol 
tJie loner jaw. They are o<<(<illed by an cxt^^n.'.ion frotn the wirroundine niejubrruie uonc. 

llie prorcNi of nKHiticntion of Uie lo^fi jaw rnmmeneOK \'erv evrlv, ln-twrcn the aixth and 
eighth week, and procvcdn rapidly, bo that hy tha fourth month tTic variouK parts are fonnnd. 

At Mrtli the mamliljle is rt'prcscntc"! by two liearly liorizoiital ti-oughs of bone, 
lodging uiiLTuptiNl ii.'etli, aiiU juiiifHJ at Llie s>'mpliysia by fihrous ti-isue. The body 



THE HYOID BOSE S9 

is mainly alveolar, tlie ba«al part Ikmiik l>ut little (levelopwl; the condyle and tho 
upiM^r e<lpe "if the symphysis are nearly on a level; the meiilai foramen in nearer 
.the lower tluin tlie upper margin, ami the angle Is about {IXtP. The inferior alveolar 
\ ner\'e lies in a «hulliiw groove l)etween llie splenial ami dentni->' plate-t. 

Ihiring the Hrst year osseous union of the two halves lakes place from lielow 
[upwanls, but is not compleu^ until the !?erond year. After the fir^tl dentition, the 
\ rniDU^ foniia with the body of the mandible an anjik' of aiiout 140°, and the mental 
foramen is situated midway between the upper and lower borders of the bone oppo- 
site the second mi] li -molar. In the lulult. tin; angle ftmiied by the nunuB and btxlv 
is nearly a right aiiijU;. and the mental fcirsunen \a opposite the seccmd bienspirl, 
i») that ltd relative pitriititm reniniiLs unall<;rcd aft^r the first dentition. In old 
[age, sifter the fall of the tpeth, the alveolar margin is absorlied, the angle fonned 
[by the ramus and body is again inrrea>!e«l, and the ntentiU foramen approaches 
the alveolar margin. In a young and vigourous adult the mandible is. with the 
lexccption of the ix^timis portion of the tem|>i)ral, the densest bone in the skeleton; 
'in old age it liecoineis e.\eeudingly pon>u.s. :ind often ho soft that it may easily be 
broken. 



THE HYOID BONE 

The hyoid bone or os linguK, situated in the anterior part, of the neck between 
^the chin and the tliyrtioid i-iirtilagc, j^npports the tongue and gives attaehnient to 
nuracroua muscles. U is tiuspended from the lower extremities of the styloid prf>- 
ce&ses of the temporal bones by two slender b:m<ls known as the stylo-hyoid liga- 
ments, and la divisible into a body and two pairs of processes, the greater and 
lesser comua. 

The body, mn.-<tituting the nenirnl |)ortion of ihe bone. \a transversely placed 
^Jmd (piadri lateral inform. It ts t:nmpre.'<scd f rom befnrf? haekwanlsand lies obliquely 
8o that the anterior surfaec look.s upwards and forwards and the posterior .-surface 
I'.in the opjxisilp (iirectiim. 

The anterior surface is convex and divided by a horisoutal ridge into a superior 
and an inferior ptirticin. Freijuently itals'iprt^sent-s a verlicul ridt;iMT<)s.«ing thefnrtjier 
at right angles, and at the point of inlerseetion is the hyoid tubercle, the vestige of & 



Fio. 104.— Thk HrotD. 



MUTUI OOOMU 



Utttteono 



^'ell-developed proecssin this situation in thehyoidbonenf »omc of the lower animids. 
in this way four .ipaecs or depressioat for muscular attachments art; marked off, 
'two on either side of the middle line. The posterior surface is deeply concave 
and separated fnnn the epiglolti-s by the thyreo-hyoid inenibrane. and by tsome luo«e 
rAreolar tl-tiue. The membrane piusses upwanls from the ihyreoid cartilage to be 
attaelicil to the superior border, hiuI inter]«»Hed betwi-en it and the roiu'avity on 
the baek of the body i? a small synovial Imrsa. The inferior border, thicker than 
the upper, gives insertion to muscles. The lateral borders are in relation with 
the greater cornua, with which they are connected, up to middle life, by 8>'nchondro- 
^■is. but lifter this period, usually by bone. 

The greater cornua projects upwards and Imckwards from the Hides of the body. 
ey lire flattenwl from above downwanls. thicker near their origin, and (erminale 
steriorly in a n»nnde»l tubejclc to which the thyreo-hyoid ligament is attached. 



90 



THE SKHLKTON 



The lesser comua are small conical prrn-esses projecting upwards anti back-J 
wards oppoaite the lines of junction between the body mid ihe greater comua, and by 
their apices give aiiachment to the sty!t>-hyoid ligaments; they are coimected to thel 
body by a aynovial urticulatioii wliicli usually persisfw tliroughout lifn. The lesserj 
comufl lire sonietimcw parity or even completely cartilaginous in the adult. 

Fia. 105.— UioiD Bonk Emlargbd to bhow Mvbcuuih Aitackuf:.\t». 



tlUU WUllI 



Ciioii4r».<lttMtM 



-Hi'«*iloMai 



- Tbrraa-hjoM 



•on 



sirio-urotd 



O«BIO-ll]-0td 



8tei«o-hrM<t 



Tlic muscles attarlter) In each hair of the hyuld tK>ne may bo enumerated as 
folloi^'s: — 

Body Genio-hyoid, Genio-glosaus, Mylo-hyold, Stpmo-hyoid, Omo- 
hyoid. Stylobyoid. Digastric, Thyreo-hyoid, and Hyo- 
glossus. 

Greater Comu . . Thyroo-hynid, Middle constrictor, and Hyo-glosaua. 

Lesser Comu . , ,t'lintittri)-slos.tHH, Superior lingiialin, Inferior lingualis, and< 

Midiile constrictor. 



Osdflcadon. — In the earlv mimths nf tntra-iitorine life the hynid hone is cntnpo«wl of 
hyaline rarlJI.-txe and is directly <wntiiinou!i with the htyloid procew^n of the tenifioral bones. 
(Migration isMea place from eix centres, of which two appear in tlie eeulnil i>tece of carljhice, 
one on cither side nf tlio middle line, during the last inoitthfi of frrtal life; etwn after their 
■|i|)e»raiK--e. however, titey coalesce to form the liody o( the l>one (baai-liyal ). 'Vhe centre fur 
eiidi uf ihe greater cornuu 'thjTeo-hyaU) uppeuis juat hefore the time of birlh. und for each 
rtf the le«er comiia (cerat'i-hyalsi in the seeond year jifter hirtli. The pfpater lomuA and the 
body unite in middle hfc; tiie le.s>er cornua rarely »nky[o*e with the body aiid only in advanced 
age- 

Tlie rortiinx)^ which joins tiie leeaer comua of Hie hyoid with the styloid |troi-«6s in earlf I 
ombryooic hfe eventually Iteeomes convened into the tiylo-hyoid ligameiit. It is aol r 
CDtiunon, hotrever, to find Uiis Ugatnent nssificd in noam part of its exlenl. 



THE SKl'TX AS A WHOLE 

The skull, forrnod by the union of the cranial and facial botics alre*;uly described, 
may now be considered fls ft whole. Tnkingageneralview.it is i-pheroidal in shape, 
«nioolh alx)ve. roiiipre!sse<l from side to side, flattenetl and uneven l.«lo\v. and dl-i 
visible into six reiiions: a superior reeion or vertex, a pofilerinr or occipital region, 
an anterior or frontal region, an inferior region or base, and two lateral regions. 



(1) THK Sl'PEHIOR RkGION 

Vieivttl from above innrmn nrlicalis) the ukull presents an oval outline with 
the broader end Iwhind. ami includes the frontal, parietals, and tlie interparietal 
portion of Ihe occipital. In a .skull of average width the j:\-gomatic arches are 
visible, but in verv luojid skulls thev are obscured. 



9 K^m 



TNE SKULL AS A WHOLE 



91 



The sutures of the vertex are: — 

TIiP metopic, which in, in most skulls, merely a median fissure in. the frontal 
bone jUBi above the glabella; occa^uually il involves the whole length of the bone. 
It 18 due to the |x;rsLsteni'e of the fissure normally spparatino; the two halves of the 
l>one in ihp infant. 

The sagittal is situated between the two parietnlg, and CTtends frona the bregma 
to the lambda. 

The coronal lieu between the frontal and parictaU. and extends from ptcrion to 
ptcrion. 

The lambdoid ta formed by the parietnls and intcrfNuieta] portion of the 
occi[}ital. It extends from a.sterion to asterion. 

The occipital suture m only present when the interparietal exist? as a separate 
element (hgs. o2 and 53). 

The inurt- iin|K)rtant regions are: — 

The bregma, which indicates the situation of the anterior fontaneilc, and marks 
the ponfluerire of the coronal, the sQ.eilltLl, and, when prrscnt, the nirtopir suiiirpi*. 

The lambda, where the sagittal enters the lambdoid suture; it marks the situa- 
tion of the posterior fontanelle. 

The obelion, a little anterior to the lambda, is usually indicated by a median 
or two lateral foramina. 



(2) The Pijstkrior Rkoion 

Viewed from bchlnti (norma occipiUiliB) the skull Is somewhat pentagonal in 
form. Of the five angles, the sujx'rior nrm<H]ian is situated in the line of the sagittal 
suture; the two upper lateral angles coincide witli tlie parietJiJ eminences and the 
two lower with the mastoid prnces.-«cs of the t^'mporal })oncs. Of the sides, four are 
somewhat rounded, aud one, fom^ing the basal line, running between the mastoid 
proceeeea, is llaLtened. 

The centre is occupied by the'lamlHla, aiid radiating from this point are three 
sutures, the sagittal, and the two parts of the lambdoid. Each half of the lamhiloid 
suture bifurcates at the mastoid portion of the temporal bone, the two divisions 
constituting the parleto-mastoid and occipito-mastoid sutures: the point of bifur- 
cation is known as the asterion. 

In the lower part of the view is seen the occipital protuberance or inion, the 
occipital crest, and the three pairs of nuchal lines, which give it u rouyh antl uneven 
appearance. The occipital point i^ the point of the occiput farthest from the 
glabella in the median plane. It is situated above the external occi]>ttal protuber- 
ance. 

(3> Thb L.\TEBAi. Region 

The lateral region {norma Interalia) \% Homewhat triangular in shape, being 
boumled above by a line extending from the zygomatic process of the frontal, along 
tlic temporal crest, to the outer exireiiiily of the superior nuchal line of the occipital 
bone; this forin-t the biute of the triangle. The two sides are repref«nted by lines 
drawn from the extremities of the ba^c to the angle of the jaw. U is divisible into 
two portions, one in front, the other behind, theeminentia articularis. The posterior 
portion presents, in a horizontal line from behind fonvartls. the mastoid portion of 
the temiwral, with its process and foramen, the cxtenial auditor>- meatus, the centre 
of which ii^ known as tne auricular point, the mandibular fossa, and the condyle of 
the miuuiible. 

In the anterior portion arc three fo.'wie. (n) temporal, (h) zygonialic, (c) pter\"go- 
palatinc (spheno-maxillar)'), and two fissures, the inferior orbital (spheno-niaxillar)") 
luid pter>i;a-pahitine. 

(a) The temporal fossa, somewhat semilunar in shape, is bounded txhore and 
behind by the temporal ridge, in frunt by the frontal, zygomatic, and great wing of 
sphenoid', and fxtertialty by the zygomatic arch, by which it is seimraled hupfrficially 
from the zygomatic fossa; more deeply the infratemporal ridge separates the two 
fossfe. 

The fossa is formed by parts of five bones, the tygomatic. temporal, parietal, 
frontal, great wlnii of sphenoid, and is traversed by six sutures, coronal, splieno- 
aygomutic, sphenivsquauiosal. sphcno-pftricial, wjuamosal, and spheno-frontal. 



92 



THE SKELETON 



The point where the temporal ridge is croased by the coronal suture is tlie stepban-j 
ion, and the region where the frontal, sphenoid, teuiponil, and parietiil niwl ifi thoj 
pterion. 'I'he latter is frequently occupied in the adult by the eplpteric bune. 

The tvnijmral fossa \& concave in front,, convex Ireliind, lilleil by the temporal] 
maaele, and roofed in by a strong glisteaing uponeurosis, the temporal fascia, ' 
which server to bind do^vn the muscle. 

(h) The zygomatic or infratemporal fossa, irrej?ular in shft|«;, w situated below- 
and to the iimtT side of the zyKW". fi'veri'd in part by the rsiiuuB of the mandible.' 
It is bounded in front by the lower part of the inner surface of Uui zyponiaiic. and 
by the xyyonmiic surface of the inaxilJa. on w hicli are six-ti the orifices of the posterior 
sujjerior idveolar camdt>; lifhiml by the posterior border of the external pterygoid' 
plate, the spine of the sphenoid, and tlic eniinentia articularis; nhwe by the infra-j 
lempoml ridge, a email part of the squamoua portion of the leniporol, the great 

Fto. MMi.— Thb Seth.^. (Norma lalonilia.) 



a 



Tiwnpoi^ 



,iDaci% 






MiUtf 



.Tftiapc 



•ocomw. 
mm 



Mtm 



*^ 



Sctavaal pwrncold 



cln^U 



wing of the sphenoid perforated by the foramen o\'ale Qn<l foramen spinosum: fte&wff 
by the alveolar border of the maxilla: erternally by the ramus of the mandible and 
the «yiionitL fnruied by zyiiomatic and teniixjrHl; iTttatuilbf hy the external pterj'fjoid 
ptitlc. a line from which to the spine of the sphenoid separates Ibe zygomatic fossa 
from the bawt of the skull. It ixHitains the lower part of the temporal muscle and 
the roronoid proce,ss of the mandible, the external and int^Tual pterygoids, th' 
internal maxillary ve~s.selfl. and the mandibular divwion of the fifth nerve with numer- 
0U3 branches. At its up|jer and inner part are seen the inferior orbital and pterj'go- 
palatine fuwures. 

TIip inferior orbital or spheno-maiillary fissure is horizontal in position, 
and Ufv Iwtween the maxilla anti the ureal wmg of the sphenoid; externally it 18 
u.Mi!ill>' I'oinpleted by the zyj;otti!itii', though in some cases the sphenoid joins the 
inaxilln. nnd in this way excludes the zygomatic bone from ihe hfwurc: internally 
it is terminate*! hv the zygomatic surface of the orbital proccas of the palate bone- 



J 



THE tiKCLL AH A WHOLE 



93 



Throufih this fissure Uie orbit comimmicate* with the plengo-palaiiiie (spheno- 
mikxillary). zygomatic, and temporal fossa?. It tranfliuits the infra-orbitiil nerve ami 
vessels, the ?.y^;om;it.ic nerve, jimeentiirm branches from the spht'tUf-piJatitic gatiKlion 
tothcorbit.aiul a cttnimunicatiiig vfiii fnnn tlie (iphttialnrK: In the ptcrj-gdiii plexus. 

The pterygo-palatine (pterygo-maxillaryi fissure forms a riglit. angln with the 
spbeno-int^xill;iry fis.-sure and i* ••iiuiitj^d iH'twecn tlio maxilln. an<i the nnl^rior \Hyr- 
der of the ]>ter>(ioi«i procesf of the uphennid. At its lower an^le, where the two 
limbs of the lij«ure approximate, the external pt*ryi;oid plute occasionall^s' artiru- 
latca with the uut.xilla, hut they ivk usually separated by a iliin ptirtion of the 
p>Tamidal process of the palate. 'Hie pterj-itft-palatiiie fissure, which serves to con- 
nei-t the zyKomatic fossa with the pterj'go-palntine fosw, is bounded internally 
by the perpwndicular plate of the jwilat^?; it irnnsmila branches of the inlenial 
maxiilarj' artery, and the conies jwnd inn veiiw, to and fn.nn the pter\'so-palatinc 
fossa. 

(c) The pterygo-palatine (spheno-maxillaiy) fossa is a small spiLce, of the 
form of an invertetl pvu'amid, situated at the anple of junction of the inferior orbital 
(spheno-maxillar}') with the pteri'fjo-palatine (ptcrj-go-mnxill.'ir>-) fissure, below the 
apex of the orbit. It is bounded m jroni by the zygomatic surface of the ma.xilla; 

Fio. 107. — A Sbctioh of tok Skuli, skowiko the Ixnbr Wall or the Orrit, tb« Innvb 
Wall or tub Antodu, and tub Srai:No-u.\xiLLAar FoesA. 



mWTU. MVt ■ 



wMi. ao«t - 
nu»m ftMt» Of iii4iitu . 

U1CHKTV4L 
lAMIIIIU OUHiL 

o<nn« 01 Auriini . 
mrtRioH villi eoNcti ' 
puiTE tone 
mTmm mul tniii ' 



INTERIM ETHMOID UML 
raituaoN IThHOIC ONU 



Liiiim Mmucu at ethwid 



SFMilin ruOlM laRllttEH 

?nn<dtiib ciNu. luB'Ni mo ixt 
niinuD-rtiJitmt lotu 

SPMEHOie 



munuL rmtma run 
mm ton 



bdiinti, by the base <if the pterygoid procew* and the lower part of the anterior sur- 
face of the great wing of ibe sphenoid; inlfrnallff by the perpendicular plate at the 
pahilo with itti orbital and sphenoidal pnirfwses; above by the under surface of (he 
body of the sphenoid. Three fis-^ures terniinate in it — viz,, the superior orbital, 
pter>'go-p«l:ititie. anil inferior orbital; through tiie !su|)erior oHnlal fiswure it commu- 
ninites with the cranium, through the ptcrj'gtKpalatine fis-sure with the zygomatic 
foBHa, through the iid'orior orbital fissure with the orbit, and tlirfiugh the spheno- 
palatine foramen tin the inner wall it cnmmuni(!at«.s willi the upixr and back pari of 
the nofuU fossa. Including I he spheno-palatine foramen six foramina open into the 
fossa. Of these, three are on the posterior wall : enumerated from without inwards, 
and from above downwartls. they are the foramen rotundum, the pterygoid 
(Vidian) canal, and the pharyngeal (pterygo-palatine) canal. 'Hie apex of tlu> 
,|n-nuiiid U-adg below itito the posterior palatine canal and the accessory palatine 
canals which branch from it : and anteriorly is the orifice of the infra-orbital canal. 
The fosfta contains the spheno-palatine ganglion, the maxillary nerve, and the ter- 
minal part, of the internal maxillary artcr^'. and the various foramina and canalu 
in relation with the fossa ser\e for the transmiiwion »rf the numerous branches 
whfch these vessels and nerves give off . 



94 



TJIt' tiKfLETON 



I 



(4) Inferior Hkoiov or B.vsp. 

The base o( the skull (nomui bagitans) extet»is from the incisor teeth to th 
occipital protutieriiiice, and is bounded on each side by the alveolar aix'h, the xygo- 
matic, the zygoma, the leuipural. aixl the ifUi)erior nuchal hoe of the occipital bon 
It i« very uneven aad, excluding the lower jaw. divisible iiitu (hrt»e iM)rtioiia 
(a) iinterior. (W) middle or suhtiranial, and <c) p(i.sU;riiir (»r miboccipital. 

(ii) The anterior division cousista of Uie hard palate, the idvoolar arch, a 
the posterior narts. 

When the skull is inverted, the hard palate stands at a higher level than the 
rest, and is bounded anteriorly and lalendly by the alveolar ridges containing the 
teeth. Tlic bones appearing in the intermediate space an: the premnxilhtrj' and 
palatine portions of tlie maxillie and the horizontal plates of the palate bones. 
They arc rough for the iLttaehinetit of the niuctvnerioBteuni, and nrar tlie po^sterior 
margin is the ridge for the fibrous expansion of the tcniutr pnhti. The following 
points are readily recognised (fig. lOS): — 

The me so-palatine suture lommences at the alveolar point, traverses the 
incisive fosMa, and terminates al Ihe ptwterior nasal spine. 

The transverse palatine suture, between the palate bones and palati 
proccss&s of the maxinjp. 

In young skulls the incisive sutures, and l>ehind the incisor teeth four sm 
openings known as the guberaacuUr canals (sec ligs. i»4 .ind 108). 



Fio. 108. — Haho pAt^TC in" \ Child Five VE.\as Old. 



suaniHiaiuiR uhu. 

aiann nut. 

mClllTL (UTMI 



Mutttnt 




mUTE FttXttSOf MMilU 



^ aNumi nuiriKi niuHui 
LfKtu nuTM tmuot 



The incisive fosea containing the termination of foxu- canals: two small orifi( 
foramina of Scarpa, situared one behind ihe other in tlnr nie»o-j>alaline suture; 
ami two larger openings, the foramiaa of Stenson. The fi;nm)itia of Hearpu I raimniic 
the naso-palatine ner%'es, and those of Stenson arc in relation with tlic organs of 
Jacobson. 

At the posterior angles of the hard palate are titc greater palatine foramina, 
through which tlie descending palatine vesseis and the anlermr palittinu nene« 
emei-gi- on to i.tie palate: a thin lip of lione wpamtiw I.liem from the lesser palatine_ 
foramen in the tuberosity of the palate bone on eat^h side, for the jHititerhir palatii 
nerve. 

The hamular process of the internal ptervgoid plate is the mfwt posterior 
of the hurti palate. 

At the posterior extremity of eaeh alveolar ridge is the tuberosity of the maxil 
and bct^^'ccn it and the pidate Imiie iR a fonitnen (variable in size and sometil 
absent), tlie middle palatine foramen, for the middle (lalatine nen,'e. 

Behind the hard palate nrf the choans (posterior nares), separated from ead 
other by the vomer. Kach i.s boundpil i^\trrii;illy by thn inicmal pterygoid plale; 
l»eIow by the horizontal plate of the palate bone; above i>v the imder .turface ai tl 
botly of the sphenoid, with the ala of the vomer and a portion of the sphcnoif' 
process of the palate bone. 

External tu the rhoanu: thei-u it> on each ijtdc a vortical foesa lying between 




THE SKILL AS A WHOLE 



96 



pt«n'KO)d plflt*8. It extends upuiirdw to the uitdcr surface of the ureBt wings of 
tlie sphemml; it in completed anterioHv by the coalescente of the pten'goid plates 
and below by the pyramidal process ot the palate bone. It coniaiu« vlie following 
pnintt^ of imerfHl;— 

An eloiiKHted furrow, the scaphoid fossa, for the Irnaor palati mueclc and the 
cartilage of the [Cu.stachian tube. 

The j^enornl ravity of the pterygoid fossa which lodges the tettsor palati and 
internal pttryijoUl nmsclesi. 

Frequently there is a notch In the external pterygoid plate cIckc beside the fora- 
meu ovale. 

The (Kjsterior termination of the pterygoid (Vidian) canal. • 

If a line he drawn afrnwi the base of the skull from one preglenoirl tubercle to the 
other, it will fall immediately behind the external |>lor>-icoid plnlc ami bisect the 
fonimen siniiosuin nii euch side. A secoml traiisverw line, drawn acr<jfis the opis- 
thion or poalerifir margin of the fonunen magnum, will fall behind ilie mastoid 
processes. The !^p.ioe hetwivn the^^e im:i;;iruiry hue;? may be called the subcranial 
region; that behind the second line, the 8iihoecif>iiat region, 

0>) The subcranial region Is separate<l fmm the xygomatic fowa by a line 
drawn from tlio posterior mai-gin of the external pter>'Koid plate to the spine of the 
sphenoid. It la formed by the under j^urfm-e of the basilar i)rtjcu«i of the occipital 
and the body of the sphenoid, the |)etrous portion of the temporiil bone, a small 
piece of the twiuanuk^al portion, the hiiiiier part of the great wing of the sphenoid, 
Mvi the condylar portions of the occipital r»one. It presents the fallowing [loints 
for examinariiin: — 

The pharyngeal tubercle. 

The foramen magnum and the occipital condyles. The most anterior point 
of the foraaien is lernic<.l the basion, and the most posterior point the opis- 
thion. 

On each side will tie seen: — The hypoglossal foramen for the IiynoglosBal ner\'fi 
and a meningeal bratu-Ii of the aacending pharj'ngeal artery. 

The condylar fossa with the condylar foramen (this foramen is not eonstint). 

The under asjiect of the jugular process, from which the rectus copili* tateraU^ 
take^f origin. 

« The foramen lacerum and the oritiee of the pterygoid (Vidian) canal. 
■V The caaalis musculo-tubarius for the trnaor ti/mpani muscle and Eustachian 
tube. 

The carotid canal. 

The quadrilateral area for the origin of the levator palati and ten»or tympani 
muscle*. 

The canaliculus cochlea, or ductus ijerilymphaticus. 

The jugular foramen and fossa for the glosso-phiin'ngeal. vagUH, and .spinal 
accessory nerve.*, the int*'rnal jugular vein, and a meniiigeiU bnineh of the ascending 
phar>-ngea! .^rte^y. 

The tympanic canaliculus for Jacobson's nen'e {tympanic branch of glcwao* 
pharyngeal). 

The spine of the sphenoid; this is sometimes fifteen millimetres in length. 
^ The mandibular fossa with the petro- tympanic fissure. This lodges Llie 
nnlerior jjrocess of the midlous, the tympimic twig of the internal maxillary arterj'. 
\ Kmall iMWwage lie.-side it. the canal of Huguier, conducts the chonia tj-nipanl nerve 
from the tympanum. 

The external auditory meatus. 
, The auricular or tympano-mastoid fissure. 

The tympanic plate .'Uid vaginal proces.'s. 

The styloid process. 

VThe stylo-mastoid foramen for the stylcvmastoid arter}' anil the exit of the 
facial ncri'e and, in some cajtes, the auricular branch of the vagus. 

The mastoid process with the digastric and occipital grooves. 

(c) The suboccipital region is largely formed by the tabular portion of the 
oncinit.i] bone with it-ii ridges and areas for niuMsular attachment. E.\lemally a 
wniiil part <>l ihi- mastoiil |>ort.ion of the temporal is wen, pierced by a small furamen, 
of variublc size, the mastoid foramen, whieh tran.tmits a vein from the lateral 
wnua and a meningeal bniiieh of the nrcipital arterj-. 



98 



THE SKELETON 



(5) TiiK Anterior Rbqion 

Tlie anterior region (rmrm/i fariatis) comprises ttie ant«rior end of the cranium^ 
or forehrad, and the skeleton of the face; also the cavities known as the orbits, 
formed hy the junrtinti of the two parts of this region, and the nasal fosss, situated 
on either side of (he septum of the nose. 

The upper part or forehead, narrowest het«een the tetnporal cresljs about hal 
an inch ahovp the zygomatic processc-s of the frontal, presents at this level the twi 
transverse sulci; above are t)ie frontal eminences, below the superciliary ridges, ' 

FiQ. 111.— Ths Skdll. <Nomui lacialiaO 



rX' 



/ 






j^ - 



oMipn *-u«Bt*Ua 



■'. 1 



KycomaueiM olnor 



- OarmoMT vof 



TsDdo oauU 

Oibioularli 



. Lot ale T l»bU 
■iiparlorU 



^^^ 



N^ 



pOftloo; 



ITudls lalw porUea) 



Orbtoulaila otu 



and still lower the supra-orbital marRina, interrupted aoflr their inner ends by 
supra-orbital notches. 

Below the forehead are the opening of the orbits, bounded laterally by th 
zygonialic bones coimtJlutinft the prorninenc^e nf the cheeks, and Ijetwccn them thol 
bridge of UienoBe, fonned liy the nn.sal bones and the frontal j>rorr-s«trs of the inaxilltP. 
lielow the nasal Ixtnes in the apertura pyriformis or anterior nasal aperture, 
leniling into the nasal fos«.T. The ttt-lli fonn » roojipicufus feature in tliis viev^ 
of the skull, the outline of which is completed below by the mandible. 

The bones entering into formation of Iho nonrui faciaiis are:— the frontal, nasal 



7'//i.' SKULL AS A WHOLE 



m 



lachn'maU. orbital surfaces of the stnal] and the Kreat widjies. and a portion of the l>ody 
of the Hj)henoid, the lamiitae papyrace* of the ethmoids, the orbital procestses of the 
palate bonQs. the zygomatics. maxillBe, inferior na^al cmichff, and the mandible. 
The sutures are numerouji. and for the niiwt pari unimportant;- — 
The transverse sutvire extends from one external angular prwsess to the oth^r. 
The upper part of the suture is formed by the frontal bone; below are the zygomntir. 
great and small wings of the sphenoid, lamina papyracea. liichrymal. maxillar>'. and 
naaal bones. A portion of this complex suture, lying between the sphenoidal and 
frontal bones, appears in the anterior cranial fossa. 



Phi. tt2.— Thc Skull. (Nonn>(aciali)i.) 



OMtTBI 
•UKkSLIikllT MOH 




Mn( titwuec 
ALflDlM WDT 



Other fissures are the inlermwal, nfl.«oJinnxillar>-, intei^niaxillar)- and KyRomHticfr 
maxillary. The small sutures seen in the orbit arc described with that cavity. 

The foramina iire:— the supra-orbital, infra-orbital, optic, zygomaticofacial, and 
mcntul; the naso-lachn.-mal canal; the ethmoidal canals; and the inferior and 
superior orbital fi.<wurc«. 

The fullowine; points may also be noticed; — 

Tlie glabella, a smooth i<|>are between the converging superciliary ridges. 

The ophryon, the most anterior point of tlie melo|>ic suture. 

The nasiou, the middle of the naso-frontal suture. 



100 



THE SKELETON 



The subnasal point, the middle nf the inferior border of the anterior nasal aper- 1 
ture at the base of ihe nas.il spine. ^ 

The alveolar point, the centre of the anterior margin of the upper alveolar arch. 



THF, ORBITS 

The orbits arc two cavities of pyrnmUial shape, with their bases directed fon\-ar(is . 
and outwards niid thpir apices backwards and inwards; their inner walls are nearly" 
paraJlel. but their outer walls diverge so as to be nearly at riRht anglej^ W tach other. 
Each cavity forms a socket for the eyeball and the muscles, nerves, and vessels 
Associated with it. 

Seven bones enter into formation of its walls, via., the frontal, zygomatic, sphe-' 
noid, ethmoid, liichrymai, palate, and maxilla: but as three of these — the frontal, 
ephenoid, and ethmoid — jire single mcdiiin bones which form parta of each cavity, 
there are only eleven bones represented in tlic two orbits. Kach orbit presents for' 
examination (our walle. a circumference or base, and an apex. 

The superior wail or roof, vaulted and smooth, is formed mainly by the orbital 
plate of the fnnital and is complctt^i |)osteriarly by the small winji nf the sphenoid. 
At tlie outer angle it presents the lachrymal fossa ff)r the lachri'mnl gland, and 
at the inner angle a deprctuion or a spine for the pulley of ilic superior oblique muscle. 



Fra. 113. — Thk 1.VJCKH Waix or the Okbtt. 



noNTAL aims 



niMtM, moctks ar miiiu 
amet of uniuw 

IHn(tC4 RAULUmtM 




ANIOUDA [IHMOID UNU 






SMFUQ-KLtllM KM KIN 

niRioo-PUjiniii (D»m 



UTUKU. fTCRYHIO PUTC 



The inferior wall or floor is directed upwards and outwards and is not so large 
as the n)of. U is foniied by the orbital plate of the ma.\illa, the orbital process of the 
xygomatie, and the orbit>al process of the palate boiic. At its inner angle it presents 
the nasii-lachrytnal canal, ami near this, u depression for the orijnn uf the inferior 
oUiifue muscle. It is marked near the middle by a furrow for tlie infra-orbital artery 
and the fwrond divisJiHi of the fifth nerve, terminating anteriorly in the infrn-orhita] 
eimal, through which the ner\'e and arterj- emerge on the face. Near the commence- 
ment of tlte canal a narrow passage, the anterior alveolar canal, runs forwanls and 
dowmvards in the anterior wall of the ahtrum, traiwniitling nerves and vessels to 
the incisor and canine teeth. 

The outer wall, dire<'ted forwards and inwards, ia formed by the orbital surface 
of the great wing of the sphrnoid. and the zypom.itic. Retween it and the roof, near 
the apex, is the superior orbital (sphenoidal) fissure, by means of which the third, 
fourth, ophthalmic <livi!<ion of the fifth, and sixth nen-e?? enter the orbit from the 
cranial cavity; it also transmits some filaments from the cavernous plexus of tho 
s>'inpathctic. the orbital branch of the middle meningeal artery*, recurrent branches 
of the lachtymal arter}', and an ophthalmic vein. The lower margin of the fissuro 



I 



1 



THK NASAL ^OSSA' 



101 



presents nenr the middle a small tuberrli*. from whirh the inferior head of the aetemal 
rrctus iiniM^le arise?, lietween the outer wall and ihe floor, near the apex, is the 
inferior orbital (spbeno-maziUary) fissure, thrcujub which the secund division of 
the fifth and the infra-orb it a] vessels pass from the pterygo-palatiDC fossa to enter the 
infra^irhitiii yriKive. At tlie anl-erior margin of the litwure the sijliennid occaeiotudly 
articulates with the maxilla, but the two are usually sp|)arnted by the orbit-al plate 
of the zygomatic, and on the latter are seen the oritioes of t!ie zygoiiiatioo-t^mpoi-al 
and ?,y^omat-ico-faoial canals, which traver&e the zygomatic bone. The conimeiite- 
ment of the zygoin at ico temporal canal is sontt>linie« i$eeu in tlie spheno-zygomutio 
suture conupctitig the sphenoid and zygomatic bones. 

Til* inner wall, narrow and nwirly vortical, is formed from before backwards 
by the fronial process of the maxilla, the lu(du*ymal. the lamina papymcea of the 
ethmoid, and the body of the sphenoid. At the junction of the inner wall with the 
roof, and in the suture lietweeii the ethmoid and frontal, are xen the orifices of the 
anterior and posterior ethmoidal canals, the anterior, transmitting the anterior 
ethmoidal vessels and nerve; and the posterior, the [wsterior etlunoidul vessels. 
Aul^critirly Ik the lachrymal groove for the lachrymal sac, and beliind tliis the 
lachrymal crest, from which the tensor tarsi arises. 

The inner wall, which is the smallest of the four, is traversed by three vertical 
j: — one between the frontal process of the maxilla and the Iachr\'mal, a 
eond between lachr>tual and lamitia papyracea, and a tliird l^etween the lamina 
papyracea and the sphenoid. Ucciusionally tho splienuidal concha appean; in the 

, orbit between the ethmoid and tho body of the sphenoid. 

The apex of each orbit corresponds "to the optic foramen, a cimularorifiee which 
transmits the optic ner\*e and ophthalmic aner>*. The base or circumference is 
quadril;it<^ral in form and is bouiide*! by the fn)ntal bone above, the fronlal process 

fOf the ma.villa and the internal angular pro'-i-MS of the frontal on the inner side, 
the zygomatic boue and the zygomatic process of tlio frontal on ttie outer side, and 
by the zygomatic and the body of tlie maxilla below. The followinji points may also 
be note<l:— The suture l>etween llie zygomatic pnwesH of t\w frfintal bone and (lie 
^gomatic; the supra-orbital notch (sometimes a complete foramen); the suture 
Kelwecri the frontal bone and the frontal process of the maxilla; and in the lower 
eetiment. the zygomatico-iuaxil[ar>' suture. 

The oriiit coiuiuunicates n-ith tho cranial cavity by the optic foramen and superior 
orbital fissure; with the nasal fossa, liy means of the naso-laclin,Tuai canal; with 
the zygomatic and pter>'go-]>alatino fosszE, by the inferior orbital fipsure. In ad- 
dition io these large ojRMiiiigs, the orliit has live other foramina— the infra-f^irbit-al, 

-Kygomatico-orbital. and the anteriOT and posterior ethmoidal canals — opening into 
it or leading from it. 

The following muscles arise within the orbit : — t he four redi, the auperior ofth'^w*, 

|an<l levator patpehra superiaris, near the ai>ex; the inferior cbUque on the floor of the 
orbit cxtenuil to the naso-lachrymjd canal ; and the tensor tarsi fmm the Iitchr>'nial 
crest. The margins of the inferior orbital fissure give attachment to the orbUab'a 

t muscle (sot section on the ElXk) . 



THE NASAL FOSS.E 

The nasal fossae are two irregular ca\-ities situated on each side of a median 
vertical septum. They open in front by the pyrifomi aperture and communicate 
, behind witli the pharyn.x by the choanB". They are somewhat oblong in transverse 
section, and extend verticidly from thft anl-erior part of tlie ba.se of the cranium al)ove 
to the tniperior sunace of the lianl palate lielow. Their traa>«ver=ie extent is very 
limited, especially in the upper part. Kiu-h fossa prcj^cnts for examination a nn>(, 
Boor, inner .and outer walls, and communicates with the sinuses of the frontjjl, sphe- 
noid, maxilla, and ethmoid bonee. 

The roof is horizontal in the middle, but sloped downwards in front and )>ekind. 

[The anterior slojX! is fnnned by the posterior surface of the nasal bone and the nasal 

[process of the frontal; the horizontal portion corresponds t^) the cribrifonn plate 

.of the ethmoid and the sphenoidal concha: the jMBterior slope is formed by the 

inferior surface of the boily of the sphenoid, the ala of ihevonior. and a small 

portion of the sphenoidal process of the palate. The sphenoidal sinus opens at 



1U2 



THE SKELETOX 



the upper and back part of the roof into the spheno-ethnioidal recess, aho\e the 
superior meatus. 

The floor Ls ooiipavc from side to side, and in the transvewse (iiwnetcr ttider 
than the roof. It is formed mainly by the palnial process of the maxilla and com- 
pleted posteriorly by the horizontfil plat*' of tho palate bone. Near its anterior 
extremity, close to the septiim, is the incisive canal. 

The septum or inner wall is formed by the i>er|>endicular plate of the ethnioid, 
the vomer, the rostrum of the sphenoid, the crest of the nasal bones, the frontal spine, 
and the niediiiii vnst formed by the apposition of the palatal processes of the maxilloe 
and the horizontal plates of the palate bones. The anterior border has a triangular 
outline limited above by the perpendicular plate of the ethmoid and below by the 
vomer, and in the recent state the deficiency is filled up by the septal oartilage of the 
nose. The ptwterior border is formed by the phflrj-nRoal edfce of the vomer, which 
separates tlui two posterior nares. 'Hie septum, which is usually dellected from tho 
middle line to one side or the other, h occa.'iionally jM^rforated, and in some cases n 
strip of cartilage, continucue with tlic triantrular rartilaf^e, extends backwards 
between the vomer and vertical plate of iheetlmioid (pnsU-nor ot iiphrrioitinl process). 

The outer wall is the most extensive and the nio<t compnrftte<l on account of 
the formation of the nieatusee of tlie nose. It is foimed by the frontal process and 



Fia. 114. — SwmoN xaHouoH thk Xa«ai. Ft>*o«4 m xmoiv the SKi-rvjii. 
Siu^uu Looiu^ta 'j'OH.inu^ Right Najial FutMA. 



Lett Ualt, with 



mtui 



giiar or wkimio ■ 



-niONtu tniE 



MCSITHMOID 



tmUK mi MIO-MUTINE MERVE 



Mm Of nan mtt 

WMHMUTIMK 



' Oktn 0* VAiiiu 



the Inner surface of the maxilla, the l.ochrv'mal, the superior and inferior conchas 
of the ethmoid, tlie inferior na^al coucha, the vertical plate of the palate bone, and 
the inuer surface of the internal pterygoid plate. The three conchs, which project 
inwards, overhanc tho three recesses known as the meatuses of the nose. The 
superior meatus, the shortrat of tbe three, is situafeil l»etwcen the superior and 
middle nasal concha', and into it open the oriiicc of the posterior ethmoidal cells 
and the spheno-palatine foramen. The middle meatus lies i>etueen the middle 
and inferior conclue. .\t its fore part it communicatee with the fnmtal sinus by 
means of the infundibulum, and near the middle with the maxiUarj' sinus (an- 
trum); the communication with the sinus '\s very irr^ular and sontelimes repre- 
seuted V>y more than one 0])eninK (fiK. 11,5). Two sets of ethmoidal cells — th« 
middle and anterior— also open into the middle mcatn,<», the anterior in common 
with theitifundibuluin, the middle on an elevation known n.s the bulla ethmoidaHs. 
The inferior meatus, longer than either of the prei.-edinK. is situated lietween the 
inferior nasal concha and the floor of the foe.sa. nnd presents, near tbe anterior 
p:trt, the lower orifice of the canal for Ihe naso-lachrymal duct. 

The nasal fosss open on the face by meaiLt of the apertura pyriformis, a heart- 
shaped or pyriforra opening whose long axis is vertical and whose broad end Ls below. 
The orifice i.s bounded abo\*e by the lower borders of the nasal !>one8, laterally by the ■ 
maxiliie, inferioriy by the premaxillar\' portions of the maxillffi, and in the recent; 



I(H 



THE SKELETON 



sinuses of Che skull. By means of the foriimiim in the ruof tKey are in connection 
R-ith the craninl cavity; hy the infundibulum chpH fossa is in rommiinication with 
the frontal and anterior ethmoidal nrlls; the pristerior ethmoidal cells open into 
the superior meatuses and the sphenoidal sinuses into the rece^-e* above; the spheno- 
palatine foramina connect tlieni witli the pter>"go-palatine fassie, and by mean* of 
nn irregular orifice in each outer wall they communicate with the maxillary sinuae^. 
The canals for the nawii-lachrj'nial ducts irotmect tlieui with the orbits, and the in- 
cisive canals witli tlie oral cavity. 



THE INTERIOR OF THE SKULL 

In order to study the interior of the skull it is necessary to make sections 
three directions — sagittal, conmal. and horizontal. This enables the student to 
examine the various points with far^ility, anrl displays the prcat proportion the 
brain cavity I>ear8 to the r&st of the skull. The sagittal section should l)e made 
slightly to one side of the medi:in line, in order to presen'e the nasal septum. The 
blaek line (fig. 117} drawn from the basion (aiiierior niargiti of ilie foramen m^- 
nunO to the gonion (the Huterinr extremity n{ the sphenoitl) represents the baai- 
cranial axis; wiiil't the line drawn from the gonion to the subnasal point lies 
in the basi-facial axis. These two axes fonii an an^le ternie<l the cranio-facial, 
which is useful in making comparative nieasurements of crania. A line prolonged 




Fia. 117.— Tun Skitu, in SAoriTAL SEcnos. 

Bfte«MA 




SONtOM 



BAilOH 



vertically upwards from the basioo will strike the'bregmB. Tliis is the basi- 
brepnatic nxln, and gives the gn'uiesi height of the crania) eavity. A line drawn 
fnMu the ophryon to (he occipital point indicates the greatest length of the cnmium. 

Near its middle, the cnmial cavity ia encroached upcii by the petrous portion of 
the iemp<iral bone on each side; the wiUls are channelled vertically by narrow 
(jRKives for the middle ami small meningeal urUTiCi;, and towanls the l«ise and at 
the vertex are brooder furrows for the venous sinuses. 

The coronal section is moist inntnictiw when mo^le in the basi -bregma tic axis. 
The section will pusn through the ["(etrous portion on each side in such a way as to 
traverse the external uuditon* passage and cxpow liie tympanum and vestibule, 
and will aho partially traverse the inlcnml auditory niea'tu.s. Such a R-ction will 
divide the [nirictal bones slightly posterior to the ])ai-ictal eminence:;, and a line 



THE INTERIOR OF THE SKULL 



105 



dra^D transveceely ucroas the section at the mid-poiot will give the greatest ttansverse 
lueiisureiiitnt of the cranial cavity. A skull dividwi in this way facilitJiiea the 
examination of tlie part-'? about the posterior nares. 

Th(' horizontal section nf the ekull should l>e made through s. line extending 
from ilio ophryon to the occipital point, passing laterally a few millimetres above 
the pterion on each side. It is of great advantage to study the variuus parts on 
the Hoar of the crauia) cavity In a second skull in which t lie dura mater and itu various 
jjroce-ssi'B hiive n(>t been removed. 

The floor of tlie cranial cavity prescnt-f three irregular depresBlons termed the 
anterior, middle, and posterior fthwa- (ligs. 118 and 119). 

Thh Antkri(*r Cranjai. Foa-*.*. — The floor of this fossa is on a higher level than 
the rest of the cranial fioor. It is fonnetl by the liorizontal plate of the frontal 
bone, the cribriform plate of the ethmoid, and the lesser uings of the sphenoid, which 
meet eaoh other and exclude the pre-ypheiinid from the anterior fossa. The free 
marpns of the letter wings and the anterior margin of the optic groove mark the limiia 
of lhi.s fos-sa p<wteriorly. The cctitral portion b <lepres.sed on each .^ide of the crista 
galli, present* the numerous apertures of tlie cribriform plate, and take* part in the 
fonnatiou of the nMjf of the nasal fossie; laterally, the fl,oor of the anterior cranial 
foesa ifl convex; it forms the roof of the orbits, and is marked by irregular furrows. 
It supp<irts the fmntal lol>ea of the cerebrum. The sutures traversing the floor of 
the fosisa arc the fronto-ethmoidal, forming three sides of a rectangle, that, portion 
of the transverse facial suture which traverses the roof of the orbit, and the ethmo- 
spbenoidal suture, the centre of wliich corresponds to the gooion. The other points 
of interest in the fuBsa are: — 

A gnmve for the -suix'rior sjigiifal pinus. 

The foramen caecum wliicli transmits a small vein. 

The crista galli. 

The ethmoidal fissure for the anterior ethmoidal branch of the fifth nerve. 

The cranial orifice of the anterior ethmoidal canal, transmittuiR tlic anterior 
ethmoidal branch of the fifth ner\'e, and a meningeal branch of the anterior 
ethmoidal artery. 

The cranial orilice of the posterior ethnioidal canal, tranftmitttng a meningeal 
branch of the posterior ethmoidal aricrj". 

The ethmoidal spine of the sphenoid. 

Furrows for nieniimesl arteries. 

The MiDin.K t'aA.M.M. Fos.sa. situated on a ]o%\'er level than the anterior, con- 
sists nf a central and t\Yo lateral imrtion.--. In fnmt it is limited by the posterior 
bonlers of the lesser wings i»f the sphenoid and the anterior margm of (ho optic 
groove, behind by the dorsiun scilte and the upjwr border of the petrous portion 
of both teniporftl bones. Ijaterally it is bounded on each side by the squamous 
portion of the temporal, the great wing of the sphenoid, and the parietal bone, whil-st 
the floor is formed by the bixly and greal. wings of the sphenoid and the superior 
!njrfai>« of the (>ctrous portion of the temporals. It contains the following sutures: 
— sphcno-parictal, ix^trfKsphenoiflal, sriuanio-sphenoidal. squamoufi. and a part of the 
transverse suture. The cciitnd portion of the f<xs.«a prej^ntf from before backwards: 

The optic groove, above and behind which is the optic chiasma. 

I1ie optic foramen on each side, trnnstnil.ting the optic ncr\'c and ophthalmic 
arten'. 

The tuberculum sell«, indicating the line of junction of pre- and pnBt-6i>hen«id 
elements. 

The anterior clinoid processes. 

The sella turcica, with the middle clinoid processes, and grooves for the inter- 
nal carotid urt^M'it^'. TIih dorsum sellie, with liie posterior clinoid processes, 
and notches for the sixth pair of r/ranial ncr\'cs. 

The central portion h in dirrrt relation with the parts of the brain within the 
circle of Willis. 

The lateral portions are of considerable depth and marked by numerous eleva- 
tions and depressions correpponding to the convolutions of the temporal lolses of 
tlie brain, and by groo\-e8 for the branches of the middle and Muall niemngeul 
arteries. The following foramina are seen on each side: — 

The mipertor orbital Csphenoidal) fissure, leading into the orbit and trans- 
mlttinE the tliird, fourlli, tlircc branches of the opbtludmic division of the fifth, and 



106 



THE SKELETON 



sixth cranial nerves, some filaments froai the cavernous jilexus of the sympaibetic, 
an ophthiiliiiie vein, the orbital branch of the middle meningeal, and a recurrent 
branch of ihe lachrvnml arten-. 



Fiu. 118. — Tu£ SauLt. in Hoiiiiontal iJEcnoN. 



mriiMi 




ETHHOIIMI nttlini (OR 4*T1)I«II 

AKILRiDft IlHItaiMl ClHtL (Alt 

Mrtnto* rtKittnon iirvij 



FTNaOIUl FOMtlllM fgt QMC- 
lOM HUH 



riariL 



orTiC KUnu 



rontiftk fioTuiiom 'Sicoxo 
(KvntDii OF mvh Nunu 

rcuvEii Hint itwjip puiBign 

01 rrnn ^(Sil. 
NOTCH Fon tom »an 






nnirioii tuBTOot wmtv* 



juauu* MUirnt <ii»tii tint 



NtRllj 



The foramen rotundum, for the passage of the second division of the fifth nerv( 
into the ptcr.'go-paiaUnc fossa. 



lOS 



THE SKELETON 



at the aphenftid, and the apex of the petrous [jortion of the temporfll. In the reoent 
state it U closotl belnn- by n layer of fihro-rartilage which is [wrforiitcd hy the Vidian 
nen'e, » meningeal branch of the ascending pharj-ngeal artery, Ami an eniLssaiy vein. 
Tho carotid canal opens on its outer wall ami the pterygoid (Vidian) canal in front. 

On the superior surface of the petrous portioa of the temporal bone are seen: — 

A deprcffiion which ItKiges the semilunar (tiasserian} ganglion. 

The hiatus canalis facialis for the great superficial petnisal ner\'e and the pet- 
rosal branch o( the middle nieninj^eal artery. 

The accessory hiatus for the snuill superficial petrosal nerve, 

A minute foramen for the external superficial petroBal nerve. 

The emjnentia arcuata, formed by the superior semich-cular canal. 

Anterior and slij^liily exlenial to the enunenLia arcuata the bone is exceeilingly 
thin and translucent, forming the roof of the tympatmm (le|?men tympani). \\'hen 
the dura mater is in situ, the depression lodging the semilunar ganglion is converted 
into a foramen, traversed by the fifth nerve, and in the same way the notch on the 
side of the dorsum sell» is convertwl into a foramen for the sixth nerve. In many 
skulls the middle clinoid process is prolonged towards the anterior clinoid process, 
with wliich it may l«; joined to complete a foramen fnr the internal carotid artery*. 
The groove^ for tho middle meningeal arteries are sometimes converted into canals 
or tunnels for a short distance, e-speoially ir old skulls. The bonea most deeply 
marked are the squamous portion of temporal, the great wing of the sphenoid, and 
the parietal. 

The PnsTKRtnn Cranial Fossa is the deepest and largest of the series. It is 
bounded in front by the dorsum sellre of the sphemiid and on each side by the superior 
liortler of the petrosal, and the mastoid portion of the temixirsil bnne, the posterior 
inferior angle of the parietal, .and the groove on the occipit;il bone for the lateral 
sinus; each of the bones mentioneil takt.ss pari in the fomiation of its floor. 

In the recent rtate the fossa kxlgo-s the cerebellum, pons, and medulla, and is 
roofed in by ihe tentorium cc-rfibelli. a tent-like [mx-es-s of Ihe dura maler attached 
to the ridges limiting the fiis.ia alH)ve. It nimniunic-ates with the general enmiid 
cavity by means of the foramen ovale of Pacchionius, a large opening bounded 
in front by the ba.silar groove and beiiind by the anterior free edge of the 
tentorium. 

The posterior fossa is market! by several sutures, viz., j>etro-ocrtpita], occipito- 
mastoiii, pane to- mastoid, and in young skulls the basilar (occipito-sphenoidal). In 
addition, the following points may he noted: — 

The clivus, extending from the dorsum j*ellff> to the anterior margin of the fora^ 
men magnum, and in relation with the l>asilar artery, Uie pon.s, the medulla, the 
sixth iier\es, and the basilar sinus. 

The foramen magnum, <iceupie<l in the rei-ent stale by the Iowxt end of the 
medulla oblongata and its membranes, the vertebral, anterior spinal and posterior 
spinal jirteries. tho .'^pinal accessory ner\'e8, and the teelorial menibrane. 

The hypoglossal foramen, sometimes divided by a spicule of bone into t^S'O 
divisions, for the two parts of the hypoglossal nerve an*.! a meningeal tiranch of the 
ascending phar\'ngeal arter>". 

The internal occipital crest, l>ehind the foramen magnum, for the attachment 
of the falx cerebelli. It Bometimea presents a depression known aa the vermiform 
fossa. 

The internal auditory meatus, for the seventh anil eighth cranial nen-es, the 
pars interineilia, and the internal auditorj' vessels. 

The jugular foramen (fommeJi laeerum posterius), somewhat pyriform iti shape, 
and divisible int<t three cotnpartnients. The anterior division, placed somewhat 
intenially. tnmsmits the inferior petrosal sinus and is sometimes completely sepa- 
rated by an intm-jugulnr process of Iwine; the middle division transmits three nerves, 
the ninth, tenth, and eleventh: and, in the posterior division. pl;n-ed somewhat 
extcnially. the lateral sinus (becomes continuous with the internal jugular vein. A 
jneniuKcal branch of the ascending pharyngeal or occipital arterj' enters the cranium 
through this division of tlje foramen. 

The termination of tlie groove for the lateral snus with the internal orifice of tiie 
mastoid foramen. 

The aqueductus vestibuli and the fossa subarcuata, on the postenof 
surface of the petrous pttrtion of tlie tempond. 



THE TEETH 



100 



The iTttiiiuni of an average European has a ropncify of 1450 c.r. 'I'he cirrum/cnntr, liikoa 
in n plane pa^ninK thrmigii the u|>!iiy»n in frunt, t)>e occipiial point behind, And t.he plerion 
at Ihe BiJc, Ik JiJ cm. The length from the ophrj-on to tbo nccipiini jioint ia 17 «ii., lunl Uib 
width belM'een tliepariel-.HU at rhe levtl nf tlie zygoniatii is I'i'^ ctn. The r*'^P'^'''>'''> ^^ the 
fnmteat width to the length in knuwn as ihe ctrphalic index, i. c. index of hrcndth. A lOcuU 
with an average cephalic iiidex is meMttktrphalK. When the index is above the nvtrage, it ia 
bracbycrpfuihe (short and l.iroad), and when lieluw tise average, ilolirbixt-phalw Oone aiid num>w). 
The height from Iho hiifiiun tu the bn.'gnut ia nourly Lhe aaiae as the width at uia level of the 
zygomata. The cranio-(acii»I angle i^t nbout 9fi*. 



THfcl TEETH 

Ati adult individual with pc^rfwl deiitttioii fKBwespeB tliirty-two teeth, equally 
(liBtrilmted iii the maxilla ntul mandible. The upper set arc ealled maxillar>' teeth 
and the lower set mandibular. The four central teeth in each dental arrh are tcTTned 
incisors; the tooth next these on each side is the eanine: tx-^hind these are two prie- 
molars or bicuspids; and lastly, three niolaru. This relation of teeth is expressed 
by meams uf a formula: — 

Each tooth has a portion coated with ename! exposed above the gum — named 
the crown; and a portion coatefl with cernentum cinl)«ldefl in bone — this is the 
root. The line of union of the crown and the root is termed tlw neck. 



ntmioia 



Fto. la).— TaB Tekth or as A.Din.T. 
euu« muoiM nuuii 



vrrlDOH TOOTH 



^J 



UPPEH OR 

MAXILLARV 

TEETH 



I ■ .VEB OR 
LAR TEETM 



The surface of the tooth directed towards the Ups and cheek is called labial 
and buccal respeetively . and that towards the tongue lingual. It is also neccBsary 
to iipply definite teniiH Ui (he oppoeed surfaces of teeth, lienci; Hie surfare din^cteii 
Wwards the middle of the mouth, if the alveolar arch were slraiphtened out. is 
median, and the opposite side is distal. Each tooth has dwtingui.>fhing foature.*!. 

The incisors. — The centra! maxillary ijiciaor is ver>' much larger than the 
lateral; the crown is somewhat oblong in outline, its lenj;rth exceeding the breadth. 
The miediuD is longer than the distal bonier. The labial surface is conve.\. tlie 
lingual concave, and terminates near the gum in a low eminence, the basal ndgo 
or cingultun. In recently erupted teeth, the cutting edge is elevated into three 
small cusps: these soon wear down and leave a straight edge. The root is long, 
single, and flattened laterally. 

The maxillan,' lateral incisors are much smaller than tlie central, which they 
resemble in tlie general contour of titc crowTi. The distal angle of the crown is 
more rounded than in the central incisors, and the cinguluni is more pronounced. 
The root is single. The maxillary inciaors are lodged in the premiixilla!. 



no 



THE SKELETON 



The mandibular central incisors are much narrower than those of the upper set, 
and le-ss than half their width in the cutting edges, and the crown becomes contracted] 
towards the neck. The cingiilum Ls scarcely marked, and the root single. The| 
lower lateral inciaors are distinctly larger than the lower central incisors in every i 
direction. The distal an^le of the crown ia rounded off; the root is single andj 
f^p^^uently pnaents on each side a longitudinal groove. 

The canines. — These differ from the niciwirs in possessing larger crowns, and' 
thick, long rooLs. The c^o^^^l ends in a blunt point, and the cutting edge slopes 
away on each side. The slojie towards the premolar is the longer, and ciuses the 
crow7i to be aaymmetrical. The linKua! surface preset»ts a median and two lateral 
ridges; they converge towards the well-murked cinguiuin, which is often produced i 
into a distinct cusp. 

The mandibular canines have not sueh pronounced features as the maxillary; 
the point is blunter and the median ridKe is absent from the linffual surface. 

The maxillary premolars or bicuspids. — The crown of the first premolar haa, 
a grinding surface which is somewhat quadrilateral in outline, longer nn the labial] 
than on the lingual border, and has two cuspa. of which the labial is much the larger.' 
The cusps or tubercles are separated by a pit. but are connected by a narrow ridge 
along the median and distal Ixinlers; the niwlian border i.s nearly straiglit, the distal 
is convc-.\. The root may be single or bifurcated near the npex. In some cases 
it is marked merely by a longitudinal depre^ion; in others it is double throughout 
the greuter part of its length and it may even present three distinct roots, Uke a 
ttiolar. 

The second premolar difl'era from the &rst in having its cusps nearly equid 
size. Its root is more deeply grooved. 



Fw. 121. — A Molar Tooth im Suction, ano a Caatme Tooth. 



OMt- 



NGM- 



r*n 



■ mr oiViTT 




■DOT 



cnowH 



The mandibular premolars are smaller than the upper and differ from them in 
shape. The labia! cusp is larger than the Ungual: the cusps arc connected by a. 
low rid^e; the grinding sxirface presents two small pits. The root is single, rounded,, 
and tapering. 

The second lower premolar is larger than the first. The labinl cusp is highe: 
and stouter, and the distal border is much nuire pronounced, l-ike the first, Its roo 
is single and tapering. 

The maxillary molars. — 'Hie first aild second resemble each other so closely 
that one description will ser\'e for the two. The grinding surface is quadrilateral, 
with roundeil angles, h haa fnur eusps, two buccal and two lingual. Of those, 
the anterior lingual is the largest, and is connected with the posterior buccal by 
an oliliquc ridge of enamel. The groove separating the buccal and lingmil cusps 
extends on to the sides of the crowTi and is lost near the neck. The mwlian and distal 
borders usually present a slight jidge. The rotjls are three in number, two ()n the 
labial, and one on the palatine aspect; this last is usually referred to as the palatine 
root, aiwf often diverges from the c-rown a( a considerable angle. 

The mandibular molaTS.^Thc first is the more constant in form. It has five 
cusps on the grinding surface. Four occupy the angles and are .separated by a 
crucial fissure. The fifth cusp is situated at the posterior extremity of the longi- 
tudinal fissure. It has two roots, inclined somewhat ijackwards. placed one in 
front of the other; each is marked by a vertical Kroove. sometimes .<<> deep as to 
divide it into two parts, protiucing four roots in all. In some cases one root only 
divides in this way. 

The second molar difTcrs from the first in that the fifth cusp is frequently wanting, 



I 



1 



THE TEETH 



in 



and, when pretientr is feebly developed. Tlie roots have a tendency to become 
confluent. 

The third molars (wisdom teeth).— The thini upper molar resembles in its 
grinditig surface the mljaceut molars, It differs from them in that tlie t^o palatine 
tubercles are usually bleiided and the routs coalesce and taper to a cone: the apex 
is often bent. The general characlcre of thin root are subject to consiiiemble varia- 
tion. 

The third lower molor has a larger crorni than the corresponding tooth in the 
upper set. It has usually five cusps, and two root« whioh may he confluent. 

The amotions of the Crou^m o/ the Upper and Lou>er Teeth to one another. — In a 
normal condition the upjjer teeth form a laricer arch than the lower. The upper 
incisors and canines clase in from of the lower; occasionally they fall upon, but 
rarely fall Iwliind, them. The lal)ial luberclcs of the premolars and molars of the 
lower jaw are received in the depressions between the labial and lingual tuljcrcica 

Via. 122.— Ths Trkpo».*rt Trrra. 



mema cuac nroououi hours 

fa if* 



MAXILLARY 0* U^PER SET 



MANDIBULAR OR LOWER SET 



"of the upper set of teeth; hence the labial tubercles of the upper overlap the cocre- 
pponding tubercles in the lower teeth. 

in cDiisequence of the dltTprence in width of the rrowns of ilie ujiixr and lower 
incisors, it happens that in closure of the mouth each tooth impinge? upon two 
teeth. 

The deciduous or milk teeth.^Theae are siuallcr in numlier than the teeth of 
the penaanent set. The fonuula is: — 

Tlie deciduous teeth are smaller in sire than their suoceworp; the enamel of the 
crown lonninates in a thick edge; and the tubercles on the crowns of the molars 
ore less regular and pronounced. 

The incisors are similar to thoee of the pcrniauent set, but the canines have 
shorter and broader crowiui than their successors. 

Times of eruption of the teeth : — 

A. DEOouotn* Teeth 



Lower central incisors. 
Upper cent ral incisors . 
Upper lateral inci»4.>rs 
Lower lateral incisors 

First molars 

Canines. . . 

Second molars. . . . 



Mojrma AfTKii Birth 

(ApPKOXIHATELr) , 

7 

s 

9 
,..12 

14 

..18 

22 



112 



THE SKELETON 



B. Permanent Tketh 

The tmio at which the teeth in the lower jaw uodergo eruption is shown in the 
talile below. The coiTesiwinding teeth in ilie upper jaw app(rar a little later: — 

First molars 6 

Central incisors 

Latenii inci»»r8 , 

Kirst prciDoIiirs , 

Seconii premolars 

Canines . -^ 

ijecond molars 

Tliiid molars (wisJom teetli) 

THE MORI'HOLOGY OF THIC SKILL 

In mai] the skull during ri^vplopinpnt pasKes tlirougti three Htagen. At {\mt the bram veKi- 
des are eiu-lotied in a ^;i<- of indiEFi>n>uL tisauo which uTUtuatcly bwunivi- touKh nnii fibruus tu 
rcirm tli(^ membranous cranium. 1'his. in tum. ia partly convrrlod inio tJic mc-mbnuit or ronf 
boD«e of the cr:uuuiii, nliibt tJie remainder ii§ represenUwi in the a<luli b_y tit* tliim tiintcr. Al 
the sides and hiuif> of thu mcmbr:i.riuuK crruiiiiim, liowcvrr, rarlilitsi' if <I<^pii^tod, chondro* 
cranium, in whidi. an well as in the maaVtrmi'mn tracts, om«c>U!< tihtiue appears in due rotirtC. 
Eveitluitlly, an oeseous box is fonned, oonsiating of tnembmne botie« ami cartilage- bonus in- 
tricately interwoven. 

A study of the :>ikull iu the chondral flta^e it> vei^ itiiilrurtive. It conusts oi two parte: 
(1) The skull proper and <2) tlie appeiidicubr elements. 

SI) The skull proper coniiidts of |]irf<e pegionH:^ 
a) The notochordal region, whicb viltiniately give* rifve to the ehtef par1« of the oeeipitol 
oone and ii part of the Kphenoid, It i-i named nolorhortlal because the notuchord runs 
in it UH far a.-* the [tiiUrior extremity, i. e., the level of the eella tureica. At an early xlacc 
of developtucnt two cart ilngi nous barn (fMiraclumtui cnriilagea) lie on either side of the 
notocliord aud wvnlvudly »n.irround it. 

{b) Anterior to tlio nulueliurdiil ik the trabecular region, from which the remainder ot tlie 
sphenoid IB dc%Tlopftd. ft cnn^i^ls nt firMt oE two carti)af;iriout bars {trnhrmUr cmnii of 
Ralhkel, nhich fuse tngnllicr tu fonri the prwhorilal portion of the cjirtjhiKiniHii ba»e of 
tlie eruniuni, 1. e., Uie porlioii in front of the iinlcrior end of Uie notochord. The pani- 
chtirdal and prechordnl jKirtion-* tunn fu^c to form one contiiii]on> inaiw. 

(c) The nHB-t. iuittrinr ]ittrt of tin* prechordal portion of the biuio in the ethmo-vonierinv 
region, from whii-h ilie aivji\ 0>eptuiiL nnd il.-<i'arlilagf» arise. T)i«§c three part^ eontinue 
forwards tho line of the vertfhral dxis and w»nstitiile a cmnio-faf:iaf axt» tcmiinatnig, in 
front, iit tlie preinaxilbe. Finiilly, ni'djii-il in on eaeli »idc, b<*lwecii tho ooU>c)iord»I luid 
trabecular reKions, in the eomplieiitvd peiiotic capsule. 

Fia. 123.— The CHONoito-CKANiuiiir. 



rrMUOiQ ciniuuc 



ortio toMNtii 

ttlMlHR WIUNOU* 
nmUKM 9M1L 

Hunn cuutn fuuui 

INIUUL lUIXOXI Mtnt 

mmioBut roAAwu 
ODsmti 



HtlMUIlF 




man oaviAta 
nimuui 

ORBITO-SPHEHOtO 

U.I-EFHUOID 

renoTic uPtuLi 



toitxDMiTui Tmimw 






The chondri>^rantum at the third month pmentA tlie following parte. Seen from ahove, 
the cartilni;e e:ttend^ from the <T.'iniHl l':i«e to n ifutt niidnay ijctacen the base and the vertex, 
ebadiag oS indefinitely on thu muiubrauous wolL The ovul moaseti on each side arc tlie peiiotie 



J 



TUE MOHPHOLOGY OF THE SKULL 



113 



cartilages, in which the flocnilar Jamie arc rnnsniciimu Ahjerbt. Kadt paiiotic cartiLig* ts 
juuiwl lo the fiplienoid by a Hirip. teniiMl the spoeaotic cartilage, which unuitll^ pensist* in 
fhc jidiiit »kulJ. The cftTlilago for the ortiito-wphcnoid (the miinll wing) i.'* co-extwiflivc with the 
uli-«(iheiioi<l. and form" part of the Ufcrml wnll of the clcuU. The mioiit-hke »p)K'iiniiir-i:' of thi" 
iin[(?ri<ir piirt of tJie skull Is causvd by the (ronto-nasal 'pliite. <Jn vnrit Kide uf tlic ctlinio- 
voineririe pUite. near it»< nntfrior tcrtninntton, nre two Kniall roncive piwi* uf rartihige (or Juroh- 
K'llV QTKtin''. They are ntHnptimi'M n-frrrrtl In il- thr pKiugii.-iliart- i-Mrlilnijiin, owing Iji ihi-ir nhnpc. 
(2) The appcaiJicular elements vi the skull are a uujiiher of curtihiKiiiouK ruJ» i^urruuuduig 
the visceral cavitj* — i. c, nocc. mouth, and phar>-iix — which undergo a remnrkAblfi inetflmoi^ 
pboWt a»d are repreaent«d iti tlui udtilt by Uw ear botujt, the iritfUiid j>rocci», and Uie hyoid bon*. 



ilefnm^phoais of thr BranrJiutl or Visrcral Bora 



r These nxb of cArtilogp an- nnrtied, from IWore Iwirkwnrdi. (be mandibular, hyoid, and 
thyreoid bare, lliey may with vurc bo eiuily diiotected in tlie fa'lUM lwl^«ccu the ihinJ uud diurth 
month"!. Their *mp tamo rpho^ii* i^ «-* follnivs: — 
The two pxtrcmilit.-* nf the mandibular bar oa^ify; Um* dt«I:il end ullini.tt'cly (onnn that por- 
tion uf the maJL<.{ilHc u'JjuL'cul tu tlic nytuphyni.^; tlie proxinml vnd uH>ilic»^ s# tliv malleus and 
Incus. The intcrmL'diate portirtn di*.tippcjir«; ihe only ve^iicc i* b hrtinl of fibrous t»aue. the 
§pheno-ninndil>iilnr hgauiiPtil, extending from the spine of the Hplirrioid to Uio npine of tlio nuin- 
dible. 
In th« connective tissue Burroundlng the bar there nppcdf, however, oanficatJona, one of 
which invcfflx the dinlnl portion of tite bitr to form the U)dy nod ramus of the miutdil>lo, w-hilv a 
second, utuated neiir proxiinHlly, formi! iho tympanic hone. 
'I'hc hyoid bar fuvi lii'tally with the thyreoid bur, and forms part of tl»c hyotd bone. Its 
proximal end become* the stapes, the tynipuno-hyat portion of the eivloid pn>ees« (fuFK^d with the 

CE!iro-m:LHtoi'l>. nnd the atylo-hyal or irvc pcirtiuti of theproeefts. 'The succeeding portion (cpi- 
yal segment I m repre;>c-iitcd in the adult by the fttylo-hyoid ligament, and the loMV«t seg- 
ment, or cvrnto-hyal, by the Binall coniu of the hyoid. 

Tlic thyreoid bar forms the great comu of the hyuid bone (thyreo-hyal). Tlie body of the 
hyoiii (basi'hyah i^ regarded as repreMnliiig the ftiAed \'eiilrul ends of the hyoidean and thy- 
reoideiui arches. 

In addition to theee sEructures OMlScAtinnx occur in the eonnectivo tiaxue of the maxillaty 
ptoceas, a trtntcturc wliirh inny be regarded an f'Tiwmfc tlie anterior part of the Gn<t branchial 
arch, and in the fronto-im*.il pmi-c*". The o-.vifn-nl((>ii« in the maxiUar}' process give Hae to 
the pler>;^oid {inturnnl picrt-icuid procota of llic Kpheiiuid), the paUtc. the niuxilbi. and the 
xyijoiniitie, nhile thnt in Tlic fronto-oasa] pTOoem forma the premaxiUa. 

The hnnv ek-nicnt» of tho head tnuy UiwvfiTn) b« arranged, according to their origin, in the 
following table;— 



I. B^srLAn RoNts DrptLoreo ik rtn Cahtilagixocs Cramicu 

Basi-occipital . IVuHJInr jNirtion of the oa-ipitnl hone. 

Exoccipitals Oitidytar |Mrt« of thu occipital bono. 

Supra-occipital Lower part uf llw nquamous [mrtion of thu occipital. 

PrV-^henoid " } Constituting the Imdy of the sphenoid. 

Ali-spbenoids. .Creuter iringa and external pter^'goid [Jntea. 

Orbito-aphenoids I/ss^er wing*. 

Petro-mastolds. ... . . I'etroiw and mastoid portions (excepting post-audilory 

pmitfttties) uf tho temporal bouos. 



n. Roor UoxM DKVELopia> ix thk .MEMBnANoca CRA.vniu 



Squamosals . 

Pariclals 

Frontals 

Interparietal 

Epipterics 



Siiu«fiiom portions of teni]K>ral«, 
Tlio two panetal bones, 
.rnited to fonn a nic^liuti fronljil Imtie. 
. Ij'P^r |>firt of Hquamous portion of occiplttl. 
, file ppipteric honea. 



III. Bonks oi- tiik Na&u, Rbgion 

Hvaethmoid Vertical plate of cthmokl dcvvloped iu tho eortilage of tho 

onmio-niciftl axis. 

Ethmo-turbinala Su[»cn<ir mid inferior concbul proo ea a as of ethmoid. 

Maxillo-turbinalE ..The inferior mwul coneli^. 

Cribriform lamina .Cribrtfonn plat* of ethmoid, 

'ITteae eleitiPiiti are dewI(i[)«Mi in the eartilnge of t(»e lateral nnwl process. 

Sphenoidal turblnals .'^phenoidid conuhic. 1'lie«e ant derivalivus of the ethmo- 

turlMnals. 

Lachrymals. . . The UrhriTna! Ix>nes \ Develope«i in the membrane over 

RaiaU .'Ilio niuuil boue4 _ f the lateral uasal proceBS. 

Vomer ....Tlie vfHner. Ossified in the membrane investing the carti- 
lage of the cranicKfocial axis. 
8 



ll-J 



Zygomatics. 
Premazillae 



THU 6KELiiT0\ 

IV. Faciai. Bomiw 

.Tlir iiinxillip I Detiilopcd in thp connective tU«ue 

.'Hie z/coimitic bouOT l of rJie masillajj- prwi-cw. 
TJjfi iiiriw>r pann of the ninxillir. Kormcd at tJic anterior 

t-xl.rmnitj' o1 tlw rninio-liiriiil iixin in tiie tuuue of the 

fttiiiloiiiiMd ]}ru(.Tvw (pnx-. globularcs). 



V. Ai'peMDirDi.AR Elumfa'ta [Boxra or thk Viscxkal ARmcA) 

(A) Cartiiafftn'mt 
Ualleus, Incus, and 

Stapes llic ossiculu ^luiUtuH. 

Menio-UcckcHfta portion 

lit tlie lower jaw Small part on either side of (^3^nptlyf4» nicnti. 

Tympano-byals and Stylo- 

byals - Styloid proecwieH o! the tenijiorjil bimcM. 

Epihyals.. Slylo-hyoid ligaiU'entii. 

CeraiO'hyals Lesser L'omiui of hyoid hoiip. 

Thyreo-hyals. .. . tlreatcr coniuu of hjitid bone. 

Basi-hyals Body of hyoid byne. 

(B) Mrmbranfua 

Mandible. . . 'Hie lower jnw excluding a Email portion near symphysis. 

Tympanies Ilia lyinpanic pluteii. 

Pterygoids . . .The inlcmiil pterygoid platea. 
PalalalK. . . The pKlntv ImiicK. 

The Skuil ot Birth 

The akun iit birth prcenita. n-lieii compared ^rilh the adult ultull. se\'enil imjiorlant and 
iiiterHNtin^ features. Ita pctTiUaritics niay f>c L'oriaiderwd under ihrce licadiiigs:- The jiei-uli.ir- 
itics of tiie fcetul skidl an u nliole; Uto vou^tniction uf tlio individuiil Uines; the remiioulA of 
the chondrul skull. 

(1) Thr Gnxn-al Chtimcla-n of the Ftrlat Skul! 

Tlie miKft atrikinK fealure^of the skull at hirth are, its rclaliv-ly lun^i- eixe in eompjiru'on 
wiih ihcUidy, iind the prwlomiimn<*cof the cmtitttl over ihcfacbljKjrlion of thoEkull (Kto 1); the 
Utter is, ill fact, very auiall. 

Pta. 124.— TnE CtuNixru ai Uibi-h. 



^Jl--^, 



The frvtital and psrieta] eminencm are Inrce and nonsnicuoiu; thn siitiirM are nheent: tlie 
tuljiu'eiit innr^mx «i tho tionen of tho vAuil an? <^^parnted i>y nopta or liltmu.-> li&Hiie (HVitinuoun 
Willi Uic duru muter iuleniully and th«^ |icricritniiuii externally; Iieiive il in ditlicult lo separate 



UJUIfl ji 




Tnmtiig to thf biwc of the akull, the mrxit strikini* pointA an thr^ ahftciicc^ ot tho miuilaid 
procr-tHM, .iml tlip l.irgp aiivli? wliifh the plprygnni plnk'^ fomi wilti Ihe nkull-hafe, wli(?rea» in 
the ud'ili il is alitiuvt a Helit luiglc. Tlw bai!« uf the skull is relaiivply short, and ibo iovrvt 
bnnler n( ihr mrjitnl r<j-inphiraia is on a. level n-iUi the oeripitnl condyk«. 

TIm^ (iii-iiil iVrU'tiiii »« n,4,itivply Htnitll in rotioi^iifnce i>f the wnitll siw of the nasal foBBW, 
the sruiill KUf of IIk- iniixiLLury t-iiiuE. tuid lh« niiiunciKiiry eundiiinn of the olveular bordi>n> 
of Uie mftxilitt' and intindilile; the naaal tosaa: ore lu wide as they arc high, and are almost fill«i 
with the conchv. 



110 



THE SKELETON 



Growth UiltcK pinrp rnpidiv in the fi»t seven yeftw ftftrr birth. There in n fierfnid period 
of rsujd growth al \t\ihiaiy. wWn llie air Biuuaex develope, and tliis aGTecU cEjicciuUy the face 
nad trontal porUon of tiic prnnium. 

(2) The Pendiarily nf IntUvi'dital Bonrx at Birlh 

The occipital bona coiwisU of tmir dislinr-l part-*, which have already ticon dcscrihctl. 
Compand with the iidulL bonu. thv rolkminc luv Ihv niutii important poinlH o! rliMinclion;^ , 
lliere is no pbaryngeaL tubercle or jugular process; the w|uainoua |>ortioii pre»eiittt IwoJ 

Fiii. 127. — Tub Oceiyn-Ai. at Biui^. 



■tniiuiiti 



THE iHTturuuiii. MD «untt< 
MciNTit rosnaiii foty nt 
sguiyom rMnoi or the 

ABUII 
WMX-OSOPITU. PWrnOM iQEVELOn ' 

IN uitnuaii 



FORAMEN 
WACHUH 



uai-oc(ii*iT«i 



deep fiwufGfl eoparating^ the inUnparietal from tbo supra-oc«ip!la] r'orlton and pxtonding lb 
far Inwaida aa the occipital protuberanec llie eroovet for the l^iicrnl khhihcs :irc »l>9ciit. 

Thi- sphenoid in » nwreral*^! fortid xkul) falw in(«i threp piivi-s: (1) united pre- and post-' 
Sphenoids, orbiio-kphenoids, .'ukI linguls, tuvii i2 and 3j (he ati-splienoidt. I'he pre-spht- 
noid in e\mte H>h(l nnd cmrni-ti-d with th<; cthmf'-viMin'rirn- rurlilitg*', nnd pmwnlii no trACe« of 
ihi- nir ftiniHi.w uhirh oiviipy thi" juirl in the mliiU xkidl, '^I'hti pivf'phmuiJ Ity its ujijier mirfaco 
furuui |)art uf the nnteriur i-niniul lut^i. from which it \» Mti»is\umiliy cxchided by (he RT^'Vtlh 
of the orbito-Mphcnotdx. Tlie t^tic foramina cuv large niid Irinugulur in sltapo. Tlic Unguis 



Fid. 128. — ^1'tie Sphenoid at Biioh. 




pTanoa uuu. 



UMdU 



stAnd out fr'^m live l>iiJii-xphi?notd ah two latetAl huitresvea, and the floor of tbo sella turcica 
pf«sen(.>: diL' basi-pliaryngcal canal, which in thi^ nx?ent bone Is oocupjed by fibrous tlwiue. 
_.ii_ :. -.:ii ....:i-_: -ji^j. ali-6ph*OoidS with Hw pterygoid prureiwrii are 



The dorsum sellK ie f^lill rartilaginoos. ___. ..., , __^^ _ _ , 

aeparated from Ibe rwt of llw bone bj- cartilage. "Iiie foramen rolundum in eoinplctc, but the 
(utur« fonitueu ovale iv merely a deep notch in the poaterinr border of ihr (inutt wing, and there 
ia no foramen dpinotmm. The pterygoid procc^&ts are abort, and eiich iiiU-rn;il ptf^rvguid ptttto 
pnmmU » bnwid miHaru for .trliciilution with the lingula. The pterygoid canal is a gruoVB 
f<^fwmB tbc iatemiii tjivrygoidpiaui, the liu^ula, and great wiog. 




lis 



THE SKEIETOS 



Tito front*! roiiAint« nf twn bonm si-f>nralM] b^ a nicdiAii vertical (niptopic) suture. 'I'h« 
fruiiliil iiiutici)<.'(> ia verir proiioiincod, but iho tiu^xfrtliai)' urr)i^ and fnttiint t)inuM» an: waoHlie- 
Thr tmittnl nprnn, vrliirli later hoooma^ one nf the moHt roit3pirnoii.4 fcfttiiren of this bone, \a 
.-ilwir-nl. 'Ilicrc in no t^mixiral ridffp. 

Tlie parietal ia siniply a •|uadnlat«rnl Ltminn of bone, voncave oii its inner and convex on 
ili« oiitnr riurfacc. The purmtal pminciice, wbic-li intlicnlee the sT>nL in vrhtcli the owtificul ion of 
the Ik>ih? r(M I II 1 1 Mired, is Inrgr- aud proniincnt. The grooves for blood -ainiisiT.. a.i in nllirr rnuiml 
l)oii«». iifx; iiljwuiit. K'lrh aii^li' of the jjanetid i« in Tvliitiun witli a fontanel It-. A* in the udult, 
tJie nnt4>rior inferior iiiigle of the bnne w prolonged downwards towanlH the lUi-^plicnoid. 

The ethmoid con^Ltts of two btcral portion'^ f^cpaniled by tite still cartihLgiiioiut elhmo- 

FlQ. 133. — TiiK Maxilla at Bikiu. 

nwuuuAtr roiiisaa 



Outat tI*«. 




Inhtlor *l«i 



lann *low. 



vomennt plate. l*he ethmnid cells are roprosontcd by shallow dcprtwHions, and the uncinate 
procem is uiidt-vi-lopMl. 

The spbenoidal coocbn are two mnall triimgithir pierw ttf Ikmip lying in Iho pcrichondnum 
on ea^-h swin of ihe c-thmo-vomcrinc pliilo near \\» jiinctimi with the pre^tiphonoid. (Indicated 
by llie • in Sr. ]2tl.) 

'Ihe maxilla present* the following charnclorx: — 'Hip iiicinj*-*- *utun.' U visihlo on the palatine 
aapectof the bone. The alveolar honlor pnKCntd live ))ockul« fur tueth. Tlic infra-orbital 
fonuncu commuoicates with the floor of the orbit by tv deep hiwiiTv; thit li&-«ure sometimes 
perHSta in Ihe adult. The sinus a a kIiuIIow gmove. 

The mandible nt hinh consists of two hiilvtw miiled by fihnxui tiiu<uc in the line of the future 
syiitphysii). Iviu7h hiilf is a bony trough lodging teclh. The trouf^h i.i divided by thin oMeous 
pariitions into five comparlmenlw: of tht-xe, iln? fifth \* Ibe IrirKr--!, iitid li oFlen Kubdi\-idc<l by 
a ridge of bone. The floor i:^ traver««d by » furrow a.* fur fonviirds iw ihu fourth i>ocket (thai 
for the fiwtmilkmolarl. where i1 tunis outward.iftt the mental foramen. This furrow lodges the 



Fio. 134. — The Mandiblk at IIimtii. 



OUTBN VIIW 




INftCM VIEW 







inferior al\-Polar npr\-R and nrterj-, which enter by the Urge manriibular foramen, "llie condyle 
ia on -A level wi!h Ihe up|»-r Iwirdir nf rhr .-inlenor exiremitv oi the Iwne. 

'Ihe paUte bonc« differ iii.iiuly (ixjui th'jw; In tiie adull m (hut the i-crtical and horixonlal 
pL'ites uro of the saiiie leniith; tlius the natwl foL-u«^ in the ffrlus are us wide as they arc high, 
whcrcaK in th<* adtilt the height of wirh \\i\im\ foE>wa grcotlv p^et^eilx the w-id(h. 

f^nnrniinp the remaininx Wncs little need be fuid. Tlie vomer is n deliL-ate trough of bone 
for the nreplion of the inferior border of ih** ethmo- vomerine plnte: it* inferior l*or9er. which 
restfl upon the hard palate, is hrond, and the t>oitc preitr-iitH qiiJU- a diffcri'iit appr.ir.ince from 
Umt in thr adult 'ITie nasal bones are shrjrt and broad: the zyeomatics and inferior cotMha 
are n-liitivelv vrr>' Inrpe; and the lachrymals are thin, frail, luid delifatc Inmcllir, 

Dm" hyoid ooiiM"!." of live partn. There i* n mMiiui iiuHeiin for the liji>i.byRi, anA one on 
fvtrh Mtif tor (lie gn-»leT eorrmn (thj-rvo-byiil-i). The K"«i*r roniUH are eurtiluguiutu. 



7'H£.' MOJiPJiOWUy OF THiS SKULL 



1 10 



I 



(3) HrmnantJi of ike CartHaginaus Cranium 

11 liitt ttlre«dy been pointtrcl out tbat at an e<uiy clxte (Ih; ba»e ol the ek^ill ai]d tl>e taicv nn 
reprpwnlOTl by hvAline cartilaKv. which for the mo&t purl is reitlaced by bone befitre birth. Kven 
si birlii remnants of thU primitive chondral akull aw abundant. In the crauiuii). tanjlajc>»oits 
Inu'lt exifiT. bel»«<*ri the variniu portions of lh« occipital honp. an n-<?ll iif at Ihp line of iuiiottttn 
oi liip occipital with the |>etm^I and Ppiifiioid. The ilt.>nuru witi- is i-iilirt'ly cartilafpnoiiK 
at birth, and ihc la«t portion of Thipt curtilage dicnppc-iin* with thciinkyioHiHoI the ba.si-<>mpital 
and baAi-Kphenoid aIkiuI thp (wenlielh yenr, A utriji nl rartilufi;)^ iiiiilCH IIip ali-»phenoidfi with 
thelinguhn.iuid foral leat^t u yporo/tor birth thus CBrtiliiKviKi'untmuuuM wjih that which thnHifth- 
out life oocupics the lacerated foramen. A Htrip of <vir(i]ag<' I'xi.^lc along the posterior border 
of the orbito-ephpnoid, and not tinfnvinenMy fixtwida outwartLi to llic plurinn. In the adult 
HkuU it is replaced by ligmnt'ntoais tiwue. 

The trlhmo-vomeiniie plate i.< cntirelv otutiUpnoiu. and aetir the end of the none supporU 
the lateral na«sl earlitiMjei, ntiniiintu of llift froiito-nftMtl plalc. Thi^ fnln of the ethnio- vomerine 
piale ia instnjctivc. The uppvr iKirl \» os-'ified to [r.>nti the iitthutlunuid; (In; lower pari atru- 
phiM from the pn».*urc exerted by the vofnw; the luilehor «nd rcmoinK lu* the septal oartilaee. 
The lateral unout-Ukc extremitKS of the (ronto-rinaol pUtu iienial as tW lateral eartilagex of tne 
ooee. 

Among the npncndirular elenien1.i of the nkull, th« atyloJd proccM and A large portion of 
ths hjroid are cartuaginuua at birih. 

The Nerve-loramina oj the SktUi 

'Hit! varioil.1 foramtnn and canAla in the nkiill which gire paMflge to nerves may he arranged 
in two gmiipH, primary ami secondary. Primary foramina mdieale the B\H)i% where the n»rveH 
lesLve the Konoral envity of the dura maK^r, aijd an Ibltt nieciibraue indicatee the linnl of the 
primitive cntiiiiim. a cranial nerve, in a morfiholnpeal nensr, beeomes extm-erflnia! at the pniiil 
where it pi«-n-«v> Ibis membruiie. In corix'«|Ui--ii(* of llm complii-nteil and »-xlriM)nliti:»n- mcKli- 
ficaijons the vertebrate ^kuU has undersone, mimv iien'cw iravurM.-, in the aduli Kkall, bouy 
tunneli and canals which ara not represented in the lefM eninplex itkiiHo of low verlet>ratea, 
>uch us iJiarka and raya. To Budi foramina and eanaU lUc lerniK aecondary or adventitious 
may be applied. 

Nen'B-forainina are further inlereaUng in that they oerupy tnitiirea, or indicate the potnla 
of union of two or more oaaifiL' cenlrca. To thia rulc the foramen ratundum is the only exce(>- 
tion in the human *k>iil. 

The Primary Foramina 

1. Foramen magnum. — This is boiinde«! i)y four distinct centres, the euprn-, basi-. sad 
two ex-oreipital>i. It tmnsmils the itptnal aeccjisory ne^^•e<^. the vertebral aneriea and their 
anterior and [to>ilerior spinal branches, \hc medulla oblongata and ita nicinbrauefi, and the 
membrann tecioria. 

2. The hypoglosBsl. -At birl,h this is a deep notch in the anterior extremity of the ex- 
oeejpital, and hecomM a complete foramen when the liajii- and ex-oi-cipitalu fuse. Oeeadionally 
it may be complete in (he ex-oecipit.-i! , but it indic.Tli« iMcunitely 'he lino nl union of (heee two 
elenientH of ihc occipital t>one. It IranKinitA thv hy{>oB:luiu(nl ucrvc, the meniiLgeal branch of 
Uie a«cen(Lnf; plmryiigciil artery, and it.'< vcn/c cnmitest. 

3. Jugular foramen. — This orciipie* tlio f»etro-«>ccJ]>ital miture, and is fonned by the basi* 
■nd cue-occipital in conjunction witii the pctroMul. It traiwuitc; the gloMto-pharyn^il. vacitf, 
and spinal aecftwoiy ncrvet, a meniri|jeftJ brnnch of tlw a.-tr.ending pharyngeal artery, and reeetvea 
the tra)i«ven>e and inftnior iKtlixxml »uiumos. 

4. Auditory. Thi:< ntark« the point of confluenec of the sroupa of centres termed prtMitie 
and npi^thotic It i rttumiitJi the fneinl and auditory ner\'es, the pari intormodin, and the au- 
ditory twig of the bitf>ilur artery-. 

5. Trigeminal, -Thitt i^ only a foramen when the dura mater is present in the akull. It 
in a notch at tli« aiifx of tliV putrfiiutl <-on\-i'rtMl into a fonunen li^ the tentorium. Ttw main 
trunk of (Im! triiieiuiiial nerve, with the wnalt mot<ir root, traveratw it. 

A. Petro-Bphenoldal. — Thi^ in a notch between t)ie aide of the dorsum Bella* and apex of 
the petni.i;il which iMtvjnifs eonverted into a foramen hy dura mater, 

7. Optic. — Tlii?! foramen it formed bv theronflueneeof theorbito- and pre-^ienoidal ceu- 
treii. It opeiLi into the orbit and transralta the optic ner%'e and ophihalniie artery. 

The Secondary Jlerve-foramina 

Foramina traosmtttine the vaiiout eubdivicions of the fifth aerve. -The primary fora- 
men of exit for the Irigeminal ner\-e is formed partly of bone .ind pivrtly of membrane at the apex 
of the petro«ial. The three dii-isions of the nerve ixntie through wctindary foramina. 

(a) The superior orbital (Bphenoidall fisiure is an donsuted chink, bounded above by 
tlie orhiml wing and Iwlow by trie great wing of the ophenoid, internally by the Irody of the 
W|>}irnniil, and i'\lerii;dlv by the front.sl. It "pent iiit.n the orbit, and (T:in>«riiitji Ihc Ihird. fourth, 
finit')](oi.>hthahtiic) divlNon of the fifth, and ;>ix(b nor^'us, bImi the uphthulnne ^t•tn. 

lb) The foramen rotundtnn ia the only exception t-o the rule rwlatins t^ the fomintion of 
her\'e-f oraiiijn:i ; it it probsV>ty a B«^m»fnt of the sujierior urliilal (i»uire- Tt»* furiimen i.-i really 
ft eanal numinx frvm the middle crnniHl fosna to lite pierygo-pahiltne foMa, and tnuutnlU the 
second or maxilhiry divi-ion of (he triseminnl. 

ic) The foramen ovale at birth i.i a ipip in llie hinder )M)rder oi the fcreat wing 'itli-^phe- 
noid) of the .tpheiioid, uud is convcrli'd into a fitramen by the petrosal; sub-wMiuently it l>eetim(« 
cuinplete in Ine Kf^r^noid. It trannmitH the third or mandibular division uf tJie trigeounal «sA 



120 



THE SKELETON 



the smiill or motrir ront, the umall superficial pctroeni nerve (wliich otwBanniUly puM* through 

« sep-iTiiU' (oranifii), and tin* .-iiiijill ii:i>iiiof!;eiil artery with its ven* comiles. 

The ethmoidal canals. — Iliew lommence in thesiiture between lheIiunintipiipyra(.<eHiuicl 
the (ronlfll Itttno, and imveivn itic t^pnce between llie iipi.'ot surfai-e of the lateral miuw of the 
ethmotd imd the liori«intal plate of the frontal, to emerge on the cribriform plate; tiny are 
8)tuate<j outnide the dura mater . Die anterior foniiiien tr»n»mit« the anterior ethmoidal bnuicli 
of the opltilialmit.', vtbkh Btitisequetitly fiaias the nteai cavity by pairing Ibroxigli the ethmoidal 
fisMirr by thi> skie of the erista gallJ. 

The infra-orbital canal iiidirateH iVip line of nmRucnce of the maxillary and ninltir i-oiilnw 
of the ma-xiiia; ociufioaally it is cotiipU-ted by tlii- jygomanc: rarely it is inmmplerc atiove, 
«nd cuMiinunicatea by a narrow fiaBurc with the orbit. It lodges the infrs-orbital iwrve and 
arterj-. 

The zygomstico-tempurBl forameo U vituntL-d in Uii.- Mjture bt-twn-u the Kypnniiitir and 
the gn-ater wine of the snncnoid (ali-splienojcl); it trnnmnit,-* ihe temporal branch of ilin^j-j-ari. 
matio m-rve and a brsnrti of fho lacbrj-mal artery. In the adtilt- thin frmmen may lie wlioUy 
COllfinM lo the zygomatic bone. 

'llie zygoroatico-faciftl canals traverse the n'gomatir bone, and indieatc the line of con* 
fluence of (he two chief iieiitres for this bone. The fnrial twig« of the zygontatjc uer\-e luuoj 
from them aceompaiuwl by arleriiU Itrigs. 

The aphenO'palitine fonuneo is a deep groove betn-ccn the orbital and sphenoidal pro- 
nOlirrii of the pakite bone, eonvertetl into a fornnu^n by the (iphenoidal concha. It in traventetl'' 
by the nafio-|>a[atiue nervu anil arlerj- as (Ley enter llie imml trvni [he pteT^'gn-pulutine fn«a. 

Scarpa's foramina are two minute openings in the mcjo-paiatine sut\ire where it is in 
relation with the incisive fo^jja. They are travereetl by the niu-o-palatiiie nerves. 

The pharyngeal foramen in GilualeU between the ephenoidal tirucoas of the palate hone, 
the intem.<d plerjgoid plikte of ibe Hplienoid, and the sp})enoidaI concha. The pliarj-iuceMl 
bruiivh of the apheno-palatinc ganglion and a branch of tiie sphmo-palatine artenr^MUS IlirciugVl it. 

The pterygoid cAoal in irunipel-aliaped: t)io narrou'er end is siluatea in the fnrAmen 
lacerum; the broader orifice ogtonaon the posterior wall of tbeptcr^-eo-palntine foKsi. TbecatinJ 
la 10 mm. loa^; in the ftrtal skull it in a chink between the ba«e of the internal pterygoid plule, 
Che nli-nphenoid, and the tinKiula of (he aphonoid. The raiiul ia traversed by the Vidian bnuDch 
of tlie spheiio-palatine ganglion and the \'idian artery. 

'Hie posterioi palatine canal iu u paMitco left between the maxilla, (he \-er(ienI plate and 
ttibenxiity of the palate Ixine, and the internal pterygoid plate; it comnnences on the hunliWatej 
by the greater palatine foramen. The deaoendinz palatine nerve and artery travem* thin ennal. 
Several foramina open from it. In the suture between the vertical plate of the pn.lnle brae 
and the maxilla, two small openings allow minute ner\-es to issue for the middle and inferior 
naani wimlisB- In the Gaaurea jjetwcen the tubero».itie.< of the palate and maxilla-, and the ptery- 
goid platee, the posterior luid middle palatine oervee ifi«ue. Tbe«« are aometiuies called the 
pciterior and middle pulaline canabi. 

The mandibular or inferior dental canal nina in the mandible between the deutar>' and 
Meckel's cartilage of cbe nuuidible. The posterior ori^ee of the canal is the mandibular (iiife~ 
rior dental) foramen; the anterior oritiro is the mental foramen. The inferior alveolar nerrttil 
aud artery enter the canal at ita posterinr orifice; the mental foramen allows the mental uerv#J 
to escape from the canal itceompaiiied by ilie mental ailerj'. 

FoTamlna transmitting the facial nerve and its branches.— 1'he main trunk of the facial ' 
enten tite internal auditory mealuft and travenea the facial canal. In the early eml>ryu tlw 
ncn'e lioa on the petrosal, and is not covered in nith borke until the hfth month of fojtal Ufo. 
The terminal orifice, the sly io -mastoid foramen, is Rituatod between the tympanic, tymponor 
hyal, and epiotic elemental of the eiiitiplcK temporal bone. 

i'be * iter chordEC posterius' is a cliink between the squamosal and the tj-niponic elements, 
and allows the chorda tj-mpani nerve to enter the tj-mpjmum. The fissure of exit for thia nerve 
is the fubdiviHioo of the petro-tympanic hh^nre termed the ranai of lluguitrr. or 'iterchonlM 
onterius.' Ilie patro- tympanic fissure liei^ between the tympanic plate and llie equomonal. < 
jt inuiHinit-s the tympanic branch of the internal miutillaryarterj', and kidgeHlheanteTior proce 
of the lunlloiiii. 

The inferior orbital (spheno-mazillaryl fissure b situated between the nosterior hordf 
of the orbital plate of tlie maxilla aud a smooth ndgc on theorbitjU tturfaee of the great wing 
of the sphenoid. It transmits Ibe superior maxillary divjKinn (second) n( the fifth ner>-e, the 
itygomatio nexx'e, branclie-n of the Rplieiio-palatttic gungUun to the orbit, and a eommiuiicating 
\-ein from the oplilhalmie to the pterygoid plexu:s. 



C. THE THORAX 

The thorax ia a boay cage fomted by the thoracic vcrtebtae already described, the 
ribs u ith their ctwlal canilages, and tlie sternum. 



THE RIBS 

The ribs, twi?U'e in numljer on each siiie. ooiwt jfuie a ggfiee nf narrow^ fial tet 
l>one«, pxtcndinff from I lie sidps nf the tlioraeic vorlebnp tnwimia the median ltn( 
JO r/ie anterior nApect- of the tnink. The anterior cnd.i of the Urst seven ptiira ai 



THE RlfiS 



121 



connected, by means of their costal cariiJages.. with the sides of the stenium, and 
on this account the first seven rilw on each side arc termed stem&l or true ribs. 
The reniaininft five pairs, known as asternal or false ribs, may be arran/jed in two 
«ets: — one. including the eighth, ninth, and tenth ribs, in which tlie cartilases of 
the anterior extremities are cmnetted t-<»Ketiier. and the otlier, including the eleventh 
and twelfth, in which the anterior extremities, tipped with cartilage, are free. The 
eleventh an<l twelfth atv known, In cotisetjuence, as the floating riiis. Thu.''. the first 
seven are vertebro-stemal; the eii^hth, ninth, and tenth, vertebro-chondral; the 
elcventii and twelfth, vertebral ribs. 

The ribs increase in length from the first to the seventh, and decrease from the 
seventh to the twelfth. They also vary in their direction, the upper ones being 
less oblique thim the lower. The obliquity is (greatest at the nintli rib and gradu- 
aliy (JeiTeawes from the ninth to the twelfth. 

Typical characters of a rib. — The seventh is regarded as the most tvpical rib. 
It prpseiiM for exumination a vort-ebral extremity or head; a narrow portion or 
neck; a sternal extremity; and an intennediate portion, the body or shaft. 

The head pnesenta two facet* separated by a horizontal crest (n^to oapUuli). 
The crest is connocted by an intcrarticular ligament with an interverlcbral disc, and 
the facets articulate with the demi-facel^ t>n the sides of the ixidies of two venebne 
(fflxth and seventh). .\3 a rule, the lower facet is the larger, and oiticulates with 
the thoracic vertebra, to which the rib corresponds in number. This \h the primary 
facet, and is the one repre.sented in those ribs M'hicli possess only a single facet on 
the rib-head. Tiie anterior anargiu is lipped for the attachment of the ciMto-vert*.'- 
bral (radiate) ligHment. 

The neck is that portion of the rib extending from the head to the tubercle. 
It is flattened from before backwards aitd the posterior surface is in relHtion with 
the tron-svcrsc proces-s of the lower of the two vertebra; with which the head articu- 
lates: it forms the anterior boundary of the costo-transverse foramen, and is 
rough where it gives attachment to tlie middle coeto-traugverge ligament. The 
anterior surface Is Hat and smooth. The sujjerior border of the neck, continuous 
wit h tlif corresponding border of the shaft, presents a rough cre.st {crista colli su-jvrior) 
for the anterior rostivtniiwver^^e ligament. The inferinrtmnJerof tbeneck is rounded 
and continuous with the ridge of the costal groove. This difTerenco in thft rela- 
tion of the neck, to the n|>iier and lower borders of the rib-shaft, is useful in deter- 
mining to which side a rib belongs. 

The tubercle, situated behind at the junction of tlie neck with the .'»haft, consiats 
of an up|)cr and outer part, rough for the attachment of the posterior costo-transverse 
ligament, and a lower ami inner part. I>earing a facet for articulation with another 
one near the tip of the transverse process. The tubercle projects below the lower 
edge of the rib to forra a crest {eriata coUi inferior), marking the beginning of the 
costal groove. 

The body is strongly cun'cd and presents for examination two surfaces and 
two borders. At first the cur\'e is in the same plane as the neck, but it quickly 
turns for^vards at a spot on the post^^rior surface of the shaft knomi as the angle, 
where it gives attachment to the lUo-ccsUilis muscle and some of its subdivisions, 
The rib has also a second or upward curve, beginning at the angle. These curves 
are exproeaed by desciibing the main cun'e as disposed aromid a vertical, and the 
eecond or upwani curve around a second transverse, axis. 

When a rib, except the hrst. second, and twelfth, is laid with its lower edge 
upon the table, the rib-head rises and the rib touches the tabic at two places, vit., at 
the anterior end, and in the neighbourhood of the angle. 

liesides the two cun-es now dejwribed. the rib is slightly twisted on itself, so 
that the surfaces which look inwards and outwards beliind are placed obliquely 
in front and look ilownwards as well as inwards, and upwards as well as outwards. 

The extenial surface of the rib is convwc, and gives attaehment to muscles. 
Near its anterior extremity it forms a somewhat abrapt cur\*e, indicated by a ridge 
on the bone, which givp-s atLichment to the saratuB anlerior (magnus) muscle, and is 
BOtnetimes called the anterior angle. • 

The interna! surface is concave and ]>resent8 near its inferior border the costal 
groove. The groove is best marked near the angle, and gradually becomes »h:d- 
Kiwer lowiinU the anterior extremity of the rib, where it ia finally tost; it hxiges 
the intercostal vessels and iien'e. The ridge limiting Uie griMJVe alKivc is continuous 



122 



THE SKELETON 



with the inferior border of the neck of the rib, and gives attachment to the internal 
inlercostal muscle. 

The superior l>order is rounded, and affords attachment to the internal and 
external intercostal muscles. The inferior border coiimiences abruptly near the 
angle, and gives attachment to the external intercostal muscle. 

The sternal end of the shaft is cupped for the reception of the costal cartilage. 



Fig. 135. — The Seventh Uib op the Left Side. (Seen from below.) 



CDSTU ORDOVE 



Bitamal Inter - 

□oilml 



lQtam4l inter. 




ARTICULAR PORTION 
or TUBERaE 



SIEHIHL EUd FOB COBTtL MftTILABE 



The ril)3 are ver\' vascular and derive numerous branches from the intercostal 
arteries. The branches in the shaft run towanis the vertebral end, whilst those 
in the liead and neck run, as a rule, towards the shaft. In the neighbourhood of the 
tuberosity the vcsseLs do not seem to have any constant arrangement. 

Peculiar ribs. — Several of the rilts present certain peculiarities and differ in 
many particulars from the general description given almve. These are the first, 
scv-omh tenth, eleventh, and twelfth. 



THK HI as 



123 



The first rib is the hrondest. flntu;st. fltrongest. shrtrte<«, nnd moat cun'ed of all 
the aeries. It is not twisWtl, nnd is ao placed that it* superior surface looks fonvanljj 
as well as upwanls, and its inferior surface Iwwkwanis as well as dowTiwards. The 
head is small, and as a rule is furnished with only oue artit-ular facet. TIir neck, 
longer thaii that of most of the ribs, is slejidpr ami roiiniled. 'I'lie tubercle h lui^e 
and prominent. The sliaft lies for its whole extent nearly in one plane, has no aiiffle, 
nnd is curve*! in one direction only, i. e.. around a veriical axis. The siijx'-rior 
surface presents two sinxllow grooves, separated near the inner border by a rough 
surface (scalene tubercle or tubercle of Lisf ranc) for the scalemts antaior muscle. 
The groove in front of this surface is for the subclavian vein, and the groove behind 
it 18 for the subclaii-ion artery, Between the groove for the artery and Ihe Cul>ercle 
is a rough surface for the insertion of the sctUenus nmiiug. and between the Rroove 
and the outer ninjgin is an area for the origin of the semjlus anterior {macfixMs). 
The inferior surfa^-e is uniformly fl.it and lacks a suHrt*sts! groove. By the outer 
portion, which is rough, it gives attachment to the internal intercostal muscle; the 

Fio. 136. — FiuitT anmSkcoxo Hina. 



IWBttU 



IIIu-oaMaliadonl 

.tnaoTticibi 
111a.«(»aU>lI* (Mf vMa 

S«rr*lu* poMvnor 
mparloir 
lUia«Tt(oai 

■ealanss poatorUc 



LaraUtr ocwa >ad 



■oftlaoiia BMttna 



tsnan 



::^^ 



iTit«reost«.la 



Sarratu* 
antartof 



UWIA roil MMUTAM 

van 



. Tlilrd dialtailani of 
•uraid* MiiMlor 



. Biuiaal Iota 



BMirr 



Tpmalnder of the inferior surface is in relation to pleura and lung. The outer border 
is thick and rounded, and give-s nltachment to the external inlercosUil muscle, whilst 
the inner Ixmler. thin, sharp, and concave, receives the attachment of the fascia 
(Sibson's) covering the dome of the pleura. The anterior extremity is thick and 
broad, and its upper margin, as well as the cartilage to which it is joined, afford 
attachment to the co»to-clavicular ligament and ihe avhcUiviua muwle. The costal 
eartilagc of this rib is directly united to the manubrium stemi, and occasionally the 
cartilage and the adjoining part of the imterior extremity of the rib are replaced 
by fibrous tissue. 

The rib derives its nutrition mainly from the superior intercostal branch of the 
subclavian arlcn'. 

The second rtb is much longer tlian the first, and although like it in being 
strongly cun'ed round a venical axis, in its form and general characters there is 
a cla-aer re.vmblance to the ribs lower down iti the scries. The head is rt>und and 
presents two facets, the costal groove is present, though faintly marked, and an 



124 



THE SKELETON 



angle is situated near the tubercle. The apecially dislinpruiehinR feature of the rib, 
however, is a well-nmrked tuljerosity on its outer surface somewhat near the middle, 
fur the atiachiiient of a part of tlie firtit digitation, and the whole of the »eo<ii»l 
digitation of the senxUita mitvrior (magmiB) . l-tetween the tuberosity and the tubervle 
the outer surface is smooth and rounded aud gives atfjichment to the acalenux 
posterior, the sermtwt postrrior superior, the ilio-cMlalis cervicia {cerincalis a$ccn(tfns), 
and the itto-costalia dorgi {acx-essorius) . The internal surface is amooth ami in rela- 
tion t« the pleura. The borders give attarluiient to the iniefcottat muscles, the 
upper, to thoso of tlio first space, the lower, to thnsc of the second. The shaft of 
the second rib is tioi twifiteil on it8 owa axitn. ao that both ends can lie Hat an the 
tablf. The spcoml rib receives vessels from the su|jcrior intercostal branch of the 
subclavian arter>* and the first aorti« intercostal. 

The tenth rib is distin^uiahod by a sinple facet on the head for articulation with 
the body of the tenth thoracic vertebra. Occasionally there are two facets, in %vhich 
case the rib articulate.s also with tho ninth thoracic vertebra. The tenth rib, like 
the rilw inmiediately above, i.s lung, curved, presents a deep costal gnxrt-e, a well- 
inarked tuberosity and an angle. It may be noted, however, that the distance 

Fio. 137.— Thx Vbrtf-bhal Exns nr Tknth. ELEvrNTW, axo Twelfth Riaa. 




Tm nani *ft£ f«- 

StftTi 



swats F»ctT iVint i 

HJig 4f< MQU. »UT 

Tumeun tm 
non 



XL 




imtu fun (iHn nil 
•us *E>TK» ma. 
wrr, man, noh neck} 



between the tubercle and the angle in this rib is greater than in the ribs above. 
Speaking generally, the distance between these points increases from above down- 
wards — a disposition which is useful in at once detemiiuing if any gtveu rib belongs 
to the upper or lower end of the sericB. 

The eleventh rib i.<; pecuttiir in that it has a single facet on the head, a feebly 
marked angle some distance from the head, a shallow costal groove, go tuberrle, 
and no neck. The tul>ercle is sometimes represented by a i^light elevation or rough- 
ness without any articular facet. The anterior extremity is pointed. 

The twelfth rib has a lanie head fiimisheii with one facet for articulation with 
the pcdiclo of the twelfth thoracic vertebra. The shaft is narrow and extremely 
variable in length (3 to 20 centimetres)- It in usually somewhat longer than the 
hrst rib. but it may be shorter. There is no tubercle, no angle, no neck, no costal 
groove. The anterior extremity is jwinted. Behind, the upper border is smooth 
and somewhat niuiHlcd ; the lower bonier is sharj) and rough. 

The costal cartilages are Imry r>f hyaline cartilagt* attached to the anterior 

extremities of the ribs, and may 1h? reganled as rppnwenting unossified epiphyses. 

Ijke tho shaft of .i rib, each cartilage hits an outer .-md inner rJurfaco. The outer 

ifurfa<yei* giVf origin and insertion to large muscles, and the inner surfaces, from t 



I 



THE RIBS 



125 



iiwnnd to the seventh inclusive, arc in relation with the tramrertus Ihorada {tri- 
a'lguiorit st^mi). The upper and lower borders serve for the attachment of the tn- 
ternaiintercostai muscles. The upper seven cartilages, ami ooeasiimally the eit^litfi, 
are connected with the stenmni. Of ilicHe, the lirst fuses nnth the manubrium 
stcmi and the remaining six are recei%*ed into aniall articular concavities, and re- 
tained by means of ligamenus. The cartilages of the vertebro-chondral ribs are 
united to one another and to the seventh costal cartilaKe by ligaments {sometimes 
by short vertical bars of cart ilajEe), while those of tlie vertebral ribs form no such 
attachment, but Ue free Ijctween the abdominal muscles. The inner surfaces of 
the lower six costal cartilages afford atiaolunent ti> the liiapiiragm and the transr 
vcrsalis muscle. 

ICach (if the second, thinl, fourth, and fifth c^istal cartibifies articulates with the 
ride of the sternum, at a point corresponding to the junction of two stemebne. The 
sixth and 8e\*enth (and eighth when this reaches the sternum) are arranged irregularly. 



Flo. 138.— Rib at Pt^BKinT. 




ttimmt rDR THE HUO ittUMt II 
fimtt. mi« »T TWtllT-THIIlE 



triMttiS tiM ruiitai irrcMS ii 
nntiu : lusii tr n>i«ii.rHMi 



IHI SUniLifltllSUI BHtfT K)U*£^«9 TO OWII IT 



As a nile, the sixth lies in a recess at the side of the fifth stemehra; the seventh 
CDrrcsp^nids to the line of junction of the me«o und nieta^lenium; and the eighth 
articulates with the metostemum (see figs. 139. 142). 

The coHtal cartilages derive their blood-eupply from the tenninal t^^igs of the 
aortic intercoatals and from the internal maiDmHr\' arteries. 



Ossification. — At the eighth week of intru-uterine life the ribs are rartilaeinouE. About 
thi4 dale a nucleiu appears near the angle of tach rib, and aprcAds vrith ftrcat rapidity along the 
•halt, and by tb« fourth month reaches ae f lu* n* tbe coslaJ caxtilaRe. At Ihis dute tlie leiigtti uf 
rib-ehaft bonre the eamc pmporlioQ to that of tlie (.tJiital cartilage as in adult life. Wlulit the 
ribs are in a cartilaginous cooditioa, the flntt Heht rracli to Th(^ side of the sternum, and even 
after omification has takeo place, the costal cartilMe of th* eighth rib, in many instsun-w, rct«iii» 
tti artiruJation with the etemum up to oa lat« as the eighth munlh C6g. I3t>^. This rvlulioiiKltip 
may pcrsint through life, but usurilly the rarlilaBe retrogrcesM, and is replaced hy lignmcnious 
tissue. About the fifteenth year a onxindary renlie appears lor the liead of r:irh nh, nnd a little 
later one makni ilii appeoranoe for the tubercle, except iu the dcvcutb and tweUttx nb«. Vt«r 




126 



THE SKtXETOM 



i|urnll}- <-pi[)h)-M>>^ iirc ilevrlopt-d on )K>lh parU «f ibfi tubercle (mv fifl!'. 140 oiid 141). The c(ii- 
pliy»c» (ujvT with the nbe »l«>iii tlio i«eniy-ihirtl y*iir. The rib-flhafl increAAei* in length muinl; 
nt itb line of juuctmn wttli Ihit r<iHtnl iitrtilttfje. 

Fig. lao.— The Thoiux at the Eionrn Moxth. 
(On tl»e Irfl wde eight cnrtilKges rpach fhc jitcmum.) 



Fonoh'on* I'n the Niimber and Shape of ike Rihs 

The riha may be infrreaaed Jn number by ndiliUon either at thf^ cer\-)ral nr lumbar end of the 
Kories, but it u extremely rnrtt to fuid aii ntlclilioiud rib or pair ol ribe in both the cervical and lum- 
bar feftiou^ in the same subject. 

Cervical ribs an? fairly coninmn; as a nile. tliej- nrp of ^imall ««<? and rarrfy extenJ iiwire lluiu 
a few iiiiIliiiielt>.-M I icy on d t lie extremity of tli*t Initisver* [troc«i» (see pp. 3S, 39k IJccDJiionolly 
tiiey excewl su'ch insigmttcant proportiona and n.'iH-ii an I'ar m the slcmuiii: bvtMeeii tbmt* two 

KiG. 140.— Post BRIO ti Pobtios oi- tue SiXTit \Ub in the KirrRENTH Ybak. <Afier ToUlt.) 

inN>tii an bOH-uTiouuii raiTiMt or nt TuBcnoit 



tnrnTKB OF MUD 



wnouuR f uf I 



extremes many varieties oecur. As a nde, llie existence of a e«rvical rib in not detertcd until 
the skelet^jn is miuvrnled: henre we knnw little of the corrplnipd arrjvrnempnt of soft para. In 
oiie ffrtunnle erne lunief «m able to make a tli'jH"ieh di»>K'tioJi •.'( ri ."iKK-iiiieii in which a 
roiiiplele eerviral rib existed. Its head artieiilnKii with lli*^ liody of i Iw rtoveiitii ccrviciil vertebra 
and liiid a radiate liganietil. Ihe tubercle w.is well develotH^ii . .'iiul nrtinilnlMl ivilh the tnuiH- 
vene proveivi. The nwtal cartilage blended with iliul of the lir«t ihurucic rJb, and guve attack- 

I'lo. 141.— PoaTEBioii Portion or tuk Sixth Itin is tup. Fiohtrkxtb Year. (After Toldt.) 

)IOIi-WtlOUU« WHTK)* OF IDEtnOlE 



ffimvtll »t HUD 



i^ 



imnhh m th( uT'Sixu .-tctr ar the itttno-t 



ment to the ri^wtn-rlaviniliir lijRiimcnt. Brtwr*-n it and the finit thorade rib there was a wd!"-' 
markiHl intercoHtnl "prtw? (K<eupi4-d Iij- uiu-tcuhtul mu«ck-». It recei%-(.Hj Die altai-hriieBt of the 
tcatmua nnirrifr and niiiHui< iiiiir>^lf.->, iiml it was tTosswl \.iy the »ul»rlavian artery and vein. The 
tM-rvfrv nt tlio uiteTr<mi^\ ttmiT^ wirn- Kti|r]ilH-il l>y llw eighth rervical aniJ llml thonicic. The artery 
or £/w B/vuv Mvn- JerhixJ {twn iJie deep ccrvieal. wiiich, wilii ibo supcriur iulttrviuital, 



THE 6TEHNUM 



127 



frtim the root of Ih*^ vwldjral. T!ii> ticuii of thf finrt Hmmic rib in lliin ■pwinw-n nrlinilalvd 
with the wvi^iilh eervir«|. na well n* «i(li ihv (ii>i lliuruciv vcrtwljfa. An iiilvnvxtiiuc lacl is 
■Ifto rWf)r\li'(i in the (.'Hrpf ul account of Thi.i tipwimcn — There wiw no movalili* iwclftd Ihornck' rib 
on Ihe •anii^ aide aa this well-di>vclo}jeil ri>r^irjil rili, uml thi- tw>'l(tli thoracic vertebra Und iniuti> 
miltnfy and nf^cwsory proreflAeit, and n elrotti; t-lt^riiptU'd voaIhI procvKs, and was in linear series 
with iho hnnl>ar tranevonsv proecfMai. 

CSnilxrr aiid Turner, from n careful nnd «lftt»ir«t<! nludy of this ouestioo. summariae the varin* 
Uoiisin the cervi<?al riln (liii« — ll may lie v*ry short and posMssonly a head, neck, nnd tuljercle. 
When it extends ttcyuud llio tnuieversc jiropetw. it^i shaft may end freely or join the firal thomoiir 
rih: this union may be. cffeoled by bone, eartilAfCf^, or liftament. In vcr)- rare inBtanees it mny 
have a etwUi! cartilage an<l join I he niaimbriiun a( the atenium. Not iinfrer|uetil]y a nriicesv, i)T 
eminence, pjtiats on the fifst (huracic ril) at the spot wliere it arliculatt* with a i-mical rib. 

Lambar ribs are of Ictm (itcnifirance than eeivienl HIm and mrely attain a gnat lenfjlh. Their 
presence U easily aecountvd fnr, an they are the ditTerentialed ctntjil elements of the Iransvci^H! 
proeewee. They ate nwcrBOCOmplotoiis the <;er\-ic-a! ribtr. luid urticuliileouly with the tnuuvene 
proceaoea; thchetidnox'crmichMMfAriu the l>ody of the veriehra. ond there tsnoncek or tuher- 
cle. An extra Uj^U'W cmfttF niu)«--lc it a.\i>odaled with a linnhar rib. 

Not ihe least iutcrfsling vuriuciou of a rib is (luit known an the bicipital rib. This condition 
ifl !4een exchisi^-ely in ronnection with the first thoracic rib. The vertebral end consists of two 
linibtt vvhicli lie in iiilTer«rnt t.rati^viT*i' plnncM. The«e bicipital ril« have Inwn «x|ioci»l)y ^tudied 
in wbalea and luau. 'ITiin ubnomiality is due lo tlio fusiuii q{ two ribit, oillier of u conical rib 
with th« shaft at the tint thoracie; or the marc common fortn, tho (iwion of the hnt nnd seeond 
true rilw- 

AmouK ununual ^Tiriatiuiis of ril>i should t>e mentioned the rfphK-t-iiic-iil of the cuxijd cartilni;e 
and a portion of the rili-tthuft by fjbrnat tiuuc. a |iroccft.i which occur* nnnnally in tlic ca«e of tiie 
eighth riU during it* ilevnlurxnent. 

Sonivtinic^ tlic hIiulIIb r>[ two or luon ribn may become united by Hiiall qu&drihileral plates 
of Iwne extending aen*^ the intercostal space*. 



THE STERNUM 

The sternum i& a Hat. oblniift plate of bone. sUiiaUHj in the anterior wall of tlie 
rhomx, ami divwiblo into ilm-c jKirtri, fallfMl n-Kix-Ptivcly— (I) thp manubrium 
stemi (presternum). (2) the gladiolus (nie.soBteniiirii). rnristitutins t lie. body of 
the binie, and (:i] the xiphoid ur ensiform process (metnstemtun). In the young 
uubjerl it consist!* ot .six pieies or «'Kmeiit.- [stcnit'l.nc). Of these, the first remains 
separate thruuichout life ami fomu- the mauultriiiiii: the aucceeilinp four seguietits 
fu>« together, forming tiw body; whilst the luwetst ^guicnt. uIku diiitiuet until miil- 
dle life, is represeiitetl by the xiphoid process. 

In its nnturii] iinsiiiim the 5;termm) is inclined nbliquely fmm above downwards 
and forft-ards, and cnrrcsponds in len)^.h to tlw spine from the third to the ninth 
lliaracic vertebra. It is not of ecjual width tliroiighout, being brvjailer above in the 
iitnnubriiuii and narn>w al the junction of this piet-e with the body. Towards the 
lower piirt of the b<jdy the stenium again wi<len.<, and then suddenly f<intniela at 
its junction with tlie xiphoid priHiess wliieh l'(^n.«t^tuIe^ the narrowest part. 

The manubrium or first piece of the .sternum fonjw the bniiKie«t and thickest 
part of the lx>ne, and is of a wmewhat triangular form with the base directed up- 
wards and the apex dottTiwards. It presents for examination two surfaces and four 
borders. The anterior surface, slightly convex and directed oblic)uely upwanLs 
nnd forwanls. is smooth and K'^'es attachment on eiR-h aide to the sternal head of 
the itrrrif-nutxt/tid and the pectarah'a major. The posterior surface, ahnorst fini, 
and directed downwarda and backwards, affords oripn near the lateral mnrgiiis 
on each side, to the sterno-h'/vui muscle alw^ve ami tlie stenio-^hyrtoiti niuwle below. 
Of the f«)ur Ixirders. the superior if the longest and much the thickest. In Ihe 
middle is a. curve*], noii-artieular depression, called the jugular (interclavicular 
notch), to which the fil)re.s of the interclavicular ligament are attached, and al 
eitlier end Is an oval articular gurfaee, somewhat saddle-shaj)eii and diretied upwards, 
backwards, and outwanl« for the reception of the inner end of the rlavicle. The 
circumference of the artieidar surface givee attachment lo the .'jtemo-clavicular liga- 
menls. The lateral borders slojie from above downwards and inwards and ea«h 
DTDsents an irregular surface al)ove fur tlve iiivi i^wial cartilage and a small \arH 
belnw, which, with an adjoining facet on tlte body, foniia a notch for the second 
costal oartilage. The two articular stirfaces are sepurntoil by a narrtiw cur\'ed edge 
in relation with the internal inUrc*i9tal muacle of the first space. The lower bor- 
der is thick and short and presents an oval rough surface which articulates with 
the upper burtier of the body, forming Uic sternal synchondrosis. The two op- 
posed surfaces are aeparalcd by a fibru-cariilaginouK disc, wliich may, howevei* 




fiecMil opvuds kad fonmnb. und nwked br thne tnuamam eieratioflB 
OK^rAV r!^ linee of jtmctian of tU four eonpoMnt puts. It prm$ anaehmenll _^ 
» Bhrps of the jfx'f >nW;5 nw/,.', aod ooaMOomUr prMeota a foramen — tbe 

stc;^.. ^, i4zne& — s3Uux<>d At ;hrju£ioU:>a of tbeUiinl and fourth pieces of tbe bone. 
TV posterior surface is s^if^htlr cpDraw. marked bj lioe* rarmpoufing to thoae 
Ao the AMerror suriaotj ami bri'ow ^vm attadsnest oo eadi side to SbnB of 



Imnnverausi thoracit (trianguiaris eltmi). The lateral borders presenl four whole 
facets anil two hulMaceUs oa each sklc, which articulate with the cwtiU cariilaRts 
of thn Hocuiwl to the sevenlh rihs inclusive; the iwo half-facets are completed by 
corrospomling faceu on the niimubrimii and the etwifwnii prwrees. IJeiweeii the 



OMCUUHMTM 
•wnM-kyoid 

■Mi1M-UUP*««M 



TMaamMu) tkora^U 




articular deprewiions tlic lateral border is curved and in relation to the internal in- 
Uretmtal nnwiOes, 

In tirflrr to it|i))nv-t.ilf (lin iiittiinv of Diese srticulnr depreosions, it b advantngpoUH to HlutK* 
the 6t«n)utit in u. youtin Biil>iw.-t. V.\vA\ tvpiiral sterncbra presents niiir angles ut cucli of which b 
« demi-farct. iWtCHwn evrry \-vfo Kt<rmrhnr thprc w an mtCTstenwbral diw; so iJml when in pdM- 
tion, m<'ii tidlHi for a ("oiilal citrlilni^- i% fdrmiil Itv » ■t?rn«'bni above and below nnU nn intentlrine- 
bnd diBp in Ihe middle, tluia reitejiiinn iln; reltilion of Iho rib-hvsd to thr viTtcbral centra. Later 
in life these fu?o more or 1cm tofteihtT. pxcepi in the cimo of the first and wxind skTncbro-, which 
oiiiiillv remnin aepMnle to lti« end at Jile. lliefint (pT«-«tcmunOiit tlie mo«t modified uC lA^ t.V^ 



130 



THE SKELETON 



•tcmrbn^, amd differs rirm thcni m the f*ct tluu the eoatal carUldfe of the fint rib is cootiDuotut 
with it, and in fitct tlial. tt napi'mtrt* (lie clArictes. Occa&iotuillr m nituidrfd nisifnnn liune iimmii 
un each nidu, UniuwU&Uily iutenuit to ihe anicuUr iiotcb for ili« cUxnde; Ihera are tiie lupra- 
ttenial botiM. 

The superior border prceenU an oval facet for articulation with the monubrhim. 
The inferior border is shurt and articulatefl with the ensifonn prricess, formuDg the 
meso-metastKiial joint, the two opposed surfaces ^>6ing eoparated by a laj-er of 
cartibge so long a^ they are not imited by bone. 

The xiphoid or ensiform process is the thin, clongattHl prr>c(S« pntjectuig 
downwaids between the cartilages of the se%'enth ribs. It i^ the least developed 
part of the Rtemum and is subject to many variations in form, being sometimes 
pointed, broad, and thin, occasionally bifid nr perforata bj* a foramen, and some- 
times bent forwards, backwards, or deflected to one side. In structure it is carti- 
Uginous in early life, partially ossified lu the adult, but in old age it tends to become 
ossified throughout and to fuse with the body. 

The anterior surface K'Vcs attacliment to a few fibres of the rcrius abdominis 
muficle and the chondro-xiphoid ligament, the posterior surface to the stomal 
fibres of the diaphrngm. and the lowest fibres of the traravaws thoracis {triaftgu- 
laris stemCj, whilst the lateral margins rec-eix'e (be aponeuroses uf tlie abdominal 
muscles, its tip is directly continuous with the Unea alba. 

Fto. 144. — PovTBiuos Scrtacb or thb MAjfueiuvu (Pbe-sters'uh). witb SrsBNAtE-TDS or 

CLAVtCT,» AXD TWB FlHST CoflTAL CaRTILAORS. 



Btora«-bjraM 



lMcft»-ikyt««U 




I 



i 



Differences according to sex. — The sternum differs somewhat in the two 
eexes- The female ftemum is relatively shorter, the diminution being almost con- 
fined to the Iwxly. lu the male the body i.-i more than twice as long as the manu- 
brium, wherea.'i in t he female it is usually less than twice the length of the first piece. 

Slruclurally the sternum is composed of cancellous tissue covered with an outer 
layer of compact tissue- Its arterial supply is derived mainly from the sternal and 
perforating branches of the intt^mal mammary, 

DtTelopmcot of the sternum. — Tbo cMseoua et«muin is jirecedKl by a coDttnnous or tian- 
Mftuientcd cestrAl rtcmnl cnrlilap; fomwd in the toUowiiifC way. When th* curtOaitinouB ribs 
fint anpcxr in tlii^ rtnlin.-!], llirir antrnor or ventral enda fuse loRetlier on either side of the middle 
line. For wmu lime a ni<^uui fiwurc is present. bordawJ by two eapttslly directed eltipe of 
rartihv^ with nwh of whicli M tin<t nine nhs are joined. As development prorc«d.i the two «trip« 
ntirm into mntiwrt in lh» middlr line wid Uue from before bsckuards lo fomj » median sternal 
cartilage. Tl>e cixhtli cartilifie gODoralK' toees it« slemal attachmpnt. although in sotne cases 
it Teraaiiu pemuuientlv articulated with the ride of the entuform process. The ninth costal 
cartilage bcoomes mbdi\-idod, on<> part romatninK nitnrhed to the tiiemuni and jforrntng the 
auNfornt proceff. whiirt the end ttill continuous with the rib ucquiree a nev altachmenl lu the 
Mjdntb csrtilnp. The end^ ndhereni to the sternum may remain scpamti* and give rise 10 a 
bind cnxiforni procesa, liiough mitch mom frT«]tion(ly then- unite, leai-ing a Kniall foramen. 

At fint, iherefoK, the pterouni and coital cartilage* bto cuutinuous. A joint soon forms 
betwem the prwtemum and meMvitemiim. and others between the eoatal cartilages and the 
■temum (except in the rai« of the finil) quickly Follow. TW divinon of the roemstemiun into 
■qpnenu i> a still later lormntioD aiid aiiKa during tfa« procos of 5'^ifi''it i"n , 

More ivaintijr the new h«s been advanced by Professor A. lA. Pstonoo that che sternum ii 




IIKIIU C\j<TMt (DRUDH 
or iMf '414 rttcES Of 
Tfietaof 



»IPI9L£ CEHIBE FDR 



in Lfav preetemum (tnanubrittni) by a single c«ntro ubmit the hxiIi month of intra-utcrioc life, 
though occa-iioQaliy other atceasory oeDtr« Are sii|»erflddc<l. 

The mwiois tern mil lUuaUy onsiGes from seven ceiitrw>. Tlw upper oegnietit omfies from n 
Btogle media)] nucleus about the eighth mouth, aud belon* thie, three pun a£ cmb£a^>v^«- 



1.S2 



THE ^SKELETON 



Apyear, wliich tatty retuniu fur n long time Mpoiralo. Ol tJteM, two pein for tbe accimtl tuid 
toird beKmenis arc 'visible at birtJi, uiid tJitwe for the tower K^pnent mnke th«ir sppearauco 
luU'anU the end of tlie first year. The vsrimib lateral cenlitv unite in pikin, sn tluil at ihe .-dxtli 
3r<ur tfie alvniuin nmstsln ofbix stemebnc, ttie lovi'eat (ineliMlernun)) Lieiuj; <-urtilai;iiii>UM. Very 
ofleDt however, llicrc ore only fniir <«iitn» of ossificAtion in the gladioliifi, a^^ Hhoun in fig. 14tt, A. 
Gradually Uie four piecoH leureaentinif tbe raeMUtemum fuse witli one amillier, aud id twenty 
five tlicy font) a nii^ple piece, but eichibit, even in udvanred life, truces uf iJieir oriKtiinl -^vJ>a^alioIl. 
A nterual fonuneu it usually the rGsiilt of non-union acnvte the middle Une or a defect uf o«li- 
fication. 

Tbe Diotontcmuiu in alwaysi ioiperfectiv oasitied, and doe> not join with the mouMtomum 
till after middle life, Tde pretiternimi ana memnteniuin riinly fuse. The diitiNi given abovo 
fur the viirioUK niK^lei, iind far the union of the various aegiiieutM, are merely appn^xiinule, hciioe 
the sleniuin aHurdn vtfr>' uiu'erliuii data lui up tiffe. 

Abnormahties of the Sternum. —The mnde nf development of the sternum as dwcribed 
above U of impwrtHiice in ronntvttori willi sorni- devialioii^ to which it is f>oCBsio>nntty suhicrt. 
In rare intitaiK-cx (1ic two hitvnil halviv fail w uiiiU', giving ni<« to iJie anomaly of a comptctely 
cleft Btcrnuin. Thv union uf the two halvcii niny ooiiir iti t)>e r^'flkm of The nianubriitm and 
fail beiow, wbjlet in other va«m the upper and lower puHx huvr IiimhI but rrniitin »epnrate in 
the middle. Tlie ck'fla are in many inatanceit i» small as not to Im> of any nionicnt, and are not 
«n rocofjnisetl until Ibe itkclMon itt prepared. In a few individiiiib, however, they ha^-e been 
__ extensive a» to allow the pulKalion ol Umd beart to \x> perceptible to the band, and even (o 
the^e, through (he dtia covuring the d«-'fcctiti the bone. 

A couinmii varialion in tbe sicmuiii is asymmetry of the costal cartilages. Instead of cor- 
re.i|x)iidiiig. the cartilages may articulate with Ibe liteniuiu in an alternating manner. The 
CHU!« of this asymmirtry in not known. 

Fn. 147.~Thb Tuohax. (Front view.) 
wmm nuHueiD «rtiiTV« 



<r>-^^ 



I,: ■ t^'j 



rmif an 



V 



■MCMTM. UQLf 



• lUJt 



noinNt 1 



THE THORAX AS A WIIOI-E 

The hony thorax is somewhat conicAl in shape, dwper behind than in fixmt. and 
fompre!4SMl aii(cro-|«.steri<.rly, ifi that it uieaaurvs less in thu avitliil fhmi in Uift 
transversi; axis. Tlie posterior wali, funned by tlio thorjicif \Tri/'iira: ;incl the ribs 



THE CL^iVICLE 



13.1 



as far outwards a» tUeir anRles, U convex from above doirnwards, and the backward 
curvp of the ribs pnxlurcB on eiwh side of llie vertobra a deep furrow, tht- costo- 
vertebral groove, in which the sacrosfnnalis (erediir spintB) muscle and its gubdi- 
vi.sitiiis arc lr>dt;ed. The anterior wall is formed by the fitrmutn and CDstal carti- 
lages. It i» slightly convex iind incline<l forwards in its lower part, fumiing an 
angle of about '20" with the vertical pUm*. The lateral wmII.* are fomieil by the 
rllis from the angles to the i;«»6tal curtilajKes. The top of the thorax pres4>iitfi an 
elliptical u|)enure, the superior thoracic aperture, which nieatjiireii un an aver- 
age 12.5 centimetres (5 itiehes) transverselj* anti 6.2 centimetres (2J inches) in its 
sagittal axis. It is boimdcd by the first thoracic vertebra behind, the upper mar- 
gin of the munubriuni steroi in front, and the iirst rib on each side. As the 
upfKT margin of the manubrium Ktemi is on u level with the disc between the 
se*'oml and ihird thoracic vcrt«bne. it followH that the plane of the opening is di- 
rected obliquely upwHnLs Jind forwards. The angle of I he Kternuiii {amjuliut I.u- 
dnrici) 'ta opposite the body of the fifth ilioracic vertebra and the xiphi-atemal junc- 
tiuD oorrespoiidg to the disc between the ninth and tenth thoracic vertebra-. The 
lower aperture of the thorax is verj- irregular, and is formed by the twelfth thoracic 
vertebra behind, the twelfth ribs laterally, and in front by two cuned lines, aa- 
cetirling one on either aide from tlie last rib, along the costal margin to the lower 
bonier of the gladiola';. The two borders form the costal arch (subcostal angle), 
and from (he apex the xiphoid process projects do«-nwflrds. The intervals Ije- 
twcen the riba are the intercostal spaces, and are eleven in number on each side. 



//. Tff£ APPENDICVLAR SKELETON 
A. BOXES OF THE TJPPEU EXTREMITY 

The bones of the upper extremity may l>e arrangoil in four groups eorrespoadinp 
tn ihe division of the limb iiil/> four segnieiits. In the »hauUlrr are the chivicle and 
the .scapula, which together conatilule the t»ectoral or shoulder girdle: in the arm 
is the humerus; in the fortunn ure the radius and ulna; and in the iutnd the carpus, 
the nietacarpua, and the phalanges. 



THE CLAVICLE 

The clavicle or collar bone is situatetl immediately above the fiist nb and ex- 
tends from the upper Iwrdej- of the manubrium fliemi, outwards and backwArd.s to 
the acromion process of tlie scapula. It connects the upper limb with the trunk, 
and \» so arranged that whilst the iiuier end rests on the slenmui and firet ciietal 
cartilage, the outer etid is urisoclaled with the scapula in all its movements, suf>- 
porting it firmly in its various positions and preventing it from falling inwards on 
the ihorax. 

The clavicle is a long bone, and when viewed from the front presents a double 
curvature, »o that it somewhat resembles in shape the italic letter /. The inner 
cune. convex forwarrLs, extends over two-thinU of the length of the Iwne; the 
outer, concave forwards, is smaller and eonfined to the outer part. For descriptive 
purp)]ees the clavicle may bo divided into an inner prismatio portion, an outer flat- 
tened portion, and two extremitiefl. 

Prisniatic portion.— The inner two-thinis of the bone, extending from the 
sternal extremity to a pr>int opposite the eoracoid process of the scapula, has the 
f<imi i»f a triangular prism. This jxtrtioti, however, is t-ubjei't (n r(tnsnlenil'lf varia- 
tiiin.1 of fonn, Iteiny mure cylindrical in ill-develojMnl spe<*inien.s and I»ec(»niing almost 
qn.'iilranjmhir when .'i.S!«>ci«te"I with great mu-'irulnr tlevelopnient. In a typical 
fif«'*^'irnen ii i? mtirkc<l by three bohiers sepamting three surfaces. Of tliose. live 
anterior surface is convex and divided near the sternal end by a pnmiinent ridge 
iiiui two \KirXji. a lower, giving altaehutcnt to the clavicular portion of the pertoraha 



134 



THE SKELETON 



majtrr; an upper, for the clavicular portion o£ the slerno-cleido-mastoid, Xoar the] 
middle of the shaft the ridge disappear, the surface is smooth, and is covered \>y the I 
platjflttna myoidm. Occasionally this surface is pierced by a fmialt onnal, transmit- i 
ting a cutaneous nerve from the cervical plexus. The posterior surface is con- : 
rave, forming an arch over the brachial plexus and the subclavian arten-, broadest 
internally nnd smo«ith in its whole extent. It Kives attachment near the sternal 
extremity to a part of the stcrno-hyoid and occasinnally to a few fibres of the afemo- 
ihyreoid. Somewhere near the middle of this surface is a small foramen, directed 
outwards, for the chief nutrient arterj- of the bone, derived from the transverse ' 
scapular (supniMcapularJ artery, rinnietimes the foramen is situated on the inferior' 



Fio. 1*8.— T«« Lsrr Oi^virt,B. (Superior surfaoe.) 



OMata 



Faetomlla biIot 




EPiPHISUL UUt 



Tr*s«eiaa 



Posmemiw 



Btarao-oiMMid 



surface of the bone, in the subclavian groove. On the inferior surface near the 
eternal end is a rough area, the costal tuberosity, about three-quarters of an inch 
in length, for the attachment of the costo-clavicular ligament, by which the clavi- 
cle is fixed to the first rib. More externally is a longitudinal groove for the sub- 
davius, bordered by two Ups. to which the sheath of the muscle is attached. To 
the posterior of tlie two lip8 the layer of deep cervical fascia which binds down the 
poirterior belly of the omo-hyoid to the clavicle is also attached. Of the three bor- 
ders, the superior separates the anterior and posterior surfaces. Beginning at 
the sternal end, it is well-marked, becomes rounded and indistinct in the middle, 
n'hilst extenially it is continuous with the posterior border of the outer third. 
The posterior border separates the inferior and posterior surfaces and forms the 



{ 



Fi«. 149. — ^Tbb L.BFT Cla^iclb. {Inferior surface.) 



ObUviM 
IIMtor 



Postsatok 



CoraaaM 
tutwrcd*(or 



ount. cunusEH 



tiiKHiL nerr 




iwaMiM.r>ai 



AxTsmuK 



posterior lip of the 8ubcl&\'ian groove. It begins at the costal tuberosity and can.! 
be traced outwards jis far as the coracoid tiil)en'le, an eminence on tlie under a.spect 
of the bone near the junction of prismatic and flattened portions. The anterior 
border is continuous with the anterior border of the flattened portion and separates 
the imterior and inferior surfaces. Internally, it forms the lower boundary of the hI 
elliptical area for the jitlaclimenl of the pccloralis major, and approaches the poa-fl 
lerifjr Imrder. Near the middle of the bone it coincides with the anterior lip of the 
subclavian groove. 

Flattened portion. — The outer third of the Ijone. extending from a point oppo- 
aile the conicoid pro<Ts.s of tlie scapula lo the acromial extremity, in HattentMl from 



^ 



THE SCAPULA 



taa 



above downwards and present* two surfaces and two horders. The superior surface 
is rough and tootcM directly upwards and gives attachmeJil to the tmpezitu IwUiml 
and the deltoid in front; between Uie two areas the surface is subcutaneous. On the 
inferior surface, near the [Miswrior bonier, is a nnigh eleviitiun, the coracoid 
(conoid) tubercle; it overhaiifis the coracoid prtK'cse and ^ivcs attacluncut to the 
conoid ligament. Fnim the cnrncoid tubercle, a pmniinent ridge, the trapezoid 
or oblique line, runs outwards and forwards to near the outer end of the l>one. 
To it the trapezoid ligament is attached. The conoid and trapezoid ligaments are 
ttie two parts of the Goraco-clavioular ligament which binds the clavicle don'n to tho 
coracoid prfKTss. 

The anterior border is aliaxp, gives attachment to the deUoid muscle, and fre- 
quently pnesent.t near the junction of the flattened and prisniatic portions a projec- 
tion known as the deltoid tubercle. The posterior border is tliick and rounded, 
andrpceives tlie iuseitiuii of the upper fibres of tlie trapestut. 

Extremities. — The sternal extremity of the clavicle prGsonts a triangular 
articular surface, directed inwai"dH. dctwnwanls, and a little forwanls, slightly con- 
ca%-e from before backwards and convex from above dowTiwariU. which articulates 
with a facet on the upper border of tlie manubrium sterni through an interposed 
interarticular fibro-cartilage. Of the three angles, one ia above and two below. 
Ttie postero-inferior angle is pr,ol<»nged liackwards, and so renders this surface con- 
siderably larger than that with which it articulates; the superior nngU reeeives 
the attachment of the upiwr |wrt of the fibro-cartilage. The lower part of the sur- 
face is continuous with a facet on the under aspect of tho bone, internal to the costal 

Fio. 150.— TirB Sternai, End* of Two Claviclw wrra EpimrsEft. 

A| right ijfivicle from below and l>clii»d. B. teft cinvicle from IxOow and hphmd. 

(tYoii) Itoyal College of SuTKeoni) Muwiim.) 




tuberosity, for tho first costal cartilage. The circiunference of the extremity ia 
rough, and gives att-achment to the interclavicular ligament almve and the anterior 

and posterior st*rnf>-clavicular ligaments in front and behind. 

The acromial or scapular extremity presents a smooth, oval, articular facet, 
flattened or conve.x, diivcted ulightly downwards for the acromion; its border is 
rough, for the attachment of iho capsule of tlic acronuo-clavicular joint. 

Structure. ^The clavicle c0n.si.st3 ext-omally of a compact layer of bone, much 
thicker in tlio middle and tiiinuing out gradually towards the two extremities. There 
is no true medullarj' cavity, for the interior is occupied from end to end by can- 
t^Itous tissue, the amount in the various porta of the bone being in inverse proportion 
to the thickness of the outer compact shell. 

OssificatioD,— The rlavicle \a oesified fmm two centree. Tbo primary uucluus appoun 
very early — iibout the sixth w«dt of emhiyonic life — in the tissue immediatcJy overlying tho 
cutUagtnoua ^reoorocoid bur (>ee pp. 139. 204}. The olavirle begtns a» a metabraii* bone, but that 
omification quickly extcndii into l-he underlying cartiLa^; it is therefore a compound Iwnc. being 
B denn*! xpUiit eocrkftcd on cartila^iie. .Anout the seventeenth or eighteenth year n M^OD^dluy 
centre appeart at uo •toroal eod and fomu a Kuall epipby»i« wliich juiiui tho sliaft ubout the 
tw^Jnty^llUh yoor. 



THE SCAPULA 

The scapula is a large flat bone, triangular in shape, »tuated on the upper and 
posterior jwpect of the thorax, between the levels of the second nod se^'enlh ribs. 
Attached to the trunk by means of the clayiclc and various nuisclcs it articulates 
with tlie outer end of the clavicle at the ftcroniio-olavicular joint, and with the 
humerus at the shoulder-joint. The greater part of the lx>ne consists of a triangular 
pliate known as the body, from which two processes are prolonged: one, luitetior 



136 



THE SKELETON 



ia position, is the coracoid; (lie other, posterior in position, is the «p>ne, which is 
(.■oiitinueil externally into the acroinxon. 

The body presents for examinati'^n two sturfaces, three borders, and three aiifclee. 
The costal (anterior) surface, or veater, Inoks foiisiclera.bIy inwiirds, is deeply 
ponravc, forming the subscapular fossa, ami iii»rked by scvM-al oblique lines which 
comniencc at the posterior bonier utul pass obliqudy upwntvlfj and oiitwai-ds; thesa' 
lines or ridges divide the surfnce into soveral shallow grooves, from which the ru6-J 
scapiUaris trtkes origin, whilst the ridiee* give iilUichirient to the tendinou? intersec- 
tionH of that muscic. The outer third wf the surface ia smonth and overlapped 
by the subBcapularis, wIiilsL inU-nially are two small flat arciw in front of the upper 
and lower angles respectively, but excluded from the suhscnpuhir fossa by fairly 



Fio. I6l.— The I-r-prScArn-A. (Dorsnl siirfncc.) 



Caiwro-BoroDtal llnoiaDi 



Ooia-liyold and Uw tranavvnM UsaaSM 



BI<Mi» 



AOiQH'Olil 

msEs 



>nAC( 



»"^Wf"«^**%, 



lUnmOR AMBU 






apiiuiias 



IOU<^U* HO FIX 



ArUralar oapaul* ■ 



iKxn F9D cmcuKRa urar of , 



Tn*m mlaoT . 



KIVUMT BOHKI . 



INrnABPtHOU! 



ro3SA 






■lnf>*aftpina.t\f<( 



. U lion bold *\ia 

ml DDT 



Bhomboldaiu 
major 



mrouL 

■MUM 



Tana nMor . 



mnPKNt iNsu 



I^UMiiDua d»r«l 



definite hne^ ami joined by a ridge which runs close to the vertebral border. The 
ridge and its temiiniil arcjvs serve ("or the insertion of the8prr(i/«*fin/en'i7r(Tim3ni«). 

The dorsal (posterior) surface is generally convex and divided by a prominent 
plate of Ixine^-the sptne — into two unequal partJi. The hollow above the spine ia 
the supraspinous fossa and loflges tlie supruspinaliie iiiuscte. Tlie part- hel<iw 
the spine is the infrasplnous fossa;- it is three tiuies as larg» as the suprajupinous 
fossa, is alternately i-ourave and eonvcx, and gives origin to the infraspinalvs. The 
muscle is attarhetl tn it.n inner thit'e-fourths and I'wvcrv ilic outer fuurtli. without 
taking nritcin frftm it. 

The infraspinou.s fowa does not extend as far iw the a.villar>' border, but is limited 
'■\t«.Trirdly by a ridge — the oblique line — whirh runti from the glenoid cavity — the 
iarge articular suxfiice f<*r thr head of the humerus — ilownwartls and backwiinU (o 



THE SCAI'ULA 



137 



join the posterior border a short distauee above the inferior anglo. This line, which 
givi>-s aUiirhnmiit in h stout aponeurosJa. cuts fjff an elon^'at«i surface, narrow 
above for the attachment of the teres minor, and crossed near it.s middle liy a groove 
for the circumflex (dorsal) art^rj- of the scapula; below, the surface is broader for 
the attachment of the Urea nuijnr jind occaaiotially a few fibreei of the tatissimua 
doni. The two areiw are separated by a line uluch v:ives attachiuciit to an apo- 
neiirotic septum situated betM'een the two teres raust'le:^. 

The supra- :iiiil iiifntspiiious fossa- con iinuiiio site through the great scapular 
notch nt the out^^r border of the spine, and tiimuph the notch tlie siipra.'w.apul.ir 
jiorveand trunsverse scapular arter>' itrc transmitted from onefnssii to the oilier 

Borders.— The three borders of the scapula are named superior, posterior or 
vertebral, and evternal or axillar>'. The superior is short and thin and extends 



F:o. 152. — The Left Scapl- i-a. (Ventral surface.) 

Tmpaaold li^muii Ptweralii bIdot 



a*r i Mn» uiUTtor 



lUVIiLM NOIQH OonoM lit 



./* 'L 



Ooraoo-aoriMiilal 

ILCKinatit 
Bloaiia and o«n«»< 

BMaw 



SUaSOAPU LAI 



Capaol* 



M^- 



— Tnevpa fmlddla or Iabj 



Subac&pul 



4-ti''- 



/ 



J- 



'S^-'%i 



■vmHoa aoMrio* 



from the upper angle to the coracoid process. Extemnlly it present-s a deep depres- 
sion, llxe scapular notch, to the extremities of which the transverse liganient is 
attached. Not unfrequently the notch is replaced by a scapular foramen, and 
ii \n interesting to note that a bony furainen orcurs normally ia some animals, 

I notably the great ant-eater {M yrmecojthaga juhaUi). The nuU'ti or foramen trans- 
niit.i the siipnuicapular nerve, M^hilst the tniti«\-ersft scapuhir artery usually passes over 
the ligament. From the adjacent marjtin^ of the notch and from the !ip.iment the 
posterior belly of the omc^iyoiri takes nripin. The posterior nr vertebral border, 
sometimes called the base, is the longest, and extends fruni tlu' upjXT to the tower 
angle of the hone. It is divisible inio thre*' parts, to each of which a muisrle ia 
attached: an upper portion, extending from the superior angle to the spine, for the 



13S 



THE SKELBTOS 



fcwi/or Mapuitr; ft middle portion, opposite the smooth trianEulftr aiwi at the com- 
mencement of the spine, for the rfwniboidfus mitwr; and the lowest and luo^iest 
portion, cxtcndios below this as far as the inferior angle, for the rhombouleus major, 
the attachment of which takes place tlirough the medium of » lil;rouH arch. The 
external or axillary border is the thickent, and e\t«iids from the lower margin of 
thp glpnniil cavity to the inferior angle of the bone. \ear it-i junction with th&i 
plenoid cavity there is a rough surface, a.bout 2.5 cm. (1 in.) inlenj^th (infra^Ienoid 
tubercle), from wliich the long head of the triceps arises, and below the tu!>en;Ie is 
the groo\'o for the circuniHex (dorsul) artery of the scapula. The upper two-lhirda 
nf tlie tionler Is deeply grooved on the %'cntral aspect and gives atlachnient to a 
coDsidcnible part of the subseaputara. 

Angles. — The tliree angles arc named superior, inferior, and anterior or external. 
The superior angle, forming the highest part of the body, is thin, smooth, and 
either rounded or approximating a riglit angle. It is forine<l by the junction of the 
superior and vertebral borders:mdgivesinsertiou toafewfibresof thc^txift>rsM;/uir. 
Tlie inferior angle, eonstitutii^g the lowest part of the body, is thick, rounded, 
and rough. It is fonued by the junctinii df axillary and vcrtebml borders, gives 
attachment to the terca major, and is cnisswi horizontally by the upjK-r part of the 
htissimus dorsi, the latter occasionally receiving from it a small sUp of fleshy fibres. 
The external angle forms tlie expanded portion of the Ijouc known as the head, 
beoring the glenoid cavity, imd supported by a somewhat constricted neck. The 
glenoitl cavity is a wide, shallow, pyriform, articular surface for the heatl of the 
humerus, directed forwards and outwards, with the apex above and the broad end 
l)elow. Its margin is raised, and affords attachment to the glenoid ligament, which 
deepens its concavity. The margin is not, however, of equal prominence through- 
out, being somewhat defective where it is overarched by the acromion, notched 
anteriorly, and emphasised above to form a small eminence, the supraglenoid 
tubercle, for the atiiu^hnient of the long head of the bircps. The circunifiireiice 
and adjoining part of the neck give attachment to the articular capsule of the shoulder- 
joint, and the anterior border to the three acccsitory ligaments of the capsule, known 
as the superior, middle, and inferior gleno-humera! folds. The superior fold, or 
I-'ltKxl's ligament, is attached above the notch near the upper end; of the two re- 
maining folds, which together constitute Schlemm's ligament, the middle is attached 
immo<liaiciy above the notch and the inferior below the notch. In the recent state 
the glemiid fos^^■a is covered with hyaline eartilage. The neck ij? more prtmiinent 
behind than before and below than above, where it supports the coracoid process. 
It is not separated by any definite boundai^' from the body. 

Processes. — The spine is a strong, triangular plate of bone attached obliquely to 
the dorsum of the scapula and directed backwards and upw-anis. Its apex is situated 
at the vertebral bonier; the base, corresponding to the middle of the neck, is free, 
concave, and gives attachment to the spino-glennid ligament, which luvhc*? over 
the transverse scapular (suprascapular) ^-essels and suprascapular ner\'e. Of the 
two Iwrniers. one is joined to the body, whilst the other is free, funning a promi- 
nent subcutaneous crest. The latter commences at the vertebra! border, in a smooth 
triangular area, over which the ten<lan of the trapezius glides, usually without ttie 
intervpntion uf a bursa, as it passes to its insertion into a small tubercle on the 
crest beyond. Further outwanhi, this border is rough, and presents two lips— a 
superior for the insertion of the trapezius and an inferior for the origin of the deltoid. 
Externally, the crest is continued into the acromion process. 

The spine has two surfaces: the superior, which also looks inwards and forwards, 
is concave, eontribuies to th<: fonnatir)n of the supraspinous fossa, and gives origin 
U) the tupraspituilus nnisde; the inferior surface, also slightly concave, is directed 
outwards and backwards, forma part of the infraspinous fossa, and affords oriran 
to the infraspinatus muscle. On both surfaces are one or more prominent vascular 
foramina. 

The acromion process, overhanging the glenoid caWty, springs from the angle 
formed by the jmiclion of the crest with the base of the spine. Somewhat crescentic 
it) sJiaix!. it forms the summit of the shoulder and is compressed from above down- 
wards so as to present forcvamination two surfaces, two borders, ond two rxtncmitios. 
The ivwterior part sometimes terminates externally in n prominent acromial angle, 
or metacromton, ami the [>r<jce»s then assumes a more or less triangular fonu. Of 
the tuo extremities, the posterior is continuous. with llie spine, whilst the anterior 



THE SCAPULA 



l.tD 



forms tlie five tip. Tl»e upper surface, directed upwards, backwards, and slightly 
outwards, is rough ajid convex, ami affuuls yngin wt its outer part to a portion of 
ttiL' fkUtiUi; thf! rt>nuuniiig part of this surface is subcutaneous. The lower surface, 
directed dnwnwardt^. forwanls. and sli^liLly inwanls, is raucaveand suioolli. The 
inner bonier, (vintinunus with {Yw upivr lip ot' the crcBt, prosent.s, from behind for- 
wards. :»ii area for the attacliment of the trajvzius: a sm:ill, nva!, concave articular 
facet for the outer end of the clHviclc, the edjies <>f which are n>UEh for the acroiuio- 
clavioular liRaments; and. beyond this, the anterior extremity or tip. to which 
is attAchwl the apex of the coraeo-acromial ligaiiu-iii. The outer border, continuous 
with the inferior hp of the crest, is thick, convex, and presents three or four 
tubercles with intervening depressions; to the tubercltss the tendinous septa in the 
acromial part of the deltoid are attached, anrl to the depressions, some fleshy fibres 
of the same Diuscle. 

Projecting upwards from the neck of the scapula is tlie coracoid^ a bent finger- 
hke process, pointing forwanls and outwards, li ronsiiitfi of two part.s. su^i-eniiinK 
and horizontal, arranged at ahnost a right aii^ile to eacli other. The ascending part 
arises byawidr root, extemls upwards and inward.^ for a short di.-^tance, and Ls , 
compressed from before backwarrU: it is continuous above with the horizontal 
part and below with the neck of tlie scapuU; the outer border lies above the glenoid 
cavity and gives attachment to the coraco-humend ligament; the inner border, 
which forms tlie outer Iwuniiary of the sritpular notch, gives attaclunent to the 
conoid ligament above and the transverse ]i;;nment below. Ita anterior and poste- 
rior surfaces' are in relation with the aubseapularit and aupraspinatuji respectively. 
The horizontal part of the process runs forwards and outwards; it is compressed 
from above downwanJs «i as to present two bordere, two mirfaces, and a frt-e ex- 
tremity. Tlie inner border given attachment along its anterior half to the -pefiornlis 
minor and tiearer the bjise to the costo-ctiraciiid membrane; ihc outer border ia 
rough for the coraco-acromial and coraco- humeral ligaments; the upper surface 
is irregular and gives attachment in front to the pectoralia minor, and behind to 
the trapezoid ligament; the inferior surface is smooth and directed towards the 
glenoid cavity, which it overbungs; the free exlivmity or apex gives origin to the 
conjoined coraco-hiticAialis an<l short head of the biceps. 

The greater part of the IxKly of the seapula and the central parts of the spinouB 
process are thin and transparent. The coracoid ajid acromion processes, the crest 
of the .spine and inferior angle, the head, neck, and axillar>' border, arc thick and 
opaque. The young boneconsistsof two layersof compact tissue with an intervening 
cauccIloU!< la^er, but in the transparent parts of the adult bone the middle layer 
has disap[)earetl. The vascular foramina on the anterior surface transmit twigs 
from the subscapular and transverse scapular (suprascapular) arteries; those in the 
infraspinoua f<^i»'a. twigs from the circumflex (dorsal) and transverse scapular 
(supniscapular) arteries, the latter also giving off vessels which enter the foramina 
in too siipnxspirious fos!*a. The acromion i.s supplied by branches frr)m the thoraco- 
acromial <acromio-thoracic!> anery. 

'Hie line of attachment of the spinous proceed to the dorsum of the scapula is 
known as the morphological axis, and the obtuse angle in the subscapular foeaa 
opposite the spine .is the subar/ipular angle. From the axiR three plates of hone 
radiate as from a centre, the prescapula forwards, the mesoscapula outwards, and 
the 'postscapula Uickwards, being named in accorlance with the long axis of the 
body in the horizontid [losition. In the human subject the pontwapula is greatly 
develupeii, ami this is associated with the freedom and versatihty of movement 
possessed by the upper limb. 

OsstftcaHoQ. — The scafKiIa U owitind from nine centres. Of these, two (for the borly o\ the 
acapulii imJ the ronu'oiil) may be coimidered as primary, and lhc> remiurnVr »> Recondar^. The 
cenliT for div Iwdy apiJOiirB in a plate of cartitagv near the neck ni the ecapub, alM>iil the t'iulidi 
week o( inim-ntcrinc life, nud (niickly fonwi s irinngular p3al« of boni?. from whirh tho npine 
spficMrtt lut A nlijttit riilfte nboiit the m'iddlu of the ihird niontli. At birth the glenoid fiBwi iitid 
pnrt of tlw scnpulur ueuk. Lho acromion and t'orucoid pnic»«i>«i. tha vertebral iKinlcr uiid inferior 
angle, »ro rArtilAginou5. During the fir^t year » nucleiu uppean^ for tho coracoid. and at llio 
tenth ywir » la-ctrnd centtr .ippean for the b(uw nf Ibe corwiiiu aiitl the upper |>art of tliw glctMitd 
oavitv (NulfconK-uid, fis, 1^. O, 

r^uring the fifteenth year the corncoid uniten with theMapula. and about this time the other 
seronil.iry i-cnlrrH nnp<-jir. Two niiolei axv dBpnuilnl iri the ii^niniinl rnrtihi^, .'ind funr t<) form 
the ocrotni'ii). «liicfi jujiw iht- iipiri<-> at the twentieth your. Ihi.- uniim uf r-pine und uvr^nn'mn 
may be fibrciii.i, hcrtcc the ktlcr \a sometimes found separate in mncL-niLol f<i>cctmcnfi. The 



140 



THE SKELETON 



PArtiUce ftIo»g ihe vertebral border oseilics from tvo ceotra, one in the miiidJo, sJitl anoiher at 
thn inlf^rinr aiVD;!?. A thiti lamina ie uddml alone ihr upper !<urfnr« of the rornvoiil proocKd and 
(KTasiuiially anotJier At the tnnrgiii of tlie* glonoiu ciivily. Tli««o i-jiipIijiM.w jniij liy thii twpiity 
(UUiyettr. " 

Too exwurre-nce ol a Mpocitd primiiry centre (or ijic coracoW prw^w iti of tiiorpViologitft] im- 
portsooe ia Unit the proccw u tLu n.-]irc9>m>tnljvu of wliut in tttv low«T\'crt4rl)r»ti^iKnilMttncb 

Flo. 1S8. — Owirif-'ATWK OP the RrAPtruA. 

Tb* rlchl SniMiln ni. Ilir ivcinb v<«r, iilMvInx tiM 
•ubourkKiliI i>lrui>'itT II lirtlo Uripv l)wu lulf 
Ibr luianl tiu. 1. o. tl. 



iei»Ui*L OUfTllilK 



tOMCOlS 
lllMUt 



fUBOOAMDIB anitNT 



MKDin nvtn 



Til* Rropiilft at tht Ihird )T«r, 
■hovlkg Ike iMTwiiiJ HdnUil. (AntMlor ri«V.) 



V 



«J. 



>M 



Tba acajMlft m birth. (Aniorior vUv.) 
A 



eortKoi^ (xTW. llii* primaxDv takes part in the formation of tlie gleuoid ca^-ity an<] extflode 
metttully to articulate with ilie Htumuin. In man and all the higher mammaU only the outer- 
most portion of the hon* |>crsial«. 



THE HUMERIS 

The humerus is the longest and largest bone nf the upper limb, and extends from 
the shoulder above, where it artk-ulates with the sc-apula, to the elbow Ijclow, where 
it articulates with the two bont^ of tho forearm. It is divisible iiito a i^liaft and 
upper ami lower extremities; iivi up|>er e-^ti-eniiiy incUidw tlie head, iiwk, and two 
luberoeities— great and small; the lower extremity includes the articular surface 
with flip RUrmountinj; fosssR in fmnt and brhind, and the two epicondyies. 

Upper extremity. — The head forms a nearly hemispherical articular surfare,; 
cartila#;e-c!ad in the recent etate and directed upwards, inwards, and bat-kwarda^ 
towanis the gli-iuiid cnvity. B<-1oav the head the bone is rough and somewhat con- 
stricted, t-DnstitutiiiK the anatomical neck, best marked Kuiwrifirly. where it forms a 
groov'e sepiiratinp the articular Burface from the two tuberosities. The cinnim- 
fcrenco of ihr npck givps attiwhment t<) the cafwiile of the shoulder-joint and the 
fdeno-humeral folds, the upper of which is received into a depression near the topj 
of the intertubercuJar (bicipital) (rr(»ove. The loi^'est part of the capsule dc^cenda- 
Upon the humerus womc distance from tlie articular marEUi. To the outer side and in 
front of the head aru the two tubonisitic«, .^panittil by a deep furrow. The 
greater tuberosity, external in position and rciiching higher than the leaser or inter- 



THE HUMERUS 



143 



attachment id front lo the hrachuhrxuiiatis and the rjciensor carpi radmlis iongut; 
IfeUiml W) the internal heaAl of tlie iricrjis. aiid Mwten these mueclee in front and 
behind tu the extortiul intcmiusculRr septum. It separates the external from the 
posterior siiriace. The iDternal border coimnences at tlio lesser tulwrcwitj', and 
forming Elie inner Hp nf tho intertuhercular fcmove. which ret-eives the insertion of 
the teres majur. continues tlnwnwanls ta the internal condyle. Near the middle of 

FlO, 150, — ThK LbPT [ittMUHLR WITH A SuPHACONDYLntD PaOCKftS AND BOUX iBBCOrtAR 

MirHcut ATTArHMKNTS. (Anterior ^■inw.) 



VobtoBpiilana 
Okpanlar li|ai««ni - 

Oontoo-brftahlulU bravta 
'Boiatorhumerli 

nruiviuisuufi woow- 



-MUTER TuaCROS-rV 
TranavRao basiara) I 



^ Fourth he*d <rf UooB 



HQUOM %m*V nM 4*lt«M 



OaMe»-krm«bi«it« 
Tlilrd head of Me«M . 



.JVH tXtUMl OOnOTUil RiHI 



OtrMO-tMvobUlu . 



fraiutaT lar<B . 






iBtarul lalaral lifsmaBt. 



THUOilU. 



■ EiTUMl rf RINOnl 



the shaft it forms a ridge for the insertion of the coraco-frracAin/i> and [ireeent*: a fora- 
men for the nutrient arteri-. direeicd downwards towards the ellxiw-joint. Below 
it forms a dtKtinet internal supracondylar ridge, eurveil inwartls, whieh gives 
attacfunent to the hmchialis {hraehitiHa anliruit) in front, the inner head of the triceps 
hohind. and the internal intermusrnlar septum in the interval Iwtwoen the mus- 
rles. TI)i3 border separates the liitenml from the posterior surface. 

Surfaces. — Tiie external surface is smooth above, rough in the niiddle, forminii; 



144 



THE SKELETON 



tt lar?^ impression for the insertion of the deUoid. below which \s the torminatlon of 
the RToovp for the riwiiiil nerve. The lower piirt of the surfjire gives attachment 
to the outer part of the braehiaUs. The internal surface is narrow al>ove, where 
it forms the n<>oY of the intertuljercular (bicipital groove, ami receives the inser- 
tion of the Uititsimus dorsi. Near the junction of the upper and middle thirds of 
the bone the gixtove, eradnally becoming shallower, widens out and. with the ex- 
ception of a rttUfih inipr(«siim near the middle of the shaft for ihc coraco-hmchialtft. 
the remaining part of the intirmd surfa^'O is flat and anioiith, and gi\-es attachment 
to the hrwhi/iiis. Occasionally, a prominent spine of bone, the supracondylar 
process, (>rojectei downuanls from the inner surface about o cm. (2 in.) above tiic 
internal cpicondyle, to which it is joined by a band of hbroua tissue. Through the 
ring thus formed, which corrnsponds to tho supracondylur foramen in many of the 
lower amniaLs, the inetlian ner\'e and bractiial arterj' are transmitted, though in iwimc 
raaes it is occupied by the nerx't; alone. Tlie proce-is gives origin to the jyronnUrr 
lerca, and may affortl in.sertion to a persistent lower part of the c^raco^rncfiialig. 
The posterior surface is obliijueiy divided by a broad .-dianow groove, which runs iilJ 
a spiral direttion from behind downwards and fonvards and trananiits the radJal' 
(muaculo^piral) nerve :ind tlii' pn)funda ai-ten.'. Tlie outer part of tlie wurface 
ahove the pnxtve nivtw iittai'lirnent to the external lieiul, and the part below the 
groove, to the inner head of the triceps. 

The lower extremity of the humerus is flattened from before backwards, and 
terminates Ijelow in a sloping articular surface, eubdjvided by a low ri<ige into the 

Fio. 157.— A DiAGjt.iM AHnwiNM Phkmdrr AMD Tenrion C'Vr\"ks in the 
Hbad or the HuMBniis. (Aftw Wasstaffe.) 



V-i 



rbchlea anil tl»e capitultun. The trochlea is the pulley -like surfaee which extenc 
over the end of the bone for arttculatinn with the semilunar notch (great 5i«moid cav- 
ity) of the ulna. It itt coiiatriiMtni in the eeiitre and e\ptuideit laterally to form two 
prominent edj:ea, the inner of which ia thicker, descends lower, and forms a marked 
projection; the outer edge is narrow and correapomis to the inter\'al between the ulna 
and radium. AJ>ove the trochlea are two fossse: on the anterior surface is the coronoid 
fossa, an oval pit which receives the coronuid process of the ulna when the forearm 
is flexiHi; on the fKwIerior aspect is the olecranon fossa, a deep hollow for the re-, 
i-eption of the anterior extreinity of the ok-cnmon in exleJi-sion of the fnreann. ThesQl 
fo^a; are usually separated by a thin, tranf^lucent plate of bone, sonietitiie? merely 
hy fibrous tissue, flo that in macerated specimen.*; a perforation, the supratrochlear 
foramen, e\iitt«. The capitulum, or radial head, is much smaller th.in ihi^ tmrhlea. 
,=<>nie«-liat jiloljular in .^hape. and limited Uj the anterior :iml inferior s'urfacef' of the 
extremity. It artirulateii with the concavity on the summit of the radius. The 
radial fossa is n slight depression on the front of the lM>iie. innnediately above the 
capitulum, which receivci* the anterior edge of the heail of the nidius In complete 
flexion of the forearm, whilst, between the capitulum and the trochlea Ls a shallow 
groove occu)>ied by the iimer margin of the head of the radiu.";. In the recent 
state the inferior articular surface is coveivd with cartilage, the iossse are lined hy 
synovial membrane, juhI their margins give attaehment to the capsule of the elbow- 
joint, Pnjjectingoti either s^ide from the lower cud of the humerus are the two epi- 
condyles. The internal or epitnxdilea is large ami hy far the more prominent of 



THE HUMERUS 



145 



• the two. rouph in front am] tielow, sitKKjtli behiiKl, where tliere is h shallow groove 
for the ulnar nerve. The rough ama .serves for littaclinipnt of the pronator terra 
above, the common lendfin of origin of the jlexor carpi raduiUs, palmaris longus. 
flexor di'jitorurn stublimis and flexor carpi utmtris in the tniildle, and the ulnar (inter- 
nal) lateral hjcanient below. The external epicundyle is flat and irregular. Above, 
it gives attJichmeiit to a common tcudoii of origin of the extensor carjri nuiialtB 
breviM, extmsor dujUorum commimia. extensor quinti dujitx projirim (extensor 

FlO. 158, — OflStPlCATIOK (IP THE HuUERI'K; THE Fiai'HE ALSO BHOWD THE RbLATIONS 
OF THE liPIPHYSIAt. AND CaWCLAR LINBS. 



UNtTn HrlTM DIE tMTT IT THt rwtNTItTH t»ll. 

TMt vpra Epiniws •■ tstititD bi rtit union o* m 
ttueif us FDR tHi Hua. aniAiEn lueuniTi. uo 

TH»r fOH THEUSKR rWEBOtlTT, IWSl (0N"» * 



iHirT giciHi TO osnrr w m (iqhtm wui of . 
iKDu-uiEitiiiE un 



Okpmlw LIS* 

l«Tll rvSCS dT Tut tIMTtUTX )UA 

■UDlin rM iiocHUi ursxta *i tmi imn tw . 



.Niicifui im RtiMNii moaomunuMirKiui'- 

lEUlN TEM) 

' Nuatut FOR WKTULVV tfpun m niE nnunui 



THE CUfTHa KM TME UENil Fn09*lln.l, 

rROCHIU. 1«D uriTUltH tiH\Tl TOOIIMJt *nO FORM 11 ErffHWI 

WHICH Fulil n>tM IM( SHin 11 FNE UlflTEfxTft TbIII 



minimi digit!) , extensor carpi uirians, and supinator (sU|)lnator brevie) ; to a dej 
sion near the outer margin of the capimlum, the radial (external) Istera] lit'amenl 
is sltache*!. and from an area below and behind, the auroneue lakea origin. 

The interior of thic shaft of tlie humenw is hollowed out by a large medullan.' 

canal, whnneas the extremities are composed of cancellateil tissue invested by a 

thin compact layer. The arrangement of the caiicellou« tissue at the upper end of 

the himierua is shown in tig. 157. The Ifmiellu; converge lo the axis of tha Vww* 

10 



146 



THE SKELETON 



and fonn a series of superimposed arches which reach upwards us far as the epi- 
phvsial line. In the epiphyses tlie spongy tissue fomis a Sue network, \he lumeUaB 
rwiulting frnm " pressure"' being directed at right angles to the articulur surface 
of the head nnd to tin? great tubenl^ity. 

The foronuna which cluster round the circumference of the hrad jind tuberosities i 
transmit branches from the transverse seapular (supnutrapular) and anterior and 
posterior circumflex arteria?. At the top of the iniertubcrcular groove is a large 
nutrient foramen ft>r a briinch of the anterior circunitiex arterj- which supplies the 
head. The nutrient artery of the shaft is derived from the brachial, and in many ' 
cases, an addititmal branch, derived from the profunda artery-, enters the foramen 
in the groove for the radial nerve (muaculo-spiral groove). The lower extremity is 
nourished by brinchcs derived from the profunda (suj>crior profunda), the superior 
and inferior uhiar IiUeral (inferior profunda and anastomotic), and the recurrent 
branches of the radial, ulnar, and interasseou^s arteries. 

OssillcBtlon. — The humerus is ossified from one primary centre {diaphysial) and six second- 
Riy ceritrc-1 (opiplij-sial)- The renlrc for the shaft appeius nnoiit t)io eighlh woek of int m-uCcrino 
lift itiid gniwfl vrry nipidly. At birth only tlie two (■xtrcmilif* arc nirt.ilii^iiiniiK, nml Ibefe nwiify 
in the follitwiiijt manner: Single ceiitnw appear fur (lie li*-fttl iu the iirsi- vcar, fur ihu (prulcr 
tiil^roHily in ihe iliird year, and for ihe lesairr tiiWroeiiy in thip fifth year, tliough sometimpui tbb 
latter OHsitiea by an exletjsioii Irciii the greater tiiSx^rosity. Tlii->w "l-hrm; nutlfei coaJiwc*! ut Bit 
yenre to form a tiiiiEle epiphysis, nliich joins the shaft about the twentieth year. 

The inferior extremity ossifies from four Mntras; or>e fnr the capitulum nppc&rH m Ihc third 
3'ear, a second for the internal epicoiidyle io llic fifth year, a third for the trcKrlileii in the tenth 
year, and n fourth for the exlernnl epicondyle in ihe fourteenth yiiar. The nuelci for tho capitu- 
lum, trochlea, and external cpicondyle couk-m-c to form a sir^lo epiphysis which join^ the shaft 

Fio. !M. — Thb Hkad of thr Hitmercs at the Sixth Vc^. (In section. 



THf cioiHE foK iHi KOB itmn duwdD Tht hut 

TOfl: IT 13 t«un'(UEt l>fl(ilMt tTlHtm 

in( tmTM roHTBE «nEn»s TuBtnoim Arruns m 



in the seventeenth year. The nucleus uf the internal cpieondyte ]oiaii the nhafl indej^emtently 
at Ihe uge of eiKhteeu years. 

A study Olthe upper end of thchumernlfihaft l)efureit« union with thtt epi}ihyAis ia of intrrcub 
in reUtiaa to what ia Known us the neck of the humeruK. The tenii nei-k h applied to three ptirla 
of thia bone. The analomifnl neck i« the constriction to whioh the articular capaule iiiniainljr^ 
attached, mid its position l» aiTurately iiidicntcd bv the ^rxMW which lie." iiilerual to tlie tuher- 
Dedtiea. T)ic upper extremity of thcliiimernl nhuf I, before it^s union with the epiphywn, terminate? 
in a Ion- lbrw?-^iil»f<i nyrwiiKl. the "urfwej" of which ;«rc «eparuted from one another by ridgeit. 
liie inner uf the^^e three eurfaees imdcrh'eti the head of tlio bone, and the two outersurfairea ' 
undorlie the tuheroftities. Tho part supporting the head I'orwtiltitca the mnrfthala^ical neek of 
lite hiiiiieniK. nhilat tlie nurgKai neck i* th« indefinite area below lliu tulieranities where the bone 
IB liable to fracture. 



THE RADIUS 

The radjus is the outer anti shorter of the two bones of tho forearm. Above, 
it articulates with the hiunerus; below, with the carpus; and on tlie iimer side with 
the ulna. It prrsrnts for examination a shaft and twocxtrr^mitics. 

The upper extremity, gmaller than the lower, Jnchides the head, neck, and 
tuberosity. Tliu head, covered with cartilage in the recent state, is a circular disoj 
forming the expandetl, articular end of the bone. The superior surface is depressed 
for the reception of the capitulum of the humcruft; its latonU uiargiu or circtmi- 
ferciK-e, iJeejier an the inner aaiwet. articulates with the nulial notch (lessei 
sigmoid cavity) of the ulna, and is niirrow elsewhert* for the annular ligninent by 
which it is embraced. IWlow the head is a short cylindrical portion of hone, 
somewhat constricted, and known as the neck. The upper partia surnjunded by 
tli« ligament which embraces the bead, and below this it gives attachment externally 



TlIK liADlVS 



147 



to the aupituxtor (supinator hrevis). Itelow the Deck, at thn anterw-internal aspect 
of the bone, is an oval eminciicp, the tuberosity, divisible into two ports: a rough 
posterior portion for the fltlnrhment of the tendon of the bicept. and :i smooth 
anterior surface in relation with a bursa which is gituated between the tendon and 
the tuberoftity. 

The body or shaft is somewhat pnsn:atic in fonn, griuluall.v incrcuging in size' 
from the upp^r to ilie lower end. and sliplnly curved si) as to be coneavc t^nvanU the 
ulna. Three bonlcrs and three surfucea may he recognised. Of the borders, the 



Via. IfiO. — Tub Left Ulna kvd RAnioB. (Antero-intemal vi«>K.) 

Aruaalsr mpatilB 



0IiMr l«M*al lUcaaast 



TaMrel* for ib« D«>or diKtioram mbltmla 
Vlaior ptiOtela loaaos i ■ iw »««o r» t>*«dj 



ULNA 



BiyillPMN NCTCH 

Hui or u:iui 
Mi«( or uvvt 

Lcwar tUnli of MiiialT UakBcol 

Otillqus IICUD«Dt 

Obllqu* llxftOMIII 
ttaptBatOT 

' ntsor aBbtliDU dUttonoi 



tntTo m cia niMnbniiB ' 



n«iM aifUomu pToftiadaa 



■ Hmox poIltolB lancoB 



VroaalMT avadrataa 



FroiMtot qnMbviva 



Aatarlvr radlA-alwvr ll^mtil 
Oliuu- taMval luanavt 



InlerwilQalar Bbro-eBrtllat* 



KMtUl Ul«ral IWaMMil 

\ 

Aniarlor rMUo-oBTMl UaaouDl 



inner ar interosseous ii^ liest nmrkeil. Coiiinieiu-iiig at the jxistprior edge of the 
tuberosity, its iirst part is round and indistinct, and roceivcs the attj»chnient 
of the oblique ligament of the radius; it is continued as a sharp ridge which divides 
near the Idwer extremity t« liecomo continuous with the anterior and piwterior 
margins of the ulnar uotcli (sigmoid cavity). The pnnninent ridge and the pos- 
terior of the two lower lines pive attachmcDt to the interosseous menibmne, whilst 
the triangular surface above the jjigimnd cavity receiveji a jjart of the j/ronalor 
qimttratiis. The inner bordpr separates the volar from the dorsal surface. The an- 
terior border runs from the tuberosity obliquely downwards to the outer side of the 



148 



THE SKELETON 



bone and then descends vertically to the anterior border nf the s^tyloid process. 
upper third. coiit<tir.ulinp the oblique line of the nidius, pve5 (ittachmeni. to the 
radial head of the flexor digUonim suhiimia, limits the insertion of the Mipinntor 
above, and the oriftin of the fifxor jioUicts hngwi l>elnw. The anterior border 
separates the volar from the lateral surface. The posterior borderexteinis from the 
back of the tuberosity to the prominent middle tubercle on the posterior asix-ct of 
the lower extremitv. tScftaraiing the lateral from the dorsal surface, it is well 
marked in the middle thiid, but l^econies indii^tinet above and below. 



Flu. 101.— TuK Lkft Vutx akd Raoiib. (l^^Blero-«JCtemal view.) 

OltCIUNOII 
ItaCUTUEQUl MFUC 



AraoaUr •apanto- 



- AooooMia 



rllMltol aaat»hr lUsiiMot - 



BtM^ 



laelAMOr ' 



Abdaour polHrti loncu 



BitMMWt c«UtBla brtvii- 



RAOlUS 



- Abdaoior pollMla locwua 



-AH ira«tuncM It iTTAQHi* TO thk noREiePi not] 

KHIDH THEIUmertHOuMiBarckrplnlDiUK 
Ma fluoi <Usll«niB prafuudiia M1>( 



- BsMtwor p«Uiei« l«n 



ULNA 



Or«»v*B tor abduolor looca* Aod ■«»»■■*» 
polllcla IrdtU 

7HWI<aaM(«rsindullal«n«iM«nabr«TU . 

XiMvaor poIlMla lonsua - 



bMnaor dtcllorvB oomauola 
•nd •■laiMor indlota propTlua 



\ 



, BvtfBkM qnntl dlglil prepni 



- tnnw Utan) UaaoMiu 



PMlailor Pa«l«rlai ndio-ubur Usaotcul 
rfiia-<*TiM.\ 



Surfaces. — The volar or anterior surface w narrow and concave above; broad;' 
flat. an«J Mnoolh below. The up|)ei" two-thirds is occupied by the /lexor )k>tiieis 
longug and a liltic less than the lower third by the pronator quadratm. Xear the; 
junction of the upper and middle thirds of the volar surface ii the nutrient foramen^l 
directed upwards towards the proximal end of the b<jne. It tran.'^mits a branch 
of the \-olar intemsseous aricn,'. The lateral or external surface is rounded above 
and affords in«ertinn to the supinator: marked nejir the middle by a roujrh, Inw, 
vertical ridge for the prottator teres: smooth lielow, where the tendons of the cjfefijrcn* 



THE HA 01 US 



149 



carpi radiaiis hngia and brcvis lie ui»on it. anci where it is crossed by the abductor 
jKtUicis longus (extensor obsis mciamrpi poli>ds) and txlensor poUicis brevis. The dor- 
sal or posterior surface^ smooth and n)uruleil iihove. Is t-ovened hy ihc supinator, ■ 
grooveci ioii^iludiimlly in llie luiildk' Lhird for the abductor poUicis Ioikjuh and 
the extensor poUiris hrcfis: lh(- lowrr th'ni is hroad, muiiderl. nnd covered 
by tendons. The hne which fonns the upper limit of the impression for the 
abdxiclor juMicis loiujui is known &» the posterior oblique line. 

The lower extremity of the radius is quadnlatf-ial: ii.s carpal surface is^ aiiicu- 
lar anil divided by a ridge into an inner <juailrilaLer:il purtion, concuve for articujo- 
lion with the semilunar hone; and un out^r triangubr pftrtion, extcndhig on to the 



Fio. !02.— Articclah FArem tis thk I^iweit Kxk or Lun Hauius asv Uij*a. 



lumut 



UiM 



rOK lUH«Tt ' 



- imoio nscxn CF uln* 



HUD 01 UUIA : IT ARtlCUUIII mTH 

TMt mnRAitrmuun MBRO-uiimist 



JUiurior 

Styloid process for articulation with the navicular (sscaphoid) bone. The loner sur- 
face, aUo articular, presents the ulnar notch (sigmoid cavityj for the reception of 
tlie rounded nmrpin of the head of the ulna. To tin- Itorcier »t'i)amtiiifi the ulnar and 
oarpfll articutnr surfaces the base of the trinn^ilar iibro-turtilage is attnt'hod, and to 
the anterior ami [KWtenor ImrderH, thft aiit<^rior and pn.stfrior radio-ulnar ligaments 
reK[jec lively. The anterior surface i? raiKtil iulo n. ])riiniit)eut area for the unteriur 
ligament of the wrist-jojut. Tiie outer surface is ix'pivsviilwi by the styloid pro- 
cess, a blunt pyramidal eminence, to the base of wtuch the brackio-radialis is in«*rle<l, 
whilst the tip ser\-es for the altachment of the radial {external) lateral lipameut of 
the wrist. Its outer surface is niarke*l by two shallow furrows for the tendona of 

Kto. 103. — Poi^TXRioR View or thk I^wbr Kko or thk IIaoiiw axd Vlma. 



RADIUS 



IfLHA 



Tiwrr'lrn of brBChlo^adlklli 

AMik«IOr polllcia Id Bras and 

Bilinear turpi trndimlit loncua 
•uif incTln 
Tvuwii ran rasTCHiot mnuur 

USUI EM T 
Sxt*oaer poUlci* Iodcus 



/-' J 



■■I. dtKttoruni oaninniila Bad 
calenBor lual«ila proprlu* 

Bxtaiuitr aiilDtl dwltl proinlua 
tlta Is Uio gmon b*iv#aa tha 
■■dlna and ulna 
talaaiaor oarpi uln«rlB 



the abdiuior poJIieis lonffus and ejrtenaor poUicis brevis. The posterior surface is 
convex, and marked hy three prominent ridgc« scparatinR three furrows. The 
posteriorannularliKftment is attached to these ridge-s, thu.s forming with the hone a 
aenesofluiuwls for the passage of tendon*. The outermost i* broad, shallow, and 
frequently subtUvided by a low ridce. The outer sulxliviston is for the rxteitsor 
ctirpi rudiiitix lajitjus. the inner for the extensor carpi radialii hretns. The middle 
groove is narrow and deep fur the letidon of the v-xicnsor poUicis lortgns. Tlie iimer- 
most is shallow and trananiiu-! the extensor indu-is proprius. the extensor ditjiinrum 
eitmmunis. the dorsal branch of the intentsseous arter)-, and ihe dorsal intems-oeons 
nerve, l^lien the radius and ulna ore ar(inilate<l, an additional groove is formed 
for the tendon of the exUwtor quv.iti digUi propriu*. 



150 



rZ/JT SKELETON 



Ossification. — Th« radiiis fs cMsilicd Eroni » ct-atre vhich nji^srs in tha middle of xhe shait 
in tbc uiillltti uwk o( i»t rB-ulfrin^ life and (irim two opiiiliysial i-iiurnv wliicli »iip<>jir -iftt-r hirth. 
Tbc nuoleiJ.-* (or thi^ Iowpt enit iipiKtuv in tlic »Lt.'untl vvur. uiiil lliitl fur the upiA-r end, tvhich forma 
eiinply ttu> dltrfr-nli.iped Ii4^iid,in tlie liftti j-ctir. ThcnC'tKi tmtle^ with thcrtlinli rit ihc ^cventocfith 
year.Vliilsit the inferior epipliyws and tli« »hM(t join iibout tUv twentielh yenr. 

THE ULNA 

The ulna is a long, prismatic bone, thicker above than belnw, on the inner aide 
of the forearm and parallel with the railius, which it cxpceda in lengtli by the ex- 
tent of the olecranon pnicess. It articulates at the upper end with the "humerua, 
at tlie hiwer end indirectly with the carpus, and on the outer side with the radius. 
It is tlivifiii>le inLo a shaft and two extremities. 

The upper extremity is of irregular hIuiijc and fonris the thickest and atrongest 
part of the l>one. The superior articular surface is concave from above downwards, 
convex from side to aide, and transv-ersely constricted neAr the middle. It belongs 
partly to the olecranon process, the thick upward projection from the shaft, and 

I-'ia. Ift4. — L'PPER ExD OF 1.BFT ITlka. (Outer view.) 

OltOIIMOli I. 



KVIlUtlU HOIIH 



DCMONOIO nNwoe 



Asanlar Utuwnt ' 



- vuom NOIM 



OUtave UaAinciii 



.ynpjBUttr 



Tl*»>r dWtlamai pcvraaAaa < 



-iBlaroaaaouB mamkraiia 



partly to the coronoid process, which projects horiBontally for^'ards from the front 
of the ulna. This semilunar excavation form^ the semilunar notch (greater 
sigmoid cavity) and articulatea with the trorhlear surfaee i.>f the humerus. The 
olecranon process is the lari^e curved emineni-e forminp the hiRliest part of the 
hone. The 3U|K?rior surface, uneven and soinowh.it qundrilateral in shape, receives 
behind, where there h a rouph impression or tuberosity, (he insertion of the triceps, 
and alotiR the»nteri<irmarcin the articular capsule nf t he elbow-joint . The posterior 
surface, smooth and trianftular in outline, is i^eparated from the akin by a bursa. 
The anterior surface, covered with cMrtilajie in the recent slate, is directed downwanls 
and fonvarda, and its marjnns give attachment to the articular cap.4ule of the elbow- 

f'oint. This surface, as already noticed, forms the upper and back part of the semi- 
unnr notch. On the inner surface of the olecranon ib a tubercle for the origin of the 
ulnar hea^l of the flejorairpi ulitaris.and infront of thisa fasciculus of the ulnar (I'n- 
trrnal) lateral lineament of the elbow-joint is attaeJuHl to the bone; the outer surface 
is rough, concave, and gives insertion to ajjart of tlie anconeus. The extremity of 



THE ULNA 



151 



the proi-essiies tkirinp exteiiskiri of ilie tilliow in Uie nlccrunon fossa «f ihc humerus. 
Tlie corooold process, forming iliclowrrand anterior part of the semilunar notch, 
has a superior articular surface continuoufl with (he nnterinr surfnce uf the olecranon, 
and, like it, covered with c;ir|ilitKC. The inferior a^jxiei is rough and concave, 
and gives attachment to the brachials. It is continuous with the anterior Hurfure 
of tlif -sluift, and near the junction of ilie two \s a rougii wiiincnce, niuned the tub- 
erosity of the ulna, \vliii'hR'Ct'ive.slin;al.tarhinent of the ohlitjue lipauient of thp 
radius and a few Hbrcs of the hrachialig. The inner side present,-* above a smooth 
tubercle for the origin of the ulnar portion of the flexor digiiorum sublimts. and a 
ridge below for the leasier fiead of the pronator teres, and the rounded accissor>- bundle 
of the ftexor poUicit longits, whilst ininiediately behind the siibliniis tulH'fTie ttiere 
is a triangular depressed surface for the up|>ei' hbres of tlie /frxvr dujiiorum jirofundite. 

Fto. 166. — OwmcATiox orTRS R*i)infl Attn Vlsa.; tks figuke m*o aaowv 
TBK Uei^ltionii or nu Epiphysial ani> Capsi'Lak Llmcs. 

tHUn kX TME TEtTH VUR; ma i1 rut 
CapcoUr Ha* 



Ol[wular tUW 



«rfUU HI THE fIFTH TIIR : fUlU (I EHt 



ULNA 



HADrVS 



"MM «T ra UMNO TU*: m*CS IT THf 
iwiaiiETN rev 



tpniia k^ 1IIE rouKTH tiu . rusts u thi 

liaHtlUiTH TUR 



OkPffttiwaiM 



On the outer surface is the radial notch ( lesser sigmoid cavity) , an oblong articular 
eurface which articulates with the eircuniftfnuice of the htiad of the radius, the ante- 
rior and posterior margins of which afTort^i attachment to the annular ligament and 
the radial (extemai) lateral ligament of the e]lTf)w-joint. In flexion of the elbow 
the tip of the procew is recel^'cd into the coronoid fosKi of the humerus. 

The body or shaft throughout the greuier part of its extent is three-sided, hut 
ta|)erp towards the lower extremity, where it becomes smooth and roundeil. It 
has three borders and three eurfnceK. t>f the three borders, the outer or interos- 
seous 18 best market-l. Jn the middle three-fifths uf the t<haft it i^ i^liarp and pmnii- 
nent, but becomes indistinct below; above it is continued by two line^ which pass 
to the anterior and posterior extremities of the radial notch and enclose a dcprcwpetl 
trlaagulnr urea [bicipital hollow), the fore part of whicli lodges the tuberoMty of the 



152 



TBE SKELETON 



nulius aiitl ihe insertion of the Uceps tendon during pronation of the hand, while 
from the p(j**terior part tht* aujritiator lakes oripin. The ink-rosseous border sep- 
iiratca ilio voliir from the d»rHal surface ami givei* attachment by the lower four-fiftlis 
or its extent to the interosseous nieinbraiie. The anterior border is directly con- 
tinuous with the inner edjie of the rough surface for rhe braf^hialL'^ imd terminates 
jnieriorly in front of the styloid prncess. Throughout the ftrciMer pnri of its extent 
it is Muootli and rounded, and affords origin to the flexor di^itorurn jirajundus and 
rlii; pronntoT tinm/rutus. It separalx^s the volar from the iutemal surface. The 
posterior border coinnietii-es above at the }i|»i:x of the triaiiguliu' suln-utaiieous 
area on the l)ack of the olecranon, ami takes a sinuous course to the back port of 
the styloid process. The upper three-fourths gives attachment to nn aponeurosis 
conunon to three muscles, viz.. the jlexor and extfiis^rr carpi ulnaris and the Jlexor 
(iufUormn profundus. This border separates the internal from the dorsal surface. 
Surfaces. — Tlie volar or anterior surface Ls grtwYcd in the upper three-fourths 
of its extent for the oriKin of the fle^rur dujUorum projumius, narrow and eonvex 
below, for the origin of the pronator ifuadrattis. The upper limit of the at^a for the 
latter muscle is sometimes indicate*! by an oblique line — the pronator ridge. 
Near the junction of the upper and uiiddle thmls of tlie anterior surface is the nutrient 
foramen, directed upwards towards the proximal end of the bune. It transmits 



Flo. 106. — Uppeh Exd or Ulma »h(»wino Two Epiphtbea. (E. Fawcett.) 

Hu eoiTW 

•MU « lumirr of duomnoh 



- IIHILUNJIII MOTOH 



a branch of the volar interosseous arterj-. The medial or internal surface, smooth 
ar>d rounded, gives attachment, on the upper tw<)-thirds, to the /?txor dvjitorum 
profundu», whereas the lower third is subcutaneous. The dorsal or posterior 
surface, directed outwards aa well ai^ backwards, present* at it# upixrr part the 
oblique liae of the ulna i-uiming from the posterior extremity of the riidial notch 
to iho ^HWrterior border. 'Hie line gives attachment to a few libre« of the gupimiior 
and marks off the posterior surface into two unequal parts. That above the line, 
much the smaller of the (wo, receives the insertion of the nufoneua. The more 
exten.sive part l^clow L** sulxlivided by a vertical ridge into an inner portion, .smooth, 
and covered by the niensor carjn ulnaria, and an outer portion which idves ori^n 
to three muscles, viz... the nhductor poUicis hngiis, the extensor poliicits iongus 
and the rjtt&taor india's fovprins, from alcove downwards. 

The lower extremity of the ulna is of small .size and consist-^ of two parts, the 
head ami the styloid process, wpanitcd from each other on the rmder surface bv a 
jETOOve into which the apex nf the inlemrticular librf>-cartilafi;t' i- inserted. That 
part of the head adjacent to the proove is semilunar in shape ami plays ujx.m the 
inlijrarticular cartilage which thus r.iicludrs the uhia from the wri.<t-joml. The 
tnarginof thehead is alsoseniiluimr. andis* received into the ulnar nolcliof the radius. 
The styloid process projeet^f from the inner and back port of the bone, and api>ear8 



THE CARFUS 



153 



as a eoniinuaiion of the pnst-firior horcier. To 'ns rounded svimmit the ulnar [inteman 
lateral lUiaineni nf the wrist-i"inl is attaclied, and its ixiettrior surface is grooved 
for the pussage of the tendon of the extensor carpi ulnahs. Immediatciy aliove the 
articulur margin of the hoad the anterior and posterior radiomlnar ligaments are 
attached in front and behind. 

Ossific«lioo.^nn) ulna i" twaified fmm Lhrm reniriw. _ The primarj- nucleu.i appcjira near 
the middJe of Ih* Jmft in Ihp fiRhtii wttIc <jf intra -uterine life. At birth fhp inferior exlrx-niily 
and the Kreatcr portion of llie oletranon are cartilnjpnoiis. The nucleus for ihf luworcnd appeara 
during the fourth year and the epinhyaiB joins with the sJiaft fmm the eisUti'cnih to thetwcntieth 
year. The Rrealer pwrt of the oietTanoo U osaified fn)ru tlie shaft, hul an epiphj-sis ia Buh- 
(tcqiiently fanned from a nucleus which appear* in the tenth year. 

liie epiphysLi vnri&i in .lute, and may be eitlier acale-li'ke and fonn a thin plate on the Bumniit, 
or involve the upper fmirth of the olecranon and the correnpnnding urticular surface. In the 
latter raM! the opiphyvi* in pr<jlial>ly oornposed of two parl.a fn^ed totreihvr; (1) The scale on the 
miiiunit of the olerrarion proce-ta, and (2j the benk centre wliich ent^nt into the forn^ation of tlie 
upper end nf the :M!niilunur Eiotch (see lig. 16l)). The epiphysis unites to the shaft in the trixt««iith 
or seventeonth yvw. 

THK CARPUS 
The carpuB consists of eight boncjs, arranged in two rows, four bones in each row. 

Fro. 167, — The Left llAifD. (Dorsal surface.) 

VUJUTC 



mtaiR IMlTUOULU 






>->^ 



JjA^TC 



BiUaaor «utI ulnvi* 



braiia 



0, 



or* a I 



m 



' RMUNl . 



Bil*Da«r dWIionsi nomsinBlf - 



UO«t» ntUUI ■ 



Mn»m«r atcUomai 4«au»BnU . 

THtni uNOuu, w nftuiNM nuun ■ 



Enumerated from the radial to the ulnar side, the bnnos of iho i)n>.\inia! row are 
named navicular (scaphoid), lunate isemilunar), triquetral (.cuneiform)^ and 



154 



THE SKKLETOS 



pisifonn; thom of tlie distal row, greater multangular (trapezium), lesser 
multangular (trapezoid^, capitate (os magnumi, hiuI hamate {.unciform). 

Wlieii the Ixiiics <tf rlif cirpus iiro art iuuliiied, they fomi a muss somewhat quad- 
fiinpular in outline, wider tielow than ahovR, and with the lonj;diameM;r transverse. 
The dorsal surface ia convex and tli« palmar surface concave from side to side. 
The concavity is increased by four proininencea, which project forwards , one from each 
exlrenuty of each row. On the radial side are the tuberosity of the tiiiviculnr and 
the ridge of the ETcatcr inultanpihir : on the ulnar side, the pisifonn and the hook of 
the hamate. Stretched transversely liet ween these prominences, in the recent state, 



Fiti. IfiS. — Tna Left Uako. (Palmar tmrfdce.) 

AdduotOF poUMU oblMuna AMiMitar Dolllsia br««is 



Fin or c«n>l dIiibiIs - 

AbduoturdlKlU. 

quinU 



riAiar nrwvlB and 
oppoiMDB lUgtll 
quiau 



Tlaaatouiil uliiarla 



Addnolar poll Iota 
trvuTsno* 

qnluTl 



AHtolMr and . 
digiti aiUBti 



^ ^ 



OppMieiw P0UI4U 

Owft«idiaxl ttift«Hloi] into gr^aUr 
AtMtuator p?lUcl> loucua 

D«ap h*ul or Oaior polliol* brtvto 
OvpOD«U p«11IaU 



\3'^i 



>.2^ 



r?«> 



laclss 



1«R«r bTVVU sod 

And (i«Mr 'paUiou 

Plai-or DtVTin BEid 
Ad4u01or poLJIou 



nasoF palUMa 
XvagaM 



n«spr dlBltoruon nibllBiu 



rivior dtalWwuB proTiuida 



is the transverse carpal ligament forming a canal for the posBago of the flexor ten- 
dons and the metiian nen-e into Hie paini of the hand. The upper border of the 
carpUH is convex and artieulateg with the lower end of the radius and the inter- 
articular fibnwartiliige. The pieifonn. however, takys no share in tins articulation, 
heing attached to the anterior surfuce of the hanWte. The lower border forms 
an undulating; articular surface for tlic Imlscs of the metacarpal l«me». The line 
of articulation between the two rows of the carpus is concavo-convex from aide 
to side, the external part of the navicular being received into the concaWty formed 
by the greater multangular, lesser multangular, and capitat*. and tlie caiMtate and 
hamate into that fanned by the navicular, lunate, and triquetral bonee. 



THE CARPUS 



loo 



I 



The iniiividual farpul Imnes have peveral jxiiiit^ of resemblance. Each hone 
(cxceplinji lite pisifomi) has six surfuces. of which the anttrior nr palmar aiul pt»fite- 
rior or dnrsul are mii^h for the attjM^hment of ligamentj*, the anterior surface being 
the broader in the upper row, the posterior surface iii the lower row. The superior 
snJ inferior surfaces are articular, the fornier l>eing Eenerally convex and the latter 
concave. The lateral surfaces, when in contact with adjacent bones, are alw) articu- 
lar, hut ittherwise rough for tlie attachment of ligajueiits. further, the whole of 
the carpus Is cartilaginous at birth and each bone i^ ossiiicd from a single centre. 



Tut: Navicilar un SfrAPHOio 



The navicular ur scaphoid is ilie lai^cet bone of the proximal row. and so dis- 
posed that its long axis runs obliquely downward!^ and outwards. The superior 
surface is convex and somewhat triangular in sh.ipe fnr articulation with the outer 
facet on the lower end of the radius. The inferior surface, smooth and convex, 
is divided into two parta by a ritlpe running from Ijefore backwards. The outer 
part articulates with the greater nml lingular, the inner with the lesser multangular. 
The anterior ()r palmar surface, rouph and concave above, is elevated beluw 
into a prominent tuberosity for the nttochment of the transverae carpal ligament 

Fio. HW.^Thk I.Kri- Navk-iiapi- 



n* UMIE 




m annit — V:— -'' 



TvBuatm 



and the uhdurtnr poUicia brevis. The posterior or dorsal surface is narrow, being 
reduced to a f^iK)ve running the whole length of the bone; it. In rough and Horves for 
the attachment of the posterior ligament of the wrist-joint. The inner surface is oc- 
cupied by two articular facets, of which the upper is erescentic in shape for the 
lunate bone, whilst the lower is deeply concave for the reception of the head of the 
capitate. The external surface is narrow and rough for the attachment of the 
radial lateral ligament of the wrist-joint. 

Articulations. — WitJi (he rariius above, greater and lejwer multangular below, 
lunate and capitate internally. 



The Luxate or SEinLUNAE 



^H The lunate nr semilunar, placed in the middle of the first row of the carpus, 

^Ti jnarketlly crescentic in outhne. The superior surface is smooth and convex 

f sad articulflt'es with the inner of the two facets on llie lower end of the radius. The 

inferior surface presents a deep cnncavity divided into two partx by a line running 

from tx'fore backwards. Of these, the outer and larger articulates with the capitate; 

the inner and smaller with the hamate. The palmar surface is large and convex. 



Fifl. 170,— Thb Lett Lckatb. 
mniQvcTMi 





the dorsal surface narrow and flat, and both are rough r<ir the attachment of liga- 
ments. The internal surface is marked by a smooth quadrilatend facet for the 
base of the triquetnil. The external surface forms a narrow ercscentic articular 
surface for the h^At*. . 'J r 

Articulations. — With the radius above, capitate and hamate below, 
and triquetral laterally. 




Id6 



THE skeleton: 

The Triquetral ob Cunkikokm 



The triquetral or cuneifonn is pyramidal in shape ajid placeti obliquely, so 
that its base limks UjiwivrdH ami <mt\\'iini.s and th« apes downwards and inwards. 
The superior surface presents externally neiir the Uiae a hiiiuII. Cfliivex artiruliir 
facet which pl.-iys up<in the int^rnrticular fibrn-cartiluge interposed between it and 
the lower end i>f the ulna, and int-ernally a rouKh non-articular portion for lif;anients. 
The inferior surface fonns a large, triangular undulating facet for artkulation with 
tlie htiniate. The palmar surface can be reudUy rerofiniBed by the conspicuous 
oval facet near the apex for tlie pjsif(inn hone. The dorsal surface is nmgh for 
the Attachment nf ligaments. The internal «nd external surfaces are represented 
by the base and the apex of the pyramid. The base is marked by a flat quadri- 
lateral facet for the lunate (seinilunar). The apex forms the lowest part of the hone 
and Ib rougbeued for the attacluuenl of the ulnar (intemalj luterul ligament of the 
wrist. 

Articulations. — With the pisifonn in front, lunate externally, hamate below, 
interarticular fibro-cartilage above. 

Fto. 171. — Thb Lett TaiQifETRAL. 

rOR LUNHTC ■ 

ran nsinfiu 

Fm <MHM[ 



Fio. 172. — The Left FisiroRsi. 

ion TniqUETML . 



The Pisiform 
The pisiform, the Hmalleat of the carpal bones, is in many of ita charactera 
complete contraint lo the rest of the series. It deviates? from the Reneral type In 
its shape, size, position, use, and development. Forming a rounded bony nodule with 
the Ions 'txis drrecte«i vertically, it is situated on a plane in front of the other l)ones 
of the carpus. On the posterior surface is a wiiiyle articular facet for the triquetral 
which reaches to the upper end of the bone, but leaves a free non-articular portion 
below. The anterior surface, rcnigli and niunded, pveM attat'hinent to the trans- 
verse carpal ligament, the ;fcjwr f-arpi ulnaris. the abductor quinti digiii. the piao- 
metacarpal and the piAo-hamate ligamentfi. The lateral niurface-s are also rough 
and the outer presents a shallow groove for the ulnar artery. It \» usually con- 
sidered that tlie pisiform is a sesamoid bone developed in the tendon of the jlexor 
carpi vlnaris, though by some writers it Js regatded && part of a radinientarj' digit. 

The Greater MuLTAXotrtAB or Trapezium 

The greater multangular or trapezium, situated between the navicular 
and first metacarpal, is oUung in form with the lower angle prolonged downwards 

Flo. ITS.—Thk Left Greater MrLTAXoCLAH. 



m MATHUUM 

fM iiMDi lutuweuun 



(■aovi rca nnnii vam ni»UM 
■ na nst khjiwwk 



and inwanls. The superior surface is ooncftve and directed upwards and inwards 
for articulation with the outer of the two facets on the inferior surface of the tmvic- 



THE CARPUS 



157 



ular, and on thn inferior surface is a saddle-shaped Tacct for the base of the first 
metacarpal. The palmar surface pre^nts a prrtminent ridge with a deep gm^ve or 
its inner side which traiisruits the tendon of the fiexor carpi radtolis. The ridge 
gives altachment to the transverse t-urpjU Ugameai. ihe abdvctor poUias breins. the 
opponfftis poUicis. and occasionally a tendinou« slip of iiiKcrtion of the abductor 
polticis lotujus. Tlie dorsaL iind eiteroal surfaces urc mugh for tigainetiU. The 
internal surface is divided into two purta i->y a horizontal ridge. The upper 
and larger portion is cnni^ave and articulates with the lesj^r multaiigular; the 
lower — a snudi flat facet on the projecting lower angle — articulates with the base 
of the second metacarpal. 

Articulations.— With the navicular above, ftrst metacarpal below, the leaiser 
multougulur »rid seeond iiietiiCiiTpRl on the iimer side. 



The Lb8seh MuLTANouLAn or Trapezoid 

The lesser multangular or trapezoid, the smallest of the Inmes in the second 
row, is sDint'tthut weilge-shiijied, with thp broader end Iwhind and the narrow 
end in front. The superior surface la marked by a small, quadrilateral, concave 
facet, for the imier of the two facets on the lower surface of the navicular. The 




Fw. 174.— The Lgrr I.&Asini Mci.TAKoirLAB. 

m lll»T» UUlTUtUUFt . 
nM UOWO NCTWIIirAL - 



lor surface Is convex from side to side and concave from before backwards, 
fonniiif: a sjuIillR-shapcd urticular surfacr for the base of the second metacarpal. 
Of the palmar and dorsal surfaces, the former is narrow and rough, the latter 
broarl and rounded, constituting the widc-st surface of the bnnc, and both are rough 
for the attachment of ligaments. The external surface slopes downwards and 
inwards and is convex for aiticulation with live i-orrcspouding surface of the greater 
multangular. On the internal surface in front is a smooth Hat facet for the capi- 
tate; elsewhere it is rough ftir ligament.'^. 

Articulations.^With the na\iculnr above, second metacarpal below, greater 
multangular externally, and the capitate inteTnally. 



The Capitate or Os Magnctu 



^M The capitate or os magnum is the largest bone of the carpus. Situated in the 
*■■ eenire of the wrist, the upi>er e.\patide(l portion, globular in shape and known sa 

the head, is received into the concavity formed above by the navicular and lunate. 

The cubical portion below forms the body, while the intermediate constricted part 



^HfhE RADIAL OR OUTER 
^B SIDE 

I 



Fio- 175. — The T^urr CAfTPATK. 



m itifi«T[ 

ran RwduuN 



FM LEUO KlUnRSUUI 

m HCONO HlTIMNril. 

K» THINO liniUIIMl 





J-M lltMTl 



rOR tUMITt 



THE ULNAR OR INNER 
SIDE 



nm reUBT* niTIOMtl. 



18 distinguished as the neck. Of the six surfaces, the superior is wiiwtth and 
con\-c.\, elongated from before backwards for articulation with the concHvity of the 
lunaie bone. Tiie inferior surface i^ divitled into three unequal parts by two 
ridges. The middle |>ortion, much the larger, articulates with the base of the third 



L 



158 



THE SKELETO.V 



metacarpal; the outer, narrow and concave, looks outvards as well an downwards 
to articulate with the second metacarpal, whilst tUe inner portion is a small facet, 

? laced on the projecting angle of the none behind, for the fourth metacarpal Intne. 
he palmar surface is convex and roufjh, giving origin to iibres of the adductor 
oblifiuus jmUicis; Ihc dorsal surface is broad and deeply concave. The external 
surface presents, from above tJownwards;— (Ij a smooth convex surface, fonn- 
ing the outer a^ixjct of the head, with the superior surface of which it is continuous, 
for articulation with the navicular; (2) a groove representing the neck, indented 
for ligaments; (H) a small facet, flat and smooth, for articulation with the lesser 
multangular, tlehind tliis facet. i« a rough area for ntiachment of an iiiteroese- 
ous ligament. The internal surface has extending along ita whole hinder margin 
an oblong articular surface for the hamate; the lower part of this smooth area 
aomelimea forms a detached facet. The anterior part of the surface is rough for 
an interosseous ligaJuent. 

Articulations. — With the lunate and navicular above, second, third, and fourth 
metacarpals below, I&sct multangular externally, and hamate internally. 

The Hamatb or Unciform 

The faamate or uncifonn is a large wedge-shaj^ed bone, bearing a hook-like 
process, situate^i between the capitate and triquetral, with the base directed down- 
wards and restiug ou the two iuuer metacarpals. The ape-\ of the wedge forms the 
narrow superior surface, directed upwards and outwards for articulation ■ftith the 

Fio. 176.— The Left Hamatb. 

.HAWULUS - 






anrm 



Itinat«. The Inferior surface or l>aae is divided by a ridge into two quadrilateral 
facets for the fourth and Hfth nietacarpal bones. The palmar surface is triangiilar 
in outline and presents al its lower part, a prominent hamulus {unciform process), 
a hook-like eminence, projecting forwards and cun'ed towards the carpal canal. It 
is flattened from side to side su us to present two surfaces, two borders, and a free 
extremity. To the latter the trans\'erac carpal liganient and the fiejofr carpi vtnarit 
(bv means of the piso-hamat*^ ligament) are attached, whilst the inner surface affords 
origin to the /iexor brnna and the opponens diffiti quinii. The outer surface is con- 
cave and in relation to the flexor teniinns. The dorsal surface is triangular and 
n>ugb for ligaments. The external surface has extending alung it« up[)er and 
hinder edges a long Bat surface, wider al>ove than l>eUiw, for articulation with 
the capitate. In frr»nt of this articular facet the surface is rough for the attach- 
ment of an interosseous ligament. The internal surface is oblong and undulating, 
i. c., concavo-convex from base to apex, for articulation with the triquetral. 

Articulations. — With the triquetral, lunate, capitate, and the fourth and 
fifth metacarpal bones. 



Ossification of the Carpal Bone.s 

Capitftte. firrt ywr Greater multangular. . fifth year 

t[iunate . .M>coiiii j-wur Navicular . . . . . sixth year 

Triquetral .tUird yeax Lc&st^r multan^pilar. . . . eighth ydor 

IaimW .Tourth year I*i»i(orn) .twelfth year 

Additional rarpal elenienta arc nC'CAnrinally met n-ith. The OS centrsle oroun' iiormalty in the 
eaiptis of many nianiiii.iU, and in ihc huniRn ffptu? of two monthfl it i» pretient as a small carti- 
laniKHW nodole vrhkh soon becomes fused tvilb the rartilaf^ of ihe naviruiar. Failure nf fusion, 
wHfa subsequent osiScatinn nf the nodule, leads to the formutiAii of an m twnlrale in Ihe hiunon 
caRHiB nWeh is then found on Ihe donml anjiwl. hptwe^n rhe naWcutar. capitate, and lesser 
['ViuilAngular. In mobl iadividual*, howevor. it raalwrcs with the nancular or underKoea sun- 



THE METACARPALS 



15U 



An wlditioniil cwitrc of ownficatiori, leading to tlie formfttion of an Ac<^eK^>ry citrpal element, 
occaniuaaUf appears in coiiriovtiuri nitli liiv grvnter uiulUiiigultir and tlio luuiialv. An uccuseurv 
ebsment (o* V'r«i/tanumj aim occurs ocroMJon^ly in th« iinglc bctwc<^n the hnmnio iiiid tlit lifln 
TnpUirHrp:ki , nntl (ithent occur between the aocond nod third met«car{]tL]« iu)d the kmor mulUiu- 
gular uoJ cupiUit«. 

THE METACARPALS 

The metacarpus consists of a series of five cylindrical booes, well described as 
'long hones in miniature.' Articulalod with the carpus above, they descend, 
sJiRhtly diverging from each other, to support the finjiers, and are numbered from 
without inwards. Witli the exceptirm of the first, which in some respects resembles 
a phalanx, they conform to a ueneral type. 

A typical metacarpal bone presents for examination a sliaft and two extremities. 
The body tjr shaft is prismatic ami curx'ed so as Ut he slightly convex towards tiie 
back of the hand. Of the three surfacea, two are lateral in position, separated in the 
middle part of the shaft by a prominent palmar ridge, and concave f<'r the attach- 
ment of interosseous muscles. The third or dorsal surface prcsent^s for examination 
a large, smooth, triangular area with the base below and apex alxne. covered in 
the reocnt state by the extensor tendons of the fingera, and two lateral, sloping 
areas, near the carpal extremity, also for itittrntitcoyg muscles. The tnangiilar 
area is bounded by two lines, which commence below in two dorsal tubercles, and, 
passing ui>wari3s, converge to form a median ridge situated between the sloping 
areas on either side. A little above or below the middle of the shaft, and near 
the anterior border, is the nieilullury foramen, entering tlie bone obliquely U]>wards, 
The carpal extremity or base, broader Iiehind than In front, is quadrilateral, 
and l)i)ih palntar and dorsal mirfaces are rough for ligaments; it articulate-? above 



Fig. 177.— Thb Pirbt (Lett) Mdtacarpau 



UtULtIK 




I UUIJUt tlK 



with the carpus and on each side with the adjacent metacarpal bones. The digi- 
tal extremity or head presents a large rounded articular surface, extending farther 
on the palmar than on the dorsal aspect, for articulation with the base of the first 
phalanx. The anterior surface is grooved for the flexor tendons and raised on 
each side into an articular eminence. On the lateral surface of the head is a promi- 
nent tulwrrle, and immediately in front of tlus a well-marked fnssa, to both of which 
the lateral ligament of the metacarpophalangeal joint is attached. 

The »eeond is the longest of all the metacarpal bones, and the third, fourth, and 
fifth successively decrease in length. The several metacarpals possess distinctive 
characters by which they are readily identified. Tlie first metacarpal ts the ithorre^t 
and widest of the series. Diverging from the carpus more widely than any of the 
others the palmar surface is directed inward.*) and marked by a ridge placed nearer 
to the inner border. The outer portion of the surface slopes gently to the lateral 
border and gives attachment to the opponcns poUicit; the inner portion, the smaller 
of the two, slopes more abruptly to the inner border, is in relation to the deep head 
of the flexor jtrtUicis brevis, and presents the nutrient foramen, directed downwards 
towards the head of the bone and transmitting a branch of tlie arteria princeps 
pollicis. The dorsal surface, wide and flattened, is in relation to the tendons of 
the extensor pollicis tongus and brevin. The base presents a saddle-shaped articular 



100 



THE SKELETOS 



surfate for tlie iireater multan^tular, prolonRed in from into a ttmi process. There 
are no lateral facets, but externally a small tubercle receives the insertion of the 
abductor jHiUiris Utntfus. Internally is a rougli area from whirh (ihreK of the inner 
h(*R(l of the jtexor jioUieis brevix take origin. The margin of the articular surfaee 

Fio. IV8.— The Second (Left) MBTACAnpAL. 



MtnUL II PE 



ron usin 

yjLTitiauuii 



iiJlAI St EC 



maKnUHULnNBUUH' 



'FDRTWItO HrTMUItPM. 
- run UflTUt 



^ves attachment to the articular capsule of the carpo-nietacarpal joint. The 
inferior ext remity or head i.s rounded and articular, for the base of the first phalanx; 
the greatest diameter ia from side to side and the surface is less convex thaal 
the correspondinK surface of the other metacarpal bones. Anttiriorly it pre.sent« 
two articular eminences corresponding to the two scaanmid bones of the thumb. 

Fio. 179. — The Third (Lbit) Metacarpau 



UDIII. SiSI 



ilA, 



\< 



ULMU Site 



lOR CinUTt 



> •\H 



mmeuwiDQinnu.. 



WK WUtTM NntuRru 



ttnoio wocfM 



Of the two lateral mareins, the inner gives origin U) the outer head of the ^rs/ tfortu 
xntartxavnm. the outer receive!* fibres of insertion of the opponens poUicis. , 

The second metacarpal.— The distinctive features of the four remaining metsi- 
aup.iJs nrc aJmosi exclusively confine<l to the carpal extretnitte.'!, The second is 



THE METACAKHAI^ 



161 



easily rccogniaed by its deeply cleft base. The terminal Burface presents three 
articular facets, arrfln,(i;e<i na Udlnws, from without inwurds* — (I) a small oval facet 
for the f^reatcr multangular; (2) a hollow for the lesser multuipilar; and (3) an 
eli3Dv:ated ridge for the capitate. The dorsal surface is rou^ for the uisertioni* 
tif the extensor carpi radialis longun and a port of the extensor carpi radtaiia brvpit: 
ilie palmar surface receives the insertion uf the fitiar carpi radialis and gives origin 
to a few fibres of the adductor pollicia obliquug. The outer side of the extremit}* 

Fig. 180. — The ForaTO (Lett) METACAnpii.. 



104 



MHllVOt 



MHUtlOE 



FOR THINO HtMSUfM/ 
rUR UflTUTt . 



ton 

CtflTlK 



i # 



'«9Nfirn) wdiiwiHi 



is roiigh and non-articular; the tuner surface bears a bilobed facet for the third 
metacarpal. The shaft of the second metacarjJiU gives attadunent to three inter- 
osseous mu;«*[os, and the nmrient forameei. directed upuxirds on the ulnar side, 
tranamit-s a hnmch of the wecond volar metacarpal arterj*. 

The third metacarpal 13 distin^i-<lieti by the prominent styloid process pro- 
jecting upwards from the outer and posterior aiiglo of the liasc. Immediately 
below it, on the dorsal surface, is a rough impi-easion for the exUnscr carpi radialie 



Fia. 181. — Thb Fifth {.l.mrr) Mittacarpau 



MtlMlMOE 



FOUttTH wrTIUKPkL 




ION tnl 
HAUn 



utM* rtt 



brfi'ifi. The carpal surface is concave behind and convex in front, and articulates 
with the middle of the throe facets on the inferior surface of the capilatw. On 
the outer side is a bilobed articular facet for the second metacarpal, and on the 
iimer side two small ova! facets for tlie fourth mclacarpal. The anterior aspect 
of the base is roufih aiid (lives att«rhnieiit to fibres of the oddtt/-tor poUieis nbiitpitis 
and sometimes a slip nf insertion of the flexor carpi ratiialis. The shaft of the third 
metacarpal serves for the origin of the adductor poU\cis transicrsus and two \taer- 
11 



162 



THE SKELETON 



o&seaua rauecles. The; nutrient foramen is directed upwar(l$ on the radial side and 
iransmils d branch uf the seiMiid vdliir metJiirarjwl artcrs'. 

The fourth metacarpal has a small base. The carpal surface presents two 
facets: an inlemnl, large and flat, for artic-ulation with the hanuHe, and a small 
facet, at the ouu-r and posterior angle, for the capitnte. On the outer aide are 
two small oval facets for the, corresiJonding surfaces on the third metacarpal and 
a single coneavc facet on the inner side for the fifth metacarpal. The shaft of the 
fourth meta<;arpal gives attachment to thrtjc interosstnus muscles, and th*- nutrient 
foramen, clirerted vpwarrls on the radial side, trani^niiLs a branch of the third volar 
metacarpal arleiy. 

The fifth metacarpal is distinguished by a semilunar facet on the outer side 
of the base for the fourth metacarpal, and a rounded tubercle on the iimer side for 
the exteiisor carpi iiiitaris, in plac-e of the usual inner facet. The carpal surface is 
8}iddle-shai)ed for the hamate; the palmar surface is rough for ligamenu^ ini';lu<ling 
the piso-mctncarpat prolongation frmu the llexf/r cnrjn ulnaris. The dorsal surface 
of the sliaft presents an oblique line separating an outer concave portion for the fourth 
dorsal interaiscnu/i musrie from a .smooth inner portion rnvcrec) by the extensor 
tendons of the little finger. The palmar surface gives aitachinent externally to 
the third palmar inlermseoua muscle and internally to the opponens dvjUi qultiti. 
The nutrient foramen is directed upwards on the radial side and transmits a branch 
of the fourth volar metacarpal artery. 



THE PH.\I^\NGKS 

The phalanges art the hones of the fingers, and numlier in nil fourteen. Each 

tiiiger cDnsiat-s of timw phalanges distinguished as tirst or proximal, siecund or medial^ 

Fw. 182. — The pH.\LA>OBa of the Third Piorr op the Hand. (Doraal view.) 
^Tiie amxn-s indicate tlie dircc-tion of ihc nutrit-nl canals.) 



THIM TDItlWU M UVSVU. nuuUIX 



A 



lIOCHt MlUVX 



\ 



Finn PWUM 



\ 



'A r' 



and thirtl or dtstal. In the thumb, the second phalanx ig wanting. Arranged in 
/lorixouta) rows, the phalanges of each row resemble one another and differ from 



THE PHALANGES 



103 



those nf the other two rows, la all the phalanf^es the nutrient canal is directed 
downwards, towanis the distal extremity. 

First phalanx. — The shaft of a phalanx from the first row is flat on the palmar 
Burface, smooth and rounde*! on the dorsal surface, i. e.. semi-cylindrical in shape. 
The borders of the palmar sxirfuce are rough for the attachment of the sheaths of 
the flexor tendons. The base or metacarpal ejcircmity presents a single concu\'e 
articular surface, oval in shape, for the convex head of the metucarpiU bone. The 
distal extremity forms a pulley-like surface, grooved in the centre and elevate<l 
laterally to form two miniature condyles, for artieulatlon with the baee of a second 
phalanx. 

Second phalanx. — The second phalanges are four in number and are shorter 
than tliose of the first row, which they closely resemble In form. Tliey are difi- 
tinpuisheti, however, by the articular surface on the proximal pxtreniity, which 
presents two shallow depressions, separate*! by a ridge and corresponding to the 
two condyles of the first phalanx. The distal end for the baae of the third phalanx 
is trochlear or pulley-like, but smaller than that nf the first phalanx. The palmar 
»irface of the shaft presents two lateral impressions for the tendon of the flexor 

Fio. 183. — OsairicATioN of tul MrrACAitrALa and Phalanobs. 



kP?an IN THE ThIAD TUft. fiMHU- . 
NTl* in IMt TVlNTimi lUN 






I WfllH IK ni TMim. MD oaNiou- 
{ fttlE IN TME TWnriETH rE»R 



iriFKnif m um 



ttaUUtH Of TRUM 



vmtmt >M MUD 




. FirTM tflN coniouQiirt m IHI 
ElSMTEEWtH rut 



digitoram 9ubtimi$, and the dorsal aspect of the baae is mnrked by a projection for 
the Mttaohnient of the extensor digilorum cotmminis. 

Third phalanx.— A ihini phalanx is retidily recognised by its small size. The 
proximal end is identical in sha}>c with that of a second phaliinx. and bears a de- 
pression in front for the tendon of the flexor digiiorutn pro}rmdua. The free, flattened 
and expanded distal extremity presents on its palmar surface a r«ugh semilunar 
ele\'ation for the support of the pulp of the fincer. Tlie somewhat horBeshoe-shaiJed 
free extremity is known as the unguicular tuberosity tungual process), and the 
lK>ne is accordingly referred to aa the ungual phalanx. 



ORSiFtrATiox OP THE Metacarpus axd Phalanoes 

Each of tho metai'arpal bonea aad plinlAtigcii is ouificd from a [>ruiiur>' trriiln^ for the greater 
part of the hone, uid from one epinhyiinl ccnlrt. The primary- iiuolcuit iippcAni from the eighth 
to the Iriir.h we»l< of intra-iit<rririe lifp. In the imtcr font tu«-t:i(tirp»l lKin*>t llie epiphvui* >« ilintsl, 
whilvl in ihe lirEt iiivtucarpul Ijoud. unil in itll the plmlnngL'^. il is pru.^imal. The ppiphyHtal ntirlol 
appcnr from the thir<i to the fifth yenr and are uttiled to Iheir respective shafts About the twen- 
tielh j*ejir. In m.-*!!}' nx^n the fir«1. metjirarjud hns two epipliysM, one for the baae in the third 
yeiu- And im additiuiiid une fur the head in the M>\'vnth yeiir, but ilio latter is never so larfcc as 
in the other mctaciirt>itl lK>nes. The third mcLnenrpal oceiiJ^onnlly haa an oHdittonal nucleus 
(or the prominent styloid procoM which mny mniain diatinct and (arm a lipoid ho'i*, and traces 



164 THE SKELETON 

of B proximal epiph\*sis have been obeer\-ed in the second metacarpal bone. In many of the 
0«ta<,>ea (whalea, dolphins, and porpoises) and in the seal, epiphyses are found at both ends of 
the metacarpal bones and phalanges (Flower). 

The (Huiticntion of a terminal phalanx is peculiar. Like the other phalanges, it has a primary 
nucleus and n secondary' nucleus for an epiphysis. But whereas in otner phalaiiges the primary 
centre appears in the middle of the shaft, m the case of the distal phalanges ^e earthy loatter 
u depo-Mteil in the free extremity. 

Sesamoid Bones 

The sesamoid bones are small and rounded and occur imbedded in certain tendons where 
they exert, a considerable amount of pressure on subjacent bony structures. In the hand five 
sesamoid bones are of almost constant occurrence, namely, two over the metacarpo-phaliuigeal 
joint of the thumb in the tendons of the fiexor poUicis brevis, one over the interpbalanseal joint 
of the thumb, and one over the metacarpo-pnalangeal joints of the second and Sfto finf^rs. 
Occasionally sesamoids occur over the metacarpo-phalangeal joint of the third and fourth d^ita, 
and an additional one ntajr occur over that of the fiith. 

Vei^- rarely a sesamoid is developed in the tendon of the biceps o^-er the tuberosity of the 
radius. ' 



B. THE BOXES OF THE LOW'ER EXTREMITY 

The bones of the lower extremity may be arranged in four groups corresponding 
to the division of the limb into the hip, thigh, leg, and foot. In the hip is the in- 
nominate bone, which constitutes the pelvic girdle and contributes to the forma- 
tion of the pelvis; in the thigh is the femur; in the /«;, the tibia and fibula, and in the 
foot the tarsus, metatarsus, and phalanges. Associated with the lower end of the 
femur is a large sesamoid bone, the patella or knee-cap. 



THE COXAL BOXE OR OS IXXOMIXATUM 

The coxal bone or os innominatum is a large, irregularly shaped bone articu- 
lated behind with the sacnmi, and in front with its fellow of the opposite side, the 
two bones forming the anterior and lateral walls of the pelvis. The innominate 
bone consists of three parts, nanied iliimi, ischium, and pubis, which, though 
separate in early life, are firmly united in the adult. The three parts meet together 
and form the cotyloid cavity or acetabulum, a large, cup-like socket situated near 
the middle of the outer surface of the bone for articulation with the head of the femur. 

The ilium is the upper expanded portion of the bone, and by its inferior ex- 
tremity forms the upper two-hfths of the acetabulum. It presents for examination 
three boniers and two sunaces. 

Borders. — WTien viewied from alwve. the thick crest or superior border ia 
cur\"ed somewhat like the letter /. being concave inwards in front and conca^-e out- 
wards behind. lis anterior extremity forms the anterior superior spine, which 
gives att.>tclunent to the inguinal ^Poupartsl ligament and the sariorius: the hinder 
extremity forms the posterior superior ^ine and af ords attachment to the sacro- 
tubwou? vgreat sacrw-sciatic^ ligament, the posterior sacro-iliac ligament, and the 
mtitti'tuius. The crest is narrow in the middle, thick at its extremities, and may be 
divideii ii\to an inner lip. an outer lip. and an intennei.i;ate ridge. About two 
and a half inches from the anterior superior spine is a prximinent tuberele on its 
outer lip. The outer lip of the crest gives attachment in irv^nt to the tensor fascia 
ii/.r: aiotii: its whole length, to the fascia lata: along its anterior half to the f.r- 
ttniaJ i<<iq:,f: and Ix-hind this, for about an inch, to the hUissimus dorsi. The an- 
terior twt>-;h:r.i5 o: the interraediate ridge ffives or.gin to the intimcl iTblique. 
The ir.r.cr lip iive? iiri^ir.. bv its anterior two-thir-is. to the trans'-.frf\.^i\s: l»ehind 
this ii; .-i !^;r.aii ;ire;\ for the g:n-!dr-:;:\,s /;i'»i.V>'-jri. and the rera.ainder is vvcupied by 
the ,*.:.*'-W_:v;t"< ■-■x:--- s::- t . The exTre::.e irjier ::iarcin of the lip. in the 
anterior tw^^rhir,:-;. ^^rves f'^^r the attiichnient '■>f the i'iac lascia. 

The anterior border ->:" the ii:-.::r- extends :r^>r.i ihe anterior superior spine to 
the niartir. o: the socts'-uiurr.. Be'.o'^" the spirrf i? a prv^ntinent notoh tn"*"'. which 
^:b^vs .■>: the s.:-:-— :.< arise. :-.r.v.i this is fucceede^.! by the anterior inferior spine, 
?:";'.. ,07 A"-i !tts5 i^riT.-ir.er.t thar, the s'-t:*ri'^r. '■? whi-'h the straight he.-iii '^: the 
'tv-:^ ,.« ;ir. i ;ht- i'.v-^ter.-.o-ii ;ijri"-ier.: .-ire attachovi. On the ir.r.er ■:;.■:■■- ■:■: the sr.terior 
::•.;>- ^r <:'.r.c :? a b^-va..;. sh;.i;o-v crv^vt tor the ;?:\'^iw.Vv« as it l>Asse< tr>.:r. ti'-.e a:v 



THE HIP-BOSE 



165 



idomen into the thifrh, limited 1>elow by the ilio>pectineal eminence, which indt- 

' cates the point, of union of the ilium and pubis. 

t Tht posterior border of the ilium pn^aents thr posterior superior spine, and 

Jbelow this, a shallou- notch terminating in the posterior inferior spine which 
corres|Kjnds to the binder extreriiiiy of the uuhcuiftr surface and gives attaehnwrnl 
to u portion i>f lliH Rurro-tuberous (great sacm-sciatic} ligament. lielow t lie spine 
the pa^tcrior border uf tlif ilium forifi^ ilir up}>iT limit of ihe great sciatic notcli. 
Surfaces.— Tlie external surface or dorsum is cunt-ave 'wliind, eoDve\ in 



Fro. 184.— TnK Hip-bone. (Posterior view.) 



loMMaD ot«st«nial «blliqaa 



XvaiMtMowUua 



^. \ 






Q|ut«u* 



Glut! 



■diua ^/ 



t<MIMniu d«nt 

DHUI OF rLiiiu 






OInMia 



BMlaa ranorla ■ 



mrimwiMC aoiOM' 






^ 



■l.^i". 



». *- 



m^. 



'■'lESIOft 






HUTIH tt^ATIC (ILIO-SOMTICl 

"CIOH 



OaiMule • 



ISC^UU 



tfoonti taambraiM • 



TMIIIRU UM ' 
ZaoUiMini 



^H ZmUi 

^H aiialSiiiin 

^H AiUlaotar 

^H bn«t> 

^1 OltOENWi 



JOTVLOlhUOrc- 



OltOENWi UIIU» ff . 



MUtVt OF IIDHtljy 



UMuntor •lUraiM 



»■( Of ucHniii 

iftan UUT10 KOTOH 
Oanielldii InbrtDr 

mruwToii MOTCM 
■•mlnum bruMMiw 



Qiudriuua MmorU 



B»nit«sAiiiMiia uM 



Adduclar buoui 



I 



front, limited above by a thick superior border or crest, and traversed by three 
gluteal lines. The posterior gluteal line commences at the rnwt about two inclies 
from the piwtflrior superior .spine and curves dowiiwiinLg to the upper murgin of 
the great sciatic (ili*>-sciiitic) notch: Tlie apace includwl between this ri<lge and 
llie crest afTonLs origin at its upper part to the gluteus mnximus, and at its lower 
port, to a few fibre.^ of the pirijortnis, while the intermetltate portion is sint^wih 
and free from muscular attachment. The anterior gluteal line begins at the 
crest, one inch behind its anterior superior spine, and curves acrfiw tliedornurn 
to terminate near tlie lower end of the superior line, at the upper margin of the 



166 



THE SKKLETOS 



great sciatic notch. The surface of bone between this line and the crest is for the 
origin of the gliiieus mfdiits. The inferior gluteal line commences at the notch 
imniecliiitely below the anterior suf>erior spine and t-eniiinate* posteriorly at the 
fiiHit part of the Rreat sciatic notch. The upaco between the anterior and inferior 
^lutenl lines, with the exception of a t^mall area aiijai^ent to the anterior end of the 
spine for the tensor fagcur lata:, gives origin to the gltitem minimus. Between the 
inferior phiteal line and the mar:gin of the flcetabiihini the surface iifFords attach- 
ment to tiie capsule of the hip-joint, and on a rough area (sometimes a depresiaion) 

Fig, 18S.— TttB Left Hip-dose. (Iut«ruiil surface.) 



Aaoro-aploalw 



life 






VL I U M 



FO«a* 



luIltMu 



MIUGULM UVMI 



nn. nr.tNHtM 



* »■ 






fS 



Hi 



xHi. Hjr. »m at 

aiuu 



MT. m. gnni of \um 



noM pwv 



ObtaraloT 
IQMpniu ' 



lUO-NCtlNtJL 

tuiituiac 



I S C H I\U M 



DMvt roi nwe 

VUKIS MC 

I (inn 

OUB IUMIB9I1I 






Tr«Brraraa* . 



"fi 



--A, 



r o n A M EN 



Kv 



MKiii tat etTUMioK 

NMU MB VIHIU. 






MO IICM'UM 



Cna MUi and Ootttnmtr Arauu« 



tomurds its anterior part, to the reflected tendon oj Ute rectus frmoris. The internal 
surface presents in front a smooth concave portion lenned the iliac fossa, which 
lodtres the Uioait musoje. The fi«*a Is limiteil below by the iliac jiortion of the 
terminal (ilio-pectineal) line, a rounded border seiiamtin^ the Ufi^a from a jjortion 
of the internal surface Mow thi- line, which fives attiw^hnient to the olHuralw in- 
temus and enters into the fonnation of the true pelvis. Behind the iliac f(j6sa tlie 
bone \s uneven and presents nn auricular surface, covered with cartiloge in the 
recent state, for articulation with the lalerul iwpect of the upper portion of the 



THE HtF-BUXK 



167 



sacrum; above the auricular surface arc some depressions for the posterior sacro- 
iliac lijiaments and a rough area reaching as high as the crest, from which parts of 
the vacrospittabs (rrectvr $piiuc) and mullifidus take orittin. The rough surface 
above the uuriculur facet is known as, the tuberosity of the ilium. 

The ischium consists of a body, a luberowty. and a rainuj'. The body, which 
has somewhat the form of a triangular pyramid, enters superiorly int<> the formation 
of the ncetalmlum, to which it contributes a little more than two-fifths, and fonus 
the cliief part of the non-articular portion or floor. The inner surface fonns 
part of the true pelvis and gives attachment to the obturator mtfrnus. It is con- 
tinuous witli the ilium a little below the terminal (ilio-pectinoal) line, ami with the 
pubis in front, tlie line (if junction with the latter bein^ fretjuently indicated in the 
aiJult bone by a rough line extending from ihe ilio-peciineal eminence to the mar- 
Kin of the obturator foramen. The outer surface includes the portion of the 
acetabulum formed by the ischium. The posterior surface is broa(l and bounded 
externally by the margin of the acetabulum and lieluud b}' the poetcrior border. 
The capsule of the hip-joint is attached to the outer part and the pirifonnn, the 
great sciatic and piitflori{>r cutaneous nerves, the inferior gluteal (sciatic) artery, and 
the ncr^•c to the quadraiits fet/wris lie on ihe surface as they leave the pelvis. In- 
feriorly this surface is limited by the obturator groove, which receives the pos- 
terior fleshy border of (he obturiihr extemm when the thinh is flexed. Of the 
three bonlers, the external, fonniii^ the prominent rim of the acetabulum, scp> 
aratw the posterior from the external surface and gives attachment to the coty- 
loid ligament. The inner border is sharp and fornw the outer boundary of the 
obturator foramen. The posterior border in continuous vcith the posterior bor- 
der of the ilium, with which it joins to complete the nianiin of the great sciatic 
notch. The notch is converted into a foramen Ity the sacro^piiKius (small 
sacro-si'iatic) ligament, and transmits the jririjornm muwle. the gluteal vessels, 
Ihp sufxrior and inferior gluteal nor\'es, the sciatic and posterior cutaneous ncr\'e«. 
the internjiJ pudic vessels anil ni'rve, and I tip ner\'es \m the nljliirtiior ititfrntim and 
qitadrottis femoris. Below the notch is the pmminent ischial spine, which gives 
attachment inlemally to the eoecygcua and leralor am, externally to the gemellutt su- 
perivr, and at the tip to the sacro-spinous ligament. Below the spine is the small 
sacro-sciatic notch, covered In the recent state with cartilage, and converted into 
a foramen by the sacro-tuberous (great sjicro-sciiitic) ligament. It transmits the 
tendon of the ohturator internua. its nerve of sup|)ly, ami tiie internal pudir vessels 
and ncrx'e. 

The tuberosity is that portion of the ischium which supports the body in the 
sittiiiK posture. It forms a rouph. thick eminence continuous with the inner marsin 
of the ramus, and Ls marked by an oljlique line se[>ani.ting two impressions, an upper 
and tMil^^r for the semiaiemhranosus. and a lower and Inner for the commoji lonuon 
of the biceps and memiiemtiiuisus , while the lower part is marke<IIy uneven and 
gives attachment to the adductor ma^nus. The upper border gives origin to the 
inferior ijemellut: the inner border, sharp and prominent, receives the sacro-tubet^ 
otw (great sacro-sciatic) ligament, while the surface of (he tuberosity immediately in 
front is in relation with the intenml pudic vessels and nerve. The outer bor- 
der gt^•cs attachment to the mcadnilus jemoris. 

The ramus is the flattened part of the ischium which nms upwards and inwards 
frrim the tuberosity towards the inferior ramus of the pubis, with which it is con- 
tinuous on the inner side of the oljturator friramen. The outer surface gives origin 
to the adductor magnus and obturator exterrxua: iJie inner surface, forming port of 
the anterior wall of the pelvis, receives the ems penis (or cli(oridis) and the inchia- 
cavfrruisus. and gives origin to a part of the obturator intemus. Of the two borders, 
the outer is thin and sharp, ami forms part, of the inner boundarv of the obturator 
foramen: the inner is rough and soniewhat everted and pives attachment to the 
fascia of CoUes, and the transvcrsus perinei. To a ridge immediately above the 
impression for tlio crus [x-nis (or clitoridis) and the ischio-cavemosus the urogenital 
trigone (triangular Upans-nt) is attacheii. 

Tlie pubis consists of a body and two rami^descending and ascending. The 
body is somewhat quadrilateral in shape and presents for examination two surfaces 
and three borders. The anterior surface looks downwards and outwards and 
gives attachment to the adductor lontjus. the addwtor brevia, the obtunilor extrrntis. 
and tiie gracilis. The posterior surface is smooth, ltx>ks into the pelvis, and affords 



16S THE SKELETON 

origin to the terator ani, the obturator intemvs, and the pubo-prostatic ligaments. 
The upper border of the btxly is rough and presents a prominent bony point, known 
OS the tubercle or spine, for the attachment of tlic inguinaJ (PoupartK) ligament. 
Running inwards from the spine is the pecten ur crest, teniiinaiing at the u[j])4^r 
end of the symphysis, with which it fonns the angle of the pubis. The pecten 
is a short horizontal rid^e, whii^h givc^ attachment to the rectus abdominis, the 
pyramidatts, and the conjoined tendon of the internal oblique and trans vcrsaiis 
mugctes. Tlic inner border is oval in shape, rough, and articular, forming with 
the hone of the oppi^ite side tho symphysis pubis. The outer border is sharp 
and forms paJt of the boundary of the obturator foriuiien. The descending ramus, 
like the ascending ramus of the i-schium, with whicli it is continuous, is thin and 
flattened. To its anterior surface are attached, from within outwards, the odthtcior 
brcviOt adductor magnm, and oEt/uJ-a/or extermis. The posterior surface is smooth 
and gives attaclimcnl to the cms penis or ditoridis, the sphincter urethra.' rnrrn- 
branaceiF, the obturator internua, and the urogenital trigone {triangular ligament). 
The outer border forms part of the circumference of the obturator foramen, and 
the inner border, forming part of the pubic angle, gives attachment to the 
gracilis. The ascending ramus extends from the body of the pubis to the Uium, 

Fio- ISO. — Am InndA-rmx iNNOntNATE Boxs. BHOwtNO a Cottuhd Boxk. 



W 



fMCornctBiOM- 



forming by its outer extremity the anterior one-fifth of the articular surface of th^ 
acetabulum. U is prisnmtic in shajje and increaws in size as it passes outwards. 
Above it pre.'*cats a sharp ridge, the pubic portion of the terminal (ilio-iwctineal) 
line continuous witli the iliac jwrtiou at tlie ili(>-i>eciineal etninence, and affording 
attachment to the conjoined tendon, the lacunar (Ciimbemai's) liKiiment, the re- 
flected inguinal ligament (faacia triangularis), and the pubic portion of the faacia 
lata: the Iliac portion of the terminal (ilio-pectineal) line gives attachment to the 
psoas parvus, the iliac fascia, and the pelvic fascia. Immediately in front of the 
pubic portion of the hne is the pectineal surface; it gives origin at its hinder 
]iart tn the ftertiiicug, and is limited Ivelow by the obturator crest, which exlenda 
from the pubic spine to the acetabular notch. The under surface of the ascending 
ramus forms the upper boundary of the obturator furamen and prcsptits a deep 
groove for the passage of the obturator vessel? and nerve. The posterior surface 
is smooth, forma part of the anterior wall of tiie pelvic cavity, and gives attach- 
ment to a few 6bres of the obturator inli'rmts. 

The acetabulum ts a circular depression in wliich the head of the femur Is Iodge<l 
and con'iists of an articular and a non-articular portion. Tlie articular portion 
is circumferential and horseshne-shapc<l, with the deficiency in the lower segment. 



THE HIP-BONE 



109 



One-fifth of the acetftbulum ia formed by lite pubis, two-fiftha by the wchiunj, and 
the remaining two-tiftlis ai« forniecl by the lUuni. In rare instauces the pubis muy 
be excluded by a. fourth clement, the cotyloid bone. The riou-articrulur (Kirtion is 
formed mainly by ihe iMchtuni, and is cimtimmu^ U-ltnv with the margin of the obtura- 
tor foraiuen. The iirticular portion presents an out^or rim to whifih the cotyloid liga- 
ment is attached, and an inner margin to which the synovial membrane which 

Fig. 187.— Tub Pklvih op a FiBrrs at Birth, to show thb Thbee Poutioxs or ibb 

1kkd»i.vatk Bonk>. 



THE NUCUtll rOK TMC lUUH UtVM 
UMA (M THE ItCONS MONTH 



rm Rueuus n% thi run* ^tflt.^% *eouT 

THE EKD or THI rouKTH MONTH 
tHI HUCKLfl IM THI ItCHIlM XrtUMI in 
THE mm VONTM 



excludes the lieiimentum teres from the synovial cavity is comiected. The opposite 
angles of the horscshoc-ahaped margin which limit the acetabular notch arc united 
by the transverse ligament, and through the acetabular foramen thus fonned a 
ner\'e and vessels enter the joint. 

The obturator Cihyreuid) foramen is situated lietween the ischium and pubis. 
Its margins are thin, and serve for the attaehmeiit of the obturator membrane. At 

FtO. ISS.— HlP-BOKE, 8H0WTNO SBCONDAHY CE^NTBSS. 
uRoa H fiREEM. uhuh it THraTT 



tmm n nnEEN. uwiEt jt thdttt - 



TMt URtt OF Mm Ut UtUlUI Dl- 
irrUUrED BT r>4t UIEUtH TIM 



kftun IT nmu. tuus k ntiHTi . 



tffUM IT nrTf Di. rntn K mtan 



the upper and posterior angle it is deeply grooved for the passage of the obturator 

\-e8se]s and nerve. 

The chief vascular foramina of the eoxwl lK>ne are found where the bone is 
thickest. On the inner surface, the ilium receives twigs from the ilio-lumbar, 
decpcireunifl(*.\ ihac, and obturator arteries, by foramina near the crest, in the iliac 
foesa, and below the terminal line near the great sciatic notch. On the outer sur- 



170 



THE SKELETON 



face the chief foramina are found below the inferior gluteal Hue and the nutrient 
\'csaGlR arc derix'cd from the pliit«al arM^ries. The ischium receives nutrient ves- 
sels from the obturator, internal and external circumflex arteries, and the largest 
foramina are situated between the acetabulum und the Ischial tuberosity. The 
pubia is supplied by twigB from the obturator, internal and external circunifiex ar- 
ierieS; and from the pudtc brandies of tlie common femoral arter}'. 

OssUicatioa. — Tho curlilagiiious fcpaiiciitali\'«* of the hi|>-tx)ne ccnaiRtft of three di^tinet 
portions, an iliac^ an Ischistlc, and a pubic portion; the iliac and JHrhintic partionit find unite 
and later thepu'nc portioji, nothjitevetilually there is found a «tiiiKU> i:iirtil»|ciaDUMniiuus. Eurly 
in iho second moulli a wntni uf tMailiculiun appears aliove the acetahiitum for the ilium. A 
little later a M^cond nucleus appears below the cavity for tho 'ischium. a.nd thin in follmvcd in 
the fourth iitoMlh by a depotiil in iht puMc portion of the carlilftge. At birtb, tlio three nuclei 

FlQ. 189. — HiP-BOKE flVKEB SfRFACR) AT THE KlOnm YbAU. 



■ 7 luuy 



>v 



ivmM 



»«8S 



w 



■Sr 



are of oonstdftrablc sixo, hut am Huirouatlvd hy rvUitively wide lraet«| of onrtilnge; 
hiu. hiinevnr, ttxtendf^d into the mnrein of the arctabuUim. In the eighth y<:-nr The nuif of L__ 
pul)U and is^'hiuui become united bv bonv, niul in thr IweKlli year the trimdiBlt* cnrtilujie which 
•cpAratO'-i ihc thrc« sn^ncntii of the bono in the aiTtBlmluiu bi.-ginM lo utiairy fruin fcvi-rul reiitros, 
CM UM«e, one is more constant than the olhcrw iind t-' known »?• the ncclahnlar nuclcUH, Tho 
irisniCulBr piece of bone to which it givex riw i-^ rruardyd a« tlw rvpre*pnta1ivr of ihp mUjloiti 
or acetabular l>one, conslnnHy present in » few mamniuls. It is sitiialetl at the inner part of 
tile Qi'eT.iibuIiJiii and is of siicn a tnice as to entirely exclude the pubis from the cavitv- With 
thin bone, however, it eventually fuses, and atteiwartlK Iwconics joined with the ilium anJ i*cluuni, 
so that by the eiRhleentii or tirenticth year the aeveral partfi of tlio acetabulum have become 
united, lu tin,- fifteenth year other centres appear in the carliUme of the crest of the tlinin, the 
anterior inferior spinous proceBe. tho lulwrosity of tho ischium, and the pulnV cresl. aiid the 
epiphy-'O".'' Uvm with the main bone about the twentieth year. The fibrous tissue cotineclcd with 
ne tuuercle of the pubis represents the epipubie boneo of marsupiola. 



z 



THE PELVIS 

The pelvis ia compojied of four bones; the two hip-bones, the sacrum, and the 
coccyv. The hip-bones form the lateral and anterior boundaries, meeting e5u*h 
other in frool t.o form the pubic symphysiij; ptwteriorly they are jteimrated by the 
sacnim. The interior of the pelvis is divided into the false and true pelvic cavity. 

The false pelvis is that pjirt of the cavity wliich lies above the terminal (ilio- 
pectineal) line and l>etwocn the iliac foeste. This part belonj^a really to the al>- 
domen. and is in relation with the hy|>oc(ustric and iliac re(non.<!. 

The true pelvis is situated below the terminal (ilio-pectineal) lines. The upper 
circumference, known lui the superior aperture, inlet, or brim of the pelvis, is 
boiindeti anteriorly by the tubercle an*l jjectcn of the pubis on each side, posteriorly 



THE FSLVIS ^^^^r 171 

hy the anterior margin of the base of the Sftcnim, and laterally bv thn terminiil linips. 
The inlet in nomiAl pelves is heart-shaped, heinp ohtwsely pmnted in front; pos- 
terir^rly it is entTOiwhe<i upon hy the proincHUor>- of the sacrum. It has three priil- 
eipal diameters; of these, the aiuero-posterior, called the conjugate diameter, is 
tneitjureil fnmi the sacro-vertebral angle lo the Hj-niphysis. The transverse 

Fig. 100.— Tub Maue Pilvm. 






-/i 



diameter represents the greatest width of the iwlvic cuvity. The oblique diameter 
is mcaimrod from the sacro-iliac Bynchondrotiis uf one side to the ilio-pectineal emi- 
nenre of the otlier. 

The cavity of the true pelvis in hounded in front hy the symphysis pubis, behind 
by tlie sacrum and coccyx, and laterally by a smooth wall of bone formed in part 

Fto, 191.— Tbb Fbuali PBtvra. 



O 



>y the ilium and in part by the ischiuui. The cavity is shallow in front, where it 
is formetl by the pubies. and is deepest poeleriorly. 

Tlie inferior aperture, or outlet, of the pelvis is vcr\* irFC|E:uIar, and encroached 
upon by three bony processes: the posterior process is the coccyx, and the two 



172 ^^^ THE SKELETOX 

lateral procei<ses are the ischial tuberositte$. They separate three notches. The 
anterior notch i:f the pubic arch, and ia bouuiieci on eiu-h side by the ccnjoined 
rami uf ihe pubes and ischium. Each of the two temaiaing gaj^, bounded by the 
ischium anteriorly, the sacnini and coccyx posteriorly, and the ilium above, corre- 
sponds to the greater and lesser sciatic notches. These are convertwl into foramina 
by the sacrn-tulwrnus (grejit sacro-scialic) and sjicrn-spinnus tsniall SHrm-sciatic) 
ligament.*:. 

The position of the pelvis. — In the erect position of the skeleton the plane of 
the pelvic inlet form£ an angle with the horizonial plane, which varies in individuals 
from, 50® to 60°. The base of the sacruni in an average |jeJvis lies nearly ten t-euti- 
metres (four inches) above the upper margin of the sj-mphysia pubis. 

The axis of the pelvis. — This is an ima^narj- line drawn at right angles to 
the planes of the brim, cavity, and outlet through their central potnis. 

Aa the poeterior wall, formed by sacrum aiwl coccyx, is nearly five inches long 
and concave, and tlie anterior wall at the synipliysis pubis only one and a half to 
two inches lon^, it follows that the axis must be curved. 

The average measurements o( the diameters of the pelvis in the three planes 
are given below: — 

AvTBiio<rosTtRioit. Om.igi'B. Trans\'Er»i<. 

Inlet 4 J inches 5 inches 5\ inches 

Cavity 4J " 5\ " 4} " 

Outlet 3i " 4i " - 4J " 

OifEerences according to sex. — There is a marked difference in the size and 
form of the male and female pelvis, the peculiarities of the latter being necessary' to 
qualify it for iUs functions in parturitian. The various points of divergence may 
be tabulated as folloivs: — 

Male. Fcuauc. 

Bonee heavier and rougher. Bones more slender. 

Ilia less vertical. Ilia more vertical. 

Iliac foissa; deeper. Iliac fo.swip shtillower. 

False pelvis relatively wider. KaUe pelvis relatively narro«'er. 

True pelvis deeper. True pelvis sliallovver. 

" " narrower. " " wider. 

Inlet more heart-shaped. Inlet more oval. 

Symphysis deeper. Symphysis shallower. 

Tuberosities of iitchia inflexed. Tuberosities of ischia everted. 
Pubic arch narrower and more pointed. Pubic arch wider and more rounded. 

Margins of ischio-pubic rami more Margins of iscliio-pubic rami less evert 

everted. 

Obturator foramen oval. Obturator foramen triangular. 

Sacrum narrower and more curved. t^acrum wider and leiw curved. 

Capacity of true pelvis less. Capacity of true pelvis greater. 

In comparison nilh the [>eli'*(" of lower anirHBl*. whirh, MjeakinggptifTnlly, »Kr elnngftled und 
nftiTOw. the human pelvis b charscleriHnl by ilt^broadtli, shuUowDOH, luniiireat rspnciry. Differ- 
ence> ve nlm Ia be recognised in tho form of the pcb-is in the varJouti Tnv*k of mankintf, the mcnt 
Important beiujt the relation of the antero-posterior to the I r.ii))n-enie diameter, meitaurecl at tlie 

Ifuoc. Thw iR expressed by the peine xnatx -• — ^^-s- — -, ■ 

"^ ' "^ tnuis\'errt« (liaineter 

In Ihe ii\'«raKo Knronean mnle the index jji nlxiut SO; in the lower ra(«8 of mnnkind, 90(oOS, 

PeU-ea with hii index Iwtew SK) are jiiatypftiic, froiu 90 to 95 ore mtntiptllk, and above 95 iMulut- 

pdlv. (Sir William Turner.) 



THE FEMUR OR THIGH liO.VK 

The femur is the largest and longest bone in the akeletx>n, and transmits the 
entire weight of the trunk from the hip to the tibia. In the erect iKwture it inclines 
from above downwanls and inwarfls, approaching at the lower extremity Its fellow 
of the opposite side, but separated from it above by the width of the true pelvis. 
It presents for examination u superior extremity, including the head, neck, and 
two trochanters, an inferior extremity, expanded laterally into two condyles, and 
a shaft. 




TUE FEMUR OR THIGH DONE 



173 



The superior extremity i.^ i:uiTnountcd by a smooth, globular portion called the 
head) formirig more than half a sphere, directed upwards and inwanU for articu- 
lation with the fl^^etabulum. With the cxcT]>tinii nf a small rough depression, the 
fovMi for the liganientum teres, a little lielow and behind the centre of the head, its 
surface is covered with cartilage in the recent stale. The head i» comiect^ with the 
shaft by the neck, a stout rectangular column of \x>ne which forms with the sliaft , in 
the adult, an angle of about 125". lis anti^rior Hurfaec Ls in Ihe Kunie plane with the 
front asjwcl of the shaft, but ia marked off from it by a ridge l« which the capsule 
of the hip-joint is attnrliod. The ridge, wliich conunenccs at the grtat trochanter in 
a Biiiall prominence, the superior cervical tubercle, extends obliquely downwards to 
the inferior cervical tubercle, and winditiK to tlie back of the femur, becomes 
continuous with the inner hp of the linen aspera. on the posterior aspect of the 
shaft. The whole uf this ridge forms tlii^r spiral line of the feitmr, but the part 
iietwcen the cervical tubercle is often called the intertrochanteric line and the 
part immediately below tlie lesaer trochanter w termed rhe pectineal line. The 
superior and inferior tubercles receive the bands of the ilio-femoral thickening of 
the capsule of the hip-joint. The posterior BUrface of the neck is smooth and concave 
and its inner two-thirds is enclosed in tho capsule of the hip-joint. The superior 
border of the neck, perforated by large nutrient foramina, ih short and thick, and 
runs doft-nwards to the great trochanter. The inferior border, longer and narrower 
than the superior, curv-es downwards t-o tenninaie at the small trochanter. 

The trochanters are ttie prominvnceii which aQ'ord attachment to the rotator 
muscles of the thijih; they are two in nuniVjer — great and small. 

The great trochanter is a thick, quadrilateral process sunnounting rhe junrtion 
of the neck with the shaft, and pre-sents for examination two surfaces and four 
borders The external surface is broad, rough, and continuous with the outer 
surface of the shaft. It is marked by a diagonal ridge i-unning from the postero- 
Buperior to Ihe autero-inferior angle, which receives Ihe insertion of the ffluUia 
medius. The ridge divides the surface into two triangular areas: an upper, covered 
by the gluteus merlins, and occasionally seimrated from it> by a bursa, and a lower, 
covered by a bursa to pennit the free gliding of the tendon of the gluteus maximus. 
Of the inner surface the lower and anterior portion is joined wiih the rest of the 
bone; the upper and posterior portion is free, concave, and pre&enla a deep depres- 
sion, the trochanteric or digital fossa, wliich receives the temlon of Ihe ubUiralor 
txiernus. The fore |>art of the surface is marked by an impression for the attach- 
ment of the obturator mitrnus and two rjemrlli. Of the four hunlers, the su[)orior, 
thick and free, presents near the centre an oval mark for the insf-rtion of the pi'r^- 
formix; the anterior border, broad and irregular, receives the tjtuteus minimm; the 
posterior border, thick and rounded, i& continuous with the intertrochanteric 
crest, the prominent ridge uniting the two trtH-lumterti beliind. Above the centre 
of this line ia an elevation, temiod ilie tubercle of the quadratus, for the attach- 
ment of the upper part of the qxuiHr<ttu9 frmnris. The inferiftr bonier {-mTeeponds 
with the line of junction of the ba-^e of the trm-liaiiiter with the shaft; it is 
marked by a prominent ridge for the origin of the upper part of the vastus bieraltM 
(extcrnufi). * 

The small trochanter is a conical eminence projecting inwards from the poste- 
rior and inner aspect of the bone, where the neck is continuous with the shaft. Ita 
summit is rough and gives attachment to the tendon of the ili^y-fmoas. Tlie fibres 
of the iiiacus e-ttend beyond the small trochanter and are inserted into the surface 
of the .shaft immediately below. 

The body or shaft of the femur is almost cylindrical, but is slightly flattened in 
front and strengthened behind by a projecting longitudinal ridgp. the linea aspera, 
for the origin anri insertion of muscles. The linea aspera extends along the middle 
third of the shaft and present.^ an inner lip and an nuter lip sepamted by a narrow 
inten'al. When followed into the upp«T third of the shaft, the three parts diverge. 
Hie outer lip becomes contiiumtis with the gluteal tuberosity and ends at the base 
of the great trochanter. The ridge afford? attachment to the gluteus ma-rimus, and 
when ver\' prominent U termed (he third trochanter. The inner lip curves inwards 
below the small trochanter, where it is known as the linea pectinea, and becomes 
continuous with the spiral line; the inten-ening portion bifurcates and is continued 
upwards s\s two lines, one of which ends at the small trochanter, and receives some 
fibres of the Utaeus, whilst the other joins the tuWrcle of tlw quadratus. The 




ACUCTM aimcii 
AMiiMor iKsgunii 



IVTIIUUI OMM).! UIIItHU WUrVf 



176 



THE SKELETON 



latter is known as the linea quadrat! and gives attachment to the lower fibres of 
the qundralua fcrmaris. fl 

Towards the lower third of the shaft the inner and outer ]ip» of the linea aspera™ 
again diverge, and are prolonged to the condyles by the internal and external 
supra-condylar tines, enclosing between them u triangular surfaco of bone, the 
popliteal surface of the femur, wliich forms the upper part of the floor of the ]>npiiteal 
space. The external line is (he more prominent and terminates below in the outer 
opicondyle. The inner one is interrupted alx)ve, where the fernonil vessels are in 
relation with the bone, better marked below, where it (eruiinate^ in the adduc-, 
tor tubercle, a aniall sharp projection at the summit, of flie iiitenial epit^ondyle, 
which afforda attachment to the tendon 'if the adductor maijnus. 

Kear the centre of the linea aspera is the foramen for the medullar)- arter>*, 
dircpted upwards towards the head of the bone. 

To the inner lip of the Unea aspera and the lower part of the spiral line is attachod'] 
the vastus mediaiis (intenius),and totheouler lipand to l.lio outer side of the gluteal 
ridge is attached the vastus Uiteralis (externus). The adductor maffnua is attached 
to the inner Up of the linea aspera, tn the inner side of the gluteal ridge above, 

Fra. Ift4. — A Diagram to snow rnit Prrwcbk amo Tessios CpnvES or the Ftym. 




and to the internal supra-cundylar line l>elow. Ik'tween the adductor viagnus and 
vaatun medinlis (internas) four nuL'^flcM are attaehed : the prciTTieiis and itiacus above^ 
then the adductnr hrevis, and lowest of all, the adductor hnffus. Above, in the 
inter\'al l>etween the adductor mo^us ami the iyistu» lateralis (exlemus). the 
gluteus maximus is inserted; in the inter^'al lower donn is the short head of the 
triceps, taking origin from the lower two-thirds of the outer lip of the linea aspera 
and the upper two-thirds of the external supra -condylar line. On the popliteal 
surface of the bone, just above tlie ropdyles. are two rough areas from which fibres 
of the two heads of the gatlrocnemius lake orifiin. Above, the area lor the outw:! 
head of the gastrocnemius is a slight roughness for the plantarU. 

For purjKiseii of description it is convenient to reganl the slinfl of the femur asj 
presenting an anterior and two lateral surfaces, although definite borders ?eparati 
the surfaces fmm one another do not exist. All three surfaces are smooth anc 
uninterrupted by ridges of any kind. In the middle third of the shaft the two-- 
lateral surfaces approach one another behind, being separated by the linea aspera. 

The shaft is overlap|>wl on its iimcr side by the vastus medudis (intemus). and' 
on its outer side by the vastus lateralis (extemus). The upper three-fourths of theJ 



178 



THE SKELETON 



head of the tibia. The two cnndyies are continuotis in trnm, formicig a ^tinoolh 
troL-lilciir tnirfovc for urttculutioti with the patella. This stirfm^ presents a nirdlun 
vertical groove and two lateral convexities, tlio external of which ia wder, metre 
prominent, and proloriKed farther upwards. The patoJIar surface is faintly marked 
ofT from the tibial articular surfaces hy two irregular grooves, best seen while the 
lower end i-s still coated with cartilage. The external groove eonnncnces on the 
inner margin of i\u- external condyle near the front of the iiitereondylar fossa, and 
extends nbliquely forwards and outwards to tlie outer margin of the bone. The 
general direction of the internal groove i.s from front to haek, turning inwards in 
front and extending backwards as a faint ridge wWieh mark.-* off from the rest of 
the internal condyle a narrow yemilunar facet for articulation with the lotemal per- 

Fia. 19S.— Tub Lsrr Fkmuh at tub TwcvnuTii Yuau. (Posterior riaw.) 
Tho figure ahowH thf relations of the c^tiphymal aiid capsular lines. 



itruHt I* THi rmT, Mt nisti w nr. 

NIKtttENIH MM 



Unm WIUE FOURTlK, J«D UNimiltnif 
IISMTtUTM ItUI 



rut UdllTiUlM mH 



>■•• 



It 



\k\ 



' CajMular Ua* 



A 



A^i 



^l 



'liar an* 



imMS UMT m TH( ■mtn woktm or. 

WnU-lttUmE 11(1. AKtt UNITES AT 
THt TDOlIinM tun 



pcndicular faeet of tho patella in extreme flexion. The grooves receive the semilunar 
fibn»-eartiIagos in the extended position of tlip joint. Tlie tibial fiurfaees are almost 
parallel oxoept in front, where the internal turns outwards to become contitiuousj 
with the patellar surface. 

Tlie opposed surfaces of the two condyles form the lateral b«5undaries of the' 
intercondylar fossa and give attachment to the crucial ligaments which arc lodged 
within it. The posterior crucial ligament is attached to the fore part of the cmter 
surface of the internal eondyle and the anterior rrurial ligament to the back part 
of the inner surface of the external condyle. The two remDinintr lateral surfaces ^ 
of the condyles are broad and wmvex. and each presents a tuberosity for the attach- W 
ment of lateral ligaments. The internal tuberosity, the larger of the two, is sur- 
mounted by the adductor tubercle, behind which is an impression for the Inner. 



A 



THE PATELLA 



17D 



of the (jtiatrocncmius on tlie upper aspect of the condyle; below and behind 
the external tuberosity is a deep groove which roceivca the tendon of ihc poplUeuit 
muscle when the knee is flexed, and its anterior end terminates in a pit from which 
the leiKlon takes origin. Above the out<er tuberosity is a rough iuipresslon for 
the external head of the ftattrocntmius. 

The interior of the shaft of the femur is hollowed out by n large medullary canal, and iJie 
GxtromitJeB are compoaed of cancellated tuwue inveeled by a t}iin iximpaut layer, llie arrongc- 
mcnl of th* cancf-lh in the Upjier ernl of the Iioiii* fi)mM a Rood ilhutraliun of Utv ctttrt-l pmil[ic«d 
by the nieohaaicnl conditions to which boneit are nubjecl. In the up|Kr end of the buiK' llie 
cancetluus U&iiie U arranged tn divergont curven. Oiin KyKteni springs from the lower pnri of 
the nock and )ip]>cr t-iid nf the tthaft int«riiiilly niid spn-jiilH inCn the greut Irot'liacitiTr ('ptrsuiiiitt 
liuuellie'). A »e«.-oii(l nynlein ffprio^ fruiu the outer part ol' th« siiult and arebi-s uunuj-d& into 
the neck and head ('tentiion Uinellii!',), croBRing live fomier alnicvtl at. right iingloB. A wcond utt 
of proMiirt! lainelbe Kprm^ fnini tiat Inwnr thick wall ol tlic nt-rk. nnd pxlrndo into the upper 
part uf the bead to end perpendicularly in the articular tturlncc muiiily aluui; the line^ of ereutwt 
prei&siirG. A nearly vertical pLn.t.c of compact ticsuc (calcAr femoralei projectA intn tne neck 
of the bone from (lie inferior cervical luhen'ie toward* the great t roclijui ler. This is placed tn 
the line through which the weight of the body falls, and itddii to the clability of the nnck of iJie 
bone; it ij* said to be liable to ab!Mir])lioii in old ago. In the lower end of the bone the wrtical 
and liorixontui fibreet are »o di^pofted an to fonii a rectaniiular ineHhHtirk. 

'ITie head and npck of the femur roepive bmncliwi frmn the inferior gluteal, obnirnior, and 
circuuiflifx arterita, and the I nicliant^^.% fniiri the cirfuinflex arteriw. Tin- iintri^^rit vt-iwel of 
the fhafl i» dcrixtd from either ttie itecoud or third |)erforuiinR artery, tuid thow of the inferior 
extrcmityfrotn the rtrlieuhir branchfs^ of the popliteal (vnd the ana-ttomntir branch of Ihc femoral, 

Ossincalion. — Hio fvtiiur in oxnitied fnxn one printiiry centre fur the iihaft and (mm fnur 
epiphysial ccntrcK. The ohuft bcgin-t lo oxiufy in the sovdnth week of icitru -uterine life. Early 
in the iiinrh month n uucleiin appears for llie lower extremity. During the first year the nucleuii 
for the head yf Uie Ijoae iit visible, and in the fourth ^i-ar llmt f(ir the graal trochanter. Hie 
contra for tho small trochanter appeant about the tlurteciilh or fourteenth year. The xmalt 
Irochaiilcr joins the shaft «t the seventeenth, the great trocliimter «t the cighteenlh. ihc head 
about the nineteenth, nnd the lower extremity at tho twentieth ynar. 

Tim neck of the femur ia an apophysis, or outgrowth fruin tliu Hhuft, The line of fwnoa of 
the condylar epiphyKi!> with the shaft pasaon throiigli the adductor tubercle. 

Tbe morphoiDgicid relation of the patellar facut to the tibial portione of tho condyles is worthy 
of notice. In a few matnmals, euch as the ox, this facet remaina itoparated from the condyles 
by a furrow of rough \ione. 

'ITie angle which the neck of the femur forms with the shaft at birth moasuree, on an avertige, 
IftO". In the adult it varies from 110° to HO'; honee the angtc decreaseo greally during the 
[wriwd of growth. When ouce growth in completed, the angle, aa a rule, remaina fixed, 
(.Humphry.) 

THE. PATKLLA 

Tlie patella or knee-pan, situated in front of the knee-joiot, is a sesamoid bone, 
trianguJar in f-hape. tieveloijet! in the Iwidon of the quadriceps Jemoris. Its ante- 
rior surface, nmrkixi by numerous longitudinal stria;, i.s slightly convex, and 



ViQ. 1B9.— The Left Patrw^. 



AaMriOT anrrwc 



PM(«rl»r •urftM 

OTtiuu HTieuiiii tisn 




torn 




nTEnm 

Miicuum 

HOII 



tllEMt 



luin 
psun* 



perforated by small openings which transmit nutrient vessels to the interior of 
the bone. It is covered in the recent state by a few fibres prolonged from the com- 
mon tendon of insertion (supra-pateUar tendcm) of the quadriceps fetnoris, into the 



IRO 



THE SKELETOS 



ligamentuni patelUe (infra-patellar tendon), and is separated from the skin by onej 
or more bursx. Tlie posterior surface is iaruely articulKr, covered with curtilage 
in tbc recMil state, imd divided by a slightly miirked vertical ridge, corresponding j 
\Ai the groove on the trnelilcflr surfacr of the femur, into an outer larger portion 
for the externa! condyle, and an inner smaller portion for the internal condyle. 
CloRc to the inner ediKc a faint vertical rid^te sometimes marks off a narrow articular 
facet, for the outer margin of the internal condyle of the femur in extreme Hexioii 
of the ieg. Itelow the ariieular surface is a niuyli. iioii-articular depresssion. giving 
Bttuchment to the ligamentuni putelLtc, and separated by a moss of fat from the 
head of the tibia. 

The superior borderer base is broad, sloped from behind downwards and for-i 
waxds, and afluniti altacluneut, except oear tlie posterior margiii, to the commoa; 



Fm. 200. — The Siipcrior Dordbb or Hasb of the Left Patella. 

Mruion guHrHoE 



JLna la r«l«ilOD ulin arnOTial 
BanbTKii* of kua*-}DtM 




ArM.roF iBB^rtloa of tti« quulrlMpa 
ulaoaor cruru 



tendon of the qundricrpn. The lateral borders, thinner tlmn the base, converge to 
the apex Mow, and receive pnrts uf the two vusti muscles. The apex forms a blunt 
point directed downwards, and gives attachment to tJie ligaiiientmn jwtella;. by 
which the patella is attached to the tibia. Simcuirnlly the patella consists nf 
dense cancellous tis-^ue eovered by a thin compact layer, and ii. recoivcs nutrient 
vessels from the articular branch of the suprcma genu (anast-fjmotie), the anterior'] 
tibial recurrent, and the inferior articular brnm-hes of the popliteal. 

Ossification, — The carlilaKinoiu depotiit in the tendon of the quatiricfps muscle tAktv placai 
in tlio fourth munlh of mtra-u(«rii]e life. Owilicatioti twRins from a single centre duriog tiie] 
third ynar. and u completed sbnul the age of puberty. 



Tin-: TiBL\ 

The tibia or shin-bone is situateil at the fnmt and inner side of the leg ant 
nearly parallel with the fibula. Excepting the fcnmr, it i.s the largest bone in the 
skeleton, and alone tnitismit« the weight of the trunk in the f<H)t. It nrticulatea 
above with the femur, below viixh the tarsus, and laterally with the fibula. It is 
divisible into two extremities and a shaft. 

The upper extremity or bead consists of two lateral eminences, or condyles. 
The superior surf:uiw receive tlie cnmlyles of the femur, the articular parts 
being sepanited in- a non-articular inlenal, to which ligaments are attached. 
Tlie internal articular surface is oval in slmpe and eonenve for the inter- 
nal condyle of the femur. The external articular surface !.'• smaller, si>mewhat 
circular in sha[>e, and pret^nt!^ an almost plnne surface for the external condyle. 
The peripheral portion of each articular surface is overlaid by a fibro-cartilaginous 
[uenisctis of semilunar gliape, cotmected with the margins of iJic condyles by 
bands of fibrous tissue termed coronary ligaments. Efich seniilunar menJJHius i 
attached finnly to the rough intej\'al eeparating the articular surfaces. This interval 
IB bmad and depne-tsed in front, where it affords attachment to the anterior ex-; 
tremities of the internal and external menisci and the anti-rinr crucial ligamerit: 
elevated in the middle to form the intercondyloid eminence or spine of the tibia, 
a prominent eminence, presenting at it;; summit two com})n'S.sf;d tubercles, on to 
which the comlylar articular surfaces are proUmgetl; the puKterior aspect of the 
base nf the eminence affords attachment to the posterior extremities of the external 
and internal semilunar meni.ici, and limits a deep notch, inclined towards the inner, 
condyle, knonD as the posterior intercondyloid or popliteal notch. It separateai 
the coadyiee on the posterior aspect of the ttead and gives attachment to the post»-. 



I 



THE TlIifA 



181 



rior crucial ligament, and part of the posterior ligament of the knee-joint, .inte- 
riorly, the two condyles are confiuent, and form a somewhat fiuiteiietl gurla<w of 
triangular cutliiu;, ilie a[K?x of which fonns the tuberoBity of the tlNia. The tulier- 
osity is divisible iiilo two parts. The upper part, roimded and smooili, rocnvcs the 
attachment of iho lipamrntuin patella?. Ihp lower part is rough, and into its 
lateral edges prolongations of the ligamentum patellae are inserted. A prominent 
bursa intervenes between tUc- ligiunent and the anterior asj^ect of the head o£ the 
bone. Laterally, tlie iimer condyle is less prominent though more extensive than 
tlie outer, and near the pofiterior |>art <if ilw rircuinfercnce is a deep horizontal 
groove for the attachment of the centnil portion of the suniimembranmus tendon. 
The margins of this groove, and the surface of bone below, give attJichnient to the 
tibial (internal) lateral ligament of the knee. On the under aapett of the outer 
condyle is a rounded articular facet for the head of the fibula, flat and nearly circu- 
lar in outline, directed downwards, backwards, and outwards. The circumfcience 
(if the facet is rough and givt« altuchnieiit to the ligaments of the suiH.>rior tibio- 
fibular joint, while above and in front of tlie (arat, at the junction of the anterior 
anil outer surfaces of the condyle, is a ridge for the ilio-tibial band. A slip from 
the tendon of the bireps and parts of the ertensor Inngus fiitptorum and perotrnts 
loHtfus muscles ore attached to llie head below the ilio-tibial band. 

The shaft of the tibia, thick and prismatic above, becomes thinner as it de- 
scends for aboui two-thinis of its length, and then gnulually expands towards ita 
lower extremity. U presents for examination three bonlers and three surfaces. 
The anterior border is very prominent and known as the anterior crest of the 
tibia. It commences above on the outer edge of the tuberosity and terminates 
below at the anterior margin of the internal malleolus. It runs a somewiuit .sinuous 
Course, and gives attachment to the deep fascia of the leg. The internal border 
extends from the back of the internal condyle to the posterior margin of the internal 
malleolas. and affords attarhment above, for about three inches, to the tibial (inter- 
nal) lateral ligament of the knee-joint, and in the middle third, t-o the soleits. The 
external or interosseous border, thin and prominent, gives attachment to the in- 
IcTOsseous membrane. It commences in front of the fibular facet, on the upper 
e.xlreniity, and towards its termination bifurcates to enclose a triangular area for the 
attaclunent of the interosseous ligament' uniting the lower ends of the tibia and 
fibula. 

The internal surface is bounded by the internal border and the crest; it is 
broaf] above, where it receives the insertions of the sartorius, gracilis, and semitcndin- 
onus; convex and subcutaneous in the remainder of ii.^ extent. The external 
surface Ues between the crest of the tibia and the interosseous border. The upper 
two-thirds presents a httllow (or the origin of the tibialis anterior; the rest of the 
surface is convex and covered b}' the extensor tendons and the anterior tibial veesels. 
The posterior surface is limited by the interosseous ridge and the internal bonier. 
The upper part is cnwsed obliquely by a rough popliteal line, extending from the 
fibular fa<.-et on the outer condyle (tuberosity) to the iiiienial border, a little above 
the middle of the bone. Thepopliteal line gives origin to the eoleus and attachment 
to the ])opliteal fascia, while the triangular surface above is occupied by the jmfii- 
teus muscle. Descending along the posterior surface from near the middle of the 
popliteal line is a vertical ridge, well marked at its commencement, but gradually 
becoming indistinct below. The portion of the surface betT^"een the ridge ana 
the Internal border gives origin to the /texcr ditfitontm lontfus; the outer and 
narrower part, between the ridge and the intenwseous border, to fibres of the 
tibialia poalerwr. The lower third of the posterior surface is coverr-<l by fle.xor tendons 
and the posterior tibial vessels. Immediately l>eIow the [Htpliteal line and near the 
interosseous border is the large medullary foramen directc<l obliquely downwards. 

The lower extremity, much smaller th.in the upper, is quadriLiteral in shape 
and presents a stning procew called the internal malleolus, projecting downwards 
from its inner side. The anterior surface of the lower extremity is smooth and 
rounde<i above, where it is covered by the extensor tendons, rough and depressed 
below for the attachment of the anterior ligament of the ankle-joint. It sometimes 
bears a facet for articulation with the neck of the talus (astrogalus). (A. Thomson.) 
The posterior surface is rough and is marked by two gnxives. The inner and deeper 
of the two encroaches on the malleolus, and receives the tendons of the tibi/itis 
posterior and tiexvr ditjitorum longus; the outer, very sliallow and sometimes india- 



frnni of and behind the trian^lar surface afTord attaclunent (o the anterior and 
[K)st«rior ligaments of tbe inferior tibio-fibular articulation. The internal surface, 

Fm. :i02.— TuELBrrTiHiA axo Fibula. [Poatoior view.) 

BsMnial iMiilaea* 

Capvnla 

Toaurtae orDoUl lUkmaul 

Art! 

PMUin«r UbM-SMaar llgaaMI 



TlbUUa paai*n«r 



Vtosar lialliick Ipocbb 



runm iuiiF«c( X niDu 



NVTMINr fDMHU 



ParMMOa bMVU 




iMUnor IINo-ffMllM ItfMMM 

■mm FM ruxM MuuM iMmii 

roatorUn Mto-lMUr UflWMM 

OUoHtM-aiiuUr m»m«M 



pmloiifwi (lownvvarda on thft internal mallcolufl, is rough, convex, and subcvita- 
ne«nis. The outer surface of this process w .smooth and articulutts with the facet 



184 



THE SKELETOS 



un ihe inner side of the talus (astragalus). Its lower border is nolcUetl, nnd from 
the notch, as well as froni the tip ami »riterii)r Ixmlei', the fibres of ihc internal 
Ifiteral ligament of the ankle-joint descend. The inferior or tcnninal surface, by 
wliich the tihia articulates with the tfllus, is of quadrilateral form, concave from 
before backuanls wider in front than behin<l, ami externally than jnteroally, 
where it is continuous with the outer surface of the malleolus. 

The tibia i.s a very vascular bone. The nutrient artery of the shaft is furnished 
by the ptwteri()r tibial, and is tlie largest of its kind in the l)ody. The head of the 
hone receives numerous branches from the Inferior articular arteirics of the popliteal 

Fl<>. 303. — Xrk Tibia aMd Firui^a at tmk Sixtkkxth Year, 
The figure showti tlw relntiona of t be epiphysial und copisulurUaeB. 



■-VJ! 



n 



-Capmil* 

.«mm IT smrH : tiiiimM nnrY-Biitt but 

yNIQN IS MlliniUEi DIUTEO TO mUTT-nVE 

_ IMUn tT KHt 'OURTH YUN; UMITIl *t 
r«t«IT-fCVR 



ttKua AT lEooitD run. vvitei «i tn( 

ligVftlENTN TU* 
-Capnila 

^WfaW AT iwr I10CHOm!l:»l(ITtl*T 

rwHin 



and the recurrent branches of the anterior and poslerior tibial. The lower extrCTnity 
receives twigs from the pctslerior and anterior tibial, the anterior ijeroneal. anH., 
inl^riial uialleolar arteries. 

Ossificiitlon. — 11ic tibia ii^ o>«ifi«d fmm one principal rpntra for thr .ihnft, which appeBnj 
In ttie ciiflilli wrck of intra-wtcrinp lifp, and two i')iinli>-M-» Ifw: conln-s for whicli appear Ul thftj 
i-iirtiluKitxxH hi-nil of tbi- iwnp lowardu (lie pnd of iFio 'ninth inonll), and in llio \fivfvr ©xirwnity 
liuriiix the M'ltjiid jfar. Th« lalicr unilM with the .-tliftft m rightocn. but the iinion of X\\t: head 
with tlii- thnfr. doc- net inkp p!a« until the t»enty-fir»t ji-nr, *nd it mny rvon be deUypd imtil 
Iwi-nty-fiviv llift iinppr p^rt i.f (lie tubercle of the tibia is u»yificd fmin tUo upper epiphywin, 
nud ilic> ]iiwi>r piift irum Lho diaphy^. 



THE FIBVLA 



185 



THE FIBULA 

The fibula is situatwl on iIh" outer side of the !pp and, in proportion to its length 
is the mn?t slender of nil the loiij; bones. It is placed nearly parallel to the tibia 
with uliich it is connected above mid l>elo\v. In man it is m rudiment Jtr>' Iwne 
and bears none of the weight of the trunk, but is retained on account of the muscles 
to which it gives origin and lt£ jporticipation in the formation of the unkle-Joiat. 
Like other lon(: bones, it is divJRible into a alinft and two extremities. 

The upper extremity, or head, is n rounded pronunenec. Its upper surface 
presents externally a rough eminence for the attiiehment of the biceps tendon and 
the fibular (lon^ exteroat) lateral ligament of tho knee-joint ; internally it presents 
a round or oval facet, directed upwards, for\vards, and inwards, for articulation 
with the outer condyle (tuberosity) of the tibia. The margin of the facet gives attach- 
ment to the arlifuhir i'a|>sule of llie su[)eriur tibiti-filjuhir articulation, rosleriorly, 
the head rises into a pointed apex or styloid process, which affords attachment 
to the short external lateral ligament of the knee-joint, and on the outer side, to part 
of the hu:€f39 tendon. The posterior aspect of the head gives attachment to th© 
zoleus, the outer aspect extending also ijx front of the eminence for the biceps, to 
the peroneus Utngtts: from the anterior aspect fihro: of the txtemor digitonim lon- 
gu» arise, whilst the inner 8i<le lies adjacent to the tibia. 

Fio. 204.— Thb UfeER E.VD or nii: Lkpt Fibula to snow Mdscl-i,ar and Liuauentoud 

Attai'iimbvts X 2. (O. J. Jealtins.) 



Aaiertor aiiiMttor UM<KMbaI«r 



nnulsr teuval IvuMQi - 



(HtTIMTIBU 



BUWpa. 



■ unuitoitur(ii>MTiBii>.ri!iuuit,ia<iir 



smoio mooEsa ' 



■hon osumal 



ra«l«nor*up«rlor IIUo- 



The shaft of the fibula, in its upper lliree- fourths, is quadrangular, poBseB^ng 
four l>order3 and four surfaces, whereas its lower fourth is flattened fnim side to side, 
so as to tie somewhat triangular. The aster o-exte mat border commences in front 
of the head and terminates below by di\'iding to enclone a subcutaneous surface, 
triangular in shape, immediately above the external malleolus. It gives attachment 
to a septum separating the cxtf-nsor muscles in front from the pcronei muscles on 
the outer siile. The an tero- interna I border or interosseous ridge, so named 
from giving altarhment to the intoms.'ieous membrane, also commences in front of 
the hoAd, eloiie to the antero-extomal border, and tenninates below by dividing 
to enclose a rough triangular area immediately alxive the facet for the talus Uisira- 
po/iu); this area gi^'es attachment to the inferior interosseous ligament, an^rl may 
present at its lower end a narrow facet for articulation with the tibia. The po»- 
tero-intemal border, sometime^t descriljod as the oblique tine of the fibula, com- 
mences at the inner side of the bead and tenninates Ijelow by joining the antcro- 
internal border, in the lower fourth, of the fdiaft. It gives attachment loan 
aponeurosis separating the tthiah'n poslen'or fn«n the soUna and flexor halhcia hn- 
ffm. The postero-external border luns from the back of the hcKl to the inner 
Iwrder of the penmeiil ctoovb on (lie back >if the lower exlreniity; it gives attach- 
ment to the fascia separatinc the jjcronei from the (lexor muscles. 

Tlie anterior or extensor surface i.s the interval between the antero-intemal 
and antcro-extcrual borders. In tlic uj^per third it is extremely narrow, but broadens 



18G 



THE SKELETON 



out below, where it is slightly grooved lonfritudinally. h aftonis origin to three 
muscirs: cxhTimlly, in the upper two-thirds lo xhe cilenBor digitorumlotiyufi, and. in 
the lower third, to the ptronrun tirtiiis ; inl<TniiHy, In lUtt middle thirfi, tn the extensor 
luxUucia longus. The internal surface, situated between the antem-intemfll and 
pastwo-intenial borders, is iiarnnv abuve and below, and broadfHt in the middle. 
It is griiiivwl and jionictmics i-rossed obliquely by a prominent ridye, the secondary 
oblique line uf llie (ibula; ihe surfacf givei* iiUJu-lunent to the tibUilis jM'stvruir iind 
ihc nii;^f to a tcndinons soptmn in the gubstance nf the naiwle. The posterior 
surface in the interval between tlie jinjitciii-inlcniai ami poslero-extenial borders, 
and is somewhat twisted so as lo look backwards abnvp and inwimls iwlow. It 
iserves, in its upjjer third, for the altMuhnient of thesciir-iis, and in it^ lower two-thirds 
for ihe jiexor haiiucis lomjus. Near the middle of the surface is the niwiulhiry fora- 
men, dijtu'leil downwarda towards lIic ankli;. The external surface, situated 
between the nnteni-extermil and ptigtero-external boiiiers. h* alsoHomewhat t«iHl«cl, 
looking outwards above and backwards below, where it is continuous with the 
groove on the back nf the exiemal mallenlns. The surface is often deeply prooved 
and l< (Kcupied by (he peroueus hngus in the upper two-thirds and by the jio-oncus 
brevis in the lower tvvt>-third5. 

The lower extremity ur external malleolus iii pyranudal in form, somcivhat 
flattened from side w side, and jitined by its base to the shaft. U \i^ hmger, more 
prominent, and descends lower than the internal mnlleolus. Its outer surfaec is 
convex, subcutaneous, and continuous with the triangular subfutanpoiw surface on 
the shaft, unmediately above. Tlie inner surface is divided, into an anterior and 
upper area, triangular in outline ami eonvex from above downwardft for articulation 
with the outer side of the tplUF (astragiilus). and a kjwer and jmeterior excavated 
area, llie digital fossa, in whieli are attaehrd the tninsverse inferior tibro-fihular 
lieainent and the posterior talo-fibulnr (posterior fiLsciculus of Ihe external laterul) 
ligament of the ankle. Tlie anterior border is rough and gives attachment to the 
anterior tfllo-fibular (anterior (ascieuhisof thee.vtemal laleral) ligament of the ankle, 
and the anterior inferior tibio-fibuiar ligament. The J)u.'^teri^)^ border is grooved 
for the pcronei tendons, and near its upper part gives attachment to the posterior 
inferior tlbio-fibular ligament. The tipex or summit of (he process affonl-i att**h- 
nient to the calcaneo-fibular (middle fasciculus of the external lateral) ligament of 
the ankJe. 

The shaft nf the fibula receives its nutrient artery from the peroneal branch of 
the posturittr tibial. The head is nnurislKKl by brunches fnmi the inferior external 
articular bnmcb of the popliteal artery, and the external mnlieolus is supphe*i 
mainly by the peroneal, and its perforating and extenia! malleolar branrhe-n. 

Ossilicatioa. — The ahaft nf the fibula rommflnrrs to oMify in tlifi riittitli wrt>k of intra- 
uterint? life A nucleua appenr* for the lowtr extremity in tlie AetniKl yt-nr, :ii»l orn- in tlif upper 
extremity duriiiB the fouith or lif til ye«r. Tlie lower extremity ftidcswilh the tiliult iilxiut twenty, 
but thouiipnrcxtrvniity remains (wptiraifl until the iwrnty-RWrtndyfnr fir even laHr. 

it is intcrestiiiK, i" i-oiineclioi> with tlif lirin^^ of iipivii ranee >.•[ Ibe t>vy **pipliy»«< of tlie 
Hbula. lo note that the as.iifira1i<Mi of the lower opiphy.iin in (vmlniry to rhc genernl rulc--rii., 
that the epiphysis t-owiirtlB wfiirh the nutrient arten- i- din-f-ted w llichi!>t lo undergo oswifiration. 
ThU is explained by the rudiinetitar>' nature of the upper oxtrVEujly. In birdii lao head of tbe 
boae is large and enters in to tbi- (omiation of thekTi'^^y-joinl. 

The humatt fibula ia dmrncleri-ied by Ihe lenxtli ni il.^ itialleohn, for in no other vertebrate 
does this procees descend so far below the level of the tibial niidleutus. On the other hand, in 
the inajonty of manimaU iJie tibial dpincend..! to a tower trvd than The fibular oialleoltLs. In 
the human embryo ol the third niduth, the oun-r (tit)ulari j- opi.-U in lenptli lo Die inner (tibia!) 
malleolus. At tbe fifth niMUlh tlie vxtcniul luulleulus vAcoeds tho intemal bv l-H tutd.; at birth, 
the fibular mallcoliw li Btill longer; and by tlio stcond jxar it assumes its udull prop*>rtion. 



4 



i 



I 



THfc; TAHSL'S 

Tlie tarsal bones arc groufHHl in two rows: — a proximal row, ronsistinji of the 
talus and calcaneus, ami a ilintal njw, consi^tint; of four hnnvt* which, enumerated 
from the inner or tibial side, are the first, second, and third cuneiform bones 
tmd the cuboid. Interposc<l betWTen the two rows on the inner side of the foot 
is a single bone, tbe oaTicul&r; on the outer aide the proxinial and distal rows eome 
into contact. 

Compared with the carpuj'. the tarsal bones present fewer common characters, 
and greater diversity of size and form, in consequence of the modifications for sup- 



THt: TARSUS 



189 



surfaces, the external i» almoitt rntirely occupied by a laiKe triaiiffular facet, broaU 
above, where it is continuous with the trochlea, concave from above downwards^ 
forarticuiatiouwith the fibular malleolus; on the internal surface is a pyrifomi facet 
continuous witli the troclilca. broad in fnmt and nnrn>w behind, which articu- 
lates with the tibial malleolu*;. 3elow this facet the inner surface is rough for the 
attachiueut uf the deep fibres of the deltoid ^ini-onial lateral) ligament of the ankle. 

Fro. 207. — Tbb Licrr Talcs. (rUtnlAr view.) 



- oMovi nit THi rLOOM NMJucii tooeui 



■ODt- 



nmciLUiiEn 



MIIM — 



. FD* THE lUSrUTtCULVH lAU 



HU9' 



-fDK T"! ttLUKIO-RlVIUU* an THt 



. FOA lAWOUlMI 



The posterior surface is of small extent and marked by a groove which lodges the 
te-ndnn of the /frror knlluct's hngnn. Routidiiif; (he gnwne on eitlier siile are 
two tuberclr.s. nf vvhirli the outer is uaually the more promiuent, for attaclunent of the 
posterior lalo-libularlijjament of the ankle-joint : the internal tubercle gives at tacluuent 
to the internal tah>-<'HlcaneaI ligament. Continuous with the anterior a.spect*u{ 
the body is the neck, a constricted part of the bone fiupporting the head. Above 
it \& rough, and perforated by nuinemus vascular foramina. lieluw, it presents 




Fia. 20S. — A Talcb wmr nm Os TRiaoNuM. 

01 iniGOHUII 




a deep groove, directed from behind forft-ards and riutwarda. Wlien the talus ts 
articulated with the calcaneus, this furrow is converted into a canal in which is 
lodged tlie interosseous talo-calc^aneal ligament. The head ia the roundfxl anterior 
end of the bone, and its largo artieular aurface is divisible inU> three parl-s: in front, 
a smooth, oval convex area, directed downwards and inwards, for the navicular 
bone; below, an eiooRated facet, convex from front lo back, for articulation with 
the suateulaculum tali of the calcaneus; and between these, below and internally, 



IIK) 



THE SKELETON 



ia a small fucct which rests on tlie ralcaneo-navimilar ligainont, separated from 
it hy the sj-nnvial mftnibrann of th*^ tiil(>-ciilc8neo-navicuIar jnint. 

Articulations.— The talus articulates with fnur hoin>,i jind two liffamenta. 
Above aiid intertially with the tibia, below with the calcaneus, in front with the 
navicular, externally with the Hbula. The ht-ad articulates with the calcaneo-navic- 
ular ligament and tlw outer border of the troehlear surface, at its himler jjart, 
with the transverse lipiniRMt u( the infori*»r libin-libular jnint. 

The taius is a verj- vascular Itoiie and is nourii^lied by the dorsalia pedis orteiy 
and its tarsal branch. It gives attachment to no musclea. 

Ottificatioa. — Tlie talus is oaiififtd Jrom one. oocaeionally (mm two. nui-ld. Tli* |iniit-i|ULl 
centre for this bone appears in tlie middle of the carliirtgiiiou* lalua at the aevemh iiittnth of 
intm-utcrine Hfo. The addiliunul eentro is dcpt'sitcd in lli« [loiitcrior porlion of the bono, and 
foriitN the nuU^r [xist^rior tubcrcio which may remain separate from the rest of the. b<iii«, 
and fiinii tht- o« triuonum. At hirlh. the talit* present* <mnw important peculiaritieH in the di»- 

Ivoitition of th« nnii'iilar facet oti the tibiiii sidf of its body, and in ibo oblifiiiity of iui nmlc. 
f, ill t\\f adult lalus, a Une be drawn through the middle of th<- trfKhkAi* aiirlai-e parallel witli 
it*t inru-r Ijurder, and a second line be drawn along the outer aifle of the neck of Ibe bone M as 
in intersect the fimt. the angle fonncd by these two lines will exprcaa the nbli*jmty of the neek 
of the bone. This in the adult varies preatly, but the avenige mny be taken as 10". In the 
foetai lit birth the unele averageH 3S", whitHt in a younR orant; it meaHureti 45°. In the iiunnol 
adult tatufl the arlieiilfir surface on the tibial .=ide is limited to the body of thft Imno. In the 
f(elal tahw it extends for Mirne distance on to (bn neck, and sometimcii reaclie« aliTiosl ax fur 
forwiml as the navicular facet on the heatl of the bone. Tliia dispoaiUon of tJie inner nialleoliiP 
facet ia a charftrreriatie fe.iture of the tahw in the rhimpanzep and the omnR. ft ia rehted Txt 
tlie inverted iKMition of the fiiot nhicb is found ill Ihchmiinn fci'tua ulmost up to the iieriod of 
birth, and is of intereet to the surgeon in coiuiection with some varietieaof club-foul. (Shattock 
and Parker.) 

The Ciix-.^NEis or Os Calcis 

The calcaneus is the Iar;gest and stronnest bone of the foot. It i3 of an elon- 
fjat«d fomi. flattened from side to side, and expanded at its posterior extremity, 
which project-s downwanls ami backwarrU to fonii the heel. 

The superior surface presetits iu llie uiidiUe a large, oval, convex, articular 
facet for the under aspect of the body uf the talus. In front uf the facet the bone 

Fio. 209. — TitE Left C.*LCA^■E^s. (florsal vievi.) 



imni TvtmciE 



OfeCyllUL MOO*! 



Iter rm THUS ON Tw 

SUttUT*OUUItf TUI 




HinTlLM 



KnoHtM Tusnoii 



is marked hy a deep deprewion, the floor of which is rough for the attachment 
of lipamentji. esiwcially the taltM-nlcanoiil , and the oriitin of the eitensor digitorum 
brcpis musrle; when the ealraneus and talus are articulate*!, this portion of the 
bone fomw the floctr of a cavity sometimes called the sinus pedis. Internally, 
the upper surface of the Ijone present* a well-marked proeess. the sustentaculum 



THE TARSUS 



191 



tali, fumishod with an clongntcd concavo facet, nccasinnully divkled into two, 
for artk'ulation with tlie under ii8i>e<rt. (if the liead of the 1*1113. The posterior 
part of the upper surracc is nun-nrticular. convex from side to side,iuid in relation 
with a mass nf fat plaeed in front of the tentSn Afhillis. 

The inferior surface is narrow, rough, urievi^n, and ends poat-eriorly in two 
tubercles: tlie inner is the larger am! i>r<^ader, the outer is narrower but prominent. 
The inner tubercle affortla ongin to the abdtictor hallucis. the flexor digiiorum l/rcvis, 
and the tUnIuettir dii/ili tiuinti; (he last itiuw^Ie also lu-iw-s imni the outer tubercle 
and from the ridge of bone between. The roufih surface in front of the tubercles 
gives altaehn lent to the loop plantar ligainenl (calcaneo-c-uboid) and the outer head 
of the (iuadmius planitr (flexor acfpssorius). Near its anterior end this surface 
forms a rounded eminence, the anterior tubercle, from which (as well as from 
the shallow groove in front) the plantar (short) calcanco-cuboid liKamenl arises. 

The external surface is brood, flat, and slightly convex. It presents near the 
middle a sniatj eminence for the calcaneo-fibular ligament of the ankle-joint. Bclnw 
and in front of this is a well-iimrkcd tul>errle — the peroneal tubercle— separating 
two grooves, the upper for the prroneiis brci>\a and the Inwor fnr the jtproneus lonrpts. 

The inner surface is deeply concave, the hollow being increased by the prominent 
Inner tubercle behind and the overhanging sustentaculum tali in front. The 
lauer forms a prominence of bone projecting hnrizonially inwanis, concave and 
articular above, grooved below for the tendon nf the fiexar haUiicis longus, and giving 
attachment to a slip of the tendon of the tibialis posterior, the inferior calcaneo- 
navicular ligament, and some fibres of the deltoid ligament of the aiikle-joiut. 

Flo. 2H). — Tfn Cklcaukva at tre Fjftebstii Ybah. showing the EvimraiB. 




«mMi kv INI tiHrM, M> umm it tni smaiN xta 

The hollow below the pmeesg receives the plantar vessels and nerves and its lower 
part gives attachment to the inner hcAci of the qiiadratua pfenffr (fJexoracoessorius). 

The anterior surface is somewhat quadrilateral in outline with rounded angles, 
and preMt•nt.■^ a sadiile-shu|>eii articular surface for the cuboid. 

The posterior surface is oval in shape, mugh.and convex. It is divided into 
three parts:— an U])!^^. smooth and separated by a bursa from the tendo .'\chilli.s: 
a middle part giving attachment to the teiulo AchiiU^ and the yUtutaris, and a lower 
part in relation to the skin and fat of the heel. The expanded puisterior extremity 
of the bone is known as the tuberosity. 

Articulations.— ^The ctJeaneus articulates with two bones, the talus above 
and the cuboid in front. 

The calcaneus is nourished by numerous branche.-* from the posterior tibial and 
the internal mvX external malleolar arterieis. They enter the bone chiefly on the 
inferior and internal surfaces. 

Ossification. — The ^n-imury nucleus appears in the sixth month of intnt-4it«rinp lit?. Ths 
cpiphwi.'t, for itA pn;<lfrinr exlnnnity, begins to be eieilied in tlie trnth year und is uimUhI to 
ln<i liibcnisity by tin- nistoMilh year. It iimy rxinid tiver 11)*^ wlmlc of the posterior surface, aa 
ehoHii ill list, 210. or yvcr tho lower two-thirdu tmly, loaviim a part alwve in relation to the tmr-ui 
bcncuth tlio tendd .\chillii*. which '\s formed Ironi llic primary nuoltiiis. The inner and outer 
tuborclm lire fumii-d hy i\wv\»\Aiy!nv., 



The NAnctTLAR 

The navicular nr scaphoid is ov.a] in shape, flattened from before backwanls. 
and 5ituiite<i between tiie talus behind and the three cuneiform bones in front- 



It is charact«rlaed by a lurge <iviii, concave, articular facet on the posterior surface,^ 
which n-ceivea the head of the Lulus: a broad, rou^h, I'uiJiKleJ eminence ou ihe 
internal surface, named the tuberosity of the navicular, the lower part of whichj 
projects downu-.ircU and gives att.irhment to the tendon nf the tibialiit posteriori 
aud an oblong-»thaj>cd anterior surface, convex und divided by [wo vertical ndg< 

Flo. 211. — Tac IvEFT Na^iculah. (Anterior view.) 



ran nni DUN&faHv 

LOERWWa 
TVttROim 




FOR tECDKO CVVE'CDPIH 

OUrER eORBER 
fO« IHIRS tLINtiraWI 



into three facets which articulate with the three cuneiform hones. The superiorl 
(dorsal) surface is rou^h, convex, and slopes downwaixls to the luberosUy; the 
inferior fpluntar) surface is irretrular and rough for the attHchment of the infcriar 
calcanco- navicular ligament, and the external surface is rough and sometit 
presents a small articular fiurfaee for the culjoid. 



Fio. 212.— Thk Left N'AvrccrtAH, showtkg a Facet ron xriE CrBOlD. 



m RRsi oatiBmu 



TuKRUrrr 




lox UMNC cuHfiroui 



ron TMiiw cuREirMiii 



Kill OVMID 



Articulations.— With the talus Ijeliind, with the Liu-eo cuneiform bones in 
and occasionajlv with the cuboid on il.s outer side. 



letimeafl 
1 front, I 



Ossification.— The rucIgui; for the nuviculiur appoare in the cmirsp of lh*» fourth jviir. The 
tuborositv of th« iia\-icuUr. into ivhich the ttttiaiu ponlrrior iicquires iU maiti tuaerli 
tdly develops separately, and raineCimes renittias iliHlmcL from lae rest of the hone. 



The CuNEiFORii Bones 



4 



Of the (hrce cimeiform bones, the first is the largest, the second i« the pnialle^t, 
and the thinl internie^liaie in size. They are wcdge-shai)ed Ikhics plarcd between 
the navicular and the ituier three metatarsal boties. Posteriorly, the ends of the 

Fro. 213. — TttB Lett FmsT CrxBTFonw. (Inlemal surfnoc.) 




ru nniT utTkiiitUL 



run fOR THE nspOM v tme mius MTiam ' 



bones lie m the same transverse line, but in front, the internal and external projeetj 
farther forward.s than the middle, and form the sides of a deep recess into which] 
the base of the second metatarsal bone is received. 



THE TARSUS 



193 



The first ur internal cuneifonn bone is distinguuihcd by its targe size and by 
the fort tlmt wlieD artirul»t4>d. the base af tlu* we<l>;e i.s <lirecterl downwards nnd tlie 
apex upwards. The posterior surface is concave fitid pyriform for ttrticulatioD 
with tlie mncr faeei on the anterior surface of tlie n»vicular. Tlie anterior surface 
forms a reniform articular facet for the base of the firat metatarsal. Tht- internal 
surface in rough, and presetiU an (ibli<{ue gnxive for (he lenilon of (he Hbutlin anU- 

Fhi. 214.— The Lcrr FtRST Ciinriform. (Extcmul nurfnce.) 



fw KoaNBumuiiM 



roK ntxM BiiNiirnty 



ron Nina I in 



nor: this graive is limited inferiorly by au oval facet into which a portion of the 
tendon m inserted. The external surface Is Doncave and present.'^ along its supe- 
rior and poflt^rior borriers a rc%'erftwi L-sliapeci facet for articulation with thfe aei'iind 
cuneiform, und. at its anterior extremity, with the seeomi metntarsal. In front 
of the facet a few fibres of the first dorsal interosseoua muscle arise, and in the re^ft 
of its extent it in n>Uf;h for ligament-s anil a slip of the tendon of the peroneuv longm. 

FlO. 215. — The L«pt Frcorm Ct-'NXIFObm. (Inlwnai aurfaoe.) 

■ ijR flRiT CumKOftU 
rOR 3E0DND HiT«rUSil 



The inferior surface is rough and presents a slight eminence behind for part of 
the tendon of the tibialia posterior. The superior surface in the narrow part of 
the wedge and i» direcl^tt upwards and mitwanlis. 

Articulations. — With the navicular lx>hind, second cuneiform and second meta- 
tarsal on its outer side, and first iiietatar)»al in fmnt. 

Ossification. — From a smglc oucleus wlucli appears in the course nf the third year. 
Pw, 210.— Tm« ban Skwnd Conbiform. (Exttmal surface.) 

-TOR nun ouimtmH 

^^ -MR MTIBILM 

aCCttlONll ticn fM TNKD CUMIFCIOII 



The second or middle cuneiform bone is placed with the broad extremity 
upwarrl» and the narrow end downwards, and is readily recognised hj* its nearly 
square base. The posterior surface, triangular and concave, articulates with the 
middle facet on the anterior surface of the navicular. The anterior surface* also 
triangular, but narrower than the posterior surface, artJeulutes with the base of 
the second nietntarvial. The internal surface has a reversed L-slitiped facet nin- 
ning along its superior and posterior margins for artieulation with the corresponding 
facet on the first cuneiform, and is rough elsewhere for the attachment of ligaments. 
13 



104 



THE SKELETO\' 



On the external suHace near iw posterior bonier is a vertical facet, sometimes 
bilobed, for the thini c'uneifomi, arij occusioaally a seeoriil facet, al the anterior 
inferior ande. The superior surface fomis the nquare-ciit l)aBe of the wedge and 
is rough for the attachment of ligament.'*. The inferior surface is sharp and rough 
for ligamcntH ajul a Hlip of the tendon of thfl tihudin poatrrior. 

Articulations.— With the naviculnr behind, jiecmid metalarwul in front, third 
cuneifonn on the outer side, and first cuneiform on the inner side. 

OssificalioQ. — FVum n nu%i» nucleus which appear* in thv fourth >x-ar. 



Fia. 217.— The Left TmBC CnNSiroRM. (Int«ni»l surface.) 



nM itooM ovMoraiiy 



m uviauu* 




r04l lECOMO UETITtRUL THE CIRCVU* tlXt 
RU^f >^t mtllliim UtU II lOM IHl KCMS 
CUNEIfQHH 



The third or external cuneifonn bone, also placed with the broad end direeted 
upwards and the narrow end downwards, is dUtinguii^hed by the oblong sliape 
of its base. Like the second cuneifonn, the posterior surface presenta a triangular 
facet for the naviLular; and the anterior surface a triangular facet, longer and 
narrower, for the thini uietatanial. The internal surface hjis a largt* facet ex- 
tending along the posterior border for the second ctnieifonii, ami nloiij; the anterior 
border a narrow irre^ilar facet fnr the outer side of the base of the second meta- 
taraal. Occasionally, a small facet is present near the anterior inferior angle for 
the second cuneiform. The external surface has a large distinctive facet near 



Pto. 218.— Tub Lbft Tubd Cu.vciroR>i. (ExtemiU Hurfaoe.) 



FOR rouiiTH wn>nn»tL 
FOR nm utTtunui. 




rDR QUIUO 



ita posterior superior angle for the culioid, and at the anterior superior angle there la 
usually a wnall facet for the inner side of the base of the fourth metatarsal. The 
superior surface, oblong in.ihapc, is rough for ligaments, an<l the inferior, forming a 
rounded man^in, nnreivt's a slip of t-iie (ihialis yjfwfmiw and gives origin tu a few fibree 
nf ihv flexor httllucis brevig. 

Articulations. — With the navicular Itehiml, third metatarsal in front, cuboid 
and fourth metatarsal on the outer side, second cuneiform and second metatarsal 
on the inner side. 

OMiRcation. — A siugle ouclt us appeal* tn the coiuw of the first year. 



The Cuboid 

The cuboid, irregularly cubical in shape, is placed on the outer side of the foot, 
forming a continuous line with the calcaneus and the fourth and fifth mctatareals. 
The posterior surface is somewhat quadrangular witli roundod angles and presents 
a saddhsi^h.'^itetl articular surface for the calcaneus. Its lotv-er and inner angle is 
fWMnewhat prolonged Iwickwards Ixmc'tith the sustentaculum tali (calcaneal process 
of the culjoid), an arrangement to oppose the upward or outwiird movement of the 
bone. Thia p^nce^^s occai<i<malIy tenninates in a rounded facet which plays on 
the liemi of llu! talus external to the facet for the calcanco-naviculur ligament. 
The anterior surface la mnoller and divided by a veriical ridge into two ariicular 
facets, an outer for the base of the fifth, and ati inner for llie blue of the fourth 



THE TARSUS 



195 



metatarsal. The superior surface is rough, non-ftrticulftr. and directed obliqud,v 
upwunls and outward?. The inferior surface presents a prumiaent ridge for 
the attachment of Uie long plantar (cakaneo-culjoid) ligament, in front of which 
is a deep groove — the peroneal groove — running obliquely fnrwards and inwimJa 
and lodpinp the tendon of the j>cronewi longus. The ridye lerminates extemallv 
in an ftniinence, the tuberosity of the cuboid, on wlUfh there i.s usually a fseet 
for a sesnmoid bone of the iciwUm contained in the (iroove. The part of the suri'aco 
behind Ihe ridge is roii^h for the attachment of the plantar (short) calcaneo-t-ulioid 
ligament, a slip of the tibialis jxtsterior. anti a few lil^rea of the Jfexor haUuds brevis. 

The internal surface presents, near its middle and u])[Kt |>art, an ;ovaI facet for 
articulation with the third cuneiform Iwne (lig. 21l>); hehind this, a .<iecoml facet 
for the rmvicular Is frequently seen (fig. 220). Gencrnlly the two facets are con- 
fluent and then form an elliptical surface {fig. 221). The remainder of tlie internal 
surface is rough for the attachment of stron;! interosseous ligaments. 

Tlie external surface, the smallest and narrowest of all the surfaces, presents 
a deep notch which leads into the peroneal groove. 

Fio. 219.— The Lkft Cuboid. (Inner vnew.l 



m niiw ctRiiiMM 



. n» FOUKTM MniTUSK 



IKmi 'OR iMBOH CF The 



■ 'Im 



Fro. 220.— The Lerr Cvboid. (Inner view.) 



ni THIRD CUKEIfONH 

fOR UltHIIEi.'S 

rot MUICULM (OCUtiOMU) 



\^^ 



akxm nt tirkn of m peuiiui kOHeut 



Fio. 221. — The I.Brr Cuwit). (Inner view.) 



MM Thmd cuoenini 




Articulations. — With the calcaneus Ijeliind, fourth and fifth metatarsals in 
frfjnt. IhirU cuneifonn and frequently the navicular internally; occasionally also 
the taluE. 

O«tific«tton,— The cuboid fa ouified from a single niicleux which nnpearfi aboat tho timv 
of binh. 

Accessory Tarsal Elements. — As in t)iP carpus, a numlier of udditional vlements maj 
occur in (hotar^ua. 1'hr moMi frequent of Ihrm \n the ot nigonum, vhich hui; already Iveo 
ootioed. Nexi in frei|UBncy w an additinniil firwt rinn'ifonn, n«ii1Iiiift from the OK^idcntian of 
til* plantar h;ilf of that 1>one indeponiimtly of tin; durvul luilf, tm llin( tlie botw in reprcjwntwl 
by a plantar and a clnnuil firwt cuneiform. OiIht additional HmicntA may occasiuutiUy oruur 
at the upper posterior ungle of \\\r »uM*-til.-irnlurrt l.ili; nt th«> iiiitfirior sii)i«'nor an|jlo of Ihe enl- 
caneua. Iwtww*ii thai bone nnd ihc n.ivicular; in llie angle bvlTC«;n tin; iirwt cuiiedomi and Xh* 
first and fiwond mctatiinuiU: nnd in the fibular angle between the fifth tnetatanul and tlio cuboid 
(OS Vesaltanumt. 

Th* fibular p<jrtion of (he navicular is wmetimcs united to the <rub«id and quit** separat« 
ftnm t)ie rest of the nnviculnr. the cuboid in .luih rnw.i articulating iiiith the taUi>4, Thi.H rnn- 
ditinn KUggrnlM Mi«- n-cocoition of lK4> liliiil»r |>i>rliori of tl>r nnvirular mt a distinct tircc>Mior]r 
tanialelenu-nt. theruMiJeaewundortiini, though it lint never yet been obxcrved as an indopnidont 
bono in the human foot. 



196 



THE SKELKl'OS 



THE METATARSUS 

The metatarsus conasts of a scries of five somewhat cylindrical bones. Articu" 
luted with llie tursua behind, tlit>y extend forwHrda. nearly jjarallel with each other, 
to their anterior extremities, whjch ujliculiite ivith the tt»es, and arc Jiumbered 
acctirdiiig to their |jc)jUtioii fmin within outwanls. Like the eorre^ijxindiiig bones 
in the hand, euck rr^ents for exaniiniition u three-aided .shaft, u proximal ex- 
tremity termed the Lii.se, and a distal extremity or head. The shaft tapers gradu- 
ally from the l>ftaetn the hejid, and is Klightly curvwi longitudinally so as to I)e convejc 
on the dorsal and concave on the plflniar aspect. 

A typical metatarsal bone. — The shaft iy compre/jsed laterally and pteseuts 
for exninirialion three liordcre and three aurfaces. The two lateral borders, dis- 
tinf^i.'<he<l as internal and external, are ."Oiarp and conu»enco behind, one on each 
side of the dorsad as|>e(:;t of the tarsal extreniity, and, gradually approaching in 
the middle of the shntl, separate at the anterior end to tenutnate in the corresponding 
lateral tubemle-s. The inferior border is thick and rounded and extends from the 
under aspect of the tarsal extremity Xo near the anterior end of the bone, where it 
bifurcates, the two divisions terminatinu; in the articular eminences on the plantar 



1<I 



riitt 
on 

INHU tIK 



niuun 

an 

OUTEft USE 



MCtr tO« 
CUMKPWH 



Hi 



rn reiroiitut wime 

tUCT FOR SEC40B WET*- 



aspect of the head. Of the three Rurfaw-s, the dorsal is namiw in the middle anc 
wider at either end. It is directed upwards mkI i.s in relation with the extensor 
tendonu. The lateral surfaces, more extensive than the dorsal, eo ires ponding 
with the interasseous spaces, are separated above, but meet tOfrether at the inferior 
border; they afford attachment to the intermaeous muscles, The base is wedge- 
shaped, articulating by its terminal surface with the tanme. and on each side with 
the adjacent metatarsal bones. The dorsal and plantar surfaces are rough for the 
attachment of ligaments. The head pre--¥-ntH a semicircular articular surf»i*e for 
the haw; of the first phalanx, and on each side a depression, suniiounteil by a tuhenHe, 
for ihe attachment of the lateral lipanicnt.s of the metatarso-phalangeal joint. 
The under surface of the head is grooved for the pa.'wage of the flexor tendons and 
w boumled Laterally by two eminence* coal iiiuous with the terminal ar( icular surface. 

The «.'veral nietaiarsjils possess distinctive charactere by which they can be 
readily recoftnified. 

Tlu! first metatarsal is the meet modified of all the metatarsal bonce, luid de- 
viatefl widely from the eeneral dewription given above. It is the shortest, the 
thickest, the strongest, and most massive of the series. The base prevnts a large 
reniform, slightly concave facet for the first cuneifonn and projects downwards 
into the sole to form the tuberosity, a rough eminence into whjch the i>eroneua 
longus is inserted externall\ and a slip of the tibialis anUrior internally. A little 



THE METMAHSVS 



197 



atiove the tuberosity, on its oul*r side, i.hcrc is (wcasionally a shallow, but easily reo 
ogniseti facet, for arliculatiun with tbe base of the second metatarsal. The head i» 
marked on the plantar siirfii.ce by two deep groovtw. iFeimnited by a ridye, in which 
tlie t\Yu iiesaiuuiU bones cif the /Icxor kallucis brevis glide. The shaft i.s iiiarkeilly 
prismati*-'. The dorsal surface is smoutJi, broatl, and crinvex, directed upwards 
and inwanis; the plantar surface is concave longitudinally undcovcre<i by the fiexor 
halluciv longiis and bra-is. whilst the ertemal surface i.-* t.riiingiilar in outline, 
almost verticid, and in rtliition with the fin»t {lorml vitcmssenus and a<ltimU)r hailucis 
obliquiis. A few fibres of the inner head of the first dorsui mUrosicous occasionally 
arise from the binder purl of the surface adjoining the base, or fniin the border 
seporatinK the extcmsil froni the dor»a] surface. Soniewheri' near the middle of tlie 
shaft, and on its outer or fibular side, is the nutrient foramen, directed towards the 
head of the bone. 

Tlie second metatarsal is the loiu^est of the series. Its b&se is proloDged back- 
wards to nocupy the space between the first and tlurd cuneiform, and act-ordinjtly 
it is nmrktHi by faeet*i for artic-ulution with eat-h of ihi}Mi> ImtifH. 'llie tar*Ml surfuee 
is triangular in outline, with the baae above and ajjex beluw, and articulates with 

Fta. 223.— The Sscoito (Larr) Mrtatak»al. 



TWAL 

w 

IN* ED HOE 



M oocMioN*i F*cn tn the fwi 

Hlt«IXKUl 






I^P^ 



niuuR 

DK 
OUtUt lltt 



J HOtn FOR THIRD CUNUfCm 



the secnnd cuneiform hone. On the tibial side of the base, near the upper angle, 
id a small facet for the first cnncifonii, and occasionally another for the first meta- 
tarsal a little lower down. The outer (fibular) side of the base presents an upper 
and a lower facet, separalod by a non-articular depression, and each facet is divided 
by H veriicid rid|re into two, tlitia makinj; four in all. The two poeterior facets 
articulate with the tliinl cunoiform and the two anterior with the third metatarsal. 
The base Kive.s attachment to a slip of the tibi/ilis pnsiirior and the add m-tor hnll nets 
ubliqftug, whilst fniin the siiaft the first and seeond ditrsat inlcrmst'uia niuwles take 
oriRin. The nutrient foramen is situated on the fibular side of the shaft near the 
iriic]ille and is directtsi toward)^ the base of the bone. 

The third metatarsal, a little shorter tliati the second, articulates by the tri- 
angular surface of it* base with the third cuneiform. On the inner side are two 
small facets, one below ihe other, for the second metatarsal, and on the outer side, 
a sini^le large facet for the fourth nietalanfal. The base gives attachment to a slip 
of the tibitUia posterior and the adductor halUtcis Miquus, and from the shaft three 
i?iU'rmseou8 muscles take oripin. The nutrient fonunen is t^ituaicd on the inner or 
tibial side of the shaft and is directed lowarrls the base. 

The fourth metatarsal, smaller in size than the preceding, in distinsuishcd by 



TUE PHALANGES 



199 



abductor digili tivj'nii. and the doreal surface, continuous with the superior surface 
of the shaft, rcceiv«« the insertion of the peroncua tertiua. The head i« anall and 
turned somewhat outwiinhi in ronsTqiienco of the Inteml curvjiture of the shaft in 
the same direction. The shaft differs from that of luxy of the otht-r nictatareals 
in being coinijreseeil fniiii above downwards, instead of from sifle to side, so as to 
present superior, inferior, and internal surfnees. It gives attachment to tlie outer 
nejid of the fourth dorsal iiUcroaseous and the third plantar tntavsseous muscles. 
The nutrient foramen is situated on its tibial side and lb diiftcti^ towards the base. 



Flo. 226.— The Fi»tii (Lbpt"! Mcr.MARSAL. 



[IIKL 

W 

'Ml EH Slot 



an 
ourifl HIE 



tWlKVi mllTIMU 



buuiD Hon 



iuita»rr 



• 



OBtiAcstion, — Eiurh metalnival cMaifivs fruit) two centrcn. The pnmaiy nucleus for iba 
iihaft iippcnr:« in ilic righlh we^k of naibryonic Life in t)i« middle of the rjvrtiliifinniH inctatAnml. 
At bir'h, f.-u'li vstn-iniiy is ropre*ent«(l by cvrtilji^, nnd that »l U» pn>\iiTnir«Tid in oMsJfivd by 
KlcDsioii frum tliv primary titu'lnus, c\c(^']il in tlic vitH] uf ihn first mututursiil. For thin, a iiudoiis 
ftppeara in the third yeur. 

The dislJil en<l» at the (our outer niclailnr'Jilt nre wuiifii-'i l>y iiepoii(i»ry tiijclfi whitli itinke 
their unpeurunrc about the third yi-ur. Very frojuvnlly oii <:|»ph\'Ki<( in fouiid uL Uiu di^lu] cad 
of the first mctotftntal a» well as at its ba«c. The otinfta «nil cpipny.tcs mnrwlidtiu? at tlic twcn- 
tivtli yciar. Tlie w.<wuiiuid« Uolangiug to the /tovr haiitcU bri-viv bcigin to OMify iiLxiut ih« fifth 
yoor. 

THE PHALAKGRS 

The phalanges are the hone."! of the toca, and number in all fourteen. Except 
the great toe, earh ronsist-s of three phalanges, distinguished as first or pmxinial, 
second or medial, and third or distal; in the great toe the middle phalanx is absent. 
There is thus a similarity as regards number and general arrangement with the 
phalanges of the fingers. With the exception of the phalongos of the groat toe, 
which are larger tliati t)iose of tlie thumb, the bonus of the tues are smaller and 
more rudimentary than the corresponding bones of the fingcts. In all the phalanges, 
the nutrient foramen is directed towards the di.*ital extremity. 

The phalanges of the first row are rortstricted in the midtllc and expandc*! at 
either extremity. The shafiM are narrow and latendly compressed, rounded on the 
dorsal and concave on the phmtar a.spects. The bji.se of each preMent-s a single 
oval concave facet for the convex head of the corresponding metatarsal, whilst the 
head fiiriiiK a putley-hke surface, grooved in the centre and elevated liitcrally, for 
the second phalanx. 

Tlte phaiangea of the second row are stunted, insignificant bones. Their shafts, 
beside.*! neing mnch shorter, arc flatter than those of the first row. The bases 
have two depressions, separated by a vertical ridge, and the heads present trochlear 
surfaces for liie ungual phalanges. 



THE PHALASOES 



201 



Tlie niuwlwt atmched tn the various plialanttes may I>e tabulftt«cl thus — : 

The first phalanx of the hallux giv(?s insertion t^ the flexor hallucis hrt^vis; 
ftbduou»r hiillucis; mMuctiir lialhii'i.s iraiLsvefMUS and obliquui); exLeiitior ilifjiLiirufii 
brevis. 

The first phalanx of second toe: The first and second dorsal interosseous. 

The first phalanx of third toe : Third donial intcrossemis; flwt plantar inter- 
osseous. 

The first phalanx of fourth toe: Secaud plantar iiilerosne^jus: fourth dorsal 
interossecm.^. 

The first phalanx of fifth toe : Third pUintar interosseous; Hexor digit! quint! 
brevis; and abductor digit i quinti. 



Fio. 228. — The SB<v>NOARy 0»Hnc CBifTRBft of the Foot. 



T*t Hvnt FOR TMt intnnii for tme ciiu- 
Riui %fntm «T txi TiHiH (UN; oaniOLi- 

MTU «r THE tlXIHRTM TIM 



THE CEITTRE n* THE IPinirilt nR THE KHJ- 
IIRBU (X IHI HlKiJI irtum 11 THt TMIHO 
nx*. COKtUUMTII II IHt rwENtlETN TEAR 



THf OEHTREI eon the MIE 0' TME TtRWDAt 
nOiUUlMt ItntM tt UfH tUR, <kllB W)tl- 
HUMn it THI KtHTEtUTit ?UR 



IHI CENTRES RM TME HfUS Cf TmI ■tlHURlUl 

umfl H Die TMiflD teu. wt omuliDiiie *t tme imiiiftnH tur 






The tenninal phalanx of hallux : Flexor luiltucis longus; extensor hallucia 

Tho second phalanges of the retnaining toes: Dorsal expanaion of th*- ex- 
tensnr tcndonK, mclijiiirig extensor Hi^toruni Imipw. exten.sor dijfitnruni hrcvis 
(except in the oa-Sie of the fifth toe). and cxp.in.'^ions from the intenwsei and liim-' 
bricales. 

The third phalanges : Flexor digitorum toogus; dorsal expansion of the ex- 
tensor tendon with the atwociated miLselos. 

Ossification. — I-ikt' ibc com-sponding Ijuiius u( the Biigvn, the Dtmlaoew of the (oee o«tfy 
frotn a jmmary ami .1 ^wondarj' nudcius. In rnch. llic centre for l-hc shuit appears during the 
eighth nr ninth wi ' ' * ■ ■>■ -r-. > . , . - . . . , 

tJie 
or 

cen 




202 



THE HKELHTOS 



Sbkamoid Bonrs 

III Uie font & pair of sMAiiioid honf^s arc constant over the. metatAraa-phAljuigpnl joint of the 
gT«st toe iit the tendons of the flexor hntlucis brevis. One sometime* wcure u^-or tire inter- 
pliulanKeal joint of tlic; triune tot; uuil over the nietatarBo-piialungeAl jointe of the second snd 
fiilh and rarely of the third nnd fourth t«es- 

A seaamoid also occurs in [he teiidnn of the peroneUB longu*. where it glide* over tlip grooTe 
in the eulK>id: ajiother may bo /ound. especially in later life, in the tendon of the tihiiiiiii anterior 
over the first cnndfonn bono, and anotlier in the tendon of the tibialis poslertor over tlw inner 
mirfaoe of the head of the tjilus. I'lirther a iiesanioirl. the fiihelln, ^r.■metl[tle8 occiin in tlie outer 
head of the gastrocnemius, and another may be found in the tendon of the ilio-peoas over tbft 
pubis. 

BOXES or THE FOOT AS A WHOLE 

Although the foot is constructed on the Bamf Reneral plan as the hand, there 
is a marked difference in its archlterttire to qiialifj' it for the different functions 
which it is called upon to perform, ^lien in the erect posture, the foot forms a 
firm basis of support for the rest of the body, and the iKjnes are armnged in an ellip- 
tical arch, supported on two pillars, a posterior or calcaneal pillar and an anterior or 
meiaUirml pillar. It is convenient, however. Uy regard tho anterior part of the 
arch as consisting of two scgmcntB, corresponding In the inner and outer honlers 
of the foot respectively. The inner segment ia made up of the three inner metatarsal 
bones, the three cuneiform, the navicular, and talus; the outer segment 13 made 
up of the two nuler metatarsal bones, the cuboid, and the calcaneus, and both seg- 
ments are supported behind on a common caimneiil pillar. The division corresponds 
to a differenne in function of the two lr)n;;ii.iidinal arches. Both arc intimately 
conceme^l in ordinary ItK-omotion. In addition, the inner, characterised by its 
great cur\'aturo and remarkable elnsticiiy, sustains the more \*iolent conciwsions 
in jumping .ind similar actinne, whereiis the outer, less curved, more rigid, and less 
elastic arch forms, with the pillars in front and Whind, a firm basis of support in the 
Upright posture. 

Both arches are completed and maintained by strong ligaments and tendons. 
The weakest part is the joint between the talus and navicular bone, and fl{mcial 
pro\*i8ion is accordingly made, by the atldition of a strong calcaneo-navicular liga- 
ment, for the .support of the head of the talus. This ligament is in turn supported 
by it.s union with the deltoid ligament of the ankle, and by the tendon of the tibiah's 
posterior which passes beneath it to its insertion. 

BcBtdcs being arched longitudinal ly. the foot presents u transverse arch formed 
by the metataraal bones in front and the distal row of the tarsus behind. It is 
prfKluced by the imirked elevniioii of the central portion of [he inner longitudinal 
arch above the ground, wherciw the outer longitudinal arch is much less raised, 
and at its anterior end become-f almost horizontal. Both the longitudinal and 
transverse arches serve the double purposic of increasing the strength and elasticity 
of the foot and of providing a hollow in which the muscles, nerves, and vessels of 
the sole may lie proteeletl from pressure. 



Homology 0} the Bones of the Limhs 

That there is n itenenil eorrewfxmdenw^ in the pl«n of constnietion of the two extremities la 
apparent to a nuperhrjal obKerver. and thix betmmett more marked Avhen a detailed examination 
01 the indi^-iduaf bones, tlieir fomw and relations, their embryonic and adult pefuharitieet, i» 
■jstematiealtv carried out, !n eaeh linib there are four segments, the shoulder ipidle corre- 
xpondini; tn tne pelvic girdle, the ami to the thigh, the fereann to the leu, and the hand to the 
foot. 'i*he!te part^ have t>een varioiialv muililied, in adaptation To the dttTeronl funetions of the 
t«o linihM, purticularly as regartls th"" deviatioiia or change" fr»im "hat i"* regarded ajt Iheir primi- 
ti^■e position, and as a knowledge of the^ rhnngcs is essential to a clear undcrsliLnding of the 
homoloftoiia honeis. it will fie advantageous to refer brielly to the relatjona of the linibs in the 
earlient sisfre^of developnK-nt. 

The linitw first appi^jir us flattened. bud-Uke ouli^wtha from the sides nf the trunk. Eadi 
preacntd a nufwrurr, aortal, or txiena<ir surfare. and an inff:ru<r. venlrn}, or finor surface, as well as 
two borders, an itnterwr or njAalir. drrecled toward* (he lipad pud of the emhrTr-o. am! » /««- 
Irnor or owdat, dircrteo (owanls the tail end. In rvferenee to thv axt^ of the h'mb itself, tlia 
bordett have t»en called prr-asial and p^yxt-niiai . respectively When, somewhat later, the 
various division" i>f the linifi make their appearanw, it it «een that the Rreatnr liilierosity, the 
external epicondyle, (he radius, and the lliuiub tie on the pre-axinl border of the anterior ex- 
Ireinilv. and the umall Imehanter. the internal rondj'le. the tibia, and the great toe on the pre- 
axial finnler of the pcwterior extremity. Further on the ixHt-axinl border of the anterior 
extremity are ccvn (be sioull tubetosity. the internal eptcondylc. the ulna, and little riiisfr. 



HOMOLOGY OF THE BO.SES OF THE LIMBS 

wlitbl on Uie corresponding border of the posterior limb are tbe ereai trochanter, the external 
roitclylo, ch« fibiiln, and the little toe. The pnrlJt now enumemted on the eornHpondinf bordem 
of thii twn lirabu must therefore be regarded a» Herially huim>lr>||(oua (fi^. 230). 

It in iiei-v«!(Hry to trace next the Turllief chuiiKeH whii^h t«keplace id the aeicnwDta of the liniba 
up In the time when they asoume their pemtanenl potiitjoiut. They may be arriutgcd in stages as 

<ll Bach fteipneiil of Uie liiiiti ut bent upon the one above it. Tbe htuneniB and feniur remiiin 
imchanged, with the dorsal Hurrn<^e directed upwards and the ventral surface dunrtwardji. The 
fcirounii wgiiient, however, ia beat dowitwardit ho that the ventral aurfaM lookd inward-n uid the 
doreal surface outwarda. Moreover. Ibe joinl« between IliewMcnieats — i.e., elbow nud kttoe — 
form niArited pro|ections. Ilia tenninaJ ae^enta (baud ancT font] are bent in the uuposite 
direction to the middle one, so that the primitive position is rt^t^nvd, the doreal aurfare fonkins 
upwiudit find tbe ends of the difntd directed oulw&rds. It wilt be noticed that in ihin t>rrtei> of 
cnuiccfl the T«lation.s of the pre-oxial aiid poat-oxial botdere of tbe litnbe remain a>« U-fore. 

(2) Thin «tAK'^ consilstM in a niiatio& of the whole limb from the proximal end, thnuKb in an 
axactly Ot^XMile direction in ewh case. The anterior extremity is rotated bactruytrda *u llial llie 
hitmcrua Ika parallel with tlie tnmk: the elbuw m directed towards the caudal end. the pre-fixial 
(radial) border tiecomea exlemal, and rl»e pont-axial hordi^r internal. Theenidsof thedif>iis point 
backward*. I'he prMteriur extremity unuerKoe* a rolalion /•mmnU (o tlie same extetit, »y that 
tho femur is also nearly parallel with the trunk; the knee b dinacted towards tlie head end, the 



Fio. 230. — niAORAMSiATic llErBisrvrATiOM OF THE Bn.vRs OF THB Two LlUM, TO SROW 
Uououxiutjs I'jum. (Modified from Flower.) 

iMFuttikout mu 




I 



nre-axinl (tibial) border becomce internal, and the poft-axisl border extemul. Tbe tibia and 
iibuhi an> parallel, the end« of the digits are directed foruiirds, the grvui tor ix on (he pre-axial 
and the little toe on (he jwMt-sjtiiU border of the limb, and in thid poiitinn the patterior pxI mmily 
remain<i, the rhnnffe* iKrinK (ioally completwl by the exteiHion M Ihe limb at the hij>-joint tut the 
body attains its full developnient. S, 

(3) This stage affects the anterior extremity aloite ami conafat« in a rotjitkm of tlie radhis, 
cnnyiiig the hand rmiod the ulna »o that the diptx are bnttiKhl round from the back Ui the fmnl 
of the liHib. and in many animaU the tnaniis is thii^ placed jjemiiuiciitly in the prune iKwitton. 
But m man, in whom lite capacity fur pru:intinVaiw ^pination is hiplily developed, tin- hand 
can amwne either poiition at nWt In Tti cam* th^nnl chsoKe in tUv exlfiu>)r>n «hii-h tnkrs cOiire 
at tbe dioulder-jouil nilh the imiimption of the upriRbt poslurc, the liiub droppinjc loosely at 
the side of the body, and Ix-inic I'udowed with the KT^at«9t freedom of movemenl, 

Jlonwlofcicnl con)]>jiri.*uri rSa- 

I. The shoulder and pelvfc girdles. — Primarily tl»«> lateral half of eiu-li girdle con«iAta 
of a ru^^-ed bar or rodof iMrtil.-i^c |>lii-ol vpr1ii--Blly to ihelon^itudinitl axiMof the trunk and divi- 
siblp into an upjwror dor»ftl Mryinciit, and a lower or vi-nlru! iirgmenl, the iwiint of diviiion cor- 
ns8|HmditiK to Lne pliin> of i^rliculntion with the liint»-».talk— i. c, the gletioid mid acelabulnr 
eavities. In the fore-limb the uf^ier se^ient is ihcKcapiiU.Mndthelowiprscgment themraroid, 
whibt ID the hind limb the upper fesment is the ilium und llu; lower M^gment the ischium ana 
pabt<i. V 

The upper segment* of the two girdlM-^^ Mnpnla and ilium — arc accordin|^ rvgardod 



VVN- 



^i^ 



204 



THK SKELETON 



w houioloKO'iA bon«6.tK(> chiflf 'lilTpmnrplKrtngthkl wh«r«wi th^eonpula is free from articulation 
with the wrtohral t-ojiimn. the ilium is Qnuty juiutdl to Iho rib elBRienU tULumi nuua] of Cbe 
HUTiiin. Hut th4> i-nrrc^pandcnoo is not t\\iiTc so rltur with r^ard to tho ventral aegmenlA. In 
iLu primiitve ■.■oiidition lii? conicoiil ndiciiljilON wiMi the side of tlie icternimi, an ammnetoent 
w)ii<;h pen<iHtA throughuut life in certuin uniinub, Buoh us rcptiloeandOmithorhyQchuij. But in 
all liic lUKhcr mammals it iiii(i<>rgowi rctluclion. withrlrawing from Iho side of the stomum, and 
L'vviituolly forming a more or leow nidimcnlafy prociow nltiwhsul to the »CHpiila. In iho morv 
generalised fonii uf eliuulcliT s;irdk> the vciilnil uur k duuLiIo, cuiudslicig ot curacoid and pre- 
rorncoid oleiiiPtit*. tho Inll^r being sitiiriTcd in front mid (ilmoHl pariUlH with the coracoid. The 
paMwrscoid in ninmmnl* i* Irii-^i-ly rrpiiurit hy thu drvrlopriipiif ovtrr it nf Iho cJavicls. a dermal 
or in em bra II 'ous spliiil-bunu uIir'Ii t'vi.-iitiiulJy iiiviidv.f tliv uiidvrlyiii^ rartilajnic. PurtA, however, 
remain di.stirict and form the utenml fpiphyM-i of the clavicle, with which il coalesces at tweiity- 
fiveyeart, the inter-iirt-iculjir^artihiK'- l)i-tiv<^rn il imd tin- ■t«muiii, the oupratitemal booea, and 
the iiicoiibiaiil intvr-artif-uiar I'artilaijv in lliv acmmio'chiviculjU' juiiit. 

It has alrcody I«i*n iioliiHTii rlmt, in the liip Kir(llt> iho vcnlrnl Kcgmcnt also consiatx of two 
element*, the pubis iitid inrhiiim. Ii<)l1i l.nki- jmrt in ll)i- (nmiiitiiMi uf the acplahiilar cavity, mnd 
the pubis mcclH tii the vvnlrai tiiL'dian lint? ihr ['orn's^ndijijg; Kinnt'iit uS thvopiXMiiteeide. 

It ia ecnerally agreed that, ihn comr-oid and it^rhiiim arc honioln^un .structures. The pubic 
poll ion of the vrntnii M'grrtriil iiii[ifi»rs lu t-rirn-»|ioiid nitmt fliisi'ly with thv nre-«'<>rRCoid element 
of reptiles, ao that llion; in cto tnR> hi>iiioioKue of the elavii.-lc in tJic pclviK If, houDvcr, t4iv 
clavicle concspondi to tho roptilinii pre-roracoid, as lielieved by many anutomi^l^, it tbcn be- 
comes the rcpiwu'iifativtr of ihe^ ptibii'. 

Moreover, it is po«iblo to c«titb[t»h a compariBui) ijctween the individual parCti of the iUum 
and senpulH. A referrnooto fic> 230shoTi'H that Itoth ihexeapiilaand ilirim may he resolved into 
three-sided prismaliv rod", eacli of wliirb hiu' ilirrv niirfac-cK imd ihrrv IwrderB, In the priiititive 
position of the Umb one Hurface— the intmial — in turned io«iird« the vertebral column, the 
rvtiiainini; hurfacca are rjUmnl. and named jirf-oxiof and ti»it-<ix\ai. corrcwponding to the borders 
of the limb. Tbebordcri ncpiimtini; lliv in'rnia] fmni Ihe exlemal e.urf!iees are anlero-iDlemal 
(l«rminaMng in the acnimion t>r pubis) ujid poi>u>ro-lDlcrnal (lerminating in the coracoid or 
iachiuin). The two e.ntemal surfaced are separal«d by a rid|;c lerminatiog below at the upper 
mon^n of the itlenoid cavity or aretabulum (glenoid and cotyloid borders). 

The primitive arrangement is lo*! by the marked growth of tlie borders of Ihe rods leading 
to the foriiiatioD of foaaie and by the rotation of each rod, the ncapula ouhittrdK nnd tlin ilium 
tnwyirds, in aesocialion wjfli tbe rotation which lake* place in the free part of the limb, »o thai 
the inner surface of the one eomc« Co correspond with the outer surface of the other, it reeultA 
that the primit.i\-e verlchraJ surface of the r«eaputa is noM' iheprc-scapulurontupranpinDitsfotuia, and 
the corresponding surface iti ihe ilium \n the sacral, which, on account oT its close connection willi 
the vertebral column, umlcrgoos but little change in position. Further, the primitive pre-a^iial 
Kurfacea are the infrniipinou<- fouiia and Che iliac fik^Ait, which accordingly are Iti 1m* rcK.-ird***! ax 
bontoloftous, as well a* ihe two pcwt-axial surfaccF. the subscapular fobtta and t!io dursuin ilii. 
The correspnndenco between the various parts of the scapula and ilium is shown in the appended 
table (after I'lower). 



I, Surfaces: 



II. Borders: 



Scar PL A 

f!unrasi>inou8 foeaa, 
Inlra^'piiious ftusa. 
Subscapular foE«&. 
Axillary or glenoid. 

Spine. 

Superior or eo^u^e^d. 



PaaurnrK 

AxUlNUllltNT 

Vertebral. 
I're-axial. 
Post-axiaL 
Externa). 

Anlcro-internal, 
Postoro-intemal. 
Dorsal oxiremit}'. 



lucif 

Sacral fiurface. 
Iliac foMO, 
Gluteal ttuWaco. 
Cotyloid or anterior 

burdw. 
I'erminal line. 
Poflterior border. 
Crest of ilium. 



• 



n. Bones of the arm and thicb, forearm, and leg.— It has already been puinird out in 
dowribtDii the deviation of the limu from the primitive position that the hunieru:' corTcspmuls 
to tho femur, the radiUH to tho tibia, and the uma to the fibula; also that in conHer)i>ence of the 
rotation backw.irda of the fore-limb, and forw-ards of the hind-limb, the outer aide of the bumcnia 
oarmpoiida with the inner aide of the femur, the radial (outerl Iwrder of the forearm to the tibia] 
(ianer) border of the I^. and the ulnar (inner Iwrder of the furcarm) to the fibular (outer) border 
of the le^. The eo(n»ponding parts are tabulated below*: — 



F0MK-LlM» 

HumeriM • ^ 

Greater tub«rout|r ^ 

LcHer tuboroflify 

drtemol epicondyle and eapitulum 
Internal epicondyle and (rorhlea 

RodiiK 

rina 



Femur 

I.ewier Trtjrh an ter 
Great Troehanter 
intonml ('ondyle 
Kxtenial Conayte 

Tibia 

Fibula 

Patella 



III. Bones of the band and foot. — It is obvious that t)ie carpus and tarsus, Ihe meta- 
carpus and metatarsus, and the various digits, conunimviag at tiie thumb, in ibe hand, and at 
the erti&X toe, in the foot, are serially homologotis. 

In order to trace the correspondence l>elw|^n the various elements of the carpus and tarsut 
it is convenient to r?fer jo the Drat place to the' primitive type of hand and foot on found in the 



HOMOLOGY OF THE BONES OF THE LIMBS 



205 



water- tortoise and the liznrd (fie. 231). In ttnch tfipafvil nin« o)cRU>nts mfty \ie ncnf^ixd. 
■muiged ill H proKmiHl row of Uiiw, natiied respectively nuluilr or tibtalt, intfrmtfliti'n, luid 
ulnarc, or fibulare, a distal rtiw of (ive carpalxa, or lanaiia, nunibcnxl from one to five, commenc- 
ing at the pn^-itxial Imrdor, nnd bplwocn tW two rawA an o» ceiHrale. 

In man the carpuK w <lerive<l from the typical forni in tlie following manner: The radJolo 
fomui the iiavirulur, intprmeiliiim Iht- lutmtc. and i\k ulnare, iho tn(|uelnU ; i-arjiale I forms 
the greater multJiTignlflr. carpalc II the lc««r miillaiiftular. carpale III the lapitate, wliilnt cur- 
pftlia IV and V poulecre to form the hainal«. The o^. t'«iilrule is pn^sent io tne huiiiaii i-urpil> 
Bt aa enrljr etage, liut in th« Kcrund munch it joiti." tho navicular. It is oi^caHinnally fippamts — 
a normal arrangomont in moht of the primates. 

In the (anUM, the libialeand internjetlittai uoalet^pe to forni the talun, nnd ttiefitiulare becoincs 
the nilcTanoua. ll la in ti-fwting lu note thai although in the human Bubjcrt there are three Iwncs 
in the first, row of the carpus and two in the first row of the tarsiu, id camivorca the nnWcuIar 
and lunat« are united t« form a navii-ulo-lunate bone — the homologue of the talus. In thp 
human tarHtu tlio intermedium oc^u^iondly rcmaina difitincl ofi the oa trigonum. 

Fio. 231. — DoiuuL SuRPACB or the Riokt Maxos ov a WAixn-ToitTctiHK, Chfltfdra Mo-pehtina. 

(AfUT O^unbuur.) 



U 



Tiusalp I forms the first cuneifonn, tar«ale II the second cuneiform, tar«ale III tho thinl 
cuneiform, and tarsale IV and V are joined la form the eiihoid. The us renlralc fomu the 
navirulsr. 

In addition to the cnrpal and taraal eleuienle enumerated above, brief mention must now 
be made of the aeciamnid bnnen of the twn ttppmenls. which are regarded by many anatomtiits 
tut veatlgeH of sitpprexMHl digilH. In iJie hand are the ulnar and radial sesamoids, Ihe ulnar 
being represented by the piHJfomi and the mdiul probably by the tuUenwily of the niivicnlar. 
(In ttip mole and other alliM Apeciet with foH.->f>riHl hnbita. the radial sesamoid is greatly devcluprd 
to fivTiit 11 Hirkle-MKiiiiMj Ixine whirli \uw r«H pived the nmiie of (« /(ilrijormr.) 

The <-i>rrcftx>"<h'ii: xtrtH-turtw in Die fuut are the tibial and fibular seeamoids, t}u< lilMal 
being mo^l nearly reprp.*#ntpd by the tiibf-rortity of the navicular and the fibular by the lubf;ru«tty 
of the calcaneuit. 



Tablb SitoirtKO Tint Hoyot-oooua Boveb or tre Carpcs and Taiist^s. {AfterG. D. Thatu 

in Quain't Anatirmi/.) 



CABrn t^tutnvE 

Triquetral ITtuare 

Ptsiform t^iiHT aennmotd 

Lunate [ntemiediiim 

fHndialD 
Navif ular i Rkdinl HniutMMd 

(. C«nlni|p 
Qreater multangular C'urpoJc 1 
LpNter multangular '• n 

CfiiiilAle " III 

f " IV 

Hamate i „ '^ 



Fibularv 

Fibular ■MMiuiioid 
IntfTitiMlhni) 
Tibiale 

Tibitil .-te-tainoid 
Ontrahi 
Tar^ale I 
II 

" III 

*' IV 

" V 



TAft>t« 

I Cah-aneuft 
]- Talus 

>N«vieuIar 

PirNtnmeifomi 
Second eimeifnmi 
Third cuiieifunn 

I Cuboid 



SECTION III 



THE AETlCULi^TIOXS 

Br HEXRY MOIUIIS, M.A.. M.B., Loxd.; F.R.C.S.Knc;. 

Mcston ncnaKDH to amu Lite i-BCTvnnt ox •I'noKiir troiuiau.T lbctvrtji os ahatout^ at the mibdluex 

H<>M>rTAr-: unttHiui or iiik rocsm. axi> rNAnuiAK or ihk court or KX*iiiisnu> ar Ttii KorAi. 

roLLKOB or atnacoNa, skolamu; kxaiumeb Ik icaoKBr » tub l-xituwitt or unman 



THE section devoted to the Articulations or Joints deals with llie union of the 
various luid dissimilar paris of the humaii slccletuii. The foUowuig struc- 
tures enter into the fnmuition of joints. 

Bones conHtitute the \imis of inofrt joints. The arlieuliir ends are expanded, 
and are composed of cancellous tissue, surrounded by a dense and strong shell of 
compact ti»ue- This shell has no Haven^ljin canal.'s (the vessels of the canecUous 
tissue turn back and do not perfurute it), or hirpe lacuna-, and no canuliculi. and 
is thus well adapted to bear pressure. The long bones articulate by their ends, 
the flat, by their edpes, and the short at various parts on their surfaces. 

The cartilage which covers the articidar ends of tlic h4)nes is ealletl articular, 
and is of the hyaliae variety. It is firmly implanted on the bone by one surface, 
while the other is smooth, polished, and free, tnus reducing friction to a minimum, 
while its slight ehwt icily tends lo break jars. It ends abruptly at the edge of the 
articulation, and in thickest over the areas of (ireatest pressure. 

Another form of cartiliiKC the white fibrous, is also found in joints; — 

(i) As interarticular cartilage In dtanhnxiinl juintA—viz., the knee, temporo- 
mnnciibular, stcrao-clavicular, radio-carpal, and occasinnally in the acromio-clavic- 
ular. It is interposed between the ends of thf; bones, partially or completely 
dividing the synovial cavity into two. It serves to adjust dissimilar bony surfaces, 
aiiding to the seeurity of, while it increases the extent uf luutiun at^ the juiut; it 
also acts as a buffer to break shocks. 

fii) Ar circumferential or mjirjeinal fibro-cartilnges. whieh serve tn deepen the 
sockets for the reception of ihe heads of bones — e. g.. the glenoid and cotyloid liga- 
ments of the sh"ulder and hip. Another fonn of marginal plate is seen in the 
glenoid ligaments of the fingers and toc8, which deepen the articulations of the 
phalanges and aiid tn their security. 

(ill) As coanecting fibro-cartilage. The more pliant and elastic is the more 
cellular form, and is found in the inten^ertebral discs; while the less yielding and 
more fibrous fonii is seen in the sacro-iliac and pubic articulations, where there in 
little or no movement. 

The ligaments which hind the bones tt^^ether are strong bands of while fibrous 
tissue, foHTiing a more or less perffsct capsule, round the articulation. They are 
pliant but inextensile, vnr>-ing m shape, strength, and thieknew according to the 
kind of articulation into which they enter. They are closely connected with the 
iwriostcum of the bones they unite. In ."onie cases — as the ligamenta flava which 
unite parts not in contact — they arc formed of yellow elastic tissue. 

The synovial membrane lines the interior of the fibrous ligaments, thus ex- 
rluding them, as well as the cushiotis or pads of fatty tissue situate within and the 
tendons which perforate the fibrous capsule, from the articular cavitv. It is a thin. 

21)7 



delicate m(>nihranc, frequently forming folds luid fringes which project into tl 
cavity of the joint ; or, as in the knee, stretches across the cavity, forming a so- 
cnlkd synovial lip;aineiit. In these folds are often found pad>i uf fatty tissue, which 
fill up iiitersl ices . and form soft cushions between the contiguous bones. Some- 
times thest? fringci^ Itcooine vilhjus and [leduTiculateii, and cause pain <in niuveuient 
of the joints. They ccmtjiin (iliru-fatty tissue, witli an isolated cartila^re cell or two. 
The synovial membrane is well RUpplicd with bl(KKi, cjiiK^cially near the margins of 
the articular cartilages and in the fringes. It secretes a thick, glairy fluid like white 
of egg, called synovia, which lubricates the joint. Another variety of synovial 
membrane is seen in the bursa;, which are mterposed between various movii 
surfaces. In some in-slances bursa* in the neiglilH>urlMiml of a joint may conirnui 
cate with the synovial cavity of that joint. 



steel 

1 



THJ^ vauiovs A'lixns of articulations 

Joints may he clftssified: — (a) Fmm an anatomical iwint of view, with reganl 

t he substances and tlio arriinsement of the substances by which the constituent parts' 
are united, (h) From a phy-siolo^ieal stamljjoint, with regard to the greater or 
smaller mobility :it the seat of union, (c) From a physical standpoint, either the 
shapes of the |M»rlioris in contact being mainly considered or the axes round which 
movement can occur. Or again (rf) a combination of the. preceding methotls may 
bo adopted, and thia is the plan mtnt generally fnllowe<l. None of the clfLsi^itiea- 
lions hitherto used js quite satisfaetor>', but perhaps, on the whole, that sugRested 
by Prof. Alex. Macalister la the least open to objection, and therefore with slif " 
moclification it is utilised here, 

There are three cluef groups of joints: — 

1. Synai-tkj-oscs. In joints of ihia clas.*! the bones arc united by fibrous tiasiie. 

2. Symrfu/tutrnwjt. Or joints in which tlie uniting substanee intervening between 
the bones is cartilage. 

3. Dtarthratfs, The constituent parts of joints of this class arc (a) two or more 
bones each eovereil by articular hyaline cartilage; (6) a fibrous capsule uniting the 
bones, and (c) a synovial membrane which lines the filirous cup.sute and covers 
any part of bone enclosed in theaipsule and not covered with articular CBrtilnge. 
An interart,icular plate of cartilage may or may not be prcsi'iit. 

1. Synarthroses. — 

{a) Sutures or immovable joints, in which the fibrous tissue between tl 
bones is too small in amount to allow movement. 

(1) Harmonic. The edges of the bones are cumparatively «n( 
and are in even, apposition. Ex.: Vertical plate of palate ai 
maxilla. 

(2) Squiimons. The margin of one bone o\'erlap8 tlie other. 
Tempond and parietal. 

(3) Serrate. Tlic opposed edges interlock by proceBses tapering to' 

point. 

(4) Dentate. The opposed edges are dovetailed. Ex.: Occipital 
pArietal. 

(5) iAmboux. The opposed edges alternately overlap. Ex.: Panel 
and frontal. 

(8) Schindyletifi. A ridge or flattened process i« received into a 
res|>ontling s<M^kel. Ex.: Rostrum iff spltenoid and vomer. 
(7) GnmjAoftis. A peg-like process is Iralgcd in a corresponding socl 
Ex.: The fangs of the teeth. 
(6) SynrffstMosot. Movable joints in which the fibrous tiswe between boi 
or cartilages is sutliciently lax to allow movement between the 
nected parts. Ex.: Tliyreo-hyoid membrane. Interosseiius membi 
of foreann and leg. 



VARIOUS ARTiCULATIOSS 



209 



2. Syochondroses. — lu all synchondroRt^s a certain amount of movement is pos- 

sible, and they are often called ampliiartliroties. 

(1) True aynehondroaes. TUe carrilagc connecting the bones is the remains 
of the l)ftr in which the bones were ossified. Kx.: Orcipita-splicnoiflal 
joint. 

(2) False $ttnchoiuir0s€i!;. The plate of cartilage intervening between and 
connecting the hones is fibro-cartilagc and is not pact of tlie cartila^ 
in which the hones were offflitiedf hut is developed eeparatcly. Ex.: 
Inter vertebral joint and pubic s>Tnphysis. The uniculur end of each 
hone may he eovered with hyaline rartilase and there may l>e a mot* 
or less well-marked cavity in the inlervtning plate of libro-eartilojRe. 

3. Oiarthroses. — In diarthrodial joints the surfaces in contact may be equal 

and r^milar or unequal and disfiimilar. In the former cui^ the joints are 
humomorphic; in tlie latter, heteromorphic. 

(A) Hnmnmnrphie. 

(rt) Plane or Arthrndiat. Flat flnrfare-!. ftdmittin^ phdinu movement. 

Ex.: Interrarpal atnl acroniicwlavirular jointi-'. 
(&) Epfxippial. Saddlc-shujjed surfates placed at ritht angles to each 

other, lulinttting free movement in all direetiouu. Kx.: Mela- 

earpo- phalangeal joint of thumb. 

(B) Heternmarphic. 

(a) Enarthrodiat. nall-and-socket, allowing the most free movement. 
Ex.: Hip- and sliuulder-joiuls. 

(6) Condfjlnrtkroscs. The ciinvex ^urfaee is ellipsoidal, and tits into 
a eorre.«i|ionding concavity. Ex.: Wrist and melacarpo-phalangeal 
joints. 

(e) Giiighjmi. One surface consists of two conjoined condyles or of 
a segment of a cone or cylinder, and the opposite surface haa a 
reciprocal contour. In these joints movement is only i?erniitted 
round one axis, which may be tninsverse; ex.: elbow, anklei or 
it may be vertical, in which rnsr ihe joint i? trochoid; ex.: odon- 
toid prtieess of axia witit atlas, radius with ulna. 



THE VARIOUS .)fOVKMENTS OF JOINTS 

The movements which may take place at a joint arc either gliding, angular, 
rotatory, or cinrmnihieinry. 

The gliding motion i.-* the simplest, and is common to all diarthrodial joints; it 
consists of a simple sliding of the apposed surfaces of the bones upon one another, 
without angxilar or rotatory motion. It is the oiih kind of motion jiennitte<i in the 
carpal and tarsal joints, and in those between ihe artiruhir prorex-eR of the vertebne. 

The angular motion is more elaborate, and increases or diminishes the angle 
between diffeivnt parts. There are four varieties, viit., fien'nn nn<i erUngion, which 
bend or straighten the various joints, and take place In a forward and backward 
direction (in a perfect hingft-joint this is the only motion permitted) ; and adduction 
and nhdiicHon, which, except in f he case of the fingers and toec. pignifies an approach 
to. or deviation from, the metiian plane of the body. In the case of the hand, the 
line to or from which Jidduction and abduction arematlc is drawn through the middle 
finger, while in the foot it in through th^ sseconfl toe. 

Rotation is rhe revolution of a bone about il« own a\is without muicli change 
of [Kisitioti. ft is only seen in enarthrodial and trochoids! joints. The knee also 
permits of slight rotation in certain positions, which if a distinctive feature of this 
articulation. 

Circumduction is the movement compounded of the four angular movenienis 
in quieic sviccession. hv which the moving bone dwcribes a rone, the proximal end 
of the bone forming the ajjex. while the distal end describes the base of the cone. 
It is seen in the hip and shoulder, as well as in the carpo-meiacarpal joint of the 
thumb, which thus approximates to the ball-and-gockct joint, 
u 



210 



THE ARTiCVLATIOSS 



It] soine situations where a variety of motion is required, strength, security, and 
celerity fire obiainwi by the coinbiiuitioti of two or more jniiits, e:ich allowing a 
different class of action, as in the case of the wriatf the unJcie, and iho head with 
the spine Many of the long nmwli^s, which pass over two nr mare joints, act on 
all. so tending to co-ordinate their movements and enabling them to be prtxiucetl 
with the least expenditure of power. Muscles also act as elastic- ligaments to the 
joints; and when acting as such, arc dilfusers and combinorK. not pniducere or 
niovcnient; the short muscles producing niuvement, the long ditTusing it, and 
thus allowing the short muscles to act on more than one joint. 

Muscles are S(i disposed at their attachments nc^r the joints as never to strain 
the ligaments by tending to pull the bones apart but, on the contrary, they add to 
the security of the joint by bracing the bones firmly together during their action. 

The articulations mav be divided for convenience of description into those: 1. 
of the Skull; 2. of the 'fnuNK; 3. of the Upper Liajb: and 4. of the Lqweh Limb. 



THE ARTICULATTOXS OF THE SKULL 

The movable articulations of the skull comprise (1) the lemporoiuandibular; 
and (2) those between tht; slcuLl and the spinal column, namely \a) lietween the 
occiput and atlas; fft) between the atlas and axis; and (c) the li^ntnents which con- 
nect the occiput and axis. 

The union of the atlas and axis is described in this section because, firstly, there 
is often a direct conmmnication between the s\-novial cavity of the transverse 
axoideau and the occipilo-atlnntal joints; secondly, the rotatory movenienl« of tlie 
head take place amumj the <>ilontoi<l pnwess; and, tkirdly. imiwrtant ligaments from 
the odontoid process pass over the atlas to the occiput. 



(I) THE TEMPORO-MANDIBVLAR AKTICULATIOX 

Class. — Diartbrosis. Subdivision — Condytarthrosia. 

The parts entering into the formation of this joint are:— the anterior portion of 
the mimdibular fossa and glenoid ridge (eniincntia articularis) of the temporal bone 
obove, and the condyle of the lower jaw below. Both arc covered with articular 
cartilage, which extends over the front of the glenoid ridge to facilitate the play of 
the interarticular cartilage. The ligaments which ujiite the buncs are; — 



1. Articular capsule. 

2. Articular disc. 



3. Spheno-mandibuLir. 

4. Stj'lo-mandibular. 



The articular capsule is often descril)ed as consisting of four portions, which 
are, however, continuous with one another around the articulation. 

1. The anterior portion coiwists of a few stray fibres connected with the ante- 
rior margin of the articular disc, and attached below to the anterior edge of th^i 
condyle, and ab«>ve to the front of the articular eminence. Home fibres of insertion; 
of the ejcternal pterygoid pass between them to be inserted into the margin of the 
articular disc. 

2. The posterior portion is attache/i above, just in front of the petra-hfrnpanie 
(Glmfrian) fissure., ojuI is inserted into the hack of the jaw ju.st. below its neck. 

3. The external portion or temporo-mandtbular (external lateral) ligament. 
(fig. 232) is the r^tronirest part of the capsule. It is Ijrosuler above, where it Is;] 
attached lo the lower edge of the zygoma in nearly its whole length, as well as to] 
the tubercle at the iwiint where the two roots of the zygoma meet. It is incline*,!^ 
downwards and bacicwards. to be inserted into the out^r side of the neck of thai 
condyle. Tis fibres diminish in obliquity and strength from before backwards, those] 
coming from llie tu'>erele being short and nearly vertical. 





circumferRUcft. ojid is thicker behind, where it covers the thin bone at the bottom 
of the ritandiliiiliir itt&fa wWiph sei»imt«A it. fnun the iluni iiiAter. thuii in front, where 
it fovcra the articular eminenfc. Its inferior surfac-e is conc-ave and fita on to the 
condyle nf the hnvpr jaw; while its superior surface is eoncavo-cnnvex from before 
bnfikwnnis. am! is in contact with the articular surface of the temporal hone. It 
ivides the joint intu two sepanite syiioviiil cavities, but is fn"(*:isi(mfl!ly perfDniterJ in 
the centre, uitd thu& allows them tu commuiucatc. Il is connected with tlie nrtic- 



212 



TJiK AHTlCULATtONS 



uluT capsule at iiB circuinrpronce, and has some abres of the external pterygoid muscle 
iiisenWl into its anterinr murtiiii. 

There are usually two synovial membranes (fig. 234), the superior being the 
bryer and looser. pfi.>ising dou-n from the margin nf the artH'ular surface above, lo 
Ihi' upper surface uf the interariicular cartilage below; the lower and smaller one 
parsKfj- from the inlerarticuliir cartilage above to the condyle of the jaw below, 
(^:clc-nding ^ciniewhiit further down behind than in front. When the interaxticulari 
cartihipp is iwrforutcd. the two sacs conununicatc. 

The spheno-mandibular ligament (long inipnial lateral) (fig. 233) is a thin, 
loose band, situated wime little diatatipe from the joint. It is attached above to 
the spine of the sphenoid and contiguous part of the temporal bone, and in luserted 
into tlie lirigula of the lower jaw. It covers the upper end of the mylo-hyoid 
groove, and is here pierced by the mi/lo-hyoui nerve. Its origin is a little internal 
to, and iinincdiately behind, the origin of the short int-cnnil lateral ligtunent. It 
is separated fmm the joint and ramus of the jaw by the external pten/fjoitl muscle, 
the intermit riutTillnrtt artcr>- and vein, the inferior alre/rlar {dental) nerve and artery, 
the auricido-iemporal nen"e. and the middle meninijwl artery. It is really the fibrous 
rcninatit of a part of the mandibular (Mcckclian) bar. 

Fia. 234. — Vkrticil .'^EmaN throhuh the Ch.mjvle «ii' J\w to show thb Two 
Synovial Sacb and the 1xtebaktki.x*r Kmin>-CARTiLAOE. 



^•^^.^ 



V^' 



'&Si 



fiHi- 



»i>iioi> thhoush ooHtnu 
VoManoT portlmi at 



J 



Sph«0O-RI»lwllbulBr ItCBIDVClI 



Myl^mandlbulM IKament 



'•vV 



>. 



The Stylo -mandibular ligament (stylo-rnaxillar;-) ffips. 232 and 233) is a 
process of the dn-p ecrvical iJiscia i-xt ending from near the tip of the styloid process 
to the angle and p'Wteriur l)iinJer of the ramus nf the j»w, lietween the mnssHir and 
iiUtrnai pteryjaid niuscles. It s<'parates the parotid fnmi the rtubmaxillary gland, 
and gives origin to some fibre.** of the ft ijlo-iflos.su a muscle. 

The arterial supply is derived from the tenii>oral. middle nicnmgeal. and as- 
cending pharj-ngeal arteries, and from the latter by its branches to the Kustachion 
tube. 

The nerves are derived from the masseteric and auriculo-tcmporal. 

Movements. —The chief niovemeiii of this joint is of (i) a ginglymoid or hinge 
character, anconipuniefl by a slight gliding action, as in ojjening nr flmtttrig the 
mouth. In the oijening movenient the condyle turn* like a hinge on the itnicular 
disc, while at the same time the articular dise. together with the i-oudyle, glides 
forwards so as to rise upon the cmtnentia arttcularis. reaching as far att the anterior 
edge (if the eminence, which is coated with articular cartilage to receive it: but 
the condyle never reaches quite em far as the sunnnit of the eminence. Should 
the condyle, however, by excessive moi'ement (as in* a convulsive vawTi), glide 
over the summir. it slips into the zygomatic fosiia. the mandible is dislocated, and 
the posterior portion of the capsule is torn. In the shutting movement the condyl 



^ 



oeH 

ndfl 



SKUU. ANO HPLVAL COLt'l/.V 



>13 



* 



ri«'olres back again, and the artioilar disc glides back, carrying the condj'le with 
it. This combination oi the hinge and gliding^ motions gives a tearing as tvell as 
a cutting action to the int-isor (wth, without any extra muscular exertion. 

There Is C") n borizontal gliding action in an antero-postcrior dirpclion. by 
whicli the lower teeth are tlim^^l funvards and drawn back again; thiit lakes place 
almost entirely in the u|>i)er nmipiirtnient. because nf tlie doser connection of the 
articular disc with the condvln than with the squamosal bone, and also because of 
the insertion of the external ptenjqniii into both bono and cartilage. In tliese two 
aels of movenients the joints of both sides are simultaneously and similarly enjEuped. 

The third form of movement is called (ill) the oblique rotatory, and is that by 
whiirji the grinding .■^lud chewing actions are performed. It corisisls in a rotation of 
the condyle about the vertical axis of its neck in the lower compartment, while the 
cartikige glides obliquely fonvards and inwanis on one side, and backwards and 
inwards on the other, uj^on the articular surface of the squamosal bones, each side 
acting alternately. If the symphysis be simply move<l frtjm the centre to one 
side and back again, and not from side to side as in grinding, the condyle of that side 
moves round the verticil! axis of it*; neck, and the opposili* condyle imd cartilage 
glide fonvartLs and inwards upon the mandibular in^w. But in the ordinarir' 
grinding movement, one condyle advances and the other recedes, and then the first 
recedes 'while the other advances, slight rotation taking place in each joint mean- 
while. 

Relations.— The chief relations are: Behind, and overlapping the out«r side, 
the parotid gland. Kxternnlly, the au|)erlicial tem|>oral artery*. Internally, the 
internal maxillary artery and auriculo-temporal nerve. In front, the ner\'e to the 
nias.')«ter mu-^iclc. 

Muscles acting oo the joint. — Elmvtimv of thr Ma-ntitH*. — ^T«n|ioriik, MasDolen*, Int. 
ptrryKoiils. 

tirfirrit.'i<rii.—'S\y\a-\\ym\a Digafltri«=, Oetiio-hynitl, Oenio-glfwnus, Miib4-Im r<«ini*ctiag tli« 
hyiii^f Ijotie to lower (ictinis Tin' wcislil of rlii- j.iw. 

Pr»(raetors. — Kxt. pler}'goid», Int. jnerjRoitis, Oblique fibree of Mtuset^rs. Anterior fibres of 
temi>nrals. 

Rrirarion. — PostCTior fibres of tcmporuU, Vertical fibm of MaM«l#rs. 



k 



(2) THE LIGAME.\TS AND JOINTS BKTWKEX THE SKULL AXD 
SPINAL COLUMN, AND BFmVEKN THK ATLAH AND AXIS 

(a) The Annrtri^TioN or the ATtJVs with the Opcipvt 

Class. — Diarthrosh. Subdivision.^/)ow6fc CondyJarihrosia. 

This articulation cnns^i.-'ts of a pair of joints symmetrically situatwl on cither 
side of iIk' middle line. The [mrts entering intu their formation are the cup-shajMsl 
superior articular processes of the atlas and the condyles of the occipital l>one. 
They are united by the following ligaments; — 



1. Anterior atlanto-occipital. 

2. Posterior atlanto-occipital. 



."?. Two articular capsules. 
4. Tw<i anterior oblique. 



The anterior atlanto-occipital ligament (Hg. 230) is less than an inch (about 
2 cm.) wide, and is composed of ch^nsply woven fibres, most of which nidiaie slightly 
outwarrls as they ascend from (lie fnml fsurface and upper margin of the anterior 
arch of tlic atlas to the antf^rior bonier of the foramen macnum; it is continuous 
latenilly with the articular capsules, the fibres of which overlap its edge«. ami take 
an opposite direction inwards and upwards. The central fibnps a.scend vertically 
from the anterior tubercle nf the atlas to the pharynjieal tuliercle on the occipital 
bone; (hey are thicker than the laieral fibres, and are eontitmous below with (he 
su))erficlal part of the anterior iitlaiit«>-axnideaii Itgtuiient. and thnjugh It with the 
anterior longitudinal ligament of the vertebral column. It is in ri-larion. in front, 
with the recH eapitis anleriore*; and behind, with the apical odontoid or suspensory- 
ligament. 

The posterior atlanto-occipital ligament ^fic 236) Is broader, more mem- 
bmnuiis. and not so strong as the anterior. Ii e.\U'iid$ from the posterior surface 



214 



THS ARTlCVLATfOSS 



and upper border of the pnstenor arch of the atlas to tHp posterior miu^in of the 
foramen magnum fi-nm rondyle to condyle; being inrnmplete on either side for the 
passage of the vrrit^'nil artery into, flncil suboccipital nerve out of, the carittJ. It is 
soinewiial thickened in the middle line by fibres, which pass from the posterior 
tubercle of the atiae to the lower end of the occipital crest. It in not lightly stret<?hed 
between the bones, nor does it limit their movements; it corresponds with the posi- 
tion of the ligamenta flavo, but has no clastic tissue in its composition. It is in 
relation in front with the dura muter, which is fimily attnehed to it; and bctiind 
•with the recti cnpitif p03t£Tior€9 minore^, and enters into the floor of Uie eulMiccipttal 
triangle. Its lateral margins, which do not reach the occipital bone but terminate 
on the posterior eml of the suj^rior articular prwesses of the atlaB, fonii the so- 
cailefl Miquf ligaments of the alias. The outer margins of these ligaments arc free 
and they form the posterior boundariesof the apertures through which the vertebral 



Fio. 23.1. — Antkrior Vikw of the Vpftm Cxd of the Spike. 



>3^/tv/itf.v 



^k-- 






«s?5r 



r^. 



arUouUr 
eapaitl« 



y 



CenttnoMlail »r 
ihckOivrMr 

uwTtrwiMi 

*OlBldtt 

■uniE 



Til* «Bl«nar otillQiM 
or IMoral o«aipi<o- 

«l«a<»l IICUDMII 

Atluit».ato idaao 



Atiiiiriar mtlaBI»- 



' (OD* 01 UH 



Artwvlar oapmlM ■>f 
Ui* tniM, in* ihira < 

■Bd r^utiti, And 111* 
fourtn «M arth oer- 



m 



Bktut TBrlcbrmI 



JIdIctIm 1«nclla4laBl 



i J 



arteries enter and the Buborcipiral ner\'es leave the vertebral canal. Not unctnii- 
monlv the oblique ligaments of the »tlj\s are ossified. 

The articular capsules ffigs. 235 and 2.36> arc very distinct and strongly 
marked, except on the inner side, where they are thin and formed only of short 
riieniliraiious fibres. They are lax, and do not atid murh to the seourity of the joint. 
In front, the capsule descends upon the atlas, to be attached, some distance below 
the articular margin, to the front surface of the lateral msc« anrl to the base of the 
transverse process; these fibres take an obUque course upwards and inwarrls, over- 
lapping the anterior atlanlo-occipital. At the sides anil behind, the capsule is 
attachtfd above to the margins of the occipital condyles: below, it skirts the inner 
Dtlge of the foramen (or the vertebral artery, and behind is attached to the promi- 
nent tubercle overhanging the groove for that ve.s.sel ; theso latter fibree are strength- 
end by a band nmning obliquely tipwards and inwards to the posterior margin of 
the foramen magniuu. 



ATLAS ASD AXIS 



2lo 



^ 



The Anterior oblique or lateral occiptto-atlantal ligament is aa accessory 
band which streniithens the capsule on the outer side. It is an oblique, thick bunil 
of fibres, snmetunes quite separate and distinct from the rest, passing upwards 
and inwards from the upper surface of the transverse process beyond the costo- 
transverse foramen to the jugular process of the occipital bone. 

The synovial membrane of these joints occasionally communicates with the 
synovia] sac betwijeii the iidontoid process and tlie transverse liganicnt. 

The arterial supply is derived from twigs of the vertebral, and occasionally 
from iwiK-s from [he ineiiingeal brandies uf ilie attceniliiig plmr^ngeal. 

The nerve-supply comes fr<.)ni the anterior division of the suboccipital nerve. 

Movements. — Hy the symmclricul and bilateral arrangement of these joints, 
security and strength are Rainc^l at the expense of a ver>' small amount of actual 
articular surface; the basis of support and the area of action being equal to the 
width betww-n the most distant borders of the joint. 

The principal nioveuient permitted at the«e joints K of a ginf^lymoid character, 
producinR flexion and extension up<in n transverse axis drawn across the condyles 
at their slightly constricted part-s. 

In flexion, the forehead and chin drop, and what is callwl the nmUling mo\'e- 
ment is made; in extension, the chin is elevated and the forehead recedes. 

There is also a slight amount of gliding mnvemcnt, either directly lateral, the 
outer edfte of one condyle sinking a little within the outer edge of the socket of the 
atlas, and that of the opposite condyle projecting to a corresponding degree. The 
head is thus tilted to one side, and it is even possible that the weight of the »ikull 
may be bonie almost entirely ou one joint, the articular surfaces of the other being 
thrown out of contact. 

Or the movement may be obliquely lateral, when the lower ride of the head 
will be a trifle in advance of the elevHie<l side. In this motion, which takes pla(* 
on the antero-postorior axis, one condyle advances slightly and approaches the 
middle lino, while the other recedes. This* ta of rhe nnture of rotation, though 
there is no true rotation round a vertical axis possible between the occiput ami 
atlas. 

These lateral movements are checked l>y tlie^ alar ligaments and the outer 
part of the capsules: exten.'^ion is checked hy the anterior atlanio-ocripital and 
anterior oblique ligaments, and flexion hy the posterior part, of ihe capsule and 
the tectorial membrane. 

Hutclei actiag upon the occiptto-atlaatal joto I.— Flexion whereby the chin U appnixi- 
malcd toniirtlM Uie iittrtiuai Is pmuueed I'v the weight of the anterior pitrt oi the hcnd and by 
ail mavlcif wliii"li Are iittArhcd to the hymd hone t>r to the brnipe of the alcull in front nf a tranii- 
versf. iwi« In-twwn thi^ two ceHulyiiw. TIjiwh* HiuM-leti take their fisod jxtint below cithw from 
thw vtrt^'briil t'oluiiin, the Ht«rriurti, or the boneet tif the (ihoulder ginlle. IJefore tliose connei'ted 
nitfi the DHUidible can «<•(. that bone munt hn lixed by the muscles oi maslication which, ihero- 
forv. .tlw) (uke cmrt In the inoveinentti. 

KxtettHtoi) la due (o the action of muscles or porlions of muscles inserted into the skull behind 
the lniiM>vi>nc axU Nl>ove iDentioned, and ccinneclMl belaw either with the vertebral column, 
sbuulcler girdle, or utemum. 

T.nl(>rnl movement ■!< produned bv lhi> anlerinr and posterior itrctups nf muei-les on the same 
(liciciii'titiicsiiiiult.-uieiHLily iindiiided by I lie rectiut capitis lateralis of tliat side. 



(b) The ARXicL'i-ATJONa iiktwkkx the Atla* and Axis 



1. ThB LaTCHAL ATLAVTO-AXOrDFAN JoiNTS. 



( C]Aas.~-Difirlhr{isi/t. 



2. The Central ATi.AXT(i-AXOrDEAN Joint, or ( Class.— /Jwrfftrom. 

The Atlanto-odontoid. | Subdivision. — Trochoides. 



r The ijones thnt enter into the formation of the lateral joints are the inferior 

I arriculor processes of the atlas and the superior of the nxis; Ihe central joint ta 

I formed hy the odontoid process articulating in front with the atla-s, and hebinH with 

I the transverse ligament. 
L The ligaments which unite the axis and atlas are: — 

k 



1. The anterior atlanto-axoidean. .■?. Two articular capmiles (for lateral joints). 

2. The posterior atlanto-axoidean. 4. The trauM-erse ligament. 
5. The athinto-odontoid articular capsule. 



216 



THE ARTK'VLATIONS 



The anterior atlanto-axoidcan ligament (figs. 2rt". and 23fi) is a narrow but 
strong ineinhraiie tilling ujt the intervnl helween the lateral joints. It is attached 
above to the front surface and lower border of the anterior an-h of the atlas, and 
}»low tci tlie iriirifivprHe ri<ige on the front of the body of the axis. Its fi)>re« aro 
vertical, aiid are thickened in the median line by a iJense biuid which is a coDtin- 
uation upwards of the anterior longitudinal Hgonient of the spine. 

This band is fixed above to the anterior tiihetvie of the atlas, where it becomes 
continuous with the eenlral part of the aiityrior atlonto-occipital ligament (fii;. 
'JS-I); it is wMiietiim-sscpyiated by an inter\'al fruin the dee|)er ligament, and is often 
dcsoribeil jw ihe .«u|ii'rln-ial iitiauto-axoidcun ligament. Ii Is in n-hition with tlie 
Umgiis coin mu-scli'. 

The posterior atlanto-axoidean ligament (fig. 236) ia a dtxpcr. Iiui thinner 

Fia. 230.— ViMTicAL ANTi:R<>-p(»«TERi<m 8B.'ni>N or Skival Culvuh throuub Median 

Line, showiku Lidamrnta. 






portlan o( 
orui'U) 



Tt«fu«*ra» tlcMDlat 



M aUuito-oooliiit*! iautt 



V<WMn«r ailtnto-iiaaipllAl 
luaDOiil 






InaanptaoM* Iw*m*lH 



UsaMaBlUA flkTBH 



■:^ 



^- 






m' 



■ Apteal odonlold llcamant 



Anwnor alUnlo-«calplt«t 



. Atlaale-odoalald ajnovlM 



Acierler allanlo-axqtd«*i 
llcaaasi 



and looiter meinhrane than the anterior. It extends from the posterior root of tlie 
transverse process of one side to thai of the other, projecting out\^ard^' lieyond Liuj 
past^riur part. i»f the eaiis^ulea which are ivtnnertpd with it. It is attJiL-lied above to 
the porflcrior surface and lower eilpe of the |>osNTinr arch of the atlu--*, an<l below to 
the superior e^tge of the lamina^ of the axis on their dorsftl aspect. Il is deni^er and 
stronger in the median line, and has a layer of elastic tissue on its anterior surface 
like the liganienta flava. to which it corresponds in position. It is connected in 
front with the dura raaler: l)ehinJ, it is in relation with the injarior tiUque muscles, 
and is jjcrfonited at each side by the secon/i cenncai nerve. 

I. TuK I^t?:r\l ATL-^NTo-AxnrDKAN JoiVTH arc provided with short, lica- 
meniou? fibres, forminp articular capsules (fijT- 23.")), which completely <*urTound 
the lateral articular faveti;'. Out>»ide the lunal thev are attached some little dis- 



ATLAS AAO AXIS 



217 



tanoe irom the articular margins, extending along the roots nf the transverse pro- 
oeases of the axis nearly as far as the tips, but between the roots they skirt the 
innor edge of tlw cosio-transverse foramina. They are strengthened in front and 
behind by the athinto-axoidcan ligaments. Internally eurh ciiiwule is thinner, and 
attached close to the articular niargias, being sirenpti'ienetl l)ehind by u strong band 
of sliiihtly ubiique fibres passing upwards alfinp llic outer edge nf the tectorial 
meiubranc froin the body of ifieaxiHto the latrral mass of theatluB behind the trans- 
verse ligament; some ((f these (ibrea piLss on. thickening and blending with the 
atlanto-occipilal capsule, to be inserted into the margin of the foramen magnum. 
This band is sometimes railed the accessory band (fig. 2S9). 

There is a synovial membrane for caeh joint. 

2. The Centh-vl Atlanto-axojuean Joint, although uimally described as one, 
is composed of two artieulatiouH, which arc quite sepimite froiii one another: an 
anterior between the odontoid pnicess and the arch of the atlas, and a posterior 
between the odontoid process and the transverse ligament. 

The transverse ligament (figs. 236. 237. and 2:W) is (uie of the most important 
structures in the body, for on its integrity and (hat of the bIhc ligaments our lives 
largely depend. It l.s a thick anil verj' strong band. a.s dense imd closely woven as 
fibro-i-artilage, about a quarter of an inch (6 mm.) deep at the sides, and somewhat 
more in the middle line. Attached at each end to a tubercle on the inner side of 
the lateral masa of tlie atlas, it crosses the ring of this bone In a eur\'e<l manner, so 
as to have the concavity for^vards; thus dividing the ring into a ftmaller anterior por- 
tion for the odontoid process, and n larger posterior part for the .spinal cord and its 



Fio. 237. — Horizontal SacnoN tiiRocofi tub I.ater.il Mai^seb op the Atl-vs and tds 

Tor OP Tire Odontoir Piiockm. 







Ai I u (o-odaBtol4 
■nivuiaf ospauto 

Tnacvsna 

liRnmrat 
PoaUNin' loiicl I iid - 

ln«l ll«an*nt and 

InMorta) ««(n- 

erana 



Dur« Biaivf 



I 11| 



membraties, and the spinal acceesor>' nen'es. It is flattened from before backwards, 
being smouth in from , and covered by synovial membrane to allow it to glide freely 
over the posterior facet of the odontoid process. Where it is attached to the atlas 
it is smooth and well rcmnded off tu pnjvide an easy floor of conununicalion Ijetween 
(he t ransverso-odontoid and occipito-atlantal joints. 

To its posterior surface is julded, in the middle line, a strong fasciculus of ver- 
tical fibres, passing upwards from the root of the odontoid process to the basilar 
border of the foramen magnum on its cranial a.sj>ect. Some of these fibres are 
deiived from the transvenM ligament. These vertical fibres give the transverse 
ligament a cruciform appearance; lienee the name, the crucial ligament (figs. 23G 
and ZVi) applied to the v^hole. 

The atlanto-odontoid articular capsule ffig, 2.17) is a tough, loose mem- 
brane, completely siirrounding the iippose<l articular surfaces of the atlas and 
odontoid process. At the o<lontoid process it blends above with the front of the 
alar and central occipito-odontoid ligaments, and arises also along the sides of the 
articular facet as far as the neck of the process; the fibres arc thick, and blend with 
the ca[>sule3 of the lateral joint. At the athis they an- attaeheti to the non-articular 
part of the anterior arch in front of the tubercles for the transv-erse ligament, bloml- 
ing, above and Iwlow the bonlers of the hone, with the anterior atlanlixx-cipital 
and atlanto-axoidean linaments, as %vell as with the inner portion of tlie articular 
ea|)m]les. It. holds the axis to the anterior arch of the atlas after all the other 
ligaments have been divitted. 



2 IS 



THE ARTICULATIONS 



Tlie synovial membranes (figs. 230 aiid 237) ara two In number: — one for the 
joint between the udrintoid proceaa and atlas; and another (transverso-cxicintoid) 
for that hetween the transverse Hganieiit and the odontoid. This last often com- 
muiiicates with the flt-Ianto-occipital articulations; it is closeil in hy membranous 
tissue between the borders of the tninsverse ligament and the marsin of the facet on 
tile odontoid, and is separated from the front sac by the atlanto-odcntoid articular 
capsulo. 

The arterial supply is from the vertebral arter>*, and the nerve-supply from 
the liKip hetween the first and second cervical ner\'es. 

Movements. — The chief and characteristic movement at these joints is the 
rotation, in a nearly horizontal plane, of the collar fomietl by the atla« and tran»- 
veree litiainentf round the miontoid process as a pivot, which is extensive enough 
to allow of an all-round view without twisting the trunk. Tartly on account of 
its ligamentous attachments, and partly on account of the shape of the articular 
surfaces, the cranium must be carried with the atlas in these movements. The 
rotation is checked by the liEaments passing fnmi the axis to the occiput (alar 
liitarnents), ami also by the atlanto-uxoidean. Owing to the fact that the facets 
of both a^las and axie, whirli enter into the fonnation of the lateral atlanto- 
axnidean articulations, are convex from before backwards, and luive llieaniculur 
carlilafie thicker in the centre than at the circumferenfc, the motion is not aiiit« 
horizontal but sUshtly curvilinear. In the erect position, with the face looking 
directly forwards, the most convex portions of the articular surfaces are alone in 
contact, there being a considerable inier\-al between the edges; during rotation, 
therefore, the prominent portions of the condyles of the atlas de-s^cend upon those 
of the axis, diminishing: the space between the bones, slackening the ligaments, 
and thus increasini? the amount of rotation, without sacrificing the security of the 
joint in the central position. 

Besides rotation, forward and backward movements and some lateral flexion are 
permitted between the atlas and a\Ls, even to a greater extent thim in most of the 
other vertebral joints. 

The rousclei acting upon the atltnto-axial joints. — The mitscles capable of protlnctne 
rotation at t!ie atlanto-Hsi.il jtiinlH jirfe ihtwe wlikli tak* origin from n^ear ihe medial platie 
either in fri-ml or behind and wljifb arc ivtla<'lied above either to the utlae or ihe skull, external 
to the atliinto-uxial joint.-). When the mnnrlps whirh He oX tlie bju-k of the joint on one side 
act they will turn Ihw \wtv.\ l-o (he nntuf. Midf and will he aided by the muMles in front on ihe 
npnoMte sIiIl'. If the tnuscUf in fnmt uiui behind on the same »'ideuct(>iiiiultiuieomly they will 
pull down the hcitd to that fi'\Af\ lutd will be aide^d by muscles which pau mure or Icea vertically 
irom the irftn>vwr!ie pniciTW of the Htljui to puintH beluw. 



(c) The Ligaments i'siting the OcriPiTT axd Axis 

The following liiianients unite bones not in contact, and are to he seen from tl 
interior of the canal after if rnovina: the posterior arches of the axis and atlas, and 
posterior ring of the frtramen magntmn: — 



The tectorial membrane. 
The crucial. 



3. T«'0 alar or check. 

4. The apical wlontoid or suspen8or^^ 



The tectorial membrane (occipito-cervical or cervico-hasilar ligament) 
(figs. 237. 2.38. and 2^9\ coiwists of a ver>' stmng hand of fibres, t'onneetcd belfw 
to the upper part of the body of the thini vertebra and lower part of the body of 
the axis as far as the root of the odontoid process. It is narrow below, but widens 
out as it ascends, tn be fastenwl to the basilar groove of the occiput. Laterally, 
it is connecter! with the accessor^ fibres of the atlanto-axoidean cajtside. It is 
reallv only the upward proloncatinn of the deep stratum of the posterior longi- 
tudinal ligament, the superlici-nl fil're^ of which run on to the occipital lionc without 
touching the axis, thus giving rise to two strata. It is in relation in front with 
the crucial lii;anient. 

The crucial ligament has been HlreH<ly desrrit>ed f'^Rc p. 2fl71. 

The alar (lateral occif^to-odontoid'or check) ligaments ffigs. 236 and 239) 
are two strons rounded cordis, which extend from the sides of the ajiex of the odon- 
toid process, transversely outwards t<» Ihe inner edge of tne anterior poninn of the 
occipital condyles. They are to be seen immediately above the npi>er border of 



220 ^^V THE ARTiCULATiOSS 

Ihe transverse iigamcnt, which thoy cross obliquely owing to its fora-ard curve at its 
altacluneiits to ihe jiilaa. Some "f itieir libri'S ot^cuiiioaally run across the muldle 
line fruiu (Jtie chet'k liKument to the other. At the odontoid proces;* they arccoii- 
iipcted with the atlanto-otiontoid rajwiile, and at the rondyles they strengthen 
the ntlnntn-nccipital articular capsule. 

The apical odontoid <>r suspensory ligament (titii. 236 and 239) consists of 
a slender band of fibres ascendiiie ivoin the sunufiil of the ndonloid procetw to tlie 
under surface of the (xnpitlil bone, rhwe l<» the f<ir.Hnieii tnagnuin. It is l.»est eeen 
from the front, nEter removing the anterior atlanto-occipital ligament, or frnm 
liehind by drawing aside the cnieiitl ligament. 

The aus|jen.sory ligament is tightened by extension and ivlaxed by flexion or 
nodding; the alar ligaments nut only limit the rotatory movement? of the bead 
and atlafi upon the axis, but by binding the occiput to the pivot, round which 
rotation occurs, they steady the head and prevent its undue lateral incUnstion 
upon the apino. (See Tn.\xsvERsE Lig.imknt, p. 217.) 

Hy experiments, it tins been proved rh:it the head, when placed so that the 
orbits look a little upwards, is jKiise*! upon the occipital condyles^ in a line drawn a 
Uttle in front of their middle; the amount of elevation varies slightly in difTcrprit 
cases, but the balance is uKvays [<i lie (^btiiint^I in ihe hunuui IxKly — it is one of the 
pharactcristics of the human figure. It wr\Ts to maintain the head erect without 
uiirlue muscular effort, or a strong ligament uni nuchw and prominent dorsal spines 
such as are seen in the lower auimals. Disturb thi^ balance, and let the muscles 
cease to act, the head will either drop forwards or backwards uccorrUng as the 
centre of gravity is in front or liehiml tlin balance line. The ligiuiients which 
pass over the odontoid process to the occiput are not f4uite tiglit when the head is 
erect, and only become so when the head is fiexed; if thi.** were not so. no flexion 
would be allowed; thus, nnisrnlar action, an<l not ligamenTnus tension, is employed 
to steady the head in the erect i>ositiou. It i^ through the combination of the joints 
of the atlas and axis, and occiput and alias (consisting of two pairs of juiuts placed 
symmetrically on either side of the nicflian line, while through the median line 
there pa-sses a pivot, also with a pair of joints), that the head enjoys siicli freedom 
and celerity of action, remarkable strength, and almost abBolnte security against 
violence, which could only l)e obtainetl by a bull-and-sockct joint; but the ordinan,- 
bnll-and -.socket joints are too prone to disl'x-atitnis by even moderate twists to be 
reliable enough when the life of the individual de|>cnds on the perfection of the 
nrticulation: hence the importance of this combination of joints. 



The follow!,.^ 
interior of the ca*. 
posterior ring of thft- ARTICULATIOyS OF THE TRVXK 

1. The tectorial rUpj into the following sets:— 

2. The crucial. 

Ttcbral column. 
The tectorial memb. . , ,. ,t. ,- ■ * . ■ , ^ 

(figs. 237. 23S, and Zi'Q) c6 ^^^ Iwxiies. (o) Lnion of the articular processes.] 

to the upper part of the boi ^.-^^^ (_he pelvia. 

the axis aa far as the root of 

out M it ascendn, to lie fasti 

it is connected with the flccmchondmses. (r) Intoreoccygeal. 

really only the upward pniloal. (rf) Syniphyiia pubis. 

tudiiial licaineiit. the supcrficia , „^,,__ 

touching the axis, thus giving'™ S.*^"™"; ., .. 

,, ■ I V . ^ «> t ,e front of the thorax. 

the rrucml ligauieni. 

The crucial ligament has Ixs with the sternum. 

The alar (lateral occipito-^ with the ribs. 
are two strong rounder! cords, wh 

toid process, transversely outwarcrtilnges with each other, 
occipital condyles- They are to 



VERTEliUAL LIGAMKSTS 



221 



1. THK ARTICULATIONS OF THE VERTEBRAL CX)LLMX 
There are two distinct sets of articulatioas in ihc vertebral column: — 

(a) Those between the bodies and inten-ertt-Hrnl discs which fonii synchon- 
droses and wliich are ainphiarlhrcHlial as n.'Kiir<.ls movement. 

(b) Thnee Ixttween the articular processes which fomi arlhrctdial juinis. 

The licaments which unite the various parts may ftlso W divided into two sets, 
viz. — immediate, or those that bind lunetlier parts which arc in contact; and 
intermediate, or those that bind together parts which are not in contact. 

Immediate. 

(a) Those between the bodies and discs. 

(b) Those I)etween the articular processes. 

Intermediate. 

(c) Those between the laminae. 

(d) Those between the spinous procea«s. 

(e) Tliose between the transverse pnHresses. 

(o) The AHTictn-ATioss riP thk Bodi^ of the Vertcbr* 
Class.— Fnlnv Sifrichundnma. 
The llframents \\Iucli unite the bodies of the vertebra; are; — 



Intervertebral fibrn-cartilagcs. 
Short lateral ligHments- 



.Anterior longitudinal. 
Poeterior longitudinal. 



The intervertebral flbro-cartilages (iigs. 2:16 ami 340) are lough, but elastic 
and corapresaible discs <if composite structure, which ser^'c as the chief bond of 
union between the vertebrse. They are twenty-three in numijer, and are U!terpoB«l 
between the bodies of all the vertebrse from the axis to the sacrum (figs. 236 and 
247). Similar discs are found between the segments of tfie sacrum and coccyx 



Fro. 240. — HoRizOHTAL Sbction THnocoH as LvTenvcRTGHRAL Fisro-tartilaob 

AND TUB CORIlRflPONDINO lilBS. 



riW«u> TlDc o< l&tcrverl«bral 



ADl«rla( rMllBl* or 



CDaU«a«&cvml ajnOTlAl 



Pitll>y nuelaoB M IntcrverMbCBt 

Cbc»-«krtllBa* 







Vevw-ttuuwcM sraovisl •■« 



VgatvrMr oo*MrfnHi>««na »g»— nl 



in the youn^r stafies of life, but they undergo ossification at their surfaces and 
often llirnuglmut their whole extent. 

Each disc is comjHJsed of two portions — a circumferential laminar, and a cen- 
tnd pulpy portion; the fonncr tightly surrounds and brarrs in the latter, and 
fonns somewhat more than half the disc. The fibrous ring or laminar portion 
consists of alternating layers of fibrous tissue and tibro^artilage; the mniponent 



222 



THE ARTICULATIONS 



fibres of these layers are finnly connected with two vertebrse, those of one pastHn^ 
obliquely down and to the riRht, those of the next dQwn and to the left, making 
an X-shaped arrangcniRnt of the alternate layers. A few of the suiJerfteiul lainellJE 
pmject beyimtl the edges of the bodies, their libres bein^ connected with the edges 
of the anterior and lateral Burfoces; and some do not completely surround the rest, 
but terminate at the intervertebral foramiha, so that on horizontal section the 
circumferential portion is seen to be thinner [wsteriorly. The more central laniellse 
are incomplete. iei« firm, and nut so distinct as the retit; and as they near the ]>ulp 
they gradually assume its characters, becoming more fibro-eartilaginouH and lesa 
fibrouH, and have cartilafie i-ells in their PtrUL'Hire. 

The pulpy nucleus or central portion ia situated somewhat behind the centre 
of the disc, forming a bull of ven.- elastic and tightly compressed material, which 
buUcs freely when the confining pressure of the laminar portion is removed by either 
horizontal or \'ertical section. Thus, it bos a constant tendency to xpring out of 
its confinement in the direction of least resistance, and constitutes a pivot round 
which the bodies of the vertcbnc can twist, tilt, or incline. It is yellowish in colour, 

Fio. Wl. — ^Thb A?irrEnion LosniTinrsAL I^ir.vmes-t or TtiE Si-ive. the Kadiate, tbe Ivtkk- 

AaTICULAA. ANU THIS iJUPERtOa t'OBTO-TR.VXSVEHSt J.ICAUCXTB- 



-Th«Ult«f«nl«ulaiUSUMBt 






iraiwcon* UaamaotB 



' Tlu ndlala Ucaaiaot 



|vUI.,4^^i' 



and is composed of fine white and elastic fibres amidst which are ordinary con- 
necti>'e-t issue cells, and jieculiar cells of various sizes which contain one or more 
nuclei. Together with the tnost i-entral tamime, it is separate*! fn.»iu inimetiiate 
contact with the bone by a thin plate of articular cartilage. The central pulp of 
the inter\'ertebral substance is the persistent part of tbe not^rhord. 

The inter\'ertebral suWtances var>* in ffhape with the bodies of the vertebne they 
unite, and are widest and thickest in the lumbar region. In the cervical and lum- 
bar regions they are thicker in front than Whiud.and rtium the eonvexity forwania 
of the cpn-ical, and iticreasr that of the lumbar; llie cur^'c in the thoracic region, 
almost entirely due to the ."shftpe of the bodies, b?. however, somewhat increasr<l 
by the discs. Without the discs the column loses a quarter of its length, and 
assumes a curve with the i-oncavily fonvards, most marked n little below the mid- 
thoracic region. Such is the cur\'e of old age. which is due to the shrinking and 
dr>'ing up of the inter\-ertebral subytancefi. The dipc between the asis and third 
rer\-ical is the thinnes^t of all (fi^. 236); that between the liflh lumbar and sacrum 
ia the thickest, and is much thicker in front than behind (fig. 247), The inters 
vertebnil discs are in relation, in front with the anterior longitudinal ligament; 



VERTEBRAL UGAME.\TS 



223 



behind, with the posterior longitudinal Hgflment; laterally, with the short lateral; 
aud in the thoracic reKi^n, with the int«rarticular and radiate Hgtuneats. 

In the cen'ical region lateral diarthrodiai joints are placed one on each side of the 
inten'erlebral discs. They are of ainall extent and are cmifiued to the iiiier\'alfl 
between the prominent lateral li|)3 of the up|)er surface of the body below and the 
bevclle<l lateral edgo.4 of the lower surface of ihc budy iiltovc. Situated in front of 
the is«uinK spinal nerves and between those pnrts of the bodies funned from the 
neural arches, they are hoinoitijjiouH with the joints between the atlas and axis, and 
between the atlaa and occipital bone. 

The anterior Longitudinal ligament fligft. 23o and 241) commences as a narrow 
hand attachfid to the under ioirfiicc of the occipital bone in the median line, just 
ii\ front of the atlanto-nccipital ligament, of which it forms the thickened central 
portion. Attached finnly to the tubercle of the atlas, it paewes down as the cen- 
tral portion of the atlanto-axoidean ligainent. in the tnid-line, to the front of the 
boily of the axU. It now begins to widen nut as it desceudtj. until it is nearly twu 

Via. 242.— PosTEaioa I.oxr.iTt'uiNAL Ligamext «f the 3i>irfE. CThoracic region.) 
CP^iclc^ cul Ihroiigh, and poMtrrior urchcs of v«rtebrit rviiiov«d.) 



Laiaral viiMtidBd ponion - 



(1 



1 liinBliuillual b*[d ' 



tncbee (5 cm.) wide in the lumbar region. Below, it is fixed to the upper sclent 
of the sacrum, becoming hwi in jwriosteum about the middle of that bone: hut 
is again disiinpuishable in front of the sacro-coccypeol joint, as the anterior sacro 
coccygeal lig.ament. lis structure is bright, pearly-white, and glisteninp. It3 
lateral border* are »ei>araled from the lateral bands by clefts through which lilood- 
vessels pa.ss; they are frequently indistinct and are l^etrt marked in the thoracic 
region. It ifi ihicktwl in the thoracic region, and thicker in the hnnbar than the 
cervioal. It is firmly connected with the bixhes of the vertebne, and is comptisetl of 
longitudinal fibrca, of which the su]>crficial extend over several, while the deeper 
pass over only two or three vertebne. It is connected with the tendinous expan.«<inn 
of the prevertebral muscles in the cervical, and the crura of the diaphragm are 
clowly attachcl to it in (hi* lumtiar reginn. 

The posterior longitudinal ligament (figa. 2■'^0. 242. 24.'1. and 2.'i(i> extends 
from the iiccipital Imiup tn the inccyx. It if* wider above than below, and com- 
mences bv .1 broad attnchnicnt to the cranial surf.ire of the bnsi-occipital. In the 
cen'ic.-^l region it is of nearly uniform M-idth, and e\ten<ls completely across the 



224 



Till': AKTiCVLATlOXS 



bodies of the vert«br». upon which it rests quit* flat. It does, however, extend 
slightly further outwards on each side opposile the inlcn'frtebral dists. In the 
lluifjutic and lumbar regions it is distinctly dentated, Ijeing broiider owr the inter- 
vertebral subtitancus and iiu> edges oi rhc bom-s than over the middle of the bodiee^ 
where it is a narrow bund strctchetl over the hones without resting on them, some 
areolar tissue and lilno<l-vraaels being int^Tposed. Thp narrow median portion 
couaisttf of lonjriiudinal filires, some of which arc superficial and pass over several 
vcrtebne; and ulheTs are deeixir, and exteml only froin one vertebra to the next 
but one below. 

The dentated or broader jKirtions (fig. 24:i> are fonned by oblique fibres which, 
springing from tiie bodies near ihe in(er\'ert.ebral foniniina. take a our\*ed course 
downwards and backwartls over an intervertebral fiiiro-cartila^e, and reach tlie 
narrow portion of the linanienl on Ihe centre of the vertebra next Ijelow; they then 
diverge to pass over another inten-ertebral disc to end on the body of the vertebra 
beyond, near ihe intervertebral notch. They thus pass over two discs and three 

Fio. 243. — Po«TBRioK LoxGiTunixAi. I.HMUKXT. [Lumbaf r«RioD.) 



Mwluui baod 
' IxpMidad tattnlpoTitBa 



vertebrte. Deeper still arc other fibres thickening these expansions of the lonfri. 
tudinol ligament, am) extending from one bone to the next. 

The last well-marked e\|>jnision is situated between the first two (seiinnents of 
the sacrum: below this, the ligament becomes a delicate central band with nidi- 
inentarj' expanisioiiii, being more pronounceii again over the wuTiM-occygeal joint, 
and lo^in^ itself in the lijriimcntous tissue at the back of the coccyx. The dura 
mater is tightly aitachc^l t<i it at the miirgin of the foramen magnum and behind 
the bodies of the upi>er cer^'icnl vertel>rBP, but is separatefl froni it in tlie rest of its 
extent by loow cellular tiwue wiiich beounies conden.'*e<l in the ertcral repion to 
form the sacro-<lunil liganicnt, The filum lerniinale becomes blended with it at 
tbo lawpf [lart >•( the fiai-min and back uf (he coci-yx. 

The lateral or short vertebral ligaqients (Hg. 2-11) ronM^t nf numerous short 
fibres situatefl Itctwcen the anterior and posterior longitudinal ligament!!, and passing; 
from one vertebra over the intervertebral disc, to which it is finnly adherenl, to 
tbo next vertebra below. Tlie more superficial fibres are more or less vertical, but 
the dep|>er decuKsate and have a cmcial arrangement. They are connected with the 
deep surf.ice of the anlerior longitudina] ligament, ami so tie it to the edges of the 



YERTKBRAL LIGAMEXTS 



22S 



I 



bfxlicH trf the vertchnp and to the inter\'ertehr]il discs. TJicy blend behind with 
the expan«i^ns of the p(isteri<>r longii.udinal ligaiTM^nl, iind so cnmplot^ the cwing 
n>und each arnphi^rthrodial joint. In the thnracir region, they overlie the radiute 
ligament, nnd In the lumbar they radiate towards the tran»\'erse professes. In the 
cervical region ilicy arc les* well marked. 

(6) TUE LlOAilENTS aiNNECTING THE AflTICT'Ljin PnoCEHSEa 

Class. — DiarUirom. Subdivision .^.IrJ/irfw/ia. 

The articular capsules (fifi. 235) whit-h unite llie.*e professes art) comptwed 
partly of yellow ela.^tif tissue and psitly of white fibrous ti&sui*. In the ccn'ical 
region only the inner sido oi the caiisulc \» funned by the li):Hniei>lu fliiva, which 
in the thoracic and iuinbiir regions, however, extend uiueriorly to the niarpins 
of the intervertebral foramina. The part formed of white fibrous tissue eonsisia 
of short, well-marked fibres, which in the cervical region pass obliquely down- 
wards and for^vardx over the joint, between the articular prt'cesses luid the poste- 
rior roots of the trnusx'erse jjrocesses of two contiguous vertebra?. lu the thoracis 
region i\\i' fibres are shorter, and vertical in directiiin. and are attached to the 
ba-vs of the transverse processes: in the lumbar, they arc obliquely transverse. 
The articular capsule in the eer\'icaj rt^gion are the most lax. ihose in the lumbar 
region are rjithtr tighter, and tho.se in the ihonveio rr-ijion are the tightest. 

There is one synovial membrane to each capsule. 



(f) The Lin.MiiiXTs uNmso thk Kamin.*: 

The ligaments flava (Hg. 244) are thick plates of closely woven yellow eliuilic 
tissue, interjKise*! between the lamina) of two atljacetit venebne. The first con- 
nects the axis with the third cc'r\-i(.'al,and the last the fifth lumbar with the sacrum. 



Flo. 214.' 



-LlOAMEWTA FtAVA IN TnR l.rUll,\R IlEaiOX. SEES moM WITHIN TH« 
8PI.VAI, Ca.-vai,, 



POMMB 04 IISMnantan 
■Uran ««nOTMl to 
■kow \t» mrueolai' 



Utuudium tUran 




Each liffament extends from the inner and posterior edge of the intervertcl»ral 
foramen on one side to a corresponding point an the other; above, it is attached 
close to the inner margin of the inferior articular process and to a well-marked 
tidge on the inner surface of the laxninie as far as tlic rout of the spine; below, it 
16 



226 



THE ARTICULATIONS 



is fixed close to the inner margin of Ihe superior articular process and to the dprsal 
aspect of the upper edge of the lamina'. Thus each, besides filling up tite interlami- 
tiarspftcccntersinto the formation of two articular capaules; they du so tu a greater 
extent in the tlioracic and lumbar regions than in the i-ervical, where the articular 
processes are placed wider apart. When seen from I he front after removing the bodies 
of the vertehra;, they are cionrave from side to side, hut convex fn>m above down- 
wards; they make a more decided transverse curve than iho arches Iiotween uhich 
they are placed. This concavity is more mnrkect in the thoracic, and still more 
in the lumbar region than in the cervical; in the lumbar region the lifiamenta fiava 
extend a short distance bet%veen the roots of the spinous process, blending with 
tlic interspinous hgament, and making a meilian sutcu:^ when seen from the front; 
there is, however, no sepiinition between the two pans. In the cervical repinn, 
where the spines arc bifid, there is a median fissure in the jtHow ti-"=sup which is 
filled up by fibn»-areolar tis-sue. The ligaments are thickest and -Mrongest in tirt 
Itmibar region; narrow but strong in the thoracic; thinner, broader, and more 
membranous in the cervical region. 

(rf) The Lig.vments ooNXEcrrNC the Spisocs Processks with oke anothiui 

Supraspinou:^ ligament, luler^^pinouf ligaments, and the Ugamenluui nuchce. 

The supraspinous ligament (fig. 246) extends, without inlerniption, as a' 
wcll-markt'd band of lun^ituduial fibres along the tij>s of the opines of the vertel)raB 

Via. 2t&. — Side View or Lioamiuctl-u NuchjK. 



"U- 



l-w 



A 1 



i\ 



LlCSI»aDIUIB llDollB 

Pint iBienpiBiti* in«*ci« . 



T 



S" 



from that of the wventh cen*ieal downwards till it I'lends with the fibrous tissue 
on the back of tlie coccyx. It covers in the lower end of the spinal canal, and iidds 
to the security of the sacr<»-co<'cygeal nrticulalion. 

Us niAre fni]>erl]ctal librej? are much linger Ihan the deep. Tiie deeper fibres 
pass over adjacent spines only, while the jiuiwrfictal overlie fteverul. It is con- 
nected laterally with the aponeurotic stniciures of the back; indeed, in the lum- 
bar region, where it is well marked, it itpivars to result from the iutenveaving 



INTERVEUTEHRA I. tXi 

of the tendinnuit fibres of the several muscles which arc attaclied to the tips of 
Ibe spinous processes. 

in the donsal region ii ia a round slender cord which is put on Ibe stretch in 
flexion and relaxed in extension of the back. 

The Ugamentum nuchs, or the posterior cervical ligament (fig. 245), is the 
continuation in the noi'k of the supraspinous ligaineiil, from which, however, it 
differs cnn.'*iderably. It i-i a slendiT vonical wptum of an doiijeutcd triangular 
fomi, exteiwlinc from the seventh rervic-al vertebra tn the external protuberance 
and the crest uf the occipital bone. Its anterior border is finiily attached to tlie 
tiiJfi of the spines of all the ccnical vertebrie, iiicludmi; the posterior tubert^le of ti* 
atlas, as well as to the <KTiput. Us posierinr border gives origin to the lra|)ezii, 
with the tendinous fibres of which muscle it blends, lis lateral, triangular sur- 
faces afford numerotis points; of attachment for the posterior muscles of the head 
and aeck. 

In man it is rudimentary', and consists of elastic and white &brous tissues. As 
geen tn the horse, elepliaiil, ox. and other mammifcrous quadnipeth^. it is a great 
and important elastic iigatneut. which even reachca alone the thoracic part of the 

Fio. 3i6.— The Istebspixous akd SrrnAsn.vocs I.[oaiie.vt» in the Lvubar Hegios. 



Tks tnurapiBoas tWiaMBi 



U :. 



■ Th« wpMipiapaf UsisMBt 



^a 



•<% 



^jr^ 



\^h 



spinal column. In these animals it serves tn support the head and neck, which 
otherwise fr^^in their own weigiii would lian;i; down. Its rudimentary state in man 
is the direct fonse(|uen<Te of lii.<^ erect ix^stiinn. 

The interspinous ligaments (fij;. 246) are thin menihntnou« structures which 
extend between the spines, and are couneeicd with the liaanienta flava in front. 
and the supraspinous ligament behind. The fibres pass obliquely from the root of 
one spine to the tip of the next : they thus decussate. TIhjv are best marked in the 
lumbar region, and are rrpineetl by the welUleve loped intrrspitiaUsi mu^'cles in tlie 
cer\'ical region. 




<«) Thb Lioambnts cosNKmso TiiK Tr.\nsvf.rsk Processes wim onk anoturr 

Tlie intertransverse ligaments are liarclv worth the name; in the (horacic 
region they fomi idnall rounded bundles, and in the lumbar they are thin man- 
hranous bands, quite incapable of action as lionds of union. They consUt of fibres 
passing between the apices of the trans\'erse proceiwes. la the cervical region they 
are replaced by the intcrtransvcrsaiea muscU*. 



22S 



THE ARTICULATIONS 



The afterUI supply for tbe column conierf from twigs of the vertebral, ascend- 
ing pharyngeal, ascemliiig ccn'ical, superior and aortic interctetaJi;, luinLmr, ilio- 
luuiliar, Hri<l Itit^Ttil t^ut^nil. 

The nerve-supply pomies from the spinal nen'es of pach region. 

Movcments.^The spinul eolmiin i«« sti formed of a nunjher of boaes and inter- 
vertebral discs as to serve many purjioses. It is the iixisof the jJceletoo; upoD it 
the skull is supported: ami with it the cHvitie!* of the trunk uikI the Hmbs an* con- 
nected. As a lixed column Ji in capable of bearing great weight, and. Ihnmgh the 
elaHlin intervertebral yubntiini'e.s. <if rcj^iminp and breaking the transinissinn of 
ehnrks. Moreover, it is flexiblr. and iherr-fore capable of innvement. N'ow, the 
nuige of movements of the column as a whole in very considerable; but the move- 
ments between any two vertebra- are slight, so tlifit motions of the spine may take 
place without any change in the shape of the colunm. and without any marked 
disturbance in the rotative positions of the vertebrae. It ik ab<iut the pnlpy part of 
[he intervertebml discs, which funn » central ehwtic pivot or ball, upon which the 
middle of the vprtebnp rr^l. that iht-se movetnents take place. 

The .'imount of motitm is ever\-where limited by the common vertebral Uka- 
meiiis, but it (le[>enda partly upon the width of the budies uf the vertebrae, and 
partly upon the depth of the discs, so that in the loins, where the bodii-.s are lurge 
and wide, and the iUm'A very thick, free motion bi perniitted: in tfie cervical region, 
though the discs are thinner, yet. as the ImmIIcs arc smaller, almost equally free 
motion ij* allowed. As the ball-like pulpy part of the intervertebral di."!" is the 
centre of movement of each verteljra, it is obvious that the motion would be of a 
n)lling chamcter in any direction l>ut fur (he articular pnK-e.'Jse.'*, which serve also to 
give steadiness to the column and to assist in bearinc the superincumbent weight. 
Were it not fr)r thes^e prficeHSC'*. the column, iiiste;ul nf being » statinnarn' one. 
endowed with the capacity of movement by muscular agency, would be a tottering 
one. requiring mu-wle-i to siea^ly it. The influence of the articular processes in 
lintititig the direction of inclination will appear from a study of the movements in 
the ihree re;fions of the spine. 

In the neck all movements are ponniited and arc frfie, except between the 
second and thinl cer\'ical vertebne. where they are slight, owing to the shallow 
intervenebrfd disc and the great pmlongation of the anterior lip of the inferior 
Kirface of the body of the axis, which checks forwanl flexion considerably. On 
the whole, however, extension atid lateral incljmilion an- more free and extensive 
in this than in any oiher region of the column, whilst flpxion i.s more limited than 
in the lumbar region. Kolittory inoveinenis are alf^o free, but take place, on ac- 
count of the position and inclination of the articuhir facets, not. as in the thonicie 
region, roumi a vertical axi.s, but round an oblique axis, the articular process of 
one side gliding upwar^ls and forwards and that of the opposite side downwanJs 
and backwnr«Is. 

In the thoracic region, especially near its middle. nnten>-posterior flexion and 
extension .ire ver\' slight; and. a.-! the concavity of the curve here is for%vanis. tb(* 
flat and nearly vertical surf.-^ces of the articular processes prevent an^-thing HkO' 
sliding in a cumllnear manner of the one set r)f pmcesxes over the sharp uji[>er 
edges of the other, which would be neeessar>- for fonvard flexion. A fair amount 
of lateral inclination would lie iiennitteil but for the im|)edimeiit oflferci by the ribs: 
while the ptwiiion and direction of the articular pnjccsses alhiws n>tation munrl 
a wrticol axis which pa-wcj* through the centres of the bodies of the vertebne. 
This rotation is not very great, and is freer in the upper than in the lower part of th< 
thoracic region. 

In the lumbar region, extension an<i flexion are ver>' free, esiM-cially l>etween" 
the third and founh and fourth and liflh vertebra', where th*> Imnbar cun'c is 
sharpest ; lateral ini-lination is al-«> very free between tficse same vertebra?, It ha.s 
been staler! (hat the shape and ptsiition of the articular pnK-esses of the lumbar and 
the lower two or three dorsal are such (is to prevent any rotation in these rpgionsr 
but, owing to the fact that the inferior articular prf)ceMses are not tightly embraced 
by the superior, so that the two sets of articular processes are not in contact on 
both sides of the bodies at the same lime, t-here is always pome space in which hori- 
zontal motion can occur round an axis tlrawn tlmjugh the central part of tlie bodies 
and inter\'crtebral discs, but it is ver>- slight. Thus, the motions are most free in 
those regionei of the colunm which have a convex cun-e forwards, due to the shape of 



SACRO-VERTEbRAL 



•2-2Q 



the iiit«r\'ertebral discs, whew tliere are no bony vt&IIb surrountiing scAid viscera, 
where the spinal canal is largest ami i\& conionls are less firmly attached, and where 
the iM-difles and articular processes are more nearly on a iruiiaveriM! level with tlie 
[Kwterior surface of the liodies of I he vertebne. 

NormuKt the uses of thelignnientafiavaheforRotien: tlicse useful little si ructiires 
— (1) complete the rootinp-iii of the spinal canal, and yet at the same time permit 
an ever-changing variation in the width of tlie iiiterUuninar spaces in llexion and 
extension: (2) tliey also restore llie ariiculotiiig surfaces to their iiDmial ptiKititin 
with regard to oncli other after moveriienie of the w)luinn; (3) and by forming 
the inner portion of each articular cajiimle. they take the place of muscle in pre- 
venting it from Ijcing nipped between the artifular surfaces during movement. 

HuBcIes which take part in the movemenlfl of the spinal column.—Flexors: Whfu 
acting with tlieir fellows of the oppu^itv Mtlc. Kei^tii.i ulidiniiiiii^i, --lenw-hywiJ, :ilcnio-lliyrctHiJ. 
thyrwi-liyoid, myloliyoid, ilign.-stric, su-nm-mRstdid, cxtRnml obliViu*, inlcmftl ohliqiie, iiuer- 
cOMtnl^, walcnti* «nl«rioi, pMwi" mnfcuuM and iKirvii', Imiga-i t-olli. Uii^il* cupili." (ir-cliw nipitiM 
anterior major). 

Extensors : Wken sctinc wjih their fcUown of the opixx^ite mde. SAcro-npinsliK, (|iiadrutus 
Irnnhorum, icminiiiimli*, iniilliridii.i, rotatonw i«[i!ri;i-, iril^Thiiiiialfn. wprnili [»ii!(trn"rrs, llie 
eplc>iuu'7. and with tin- M.Mpuht Jisvd ihe levator ncjipuljc und llip iii)|*r libmi vt tiie inijK-xiu*. 

Muscles which help to Incline the spfne to their own aide.— Sarnv-^jiinnlit, inindrutiw 
lumbonim, Kemi^pin.ilU. tiHiliifKliio, thit inlpnimiiilx lielpiiii( to fix ihe rilix. \]w •■Jtlvnitd &iid 
jnl«m)i] ohliipjc inii.>4i'k>ji, k-valon-i cuclanjui. M-rruli posienores, the itciUeniiij, spleiiius cervifis, 
loiigus rolli (<)blii|iic part). rotAtorc^, intcrtrftn»vt^rsnli>i, [»oas, and with tlie srapnlA fixed the 
Jevnior Tiipulic tuid die ii|>|>«r and lomtr tibrf_i i>f tin* triiijezius. 

Muscles which rotate the spioe and turn the body lo Cbeir own Bide. — Spleniiu cerviris, 
inirrnni oliliqiio [rli* nttr< ItoiriK lixcdj, scrTaiii.'* ptHiiprior inferior, and with tl*e scapula fufcd 
the iimt.T (ibrm o( iftc lr.-i|>i'j(iii.-<. 

Muscles which rotate the spine and turn the body to the opposite side.— MuUUiJtu, 
Miiii»piii.ili:t, (vtcairil oblii|ii(>, the lover oblique fibroi of the longiis colli, and Tiilh Lhc wnpuLu 
and humrnut fixed Ibe latiiiairiiuB doraj aud trapezius. 



I 



2. THE SACRO-VERTEBRAI. ARTICULATION'S, OR THE ARTICULA- 
TrON*.S OV TllK I'KIA'IS WITH THE tiPINE 

(u) Class. — Fntxe Synckoiulrosis. 

(b) Class. — [Hartkrosijt. SuMivision.— A rthrodia. 

As in the intervertebral articulations, so in the union of the firat portion of the 
sacrum with the lai^t lumbar vertebra, there are two sets of joints — vix. (a) a syn- 
chondroaiSf lictwecn the bodies and intervertebral disc; and (b) a pair of arlhrodial 
joints, between the articular procesaes. The union is eltecterl by the foUowinf; 
ligaments, which are common to the spinal colutnn: — (i) anterior, and (ii) poste- 
rior longitudinal; (iii) lateral or .^ihort vertebral; (iv) capsular; (v) ligamenta flava; 
(vi) su|>ra- and (vii) interspinous ligaments. Two special accessory ligaments 
on either side, vix.. the Hacn>-Uimbar and the ilio-lumbar, connect the pelvis with 
the fourth and fifth lumbar vcrtcbne. 

The sacro-liunbar ligament (fig. 247) la strong, and tri.ingyUr in sliajw. Its 
apex is above and internal, being attached to the whole of the lower border and 
front surface of the transverse process of the fifth lumbar vertebra, a.« well as to the 
pedicle and body. It is intimately blended wiih the ifny-lumhar liqnmetd. Below, it 
has a wide, fan-shaped attachment, extending frrun the edge of the ilio-hnnbar liga- 
ment forwards to the brim of the true pelvi.*: blending with the periosteum on the 
base of the Bacnim and in the iliac fofwa. and with Thesuix»riorsncro-iliao ligament. 
By its sharp inl^-rnal Vmrder it linill* exl^rnally (he foniinen for the Uint lumbar 
ntrvt. It is pierce*! by two large foramina, which Iransmit arteries to (he sacpo- 
iliac synchondrosis. This ligament is in series with the intertransverse ligaments 
of the spinal column. Il is sometimes dcwriljcd as a part of the ilio-himhnr liga- 
ment. 

The ilio-lumbar ligament (fig. 247') is a strong, dense. trianRuIar ligament, 
which springs from the front surface of the transverse process of the fifth lumbar 
vertebra as far as the body, by a strong fawiculas from (he [>oPterior surface of the 
process near t)ie tip, and al^n fnnn tlie front surface and lower edce of the trfins- 
verse proccv- nnd pedicle of the fourth lumbar vertebra, a."! far inwards as the Hodv. 
Bel'i-ftrn ihexe tivn lumhnr vfTfehrir il « inseparable from the intrrtraitsirersr li^jament. 



230 



THE ARTICULATIO.VS 



At ita origin irwn the transverse pmcess of the fifth lumbar vertebra it is closely 
intervvdvi'ii with the sacro-luiiilmr hgwiient. and some of its tibres ^1n•eluJ down- 
wards on to the hwly uf the tiftli verlehni. while ol.iiers iiKceiui tci the tlit«." above. 

At the pelvis it is attachttl to the inner lip of the crest of the ilium for about 
two inches (5 cm.). The highest fibres at the spine fomi the upper edge of the 
ligaineni at llie iwlvis, thoae whirh cnme fmm the piwterior ijortion of the trans- 
veive process of the fifth lumbttr vertebra foniiinji t!ie lower, while the fibres frton 
the front uf vhv saiae procti^ pass nearly horizontally outwarils. 

Xear the spine the surfai-e** Unik dirertly harkwanls and fonvurtls, hut at the 
ilium the lifr-inient gets stjincwhut twisted, so that the p<eierior Joirfaee looks a 
little upwarrls, and the anterior Itmks a little downwanls. 

The anterior surface forms part of the pf'isterior Imundar)' of the false pelvis, 
and overlies the upper part of the popteridr sacro-iliac ligament; the pcM^terior 
surface forma part of the floor of the spinal groove, and give* origin 'to Ihc muilifidttK 

Fio. W7.— AxTBRioR ViBW or thb I.iuamex-tm bktwkkn the Spinz axd Prlits. 



/ 



roru&aslorMktvrtar pniiMirr bnwak ef (ouftb 



Tb» 1U«-1bbMt 



TerkmMi for Ital 
lamkM DM** 

Itti « «>*ii*W«i Awe - 



\\. 






Ugaisaai 



arc- tuber oaa 
UcMn«ait 



cra^IHMiw lifintii. 



mu.'fle. Of the honilers, the upper i-< oblique, has the anterior lamella of the lum- 
bar fascia attached to it, and gives origin to the ([lutdnUits lumbnruin: the lower 
is horizontal, and is adjacent to the upiwr wlge of the sncro-Iurabar ligament ; while 
the inner is erescentie, and fonns the outer boundar>' of a foramen through which 
the fourth tumlmr nerve paeaee. 

The arterial supply U vcn- free, and comes from the last lumbar, ilio-lumbi 
and lattrnl siicral. 

The nerve-supply is from the svmiKitlieiic, as well as fmm twigs from the 
fourth and liitii luintKir nen'es. 

Movements.— The angle fonned by the sacrum with the spinal column is called 
the Kaero- vertebral angle. The pelvic inolinalion does not depend entirely upon 
this angle, but in great part upon the ohiitiuity of the innominate liones'to tho 
sacrum, so that in males in whom the a^'eraEe pelvic nbliquitv is a little greater, 
the average BacrtHverteltral aiiffle is considerably less than in females. 



PBIVIC 



231 



The BiUMi(>-\-enebral angle in the male Bhows that there Ih a greater and more 
Hudden change In direction at the SAcroveitebral union than in the f«ma1e. A part 
of this change in direction is due to the greater thickness in the anterior ptirt of the 
ioten'ertebral ftbro-cartila*:e between the last lumbar vertebra and the sacnuii. 
Owing to the gre^tt^r thickne^ of the inter vertebral disc here thiiii elsewhere, the 
movements permitted ut this joint are ver\' free, Iwinj! freer than those between any 
two lumbar vertebne. As tlie diameter of the two contiguous bones is lens aniero- 
posterioriy than laterally, the forward and backward motions are much freer than 
the lateral ones. The backward and fonvard motions take place ever;' time the 
sitting is exchanged for the etondtng position,, and the standing for the sitting pos- 
ture: in rising, the back ia extended on tiie aacnun at llie Bucro-lumbor union; in 
iitting down it is flexed. 

The articular processes provide for the gliding mox'ement incidental to the 
extemnon, flexion, and lateral movenienta; they al^ allow tfoiiie horizontal move- 
ment. ncccssar>- for the rotation of the epine on the pelvis, or pclvjg on the spine. 
The inferior articular procesws of the hith differ conaiderably frpm the inferior 
processes in the rest of the lumbar vertebne. and in direction they rewtnble some- 
what tho» of the cervical venebra>; while the superior Jirticular processes of the 
sacrum differ in a similar depree from the superior processes of the lumbar verte- 
bne. This difference allows for the freer rotation wliioh occure at this joint. 

The sacro-vertebral angle averages 117" in the male, atid 13(P in the female; 
while the pelvic inclination averages 155° in the male, and l'i*>' in the female. 

As already sratai, the movements at the aacro-veriebral joint are the same 
AS those in other parts of the spinal column, but more extensive, and the musclee 
which pniduce the movements are those nientioned in the preceding groups which 
cross the plane of the articulation. 



3. TFIE ARTICnU\TIOXS OF THE PELVIS 

This group may again Ije subdivided into — 

(d) The sacro-tliac. 

(b) The sacro-coccygeal. 

(r) The intercoccygeal. 

(rf) The symphysis pubis. " 



V 



(a) The Sacro-iu.^c Abticulation and Sacro-soiatic Lioamexts 

C\ASB.^DiarthrQsi&, Subdivision.— .IrtArWta. 

It is now generally mimittcd that the sacro-iHac joint is a diarlhrosis, the articular 
surface uf each bone being covered with a layer of cailitage, whilst the cavity of the 
joint is a narrow deft and ihe cajwide is extremely thick posteriorly. The car- 
tilage on the sacrum is much thicker than thot on the ilium and the cartilages are 
sometime-s bound together here and there by fibrous strands. The bones which 
enter into the joint ore the sacnam and ilium, and Ihey are bound together by the 
following ligaments: — 



Anterior sacro-iliae. 
Posterior aaem-iliac. 



Superior sacro-iliac. 
Inferior sacro-iliac. 



Interosseous. 



The anterior sacro-iliac ligament (figs. 247 and 2-lS) conatsts of well-marked 
glistenintj fibres wliich pass above into the superior, and Ix-low into the inferior, 
ligaments. Ii extends from the first three lK»iies of the saeniin (o the ilium Iwiween 
the brim of the true jjelvis and the great sacnv^oiatic notch, blending with the 
periosteum of the sacrum and ilium as it passes away from the united edges of the 
bones. 

The superior sacro-iliac ligament ffigs. 1247 and 24A) extends across the upper 
margins of the joint , from the ala of the sjicmm lo the iliac fossa, being well markeii 
along the brim of the jwlvis, wliere it is thickened by some closely packed fibnes. 
Behind, it is far stronger, especially l>enealh the trail* vei^* process of the fifth 



232 



THE ARTICULATIOXS 



lumbar vertebra. This ligament is connw^tcd wiih the strong sacro-lumhar liga- 
meot, which spreads outward-i and forwards nver the joint to roach the ilian foasa 
and terminal line. By $(m\c authura it ia deseriLKrd a;^ a purt of tlic ilio-Iumbar 
ligament. 

The posterior sacro-iliac ligament is extremely stniiig und cini.'<ist.s iti^Bcntially 
of two set8 of libres, devj) and Buperiirijil. The deep (ibr«s, tlie short posterior 
&acro-iLiac ligament, pass downwards and inwards from ihe rough anta of the 
ihum behind the auricular surface to the Iwick of the lateral nia.'?* of the sacrtim, 
both outride uf and betiveen the upiwr foramina and to tin- ujipcr sacral articular 
pnwress, and the area betweeu it and the Hnst sacral foramen. The deepest fil«re« 
of this group constitute llie to-called iiitvriA^seous ligament. The mo it; suixTticial 
nbn^, the long posterior sacro-iliac ligament, an> oblique or verliral, mid pujsH 
from the posterior superinr iliac spine l.u thf second, third, and fourth mberrle« on 
the back of the sacrum, a more or leiss wclUicfincd band which goes to the third 
and fourth sacral tubercles being called sometimes the oblique sacro-iliac band and 
sometimet) the long straight baud- 

Fw. 3*8. — Vebtical Afttero-postebior Skction' or thh Pblvw. 



Vf>.-) 



^n''^ 



Ci' 



USMS4CI 



AnUrl or •Mvo^Ulao 
tahrlar •aoro-Hlae 



^iA 



m 



w/m 



^ 



llfMMIM 






The inferior sacro-iliac ligament dig. 2-lS) is covered Whitid by the upper 
end of the sacrt>-tub(>r(nis ligitmcnt: it consists of strong fibres extending n-om 
the lateral border of the sacrum below the articular facet to the posterior lliftc 
fi|)ines; 5ome of the Bbrea are attached to the deep surface of the ilium and join the 
interosseous ligament. 

The interosseous ligament is the strongest of all, and consists of fibres of different 
lengths passing in various directions between the two l»ones. Immediately almve 
(he inlerxpimais notrh nf the ilium the fibres nf this ligament are very strtmg. and 
form an dpen network, in the interstice** of which is a quantity nf fal in whicli the 
articular ve-f.-'el.s raniifv. 

The ear-shaped cartilaginous plate, which unites (lie bones hmily, is accu- 
rately ajjplied tt> the auricular surfaces of the sacrum and ilium. It is alxmt oniv 
twcifth of an inch (2 mm.) thick in the centre, but becomes thinner towarda the 
edgM. Though closely adherent to the hones, it tears away from one entirely. i»r 
from both partially, on the application of violence, sometimes breaking irregularly 
so that the grcaier jrortion remains connected with one bone, leaving the Dther hone 



233 



rough and hare. It is, really one mass, and is only occasionally formed of two platen 
with a sjTiovial cavity bciu-eeti Ihem. Becauae of tlie opcusiooal presence of a more 
or less extensive synovial cavity witliin tlie libru-cartilage, ami also of a isynovial 
liulng to the ligaments poising in front and bcliind the articuluiiou. the teroi ' Duir- 
thro-auiphiai'tiirasiti' ha.s l>eeii ^i\en to this joint, uiiil alt^o to tlio HViiiphvius pubis. 
TesLut niciitioiiji certain folds of .■4yni>vlul inetiil)ntne filling up gafis which litre 
and ihcro occur ar tticninrf^inof ihc tilmwartilasc. hut I Iiavonm rny.-wlf seen sui'lu 

The sacro- tuberous (great rir posterior sacro-sciatic) ligament (li^. 247, 
24.S, iind 24'.t) i« altnche^l above to the jxwjteiior extremity of fite crest of t}ie iliuni 
and the external aspect i*f the nttetcrior iliac spines. From this attachment some 
of its fihrcs [KLss downwanLs ami huckwanis to Ijo attached to the outer bnrdRna and 
posterior surfaifs of the low-er three sacral vcrtebnp and upper two PCEnieiits of iho 
coccra; while others, after passing for a certain disL-intThackwanis, cur\'e forwards 
and downwai"ds to the ischium, fomiinjc the anterior free marpn of the ligament 
where it limits jjostcrioHy the sacro-sciatic foramina. These fibre?! are joined Iiy 
others which arise from the posterior surfaces of the It>wer thre^ sacral vertcbrA* and 
upper jiioces of the coccyx. .\t the iscliium it is fixed to the imicr liunler oi the 
lulierosity, and sendH a thin f-lmrf) process upwanl^ iilonfr the ramus of the ischium 
which is called the falciform process ifig. 249), and ia a prolongation of the pos- 
terior edge of the ligament. A great many fibres pass on directly into the ten'lon 
of the biceps muscle, so that traction on this musi-le braces up the wtiole ligumeui, 
and the coccyx is thus made to move on the sacrum. The ligament mny not un- 
fairly be described as a tendinous expansion of tlio nuwle. whereby it.-> action in 
extended and a more advantageous leverage given. It is broad and flat at its 
attached ends, but narrower and thicker in ihc centre, luoking like two tri.ingular 
expsmsions joineil by a flat I«tnd, tlie larger triangle being at the ilium, and the 
smaller at the ischium. The fibres of the ligament are twisted upon its axis at the 
narrow part, so that some of the su|M>rior fibres pa;^ to the lower Imrder. 

The pfBt^rior surface gives origui to the ijlntem marimm muscle, and on it 
ramify the loops from the posterior bmnrheB of the sacral nerves; its anterior sur- 
face ia closely connected at its origin with the sacrn-sjMnous ligament, and sonic 
fibres rjf the pirijormis muscle ari.«e from it ; below, the ot/turator inlemus passes out 
of liio pelvis under its cover, and the internal f/utlic vessvls iind turvc jjuss in. At the 
ilium, lis p^j-stcrior edge is continuous with the vertebral aponeumpi.s: while to the 
anterior edge i.s aiiachoti the thick fa-scia covering the gluteu-s mediiis. The obtura- 
tor fascia is attache*! to its fidrifomi edge. It is pierced by the coccyf^al branches of 
the inlerior gluteal {sciatic) arfcvff and the in/erior clunial {perforating cutaneous) 
nenr from the ntxoud and thirtl mcral. 

The sacro-spinous or small sacro-sciallc ligament (figs. 247, 248. and 249) 
is triangular and thin, s]>riiiciiig by a bmnd bitfe from the lateral border of the 
sacrum and coccyx, from the front of the sacrum Ixith above and below tlie level of 
the fourth «acrai foramen, and fmm the coccyx nearly a>i fur as its tip. By ita 
apex it is attached lo the fn>nt surface and ttie Ijordcrs uf the ischial spine as far 
outwards as its base, lis lihres decussate so that the lower one* at the coccyx 
become tlie highest at the ischial spine; muscular fibres are often seen intermingled 
with the ligiimentnas. 

It is situated in front of the sacro-tul)crou.'^ licument, with which it is closely 
connected at tlie sacrum, and scparalcs tiie greater from the lessor saero-«ci/itic 
foramen. Its front surface gives attachment to the cocci/gcus nmscle, which over- 
lies it. Behind, it is connected with, and hidden by, the sacro-tuberous (great 
sncro*»!ciatic} ligament, so tliat only the outer inch or lets (2 cm.) and a small part, 
of its attiichmcnt in the coccyx can bo seen; the infcTTw^ ;»4rfir ncr\'c ahw piu-iM'?* 
over the [KWtcriitr surfare. 

The arterial supply comes from the superior gluteal, ilio-lumbar, and lateral 
sacral. 

Tlie nerve-supply is from the su}ierior glufeat. sacral plexus, and external 
tmgs of the p<>slerior divisions of the lirst and second sacral nen'es. 

Movements. — Recent investigations have shown that in spile of (ho inter- 
locking of the arlirular surfaces and tlic strong ligaments e<innectinK the bones 
together a .slight amount of movement, both a gliding and rotator.-, doeg occur 
at the sacro-iliac joint. The gliding movement i^ both up and down, an<I fnrwanis 
and backwards, and the latter \s juiiociated with a .slight rotation round a tmns'^'crse 



2Zi 



THE ARTICULATIONS 



axia which passes through the upper tubercles on the back of \\\e sacrum. Thu 
movement is bur small in extent, nevertheless a« Ilie Iiaw of llie sacrum movos 
downwards and forwanis the conjugate diameter of the pelvic iolct is diminislied 
and at the same time, as the coccyx moves up and back, the coiijuiiate diameter 
of the uutloi is iiii^reased. ThiH mtjitury tmnemeiit is limitefl prin<'ipully by the 
8acn>-scialii: ligament!* which prevent, any extensive upwarxl and bjiokwa'rrJ move- 
ment of the cdccyx and lower part of the .sacnim. 

downward displacement of the sacrum when the botly is in the sitting posture 
Is preveritetl not only by the surrounding ligainentii. but also by the wedge-like 

Fia. 240. — SAcno-sciATic Liqa.uent». (Posterior virv.) 



V :iiiaro-liib«roiw llcaM«nt 



Sucni-cploaBs l)r>ai«i( 



Pklitlform proosH o[ Hora-UilMroiw 
ImiBofi I 






character of the sacrum, wljich is broader above than below. Dciwnward and 
forward displacement of the sacrum in the erect poslure ia prevented by the liga- 
ments and more particularly by the posterior sacro-iliac bands, while backward 
diriplacontenl would Iw hindered by the breadth of (he anterior as con(ntKte<l with 
the po>.trTior prirt of the sacrum h* well as by llie anterior lie;nments. 

Relations. — The sacnvihac jnint is in relation above with psoas and iliaeuH. 
In front it is in relation at its up|rer part with the internal iliac vessels and obturator 
nerve, and at it« lower part with the piriformis niusele. 



(i) TllE SAITR0-rO<-fYGKAL ABTICUU^TION 

Class. — False Sffnchomiroxis. 

The last piere of the .sacrum and first piece of the coccyx enter into this imion^ 
and are bound together by the following ligaments: — 

Anterior sucro-eoccygeal. Deep posterior saero-coccygeal. 

SuperHcial pa-rteriorBafro-coccygeal. I-aicral .sacro-coreygcal. 

Intervertebral substance. 

The iatervertebral fib ro- cartilage is a small oval dbc. three-quarters of nn inch 
fidunit :* cm. > wide, and a hf lie Ic-ii! from before backwards, closely connected with 
the surrounding ligaments. It resemble*' the other cWsc^ in stmciiirr, but is softer 
and more jelly-like, thoURh the lamin:e '<f tlie Tdtrou.* portion arc well marlced. 

The anterior sacro-coccygeal ligament is a prolongation of the glisteruni; 



sAcao-coccrah'A l 



235 



iibrnuti structure on the front of the sapnun. It is realty the lou-er axtremUy of Lti6 
anienor loii^itudinHl ligHnjtint, which is tlucker over thid juiiit than over the ceDtral 
part of either of ihe bones. 

The superficial posterior sacro-coccygeal ligament (fig. 2o0) is a d'mei 
continuation of the pmlerior loniiiluiliiiiil ligament uf the roluiim, consisting of 
n uarrow band of closely packe<i fibi-es. which L»ei;ome blended ut the lower bonier 
of the first segment of the coccj'x with the tilum terminale and deep poeteriur hgii- 
nient. 

The deep sacro-coccygeal or supracomual ligament ifig. 2'/j) Is ihc pru- 
!on>5atii>n of ihe supraspinous which t.>econies insepurably btended with the »po- 
neurosU of tlie sacro-sftimiUs (errciw" sjnme) upponite the lamin* of tlie third eftcral 
vertebra. »nd is thus prolonged downwards upon the back of the cocc\'x, pu-^winp 
over and roofing in ilic h)wcr cjid of the spinal ruual where the lamina-- are <lc(i- 
cient. The median tibres ^the supraspinous ligament) e\ten<l over the buck of 
the coccyx to its tip, l>londing wiih ihe suporticuil poaterior sacm-coccygcul hgii- 

FiQ. 250.— LIOA«E^JT« coxkectivo Sacrfm awo Coccyx POBTEnroitLV. 



taptrOeul pan ot \ 

Ui« Mipr«aBiu«u* 1 



w 



S/: 



kN 1 



^ '■' 



0«ep prt *t tka lu- 

liuaaduv 



'// 



ltiiii»nt 



end «rtb« fonunmt Imisi- 



J 






nawilng lb* aomoa of ifea 

■ad IIU-BA4 dawn 



lint and filuni rerminale; the deeper filires nm acrais from the stunted larainie 
on one wide to Hie next Itelow on the opposite side, and from the sacral coniua on 
one side to the coccyceul on the opposite, some pacisinK between the twu cornua of 
Ihe eame .«idn. and bridging the iipertuiT" ihnjugh which the fifth ^acral ner\'e pa.ssc». 
Its posterior nurface civcs origin to the gluhu^ maTimuf^ rtiuwle. 

The lateral sacro-coccygeal nr intertransverse ligament (fig. S.'vO) is merely 
a quantity of fibrous tissue which pa.*ees from the transverse procc-w of the eocc>-x 
to the lateral edge of the sacnun l)elow lis angle. It is connected with the sacro- 
aeiatic ligaments at their attachment?, and the^/M sorra/ ner\e escapes behind it. 
It is i>erforato<i by twia^i fnini the laleral i^aenil anery and the corcygeal nen*e. 

The arterial supply is fnitn tlie lateral sjirral and middle sacnil arteries. 

The nerves come from the fourth nnd fifth sucnil and coccypejil iien^e;^. 

The movements permitte^l at lhi:« joint are of a simple forward and backward. 
or hinge-like character. In the act of defecation, the bone ia pushe<i back by the 
fieca! mass. and. in parturition, by the fa'tus; but this backward movement is 



236 



THE ARTICULATIONS 



controllwl by the upward and fonvard pull of the levator ani and coccygeus. 
ext«raal sphincter also tends to pull the t-occyx forwards. 



The 



(c) Intkhcoccvueal Jlhxts 

The several segments of the coccjtc are held together by the anterior and pncitfi^ 
nor longitudiniil ligaments, wliich coiiipletely cover the bony ntidulcs on their 
anterior aud iwsienor asjwcts. Laterally, the sacro-sciutic ligametiis, beinp al- 
tadied tu nearly the wJmie lengih of tbe coi'cyx, serve to ntiineci them, ]leLw-«en 
the first and second pieres of the coiryx tliere ia a very perfect arnphiarthrodiftl 
joint, with a well-marked intervertebral substance. 

Movements.— But little movement, ot'cura as a role at the i^acro-cocrygeal and 
interiroccyyeal joints, but when the bead of the child is passing through the pelvic 
outlet at birth, the tip of tbe eoecyx h displaced backwards, it may be to the extent 
of one inuh. 

(d) Thk Symphysis Ptjnw 

Class. — False SipuJiondroais. 

The lH»np.s entering into thus joint are the pubic ponitms nf the hip-bones. Tliis 
joint is shorter and braader in the female than in the male. The ligaments, which 
completely -surround the artieulalion, arc: — 

Superior. Anterior. 

Inferior or arcuate. Posterior. 

Intcrpubic cartilage. 

The superior ligament t'figs. 2.'il and 252) is a well-marked stratum of yel- 
lon-ish fibres which extends ouiwanis alon^ the crest of tbe pubis on each side, 
blending in the middle line with tbe interosseous cartilage. It is continuous in 
front with the deep transverse fibres of the anterior llKament, and behind with the 
pasterior ligament. It gives origin to the redus aidovnnis tendon. 

Fio, 231. — Anteuioh Vikw or tmk Symi'hmw Puum (Malk), miuwi.vo tub Dbccs&ation 
or THK FtDHBii nr Tlia AKT«moK LlUAUE-ST. 




Atmutf* a#4&um 



The posterior ligament ((ik- 2-5-3) is alight, and, excepting above and Itelai 
coiiiiiJts of little more than thickened periosteum. Xear the upper part is a bau<! 
(if simng fibns^. reaching the »h<>le width of the pubic Uprieii, and continuous nitli 
the thickened perirtsteal fibres alitti;; llic Icnninal line. Itelow. many of the upper 
and .superficial fibrt^s of the arcuate lijiamont ascend over the Imck of the joint, 
and interlace across the median line with fibres from the opposite side nearly aa 
high a£ the mid^lle of the symphysis. 

The anterior ligament (f^. 251 and 232) is thick and strong, and is cloE«ly 
connecter! with (lie fascial covering of tbe nm-scles arising from the Ixaiy of the 
pubis. It consists of .teveral strata of thick. dwu.«*af ini; fibres of difTerent degrees 
of ul)li«iuity, tbe superficial l»eing the most oblique, aiul exten<iinp lowest n\'cr llw 
joint. Tlie most superficial descending fibres extend from the upper border of the 



TfiE SYMPJirSIS PUBIS 



237 



pubis, cross otiiere from tlie oppueile side about tlie middle of the s>*inphy£i£, and 
are attached to the mmus of the opposito Imne. TUc iiiiwl. KU]jerfu-itti iiM-en'ling 
libres come fmin tlie areiiate ligaitieiit, arcli upwartk, and decussate with other 
fibres across the middle line, and are lost on the opposite side beneath the desrenil- 
inR set. There is another deeper not of descending fibres which arise below the 
angle, but do not descend so far as the superficial; ami adeejierBet of ascending, 
which decu:«sate, and reach bigher than the Huperficial set, and arc couuoctcd with 

Fio. 252. — AjmauoR View or thk SrumTXi* Ptbib (I-'khalk), suowKa grkatkr Wiutw 

IIETWKKN THE BoXCS. 
X'ltwno* |vuMe llgamval 




the arcuate ligament. Some few Iraatvense fibres pass from side to side, ospecially 
above and U'linv iIh- points (tf deciiy-^ijiiinn. 

The arcuate (inferior or subpubic) ligament (figs. 2fil, 252, and 253) is 
a thick, arch-like band of closiely piieked fih«a which filla up the angle between the 
pubic rami, and fonna a snuKJih, rounded summit to the pubic arcb. On section, 
it is yelinwiah in colour and tlirce-eighthM of an inch (I cm. ) thick in the middle bne; 
it is inseparably cnnnecrwi with the intprimbjr cartilage. Both on the front and 
back aspects of the joint it gives ofT ilecuHsating fibre-s, which, by their intcrlace- 

Fio. 233.— PoBTF-niofi Virw op the .Sv«nin«r« Pi'»i», showi.vo tbe Backwahd Pkojeo 

TldS IIP TH*: S»MPHl!'l\L SrBsTAVCE ANU TUB ltECC"(WATlC>N OK THE FlHltEA FltOM THB 

Aaci'ATE L|(;au):nt. 




ArvDmM llgiinivist 



ment over tlie anterior and ijosterior ligaments of the a.i'mphyais. add very materi- 
aJIy to its Becurity, In fact, the ligament may lie said to split superiorly into two 
layers, one ptk-wing over the front, and the other over the back, of the articulation. 
The interpubic fibro-cartilage varies in thicknfcw in different .lubiects, but 
is thicker in the female than in the male. It is thicker in front tlinn l»eriind, and 
projects beyond the wlges of the Ixjnes, especially posteriorly (see fig. 253), blend- 
ing intirniitely with the ligaments' at its niargina. It is sometimes umnterruptetlly 
woven thmughout, but at others has an elongated narrow Jisijure, partially dividing 



THE ARTICULATIONS 

the cartilage into two plates, with a little llui(i In tlio intOTspoce (fig. 254). This 
is situatei'l townrds the upper and posterior a»pcc(.i, Imt docs luii U8ually reach 
either; it generally exteml-s about half tlw length (>f the cartilage. When this cavity 
is large, especially if it reaches or approaches very near 1« the circumference of tlm 
rjirtjlage (which, however, it very rarely does), it is thought by some anatomists 
that it mure nearly r^scmblos a diarthrodial than an ampliiarthixxlial joint, and it 
is then closed with the sacro-iliac joint under similar conditions, as 'diartliro- 
amphiarthrosis.' The intenjdseous cartilage \s intimately adherent to tlie layer 
of hyaline oirtilaKe which covers the inner surface »f each puhic Uine ; the osseous 
surface Is ridged to give a firmer attachment; and, on forcing the bones apart, it 
docs not frequently split Into tntt plateei, but \& torn from the bone on one side or 
the other. 

The arterial supply is frain twigs of the intcnial jjudic, pubic branches of the 
obturator and cpiga-siric, and ascending branches of the internal circumflex and 
8uperfici.il external pudic. 

Tlie nerve-supply has not l>een satisfactorily ma<ie out, but it probably comes, 

Ft(K 354.~SHcno« o» Syuphtsik to snow rat. Syn<i%-1ju. CAvrrr. 






1 •*-..' -• ;( 



' •• ■' ■. 






v^\ 



in part, from the internal pudic and in part from the ilio-hypofi^tric and ilio- 
inguinal. 

The movements amount onJy to a slight yielding of the cartilage; neither 
muscular force nor e_\trinsic forces produce any appreciable movement in the ordi- 
nary condition. Occsisionally, jw the nwull of cfiihl-ljcaring, the joint becomes 
umiatumlly looae, and then walking and standing arc painfully unsteady. It is 
known that, during pregnancy and parturition, the symphysea! cartilage becomes 
softer and more vascular, 80 as to permit the temporary enlnrgement of the [lel^^; 
but it must W remembeted that the fibres uf the oblique muscled decussate, and 
thus, during labour, while they force the head of the fu-tus down, they strengthen 
the joint bv bracing the bones more tightly together. 

Relations. The interpuhic joint is in relation alwve with the linea alba, nehind 
with tlie prostate and the anterior bocler of the bladder. In front with the sus- 
pensory' liganieiil of the penis or clitoris and below wit h the dorsal vein of the i>enia 
or clitoris and the upper border of tlic urogenital trigone (triangular ligament). 



4. THE .\UTICl J-ATIONS OV TUt: lUllS WITU THK VERTEBRAE 

These consl'st of two sets, vi^.:— 

(a) The capitular or costo-central: i. e., (he artJctilation of the head of the 
rib with the vertebnc. 

(6) The CDSto-transverse, or the articidation of the tubercle (oi each of the 
first ten riljs) with the tnin.svei-se process of the lower of tlie two vertcbrEB, with 
which the Itead of the rib articulates: i. e., (he one bearing its own nuuil^er, as the 
Gn^i. rib with the lm;i thoracic vertebra, the second rib with tite second thoracic 
vertebra, and so on. 



COSTO'VERTEBRAL ^^^ ^^^ 

(a) Thk Capitular AnnciiLATiow 
Class. — Diarthroniti. Subdivision. — Cotidylarthrosis. 

It U a vtry perfect joint, into the formatioti of which the bead of the rib and 
two rertebra;, with the inten-ertebral disc between them, enter. In the ciw>e of the 
first, tenth, cleventli, and I welftli ribs, it is formed by the head of the rib articulating 
M^ith a wiiifrle vertebrH. 

Tlic ligaments ure:^ 



Articular capsule. 



Radiate. 



[nicrarticular. 



The articular capsule (fig. 25S) consisls of i^hort, strong, woolly fibres, com- 
pletely surrounding the juint, which are attaclied to the bones and interverti;l)i'al 
subst-anw.s. a little beyond their Hrtirular inarBiris. At its upjHjr part it reaches 
through the inten'ertebral foramen towards tire back of the bodies of the vertebra, 
l>eing strengthened hei^e by fibres whicli at. inten'als ronnort the anterior with the 
posterior longitudinal ligaments. The loiver fibres extend douTiwnrds nearly to the 
demi-facet of the rib below; liehind, it is continuous with the neck ligament, and 
in front is overlaid by the radiate. 

The interarticular ligament (fig. 256) ronsii<t8 of short,, strong fibres, closely 
interwoven with tlie oulemioat ring of the intei^'ertebral disc, and attached to the 

FlU. 25}.— ThB CArSl'LAtt LiOAMCNTS op the CoCtTO-VBRTKBRAl. JotNn. 



Jt^M 



m 



oorvie«l VBdetira 



Cacoular lIMncnt of Btal 






'nntM 



transverse ridge separating the articular facets on the head of the rib. Tt completely 
divides the articulations into two |>arb4, but i1(k« not brace the rib lightly to the 
spine, being loo^ enough to lUluw u moderate amount of rrvtHtion on its own axis. 
There Is no intorarticular ligarnont in the coato- vertebral joints of the first, tenth, 
eleventh, and twelfth ribs. 

The radiate unterior costo-central or stellate) ligament, a thickening of 
the anterior |>art of tlie capsule (iigs. '2'jG and \i.'}7). is the most striking gf all. and 
cotisists of bright, j^eurly-white lilirei^ attarlicd to the anterior suriacc, and upper 
and lower Itoniers of the neck of llie rib, a little Way beyond llie iirtirular facet: 
from thi.s they radiate u[»ward3, forwarrls. and downwards, so ai< to fonii a c»in- 
tinuou-iUyerof distinct imd Bhari>Iy definetl fibres. The middle fibres nm .<tmighl 
forwards to l>e attached to tlie intervertebral dm-: the upper aacend to the luwer 
half of the lateral surface of the vertebra above, and tlie lower descend to (he upper 
half of the vertebra below. 

The radiate ligament is overlap;>ed ui the spine by the short vertebral ligaments. 

in the case of ihe liret. tenth, eleventh, and twelfth rilw, each of wliich articu- 
lates with one vertebra, the ligament is not ijuiie -sn disiiuctly radiate, but even 
in these the ascending fibres reach the venebru above that with which the rib 
art i dilutee. 

The synoriat membranes (Kg. 257) conabt of two closed sacs which do not 



COSTO-VERTEHRAL 



241 



the interartipular ligament; there ia also a siiplit ainouni t»f forward and backward 
gliding ; and a slight degree of nrrewing or rotator>' movement is bIbo poewible. 
There is a coudiderable difference in the degree of niohility of the different ribs, for 
while the firal rib is aliiicet immobile except in a very deep inspiration, the mobility 
of the otiiers increases from the serond to the last; the two fluatini^ ribs being the 
most rnobjlti of all. The head of the rib is the most &xed point of the costal arch, 
and upon it the whole arcfi rotaleH; the iiiLerarticular ligament alJowH iirily a very 
limite^l amount of flevion and extension (i. e., elevation and depression), and of 
gliding. Gliding ia checked by the radiate ligament. 

In inupinition, the rib is elevated, and glides fonvards id ite socket., too great 
elevation being checked not only by the Uganienl^, but also by the overhanging 
vip{)cr edge of the cavity itself. In expiration, the rib uj depi-esscd, and glides 
backwitnla in its cavilv. 



(6) The Costo-tiiansvebsb Articulation 
Class. — DUirtlirosis. Subdivision. — Arlhrodia. 



rThis joint is formed by ilie tuVierrle of the rib articulating with the anterior part 
of the tip of the transverse ftrocess. The eleventh and twelfth ril»s are devoid of 
these jointii, for the tuberrtles of these nhs are absent, and the transverse processes 
of the eleventh and twelfth thoracic vertebra are nidnnentarj'. 
The ligaments uf the union are: — 



Articular nipsule. 
Middle costo-trans verse. 



Superior civsto-transveree. 
Posterior costo-transverse- 



The articular capsultt (6f£5. 255 and 257) foniis a thin, looee, flbmuB envelope 
to the synovial membrane. Its fibres are attached to the bonw ixiAi I)eyond the 
articular martjinrt, and are thicke«t below, where they are not strengthened by 
any other strucrure. It is connected on the inner aide with the middle, alKive 
with the superior, and on the outer side with the posterior costo-tran.s verse ligi^ 
ments. The eleventh and twelfth ribs are unprovided with cost *f trans verse 
capsules. 

The neck ligament, middle costo-transverse, or interosseous ligament 
(fig. 2fi7), consists of short fibres passing l>ctwecn the back of the neck of the rib 
and front of the transverse proceew, with which the tubercle articulates. It extends 
from the capsule of the capitular joint to that of the costo-trans verse. It is best 
seen on horizontal section through th« bone.*!. In the eleventh and twelfth ribe 
this ligHuient is rudimentary. 

The posterior co&to-transverse ligament (Fig. 257) is a Ehort but thick, strong, 
and broad ligament, which cxten>Ls outwards and upwards from the extrp-inity 
of the transverse process to the non-artinihir .■'urfare of the tubercle of the cor- 
responding rib. The eleventh and twelfth riiw have no posterior ligament. 

The superior costo-transverse ligament (fig. 2.56) is a strong, broad bund of 
fibres which ascends outwards from the crest on Ihe upper border of the neck 
(rf (he rib, to the lower l>order of the transverse process alKive. A few scattered 
posterior fibres puss upwards and inwards from the neck to the transverse pro(*ss. 
It is best .wen from the frrtnt. It.*' inner bonier Ijound"? the foramen ihrough which 
tlie posterior branches of the interco«tal vessels and nerves pass. To the external 
bonier ia attached the thin aj>oneurosis covering the exitrnal ititercostals. Its 
anterior surface is in relation with the intercostal vesselx and nerve; the powterinr 
I with the tongi9iti,mus fhr.fi. Tlie first rib has no irU|>erior costo-trans verse ligament. 

^H The synovial membrane (fig. 2.57) Ls a single sac. 

^^ The arterial and nerve supplies come from the posterior branches of the inter- 

r costal arteries and nerves. 

I The movements which take place at these joints are liniite<] to a glidinc of the 

I tubercle of the rib upon the transverae process. The exact position of the facet on 

I the transverse proces.s varies slightly from above downwanls, being placed higher 

I on the processes of the lower vertebrie. The plane of movement in most of the 

I eosto-transversp joints is inclined upwards and backwanl.'s in inspiration, and 

^^ downwards and forward.^ in expiration. The point round which these movements 



242 



THE ART/CVLATJONS 



occur is the bead of the rih, sn that the tubercle of the rib glides upon (he traiu<- 
veree process in the circumference of a circle, the centre of which is at the capitular 
joint. 



5. THE ARTICULATIO.XS AT TUE FRONT OF THE THORAX 

These may be di\-ide<i im/> four sets, viz.:— 

(a) The interstemal joints, or the union of the several parts of the sternum 
with one another. 

(&) Tlic costo-cbondral joints, ur the union of the ribs with (heir costal 
cartilages. 

(c) The chondro-sternat articulations, or the junction of the ro«tal cartilftRes 
with the sternuni. 

(rf) The interchondral joints, or tlie union of li\'e costal cartilages (sixthi 
se^'eQth. eight li, nintii, uud tenth) with one another. 



(a) The Ister.sterv.\,l Joints, or the Union of the Segments ok the Sterxcm 

WITH ONE -VNOTHIIR 

Tlie stenmm beinji composed, in the aduh. of three distinct piere?!, — the manu- 
brium, Ihe gladiulu." <tr l>ody, ami the xiphoid proccj^, — has twt> articulations, viz., 
ilieWuperior, which uiiiipsthe manubrium with the gladiolus, and the Inferior, which 
unites the gladiolus with the xiphoid. 

1. The Superior Intorstemal Articulation 
Class. — False Syncttondrosi*. 

The lower border of the manubrium and the upper border of tlie body of ibe 
Btcmum present oval-shaped, flat mirfacea. with their lone axes tnin^versc, and 
covered witli a thin layer of hyaline cartilape. An interosseous fibro-cartilage 
is inlenxised Iwtween the lx»ny sui-fa<-<s: it cnrrcsfxmds CJcactly in shape and inti- 
mately adhui-ea to them. At each htteral Ixirder thid libro-cartilage enters into the 
formation of the sei^oiul rinHidn>-.st final arliculaliun ({ig. 258). In coasistence it 
vanes, lieinp in aomc eases uniform throughout, in others softer in the centre than 
at the circuiiifereiice, and in others again an oval-fthapcd synovial cavity is found 
towards its anterior part. Wlien such a cavity exists in the fibro-cartilage this 
joint ha.s a remote resemblance to the diarthroscs, and is clasjtod, with thesacro-iliac 
join( and thesymphysU pubis under similar ronditioas, as' diarthro-ampliiarthroeis." 

The periosteum pa.-i.ses uninterruptedly over tlie joint from unu segment of 
the sternum to tlie other, forming a kind of capsular lipanient. This capsule ia 
strengthened, esipecially on \U pcjsterior ii.spcct. by longitudinal Itgamentous fibres 
00 well as by the radiating and decu.«sating fibres of the rhondro-stcrnal ligaments. 

In some instances the lil>n>-rartiluge is rcplncel by short, bundles* of libruua 
tissue which unite the cartUage-coated articular bony surfaces. 



2. The Inferior Interetemal Articulation 
Class. — False Synchondrotis. 

The gladiolus is joined to the xiphoid cartilage by a thick inventing membrane,i 
by anterior and posterior longitudinal fibres, and by radiating fibres of the sixth 
and seventh chondni-stema! TigBniems, The costo-xiphoid ligament also con- 
necta the xiphoid with the anterior surface of the sixth and seventh coHial car- 
tilages, And thus indirectly with the gliidinlu-i; and some fine fibro-areolar tissue 
also connects the xiphoid with the hack of the seventh cnattii cartilage. 

The junction of the xiph<.»id with the siemuin is on a level somewhat posterior 
to the jimction of the seventh costal cartilage with the sternum. The union 'is 
a eynchondmeis, ejifli Imne lieinp covered by hyaline cartilage which is connected 
with the inier\'ening libro-cartilage plate. 



COSTO-CHOSniiAL ^^^ 243 

(6) The CnsTtv-CHOSDRAL Joints 

Class. Synarthrosis. 

The extremity of the costal cartilage is received into a cup-shaped depression 
at the end of the rib, which is somewhat larger IhaJi thp cail-ilage. The twu are 
joined together by the continuity of the invesling tnumhranes, tlie periosteum of 
the rib Iming cuiitlnuouH with (he perichondriiuii of the curtilage, much in the aaine 
way OS the epiplij'cics of the lioiics arc joined to their shafts. 

(f) ThV. Stebno-costal AHTKI'LATIOXS 

Cliss.—Diarthrosis. SubdivisioG. — Oinglynna. 

Thpse articulations lire Ijettt-een the lateral Ijordeiv of the sternum and the ends 
of the fosfjil rartilapps. The union of the tinil rib with the steraum is synchondrodiaU 
and therefore forms nn exception to the othois. Fn>m the st-cotKl to the seventh 
inclusive, the iirticulatious have the followini; Ugaments, which together form a 
complete capsule: — 

Anterior radiate stemo-costal. Superior stcmo-costal. 

Posterior radiate sterno-costiil. Inferior sterno-costiil. 

The anterior radiate sterno-costal ligament fHg. 258) is a triangular hand of 
strong fibres which cover the inner half-inch of the front of the cosfiil cartilage, 
_lnd radiate upwarils antl downwards ujjon the front of the sternum. Some of tlie 
fibrts decussate across the middle hne with (ibitfa of the opposite h(;atneut. At its 
upfier an'l lower borders it is in contact with tlie superior and inferior ligaments 
rcspprtivcly. 

The posterior radiate stemo-costal ligament consists nf little more than a 
thickening of the fibrous envelopes of the bone and cartilage, the joint being com- 
pleted (>ehin(l by a continuity of perichondrium with peristeum. 

Tlie superior nn-l inferior ligaments are strong, well-marked bauds, which 

Cass from the upper and lower bordei-s rea^jectively of the costal cartilage to the 
iioral edgrs of the t-temuni. The sixth and seventh cartilages are so close thai 
thcsufieridr ligaiiieni of i he .seventh is blended with llie inferior of the. ■<i.\ih rib. 

iJeeper than the til>rps of these ligaineiUs are short fibiies passing from the mar- 
pin.s of the sternal facets to the edges of the facet*s on the cartilages; ihey are moat 
distinct in the front and lower part of the joint, and may encroach ao much upon 
the synovial cavity as to reduce it to a very small size, or almost obliterate it. This 
occurs mostly in the ra.'-e of the sixth and seventh joint?, eypoeially the latter. 

The interartlcular ligament (tig. 258) is by no means constant, but is usually 
present In the i^crond joint on one, if not on both sides of (he same subject. It 
ciia'iislfi of ft strong tmasverse buiulle of tibro-s p!Ls.sing from the ridge on the facet 
on tlie cartilage to the symphyseal sutwiance l>etween tlie manubrium and Ijody: 
Hometiific-s the upiXT part of Ibe nynovial cavity is partially or entirely obUteraied 
by short, fine, ligjunetitoui^ fibres. 

The costo-xiphoid ligament (fig. 258) is a strong flat band of fibres passing 
obliquely upwards and outwartU from the front surface of the xiphoid cartilage to 
the .interior surface of the iitenial end of the seventh costal cartilage, and most 
fref)uently to that of the sixth also. 

Synovial membranes.— The union of the fir^l eartiloge with the sternum being 
synrhondmiliiil. it has no syno^■ial membrane: the .second has usually two. separated 
by the intcRtrtiriilar ligament. The i-est iKually have one synovial membrane, 
which may Ofca^ionally Ije sulwlividcd into (wo (fig. 2.'>8). 

Tin* arterial supply is derivetl from perforating brandies of the internal mam- 
mary; and the nerves come fmm the anterior bnmchfti of the intcn'ostals. 

Movements.— Mxifiiting the Grst, the chondro-stcmal joints are ginglymoid» 
but the motion of which they arc capable is very- limited. It consists of a hingo- 
like action in two directions: first, there i.^ a flight amount of elevation and depres- 
sion which takes place round a transverse axis, and, jtecondly, there is wome fr)n,vard 
and backwanl movement round an obliquely vertical axis. In inspiration the 
cartilage is elevated, the lowest part of '\Xa articular faret is presse*! into the 
sternal wx-kel, and the sternum is thrust forwanls so that the upper and front edgea 



MOVEMENTS OF THORAX 



245 



At thu point each of the cartilages from the sixth to the ninth inclusive is 
fiflpper than elsewhere, owing to the projection clowcwards from ils lower eilge of a 
bniad lilunl process, which comes into contact with the carlilaiie next below. Koch 
of the apposed surfaces is smooth, and they are connected ot their margins by liga- 
meiit-ous tLiwuc, which forms a complete capsule for ihe articulation, and is lined 
by ft s^Tiovial membrane ffig. 258). The Iftrpesi nf these cavities is lietween the 
seventh and eighlh: those between the eiKhlh and ninth, jind ninth and tenth, are 
BOialler, and are not free to play utK>n each other in the whole of their e-xlenr, l^ing 
held In^clhcr by ligamentous tii4sue at tlicir anterior margins. Sometimes thxa 
libroiis tjjwue completely obliterates (he aymivial cavity. 

The arteries are derived from the muaculo-phrenic, and the nerves from the 
interrostals. 

Movements. — By means of the costal cartilages and interchondrai joints, 
strength with elasticity is given to 'the wall of the trunk at a part wltere the car- 
tilages are the only firm structures in its composition; while a slight gliding mo\-e- 
mcni is permitted hotwecn the costjil curtilages themsflves, which takes place 
round an axis correapoiidinp to the long axis of the cartilages. Hy this nic-ans, 
the outwnnl projection of tlic lower part of the thoracic wall is increased by deep 
inspiration. 

MOVEMENTS OF THE THORAX AS A WlfOI.E 

Before daserihing thesa ino\'ements as a whole, it must be premised that there 
are some few modifications in the movements of certain ribs resulting from Iher 
sliapc. Thus Ihe first rib (and to a less extent ll»e second also), which is Ilat on its 
upjier and under surfaces, revolves on a trauiverse axis draivn through the costt>. 
vertebral and c«)»ti'-(ransveree joints. During inspiration and expiration, the ante- 
rior extremities of the lirat pair of costal archcp play up and down, the tulicrcles and 
(he heads of the riUs acting in a hinge-like mariner, the latter having abo a slight 
screwing niotioJi. By this movement the anterior ends of the costal arches are 
simply raised or depr(!s.<4cd, and the sternum pushed a little forwards: it may lie 
lik^ed to the movement of a pum|>-handle, as in fig. *J.'j9, a, b. 

Tlie movements of Ihe other riljs, particularly in the mid-region of the thorax, 
are more complex, for. besides tlie elevation of the imterior extremities, tlie bodies 

Pig. 259. — Dlvobam of Axis or Rib-movemcptt. tAftcr Ivirkes.) 




'and angles of the ribs rise nearly as much as the extremities themselves. In this 
movement the tubercles of the ribs glide upwanis and backwanUf in inspiration, 
and downwariis and forwards in expiration; and the movement may be likened to 
that of a bucket handle, as in fig. 259, A, B. 

During inspimlion, the cavity of the thorax is mcreased in everv* direction. 
The antero-posterior diameter in increa.sed by the thrusting fomurds of tU^ 
sternum, eaiLsed by the elevation of the costal cartilages and fore part of ihe rilis, 
whereby thoy arc brought to nearly the same level ari the heads of the ribs. Th^ 
transverse diameter is incre(L-«ed: (i) Behind, by the elevation of the middle pn»*t 
of the ribs; fur when at rest the mid-part of the rib is on a lower level than either 
the cost o- vertebral or cliondi-o-stcrnal articulations. Owing to this obliquity tli^ 
transverse diameter is increased when the rib is raised, and the increase is propor- 
tionate tu Uie degree of obliquity, (ii) By the eversion <if the lower border of lUi 



246 



THE AurrcuLATioys 



costal arch, which turns outwards as the arch is ruisvU. (iii) The Lraiisveise diani- 
eler Is inrrca»c<l in front by I he ahiluction of t he aniorinr extremity of the rib at the 
Bame time a^ it in elevHled atid ihru.st forw.'inJs. 

The increase in the vertical diameter of ttie ihomx is fine \o the elevation nf 
the ribs, especially the uppor ones, and the mnsequfJit widening of the intercostal 
gpaces; but the chief increa-se in this tlireclion is due to the descent of the diaphra^^m. 

The itreatest increase both in tlie antero-fjosterior and transverse diameters takes 
place wJiej^ the ribs are lonjiest, most oblique, and moat curved at their luiglet^, and 
where the bulkiest part of the lung is enelcuwd. This is on a level with the sixth, 
seventh, and eighth ribs. 

At (ho lower part of the thorax, whore the ribs have no relation to the lungs, nnd 
do not affect mipiration directly by their movements, it is inipnrrant tliat the rcmial 
arches should be (brown well outwards in ortler to counleract tlw conipresaioa of 
the abdominal viscera by the contraction of the diaphragm. 

By widening and sieadying the lower part of the tliorax during inspiration, the 
attachments of the muKcuiar fibres of the diaphragm are widened, and their povb'cr 
increased. 

Maecles which take part in ihe movements of inspiration. - (a) OntitMry inxpirtiium.- 
The scalane^, strnitu* fwisH-rior i-uiirriiir, Hil- i'Xttfnuil iiilercnstaK, probably the inirmnl 
tD(«m>8tAls, thu dinphriigm, t)m ()iiu(lriitUH luintwrum atul si.>rriLUi'i ixir^Loriur mfmor fixiiif; thn 
lower ribs, possibly ttiv pori>rt?nt>r hbrcs o1 tho external oliliqtiv hImi liclping t-o Kx the Iowi-t rilm. 
(b) Eiimonlinary itmjnraivm: Thf "iiiwrior cxirpinities nrv raiseil »ti(l lixc«l. The cervieal part 
of the \'oru4)riil L'olumn and thi> lirad iirc i:xlcntlod, and in addition i<t tlm inuedBs nf ordinary 
inspiration, tlic (ullowing inu^rlc^ ulsn innic iiitw ptay: The pt>'lor,il]« minor, the miiBelea wbitrh 
extend the hi-ad nnd Ihf cervi'-al jmrt ut (In; vprtebni.1 c-oiiiii)ii, tlic xtpnio-rnfu'loid luid the supru- 
and infrvliyoid iiiiLirUt^, the lower fibres of lliv p«otDr.ili» ninjor, and ffonm of lliu lower fiure* 
of the scrrui ii» iwilorirhr. 

Ezpimtion ii> ;inKJiiiv<l by llit> fltiAticttv of Lhr lung" und the weiulil' of the Iborsx. aided 
hy the cla^iic rviLrlioii and rontriii'tlun nf tnu cxtcmitl mid intenml obliqiir musrU'fi, the recti 
and pyrnmidnkv^, Itie tri»ft-*verH/dis ididciminis, and idr Icv.iI(>it->i «ni JiiiH onccyajci. In rorcifil^ 
expiralion iill itiiiKcW which deprawt the rib" and rvlucv th« dinivn»iuni> of iJio nbdomeii ore 
thrown jatu acduti. 



TfffC AUTWULATIONS OF THE UPPER EXTREJIITY 

The articuIation.s of the upper extremity arc the following: — 

sterno-costo-claTicular. 
acromio-clavicular union, 
shoulder-joint. 
elbow-joint, 
radio-ulnar union, 
radio-carpal or wrist-joint, 
carpal joints, 
carpo-metacarpal joints. 
intermetacarpal joints, 
metacarpo-phalangeal joints, 
i&terphalangeal joints. 



I. 


The 


2. 


The 


3. 


The 


4. 


The 


5. 


Tho 


«. 


The 


t . 


The 


8. 


The 


y. 


The 


10. 


The 


11. 


The 



I. XnE .STERXO-COSTO-CLAVICULAR ARTICrL.\T10N 

Class. — FJinrlhrottit. Subdivision. — ConditUtrthnms. 

At thU joint (he large inner end of the cinvicle ts unite*! to the 8Uf)erior angle 
of the manubrium sti-nii, tlie first, cojrtal cartilage also it-wisting to .support the 
clavicle. It is the only joint between the upper extremity ami the trunk, ami takes 
part ill all the movement!i of the upper limb. Ixioking at the l>one8, one would 
nay that (hey were tn no way adapted to articulate with one another, aiid yet they 
Assist in eutislructing a joint of great security, strength, and im[K>rtance. Tha. 
bones are nowhere in actual contact, li^ng completely spparate^l by an artictUar] 



STEItNO-C'OSTO-CLA I'ICVLAH 



247 



diiM. Tlie interval between the joints of the two sjdea varies from one inch to 
an iacli and a half (25-4 cm.)- The ligaraeot^ of this joini are: — 

(1) Articuliir crapsule. (3) Articular disc. 

(2) lntercla\'icular. t^J Costo-clavicular or rhomboid. 

The articular capsule (figs. 2fil) and 2fil) ronsiats of fibres, having varyinc 
directions anrl Iwing t»f various strenpth and thicknes^i, which coniplftely surroumi 
the articulaliun, and are firmly connected with the edyea of the interarticular tibro- 
caHilape. The libi^s iit the back of the joint, sonietinies tstyied the posterior 
sterno -clavicular ligament, are stroiig;er than those in front or beluw, ami consist 
of two sets: a superficial, passinj; upwanls unit uuiwanla from the manubrium 
Btemi. to the projecting [wst^rior edge of the inner entl of the clavicle, a few being 
proIon((cd onwartls upon the posterior surface of die Iwne. A deeper set of fibres, 
especially thick and numeroa<» below the cla\-icle, connect liie intemrticular car- 
tilage with the clavicle and with the sternum, but do not extend from one licme 
to the other. The fibres in front, the anterior sterno-clavicular ligament, iire 
well marked, hut more lax ami lens tough than tlie posterior, aiitl arc ovcrliiid by 
the tendinous sternal origin of the gtcrno-iuastoiti , the fibres of which nm parallel 
to those of the ligament. They extend obliquely upwards and outwards from the 
margin of the sternal facet to the anterior surface of the clavicle some lit tie distance 
from the articular margin. Tlie fibres which cover in tlie joint below arc short, 



Fio. 200. — PoBTEHioa View or the STRR-No-ooe-ro-cLAVicvLAB Jojkt. 

C«at»- 

Foatanar licuneut 
parUon of 




woolly, and consist more of fibn>-are<>lar ttsriue than true fibrous tissue; Ihey ex- 
tend from the upjier bortfer of the first costal cartilage to the lower btirdcr of the 
clavicle just extemut to the articular margin, and fill up the gap l<et.woon it and the 
costoclavicular ligament. The superior portion consists of short tough fibres 
passing from the sternum to the articular disc; and of others welding the fibro- 
cartiloge to the upper edge of the clavicle, only a few of them passing from the 
clavicle direct to the sternum. 

The interclavicular ligament (figs. 260 and 261) is a strong, concave hand, 
materially .•^trcngllicning I lie siijwrinr portion nf the cap.iule. It is nearly af]uurtor 
of an inch (6 mm.) deep, nnth the concavity upwards. it.s upper border tajiering to 
a niirnnv, almost sharj> edge. It is connected with the posterior (fuju-rictr angle of 
the alcnial exlromiiy of each clavicle, and with the fibres which weld tiie inter- 
articular cartilage with the clavicle; and then pas-^^es acniss from clavicle to clavicle 
along the posterior aspect of the upper border of the manubrium stemi. Tho 
lowest fibres are attached to rhc .'Sternum, and join the posterior fibres of the cnpsule 
of each joint. In the middle line, between the ligament and the sternum, there is 
uu aperture for the passage of a small artery and vein. 

In addition to the interclavicular ligament .Mr. Carwardine* has described a 
8i>eci!ii band of I he up{ier pori ion of the sto mo-clavicular capsule which he proposes 



* "Journal of Aoatouiy and Pbyeiuloey," vol. 7, new scrks. p. 232. 



248 



THE ARTICULATIONS 



io name tlie 'suprasternal ligament.' It dcKoends irom the upper border of the 
stomal end nf the clavirle in the upper bimier of (he .•^lerauni, and is of sppcial 
importance as it encltwes the suprasternal bone, when that bone is present (see 
pp. 130 and 21)4). 

The costo-clavicular or rhomboid ligament (fig^. 260 and 261) is a strong 
dense band. comp(te"ed of fine fibres massed together into a nietnbranous structure. 
Il extends from the anterior edge of the upper border of the first cost^ curtilage, 
upwards. bnck^vunU, .-inil ilit^linclly (lulwaniji lo the costal tulierasity on tlie under 
surface of the inner extroniity of the clavicle, to which it is utlached just external 
to the lower part of the cMpsiiIe. F'rnnieutly some of the outer fibres pass upwarda 
and inwa,rd.s behind the rest, and give the appearance of decussating. It is from 
half to three-quarters of an inch (r.')-2 cm.) tjntad. 

The articular disc (figs. 261 and 262) is a flattened disc of nearly tlie same 
Bize and outline a^ the inner articular end of the clavicle, which it fairly accurately 
6ts. It bt attached above to the upper bonier of the posterior ettpe of the clavicle; 
ftnd below to the cjirtilagc nf the first, rib at its union with the stemiun, where it 
assists in forming the socket fortheclavirle. At its circumference it is coimected 
with the articular caiwule, and this connection is very 9trf»ng behind, and still 
stronger above, where it is blended with the interclavicular ligament. It is usually 
thiimcst Ixtlow, where it is connected with the costal cartilage. It varies in thickness 



Fio. 201.— .\ntebioh View of 8TEii."(o-rri8TO-cLAVicvLAi« Jofnt. 
(The cnpatilv is cut into on th« left aide tn nhnv the urticuliir d\ae dividtag the joint into 



two caviLit^,) 






CMio-eUvloiilar 



U||iun»nl 
.AntBrloF 
■Unno- 
Olanvnlu 



.i.^ 



in different |>art«, sometimes being lliinner in the centre than at the circntnference 
Bometimes the reverse, and is occasionally ]jerforattid in the centre. It divides the 
joint into two compart men ts. 

There arc two synovial membranes (figs. 261 and 262): an outer one. which 
is refleeled from the cta^■icle and capsule over the outer side of the hl)W)-cartilage, 
and \» looser than the irmer; the Lrmer i» reflecte«:l from the sternum over tite ianer 
side of the fibro-cartilage, costal cartilage, and capsule. Occasioiuilly a communi- 
cation takes [)tare lietweea them. 

The arterial supply is derived from braiichea— (!) from the internal mammaryj 
(2) from the superior thoracic branch of the a\illar>'; (3) twigs of a muscular branci 
often arUing from the subclavian arlery pass over the interclavicular notch; (4) 
twig'' of the ti-ansver-e scapular (supnincapular) artery. 

The nerve-supply i^ derived from the nerx'e to the subclariut and sternal 
ficending bnmch of the ccn'ical plexus. 

Relations.— In from of the joint is the eternal head of the stemo-mastoic 
Behind it are the stcmo-hyoid and stemo-thyreold muscles. .Still further backj 
on the right side, arc the innominate and internal mammar)- arterie.-?. and, on tl 
left side, the left common carotid, the left subclavian, and tbe internal mammi 
arteries. Above and behind. Ijetween the stemu-masloid and steniohyoid niusolf 
the anterior juguhir vein pas.ses back and out towards the posterior triangle. 



ACHOMIO-CLA V/CULAR 



249 



The movements permiUed at Ihis joint are varioua though Hmiteci. owing to 
the oai«sular ligament l»cing tnodcraicly t«»se in every jMJsilion of the davicle. 
Motion tiike-i^ place in nearly every directiori^viz., upwanliij downwards, forwards, 
hnekwardd. and in a etrcumductnry manner. The upward and downward motions 
occur Setween the clavicle and the anicuiar disc; during elevation of the arm the 
upper ed>ie of the clavicle with its attached articular disc is pressed into i he atenial 
socket, and the hnver e«jRe glides away from the disc; during depression of the 
limb, the lower edge of the clavicle presses on to the disc, while t he rest of i he 
articular wirface (if ihe clavicle inclincj^outwanUi, l)ringingnith it to a slight degree 
the upper edge uf the artirular dif^c. 'lliese ninvenicnts occur on an antenv-fjoste- 
rior axis drawn through ihe outer conipurtniRnt of the joint. The forward and 
backward motions take place l>etweeti the articular disc and sternum, the rlaxHcle 
with the disc gliding Uickwanls upon the sternum when the fihoulder is Wrought^ 
forwards, and forwards wiien the slioulder is forced twiekwanls; the-w movements 
occur round an axis druuTi nearly vertically tlirougU the sternal socket. 



Fio. 282. — Section throi'gii STEKNo-cLAnceuiR Joint. 



SIM MM bclWDaa 
!■• aiarndtii aad 

ntat* 





The articular disc ser\'efl materially to Mnd the l>onea together, and to prevent 
the inward and upward di.^placcmcnts of the clavicle. It also forms an elastic 
buffer which tenrU to break shock.s. Tlift capsule, by being inodcraiely tight, 
tends to limit mo%'ements in all directions, while the interclaviruUr ligament i^ 
a safeguanl against upwurd di?*|flacement during deprcsaion of the aj-m. The 
ccsto-clavicular Ugatncnt prevents dislocation upu-ard;^ during elevation of the arm, 
and resL-itd di.'^placempnts backwards. 

HuMlea which move the clavicle at the sicrno-clavicular joint. Elt\-ati>n. — Trflpe- 
zfuH, clfivk'ular pwrt of fltwiUJ-mimfoiii, levator iraiMiljc. oimo-hyoiil. rl»>nilimil«. 

DepreMon. — .SiibcUviiw, pwtor.i]w minor, lower fibnw of (nk(H>nuK wid scrrstua anterior 
(iDicnuy). I)e()r«»iitoii i.t aided t>y Hie wd^ht uf the upper oxtmnity. 

rrotrarttint. — I'ectomli.* niiijor aiid tiiiiior. Serrattw anterior (mn^UB). 

Retraetitn. — Latisaimus dorsl, trapeziufi. 



2. THE ACROMIO-CLAVICl'LAR UNION 

The scapula t» connected with Ihe clavicle by a sj-novial joint wth tta liga- 
ments; and also by a set of ligaments passing between the coracoid process and the 
clavicle. So thai we have t« consider-^ 

(a) The acromio- clavicular articulation. 
(&) The coraco-clavicular ligaments. 

(c) The proper scapular ligaments are also l>csi descrilied in this section — 
viz.. tlic coraco -acromial and transverse. 



250 



THE ARTICULATIONS 



(o) The AcHDMiu-rLAviriLAR Joint 
Class.— /iiarfftrosw. Subdtvisioo. — ATihrodia. 

The acromio-cla^icular jnin( is stirrounrled by an articular capsule and fre- 
quently contains an artieulnr fibnwartilage. 

The articular capsule (lijw. 264 and 267) completely ouiTomiJjs the articular 
margins, and is co[n|H>£ed of sn-oug, coarse fibres arranged in pumllcl faseiculi, of 
fairly uniform thickness, wluch aru iiMachwi to the borders as well as the surfaces 
of thp bones. It is somewhat lax in all positions of the joini, so that, ilic clavicle 
b not lightly braced to the arrominn. The fibres extend thrcc-fiuartcrs of an inch 
(2 cm.) iilong the davirle posteriorly, but only a quarter of an inch CO mm.) ante- 
riorly. Superiorly, ihey are attached to an oblique line juiniiijj these two ptJints, 
while inferiorly they ivach to the ridge for the trapezoid lijiaiueiit with which ihey 
blend. At. the acromion ihey extend half way across the upjwr atiil lower tiurfuces, 
but at the anterior and i«>.->lerior limits of llie joint they are allaclied clotie to the 
articular facet. The anterior fibres beeomc blended with the insertion of the coraco- 
acromial ligament. The fibres arc strengthcne*) above by the aponeuroses of the 
trapenus and deUoid muscles; and all run from the acromion to the clavicle inwards 
and backward:: 

The articular disc is occasionally present, but is usually imperfect, only oc- 
cupying the upjwr part of the joint; it may comjOetely divide the joint into two 
canities, or be perforated in the cecitre. It is utiually thicker at the edge than in 
the cent rfr, and ^omr of i he fibres of the articular capsule ^re blended with its edges. 

The synovial membrane lining the joint is occasiotially eitlier purliully or 
entirely divideil into two by an articular fibn>-cartiiuf;e. 

Relations. —Above, skin and fascia and the tendinous intersection between 
the deltoid and iho trapezius. Below, the conioMirroniial ligament and supm- 
spinatUB. .\jiteriorly, part of the origin of the deltoid. Posteriorly, part of the 
insertion of the trapezius. 

Movements. — A certain amount of jiHding movement occurs at this joint, but 
the uRist imjiNirtant movement is a rotation of the scapula whereby the glenoid 
cavity is turned fur%vanl8 and upwartU. or downwards. .As the.se movements occur 
the lower angle of the scapula moves fonvards as the glenoirl cavity ttims upwards 
and the siijwrior anple recetlcM. 

The forward mo\ement of the lower angle is produced mainly by the lower 
fibres of the serratiw anterior (niugnus) , aided by the lower fibres of the trapezius, 
and it Is by this movement that the arm is raised above the level of the sliouhler 
f<rnvanU. 

The reverse movement is produced mainly by the rhomboideus major aided by 
the latissiinus dorsi. 

(f>) Tni: CoRA(■o-^LA^^rl;I.AR Union' 

The coraco-clavicuiar ligament (fifps. 26.1, 2^4, and 267) consists of two parts, 
the conoi<l and tlio trajK^zoid iitjamenls. 

llie conoid ligament is the internal and posterior tx>rtion, and passes upwards 
and outwards fmm the coracoid process to the clavicle. It Ls a ^ery stnmg and 
eoarvly fiL-^cii-ulated band iif triangular slia]>e, the ajiax lieing (ixe*J to the ituier and 
posterior edge of the mot of the coracoid process just in front of the .scapular nolch, 
some fibres joining the tran.«i\*ersc ligament. Its base is at the clavicle, where 
it widens out, to 1* attached to the posterior edge of the under surface, as well 
as to the coracoid tubercle. It is easily separated from the trapezoid without 
being alwohilely distinct. A small hursji often exists between it and the coracoid 
pnwess; internally, some of the fibi'cs of the snbciiinuit muscle are often attached 
to it. 

The trapezoid ligament i.s the anterior and outer portion- It is a strong, flat, 
quadrilateral plane uf (Lively woven fibres!, the surfaces of which look upwarfis and 
inwards towards the clavicle, and downwards and outnanls over the upper surfoeo 
of the RORicoid pniee^. At the coracoid it is attached for about an inch (2'5 cm.) 
jo a rough ridge wliich runs furwards from the angle, along the anterior border of 
the proces3. At the clavicle it is attached to the oblique ridge which run.*? out- 
wards and forwards from the coracoid tubercle, reaching as far a.s, and blending with 



CORACaCLA VICULAR 



251 



the inferior part of the acromio-rlftviculnr ligament. Its anterior edge is free, and 
overlies ihe coraco-acromia! ligament ; ihe posterior edge is shorter than the uiiterior, 
and is in contact with the (wsterior and outer portion of the conoid ligament. 

The arterial supply is derived from the tnuisvereo scapulur (suprascapular), 
acruiiiiul hnuichesof (lie thiinuni-aitminijil. and the anterior circumflex. 

The nerve-supply la derived from the suprascapular and axillar)- (circumflex) 

Movements.— In the movements of the shoulder pirdle, Ihe scapula moves 
upon the outer end of the clavicle, and the clavicle, in lum. carried by tlio uniting 
ligaments, moves upon the atemum; so that the entire soapula move«i in the arc of 
a circle whotie ninrre is at Ihejiienio-clavicular jiiint, aii<l wliuse radius is ilic clav- 
icle. The scapula, in moving upon the clavicle, also moves upon the thorax 
forwaivls and haoktvards, upw-anLs and dottiiwards, and also in & rotatory direetion 
upon an axis drawn at. right ann}Gs to the centre of the Ume. Throughout these 
movements the lower angle and base of the scapula are kept in contact with the 



Fig, 211.3,— Antbiuor Viett op Shoitmirr, simwran also ConACo-n-AVicutAii axp 

COHACO-ACROMIAI. Liti.VMRNTS. 



Oenoul llRmaiM 



■upviior Iraaann* aosimlaT lla«io«iii I 






\ 



— aboffi hma oTHMva 



.^ 



Oip«al# of ■ll•vJA•l^ 






-A 

■I. 



ii 



C4C4Df 



'-/, 



^^^^ by the hxlixfnmnn dorsi, wliioh strap« down the former. an<l the rhomboids and 
tefratus unUrior (nrngnua). which brace clown the latter. The glenoid cavity could not 
have preserved ita obliquely forward direction had thci* been no acromio-clavicular 
joint, but woulil have shifted round a vertical axis, and thus the shoulder would 
have pointed inwards when Hie scajiula \\u& advanced, atid outwards when it was 
dravni backwards. Hy means of the acromio-clavicular joint, the scajiula can he 
forcibly advanced upon the thtjrax, the glenoid ca\ity all the time keeping its face 
duly forwan.t>^. Thus the muscle.'? of the shoulder and forenrm can be with ndvim- 
tftgo combined, as. for example, in c'ving a direct blow. The acrfimio-clavicular 
jtnnt alwi permits ihe lower angle of the scapula to be retmned in contact with the 
ehost wall during Ihe rising and falling of the shoulder, the scapula turning in a 
hinge-like manner round the horiTiontal axis nf the joint. 

Tlicrc are no artionj* in which the scapula moves on a fixeti clavicle, or the clav- 
icle on a fixed scapula: the two bones, bound together by their connecting liga- 
ment, must move in uni^aon. 



252 



THE ARTICULATIONS 



(e) The Proper Sf-APVLAR Ligaments 

There arc three proper ligaments of the scapula, which pass between different 
[M)rtions of the bone, viz. — 



Coraco-acrornial. 



Soperior tmiisveive. 
Inferior lnuu>\-erae. 



The cora CO -acromial ligament i.Bks. 263 and 2671 is a flat, triangular band 
with a broad tuase, aiUtched to the outer Iwrxler of Ihe coracoid process, and a blunt 
ape\ wliifh is (ixi;<l lu tiie lip of the utToniion. It k made up of Iwu broad marginal 
bands, and a i^inaller and thinner interve'iiu^; pciiiiun. The anterior band, ivhich 
arisos from the iinierior portion of the coracoid process, is the stninger. an<! rtf>n»c of 
its marginal fibres can often be traced into the short hcdd of the biceps, which can 
then make tense this edge of the ligament The posterior band, coming from the 
posterior part of the coracoid process, is ahto strong. The intermediate part, of 
variable exleiit. i» thin and membranous, containing but few hgamentuius fibroi: it 
IS often incomplete near the coracoiil i)njr-e»j-, leaving a small gap (fig. '263). The 
superior surface of tlie ligament looks upwaixls and a little fonvards. and is covered 
by the dvUoid nmsi-le; the inferior looks downwarrls and a little backwards, and w 
separated from the L•ap^ule of the shoulder- joint by a bursji and the tendons of the 
auiiruapituitiU! and suhscapularii muscles. At the eoratoid process it overllpa tho 
cnraco-humeral ligament. It is barely one-thinl of an inch (S mm.) aliove the 
capsule of the .shoulder, and in the undissected state there is scarcely a quarter of 
an inch (6 mm.) interval. The anterior band projects over the centre of the head 
of the humenis, mid is continued into a tough fascia under the deltoid; the posterior 
hand In (soniinuous with the fascia over the supraspinatus muscle. It bimts the two 
processes firmly together, and so strengthens each^ it holds Ihe deltoid off the capsule 
of the shoulder and protects the j<iint fnnn slight injuries' directe*! dnwriwards and 
backwards again.st ii . 

The superior transverse, coracoid, or suprascapular ligament (figs. 263, 
2fi4, and 26,")) is a small triangular band of fibrous tL-^ue, the surfaces of which look 
for%vard« and backwards; and its edges, which are thiii and sharp, are turned 
upward? and downwards. It continues the superior border of the scapula, bridging 
over the scapular notch. It i^ broiuirr internally, where it springs from the upper 
boiderof the scapula on its dorsal surface: anil narrow externally, where it is attach*^ 
to the base of the coracoid process: .-some of its fibres areia^ierted under the e<lge 
of the trapezoid ligament, and others pa.is upward.s with the conoid to reach tlie 
clavicle. The tmnin'rrse scapular isuftrusaiyular) nrtrry passes over it, and the 
suprascapular mTt-e lieneath it. lutunially, some libies of the omo-hyoid muacle 
arise from it . 

The inferior transverse or spino-glenold ligament [fig. 264) reaches from 
the external border of the spine of Ihe scapula to the margin of the glenoid cavity, 
and so forms a foramen under which the transvfrsf scupular {suprawajnilar) iv«se/a 
and auprasrapular rune gain the infraapinoa-' fos-sa. It is usually a weak mem- 
branous structure with but few ligamentous fibres. 



3. THE SHOIT-DER-JOIXT 
Class. — Diarihrosi*. Subdivision. — Enarthrodia. 

The shoulder is one of the most perfect and most movable of joints, the li 
upixrr end of the humenw plaving u|>on the shallow glenoid cavity. Like the hip, 
it is a ball-and-flocket joint, tt is retained in position much Icjw by ligaments than 
l>y muscles and the efTecIs of atmospheric pres-sure; and, owing to the looseness of 
its efl|)snle. as well a» to all the other conditions of its construction and [Mwition, 
it is exceedingly lialile to be displaced; on the otlwr himd, it is sheltered from 
violence by the two iii-ojccting proi-esscs — Ihe acromion and et>racoid. 

Tbe hgaments of the shoulder- joint arc:— 



Articular capsule. 
Gleno-humeral. 



Coraco-huraeral. 
Glenoid. 



THE SHOVLDER-JOfNT 



2S3 



The articular capsule (Bgif. 263, 264. and 26')) b a loose sac, insuHicient in 
itself lo maintain the bones in contact. It consUts nf fairly distinct but not course 
fibres, clnsely woven togmher, and diroptod. some straight, oihera obliquely, between 
the two bones, ii few cimilar ones beinj; Interwoven amon^t ihem. At the seapula, 
it is fixed <>n the dorsal aspect to the pmniinent rough surface nf the glenoid pm- 
cess, reaching as far ils the ne<*k «f the l>one. Above, it is attached to the root of 
the coracoi<l process: in front, (o the ventml surfare of the (;lenoii.i process, at a 
variable distance from tlw articular margin, often rearliing half an inch (12 nmij 
upon the neck of the Iwne. and thus allowing the formation of a pouch; it may 
not, however, extend fur more than a quarter of an inch (0 nun.) Iwyutul tlie 
artlpular margin: below, it blends with the origin of the long head of the triceps. 
At the humenis, the upper half is fixed to the anatomical neck, sending a pro- 
longation downwards between the two tuberosities which attenuates as it descends, 
and covers the transverse humeral ligament, The lower half of the capsule des- 
cends upon the liunieruK further from the articular margin, some of the deeper 

FiQ. ■.>6'l.— PosiTKnioR View of thk RHori.DKn-joisT. rhqwixo aijwj the Aauiuio- 
ctAViccLAR Joist and tiik .Speci*!. Lkiamcvth ok tiii: Su-aitla. 

■apvrtor lraa>*w*« lifsiiMil 



CevAld ll«UD«iil 






Tnuloa «f mir*. 
■pdBMua ana l*i«a 

tUaclDF - - 

•p »{'•■'- 



M 






fibree being reflected upwarda so bs to be attached cloee to the articular »lgc, thus 
forming a kind of fibrous investment for the neck of the humerus. This ligament 
U more uniform in thickness than that of the hip. 

Gleno-humeral bands of the capsule (figs. 265 and 266).— There are tliree 
accessory bands, known u» the suptrmr. middle, and inferior gUno-humerai hands, 
which projeet towartis the interior of the joint frciin the inner and fore part of the 
capsule and are consequently best seen when the joint is opened from behind. The 
middle band reaehes from the anterior margin of the glenoid cavity along the lower 
border of the suljscapularis tendon to the lower border of the lesser tuberosity, and 
the inferior band from the under part of the glenoid cavity to the under part of the 
neck of the humerus. The superior band, knornj also as the gleno-bumeraj 
ligament, runs from the edge of the gleJioid cavity at the root of the cnraeoid pro- 

t~ ceaa, just internal to the origin uf the long tendon of the bleep:*, and, pai^sing out- 
wards and downwnnls at an acute angle lo the tendon, for which it fonns a slight 
groove or fnjlcus, la fixed to a deprefwion, the fovea capitis htimeri. above the lesser 
tuberoHity of the humerus. It is a thin, ribb«ii-like band, cf which the upper sur- 



254 



THE ARTICVLATIONS 



face is atiAche<l t,o the capsule, while the other is free and turned towards the joint. 
In the ftt'tus it ia often, and in the mlult occasionally, quite free from Ihe cuiMmle, 
and may be as thick as the long tendon of the biceiw (%. 266). 

The tendons of tlie mpm- and infm-tpinatuit, teres minor, and $ubscapidarut 
muselea strengthen and support the ca|}sulc, ospecially near their imints of inscr- 



FiG. 205. — Vkktical Sbctios thiiouom the Shoi-lder-joint to show tub Glkno- 

HUHBnAL LlOAMKNT. 



BuprHHtnataa 
isiucis 



•aMvronUl Mr«a 
Taodon 0* lil«*pai>ltli 

nitot 

ulurU 



AftMBlar captula 



(The joint is opined from liohinijj) 



55^^^^ 



z^ 



UCUMMl 



V 



n^: 



^mm 



>.-!» 



>«i:^l 



Ww§' 



'A 



SItiMId lUtunaat at llhrn rinHiat 



A rti^ular <i*p«uli* 



tinn, and can be with difficulty dissected o(T from it. The long head of the trieepn- 
supports and strengthens the capsule below. The capsule also receivea an upward 
slip from ihe }*ectoralis major. The tupra»innatua often senda a slip into the cap-, 
sufe from jt^ upper edv;e (tig. 265). 

The coraco- humeral ligament (tig. 267) is a >itrong bniad b:uid. which is 
att4iehed ul)'»vc to rlic outer edge of the root and horizontal limb of the cnnicoicl 



Fh;. 2'i6.— FurTAL Saoct.DKH-Jni'fT, »HOwt.v« the Glkno-kv ui!:h.m. Ligament. *xr» .vlso the 
Short HeaI> op the Bni:t'!', IIEINU COSTIStlOO with THK CuRALO-AcltCiJJl.vJ, hui.AMKNT. 



aiturl Msdoa of MmiMi niniiitic 
on Into anMniv Mart arM>r«oe- 




t/oni liDdop ot Mowpa 
Capaul* u< bIiouMcc, ixrart 1 






Fimeesa nearly as far as the tip. From this origin it is directed hnrkwards along the 
ine of the l»icei>s tendon to blend with the caiwule. and is insertwl into tlie greater 



tulienwity of tlie hunierus. Seen from the Iwick, it 
contirmatitin of the capsule, while from Ihe front it 
longation ^T*^'n^ it overlyinjr the rest of the ligament, 
tiinw a bursa iH-twocn it and the capsule. 



looks like an unimerruptcii 

looks like a ran-^ha|>nl pro- 

At it« origin there ia soniD- 



A 



THK SHOULDER-JOINT 



255 



The glenoid ligament (fijts. 265 and 26S) is a narrow rim of dense fibro-rartilapte, 
which surrounds iTie edge (ff and dcepons Iho glenoid socket. Ii is about n quarter 
uf lin inch (ti mm.) wide ul^uve uiid below, but le»« Ht the sides. Its outer edge is 
inseparably welde<l. near the bone, with the articular capsule. Its structure ia 
almost entirely tibnms. wiili but few cartilage cells intermixetl. At the upi>er part 
itf the foivsa the biceps tendon is prokniged into the glenoid ligament, the icndnn 
usually dividing .and sending fibres right and left into the ligameJit, which may 
wind round nearly the wliole circumference nf the socket. It may, however, send 
libreB into one aii.le only, usually into the outer. 

The articular cartilage covering the glenoid fossa is thicker at the eireumfer- 
ence than in the centre, ihiis tending to lieojiftn tlie cavity. It is usually thickest 
at the lower part of the fossa; over the bead of the liuiiierus the canilugc ia thickest 
at and below the centre. 

The synovial membrane linw the glenoid ligament, and is then reflected over 
the ciipaule x-? far as it^ attachment to the liutnems. from ivliicli it ascends as fur as 
the edge of the articular cartilage. Tlie tendon of the bkt'jn receives a long tubular 

Fw. 287.— OcTER View of tbr Simrr.Drn-joivT. seiowjNo toe GoRAco-nouBitAL aso 

TnAXilVRllftK Mi'UKItAL I.lri aMK.STH. 



UtfWMBt 



JMBI 
Cc wtf o .ae t oittUl lUMoMnl 

Ooraeii-huDmiUltciunam 






TnUTMM biuBarBl llcaaiaBt 



I i 



Tiadoa of M«*»a 



sheath, which is continuous with the »>TioviaI membrane, both at its allached 
extremity and at the bicipital groove, but is free in the rest of its extent. The 
STrTioviul cavity always comnnmicales with the bursa under the nubKapularis, and 
sometiine-s with one under the infrxsjiinaliis niiu^cle. It also k'UiIs a jioueh-likc 
prolongation beneath the corncoid process when tlie fibrous cajBUle is aliiichetl 
wide of tlic margin of the glenoid f«iKsn. A few fringes are seen near the edge of 
the glenoid cavity, and there is oflen one which runs dowii the inner edge nf the 
bict^ Tendon, extending iflightly below it and makmg a slight groove for the ten- 
don to lie in. 

The transverse humeral ligament (fig. 207) is so closely connected with ttio 
capsule of the i^houhler thai, alihougii it is a proper ligumcni nf the humerus, it 
may well lie described here. It is a strong band <»f tibn«w tis.<jue. which extenilt* 
bet.wccn the two tuljcrosities, roofing in the intertiiljcrcular (bici|iital) pmove. It 
is covered by a thin exp-onsion of the cajwute. It is !iiiiiti'<I t(.i die portion of the 
bone above llie Wiw of the epiphysis. {<.'. Gordon llrodie. Jouni. Anat. xxiv, li4T.) 

Relations.— The following muscles are in contact with the capsuN? of i lie shoulder- 
joint. In froui. the subscapularis; above, the supraspinntus; above and behind, 



256 



THE ARTlCULATiO\S 



the infraspinatus; behind, the terwi minor: Iwlow, the long head o( the triceps 
and the lere.s major. In the interval between The suljscapulatis and the AUpra- 
spinatus the subacromial bunta. m close to the capsule and occadionoUy it« c&vity 
comniunicat(s with the cavity of the joint. 

The axilliir>- (clrcumllexj npn-c and posterior circumflex artcr\' pass beneath the 
capsule in the inien'til between the lung lieatl of the tricept-, the humerus, and the 
leres major. When the iirni is abducted, the long head of the iriceps and the teres 
major are drawn into closer relation with the capsule and help to preveJit dislo- 
cation of the humerus. 

The axillan' vessels, the great nerves nf the axilla, the short head of the biceps, 
and the coraco-brachialia are separated from the joint by the sulwcapuloris, whilst 
the deltoid forms a kind of cup, which extends from the front to the back over the 
more immediate relations. 

The arterial supply is derived from the transverse scapular (tniprascapular) , 
anterior and posterior circumflex, subscapular, circumflex scapular (dorsalis acapulae)* 
and a bnmch from the second portion of the axillan- artery. 

The nerve-supply is derived from the suprasciipulur. by braocheu in both fosss; 
and from the axillary (circumflex) and subscapular ner\cs 



I 



Fit). 268. — BicKra Tenoon. mrnRCATtNa akd Blgwdivo on each Side with thi 

. OlKXOIU FlKRO-f'AlrriLAOB. 



TmuIoio or IMoap* • 



TeBdan o( Moapa Mandad with slaaoid 
llcMoant 



The movements of the shoulder-joint consist of flexion, extension, adductinn 
and abduction, rotation and circumduction. 

I'lexinn 1*1 the swinginn forwards, extension the eivingiiig backwards, of the 
humerus; abt^luction i;* the rais-ing of the ann from, and adduction depresBion uf 
the arm to. the side, hi flexion and c.vtpnHion the head nf the humerus moves 
upon the centre of the glenoid fossa round an obliijne line cwrresponding to the 
axis of the head and necK of the humerus. Hexion twing more free than extension, 
and in extreme Hexion the scapula follows the head of the humeru.-i, .w as to keep 
the articular surfaces in apposition. In extension the scapula moves much letis, if 
stall. 

In alxluction and adduction the scapula is fixed, and the humerus rolls up and 
down upon the glenoid fossa; during abduction the head dt".s<'endi; umil it ^)n)jecis 
Ijeyond the lower eilge of the cleudiil c:ivity. and the greater tulwrosity impinge;; 
against (he arch nf the acromitai: during adduction, the head of the liumerus m»- 
cends in its socket, the arm at length reaches the side, and the capsule Js completely 
relaxed. 

In circumduction, the humerus, by pawing quickly through these movements, 
descrit^eK a cone, nh'nx apex is at the shoulder- joint, and the l>aa> at the distal 
extremity of the lx»ne or limb. 

Rfitation takes place round a vertical axis drawn through the extremities nf the 
humerus from the centre of the head to the inner condyle; in rotation forwards 



^ 



THE SUOULDEH-JOINT 



257 



(thut is, inwards) the head of the l>onc rolls bact; in the soi-kel as the great tuber- 
osity ami slmfc are tuniwl fcirwards; in roiatiuu hackuartis (Ihat is, oufwanls) the 
hejid (tf the lione glides ft>rwiird8, luid the lubercwity aiid ahafl of the humerus are 
turned haekwaivia, i. e., outwards. 

Great freeihun of movement is perniilted at the shoulder, au'l this is increased 
by tlie mobility of the scapula. Iteslntint is scareely exercised at all upon the 
movements of the shoulder by the ligaments, but chiefly by the luusclee of the 
joiut. 

In alwluctinii, the lower part of (he eapsule is somewhat, aiid in extreme abduc- 
tion considerably, tightened; and iti mtation inwanitt and outward.s, the upper part 
of the capsule is made icnse, a« is also, in the latter movement, the coracu-hunieral 
ligament. 

The niovetrients of abduction and extension have a most dceided and definite 
resistance offered to them other than by muscles and ligaiiieiits, for the greater 
tulM;n>sity (if the humerus, by strikiug against the acmmJon process and coraco- 
acmmial ligainetit, sro[>s short any further ailvuncc of the bine in these directions, 
and ihu-s aliduciioii ecjutra altogether as WHin as the arm i.'^ raised to a right angle 
with the trunk, and extension shortly after the humerus passes the line of the trunk. 

Furtlier elevation of the arm beyond the right angle, in the alxiucted or ex- 
tended position, is effected by the rotation of the scapula round its awn axis by the 
action of th(! trapezius and serratus anterior tDUucletj upon the 8temo-cla\icular 
aiwl acromio-clavicular jeiints resiwctively. 

The acromion and coracoid processes, together with the coraco-acroniial liga- 
ment, fonn an arch, wliir-h is separated by a buria and the tendon of tiie nupra- 
spimUuf from the cajwule of the shoulder. Ileiieatli this arch the movements' of the 
joint take place, and against it the head and lutierositics are pres.<H>d when the 
weight of the trunk is supported hy the arms; the greater tulienisity and the upper 
part of the shaft impinge upon it when abduction aiid extension are carried to their 
fullest extent. 

No dcsrriptinn of the shouHer-joint would be complete without a short notice 
of the peculiar relation which the biceiw tendon bears to the joint. It pusses over 
the head of the humerus u little to the liuier side of its sununit, and lies free within 
the cafwule, surroumled only by n tubular proress of s>-novial memlirHJie. It 
is flat, with the surfaces Itxiking upwanlw and do\\nw!inijf. until it reaches the in- 
tertiilien-iilur (Enfipilal) gnwve, when it assumes a romided form. It 8trenpl,he-ns 
the articulation along the same course as the coraco-humeral liganieJil , and tends to 
prevent the head of the humerus from being pulled upwanls too forcibly against 
the under surface of the acromion. It also serves tlie purpose cf u ligament hy 
steadying the head of the humenis in various movements of the ami and fon^ann, 
and to this end is let into a groove at the upper end of the iMine. from which it 
cannot escape on account of the abutting tul>eroHitie.4 and the strong transvcrao 
humeral ligament which binds it down, further, it acts like the four shoulder 
muscles which pass over the capsule, to keep the head of the humerus against the 
glenoid socket; and, moreover, it resists the tendency of the pn-toratis mujttr and 
(ntissiinus dorsi musclas, in certain actions when the arm is away from the side of 
the body, to pull the head of the humerus below the lower edge of the cavity. 

Muscles which act upon the shoaldBr- joint. — WUxan or proiractorB. — TVlcoid tanlcrW 
fihresl, pertoralw major friavirular fihre*), coraco-brachialia, bit'4^ (aliort hpftd), nu1»>(rH|>utariH 
(upper fil>rei). 

Eiteiunrs or Relrai-J'yrf.^]MXiasim\M dotsi, deitnid ([XMtnrior libres), tcree mAJor. tcrtw 
minor, infr&.ipinat.u^ (lower fibres). 

Afiiliiiiur*. — Ileltonl. 4Upni«pinatu«. 

AiIdueloTfi. Pcctumh's major. lati»simm dowi, nuhrirnpiilaHH, infriiepinatiif), terw major, 
lerof minnr. corAco-brachialw. biceps (short head), trircpa (lower head). 

Inirriuii RuiixOtr*. — PectoralU major, lalbnimiM dorei, Utv^ major. i>ub»capulBrie, deltoid 
(anl*'rior f!l)r«.-j-l. 

F.rtfrnnI Rntator^.- Deltoid {f)Osterifir (ibrea), infrasjiinatua, lerea mmnr. 

CircumitueliTr*. — Thft abov^ gmips act ing conaeculi vely. 



17 



268 




THE ARTICULATIONS 



4. TiUi EL30\V-J01N*T 



CitLts.—Diarthfosii. 



Subdivision. — Gingb/mus. 



The eltjow is a complete Uinge, ami, unlike tho knee, depends for its security 
attdstrenRthupon the configuration of iw bones rallier lliaii on ilienuinl>er,sircngth, 
or arraiifj^inieni of its ligauients. The l>ones conipoolng it are the lower end of 
the humenw above, and the vipper ends of the nulJUit luul ulnn 1>c1ihv; the uriic-uhir 
mirface of the humerus beinij; received partly within the setnilumir notch (jrrejit 
sigmoid cavity) of the ulna, and partly upon the cui>-shai»e*i surface of the radius. 
The ligumenls fnnn one largo ajul capacious capsule, which, by blending with the 
annular ligament, and then pasaing im to l» utiat^iied to ilie neck of the radius, 
embraces the elhow and tlic superior radio-uliiar joints, uniting them into one. 
Lateriilly, it is considerably strengthened by su|>oradded fibres arising from the 
condyles of the humerus and inseparably connected with the capsule. For rnn- 
venienco of description it will be spoken of a« consisting of four portions: — 



Anterior 

Posterior. 



Internal. 
External. 



The anterior portion (fig. 269) is attached to the front nf the liunieruu above 
the articular surface and coronoid fossa, in an inverted V-shaped nnmner, to two 



Fio. 2n9. — IwTEasAL View of the ELBOW-ioircT. 



Aatmnof liiuaaai 



(Tbur lawrst 

UvuaMi 







very fiiintly marked ridges which start fn>m the fmnt of thp inlemal and extenii 
epioondyluK, nnd meet a variable dii-liuice ol«)ve the coronoid fo^aa. Helow, it is 
mted, juat Iwyond the articular margin, to the front of the coronoid pmrets and it 
is intimately blendwi with the from of the iinnnliir ligament, a few fibres passing 
on to the npfk of the radius. It varies in strength and thicknc;*s, bein^ wtmetimes 
so thin as barely to cover (lie K>iiovial membrane; at other?, thick ami strony;, 
and formed of coarse decussating fibres, the majority of which descend from the 
inner side outwards to the radius. 

The posttrior portion (fig. 270), thin and membranous, is attached superiorly 
to the humerus, in much the same tnverteil V-^huped way as the anterior; ascend- 
ing from the intomdl epicondyle. ninng the inner side of ihe olecrnnon fa-iKa ne;irly 
to the top; then, crowing the l)ottom of the fossa, it tle»cen«lj! on the outer side, 
skirtinji the outer margin nf the tmcblear surface, and turns outwards along the 
posterior edge of the ctipilulum. Inferiorly, it i.s atlachfd lo a flight pn>ove along 
the sui»rior and exienmt .surfaces of the olecnmon, and the nmgh nurface of tho 
ulna jiiHt lK\vond the nidial notch, and to the annular ligament, a few fibres posting 
on to the neck of the radius. It is composed of decussating fibres, most oi which 



THE ELBOW-JOIST 



259 



pass vertically or obliquely downwanis, a few takinK ti trantfverse course at rhc 
fluuimit of the olerranon fossa whore ihe Hganiciit is usufllly thinnpst. 

The internal portion, the ulnar lateral ligament (fig. '26^>). is thicker, si router, 
and denser than t-ilher tin- itnlerior ur [msterior iinitinns, It i» (rian)i:ular in fonu, 
itij apex being uttnched to the anterior and under asjiect of the internal epicondyle, 
and to tlie condyloid ed^e of the groove Ijctween the iroclilea and ihe i-ondyle. The 
filirps nidiale downwunis frtim this aitarhiiK'ni, the anrerior jmssing forwards to 
he fixed lo the. rough ovcrhungitis inner edge of the eorunoid proeo-ss; the middle 
descend less ol)li{|uely to a ridge ninning between the comnoid and olecranon pro- 
cessea. while the poateriorpassobliquely backwari.U to the inner edge of the olecranon 
Just beyond the articular margin. An oblique band, tlie oblique ligament of isir 
Astley Cooper, connccis the niarein of the olecranon procKW with the margin of 
the ciironoid pnwetw. It lie-s superficial to i he poKterior fibres of the internal lateral 
ligament. The anterior fibres are ihe thickest, stmnfiei^t. and moel pmnouneed. 

The external portion, the radial lateral ligament (fig. 270). is uttache<l ahove 
to the lower part of the exiernjtl epicondyle. and from this rhe fibres radiate to their 
attac'linient into the (juter side of the annular lijrainent. a few fibres l>eing pro- 
longed to reach the neck of the radius. The anterior fibres reach further fomards 
than Ihe pti^ierior do Iiehind. It is strong and well-markefl, but let« so than the 
interniil portion. 

Fto. 270. — KXTEHNAL VlKW OF THK ELBOW-JOIMT. 



3SP^ 



— — AaavlM tlnawnl 



BMUI laltral 111 >B«nt 



■ roMcnnr UaaMMit 



The synovial membrane lines the whole of the capsule, and extentb into the 
superior radio-ulnar jdint. lining the annular ligatnenl, Oul^iide the synovial 
membrane, but inside the capsule, are nflcn seen some pad!« ol fatty tis;^ue: one is 
situated on the inner Hide at the biuse of the olecranon, another is seen on the out- 
side projet^ting into tlie cavity between the radius anil ulna; this latter, with a fold 
of synovial membrane opposite the front of the outer lip of the (nxdilea, wuggesla 
the divl-sion of the joint into two part.s-<ine iniprniilly for the. ulna, and another 
CTtemally for the ntdiu*. There are also pads of fatty tis-sue at the bottom of the 
olecranon and contnoid fossa.-, and at the tip of the olecranon process. 

The arterial supply is derived from each of the vessels forming Ihe free ana.*ito. 
mosis around the elbow, and there is al?!o a s{>et'tal branch to the front and outer 
side of the joint, from the brachial artery, aiid the arterial branch to (lie brackiatis 
also feeds the front of the joint. 

The nerve-supply comes fmm rhe mu-trtila-cutan«)Uit chiefly; rhe ulnar, median, 
and riniiMl (iiiUe<-uli>-«pir!il) alxo give filnmont.s to the joint. 

Relations. — ^In front of the joint, ami in inunediate relation with the capsule, 
are the hrachialis. the sufxrficial and deep branches nf the radial (nitwculo-f5pimD 
ncr^'P. the radial recurri'iit artery, and Ihe brachio-radialis. The brachial arter>'. the 
median nerve, and the pronator teren are HupaniiiHl from the capsule by ihe 
bracUialU. Directly behind the capsule are the triceps, the anconeus, and ilit 



2fl0 



THE ARTICULATIONS 



posteriur iiiteroeseoud recurrerit arttry. Uii liie inner side are the ulnar ncr\'e, tlie 
»u])erior ulnar lateral (posterior ulimr rccmTeiit) artery, and tlic uiipiTjiarlsof the 
flexor carpi uiiiurisi jiiiil ilcxnr digiioiiJin suUiitiisj. t)ii ilie uuisideUe the exieneor 
t-arpi nulialis biigus and the upper part of the common tendon of origin of the 
superficiMl c-Xi.ffrwoi's of thf \vri.si and firipers. 

Tlic movements permitted ni the elbow are those of a true hinge joint, vi«., 
flexion and exteiL-ioii. Tlicse nioveirieiUs are oblJ'iue, so t^lat the forearm is inclined 
inwards in flexion, and ouiwards in extension; [liey are limitnd by the I'oiitacl 
respectively of the t'oroiitiid and olenrauon pnifebHiw of the ulmi with their cor- 
responding fossa; on the humerus, and their extent is detemiiued hy the Fclati\'e 
proportion hetween the length of the processes and depth of the fossie which receive 
Ihem, rather than by the tension of the ligaments, or the bulk of the j«jft parts 
over them. The anterior and posterior portions of the capsule, together with 
the i-orresponding portions of the lateral ligament, are not put nu the strelrh dunn|£ 
flexion ami yxlensiou; but, altliougli they may uisLst in checking the velocity, nml 
thu:? prevent undue force of impact, tliey do not control or determine the extent of 
these movements. Tlie limit, of extension is nmrhed when I lie ulna is nearly in a 
straight line with the humerus; and the limit of flexion when the ulna describes aii 
angle of from 3(1° to 4(1° with (he humerua. 

The obliquity of these movements is due to the outward inclination of the upper 
anfl bark pari of the trochlear surface, and the greater prtimincnc-e of ttie inner lip 
of the trochlea Iwlow: thus the plane of motion is directed from behind inward* 
and fonvartls. and carries rhe hand towards the middle third of the cla^■i^le. The 
oblitjuity of the joint, the inwani twist of the shaft of the humerus, and the back- 
ward direction of its head, all tend to bring the hand towunln the mid line, under 
the immediate oI>servation of the eye. whether for defence, employineni, or nourish- 
ment. This is in striking contrast to the lower limb, whpr<^ the direction u( the 
foot diverges from the median axis of the trunk, thus preventing awkwanlneas in 
locomoiion. In flexion and extension, the cup-like depression of the radial head 
glides up>on the rapitulimi, aiKl the inner margin of the radial head travels in the 
groove between the capitulum and the trochlea. This allows the radius to rotate 
upon the humeruM while following the ulna in all its movements- In full exten- 
sion and supination, the hend of the radius is barely in contact with the inferior 
surfaee of the capltiilum, and pnijeri.s so much backwards that Ut^ potiiterior margin 
can be felt as a prominence iii the back of the elbow. In full flexion the anterior 
e<lge of ihp radial head i.s receiveti into, and checked against, the depres.<*ion ftlx)ve 
the capitulum; while in mid-flexion ihe cup-like depression is fairly received upon 
the capitulum, and in this position, the radius being more completely steadied by 
the humerus than in.any other, pronation and supination take place must perfectly. 

Muscles wbich act upon ihe elbow-joini. — Fh-zor». — Hroeliiulb. bicepti. liraHiio-radJuln . 
pronnlor ttrm, flexor carpi rndialia, palmariji Inngim, flexor digitnnim ^iibLimis, flexor carpt 
ulnnri". 

EUtruon.—TfKepn, anconnTW. and the muflclcn which ■'Spring from the exl«mal epicordylc. 



5. THE ITN'ION OF THK KADIUS WITH THE IT^NA 

The radius is firmly united to the ulna by two joinU, and an intermediate fibrous 
union, via.;— 

(a) The superior radio-ulnar, — whereat the head of the radius rotaUs within 
the radial notch and annular li^arIlent. 

(6) The union of the shafts,— the mid radio-ulnar union. 

(c) The inferior radio-ulnar, whereat the lower end of the radius rolls routui 
the head of the ulna. 



(a) The Supeki'ir Radio-ulnar Joint 
Class.— RiorfArrt.m. Stibdivision.— TrnfAoiVfM. 

The bonee which enter into this joint are. the ulna by its radial nnleh and the 
radius by the smooth vertical border or rim on its head. There b but one liga- 
ment special to the joint, viz.: — 

Annular. 



HADIO-ULNAR 



261 



The annular ligament oonsisis of bond^ of strong fibres, !iomen-hat thicker 
than tiie capsule nf the elbow-joint, which enrirc!o the head of the radiiis, rptaining 
it agiiitist tlie side of tlie uhm. Tlie bulk of thcj* iibres forms about three-fourtla 
of a circle, and they are attached to the anterior and posterior margins of the radial 
notch; some few arc continued round below the radial notch, and furtti a coiiiplelo 
ligumentouH circle. The Itguineiit ]s iiiHepttrably couiierleii alonj; iXs upjier edge 
and external (i. e., ila non-articular) surface with the anterior, posterior, and ex- 
ternal portions of the capsule of the pUmjw, a icw of the fibres of those portions, 
especially of the external, descending to be attached to the neck of the radius, 'riie 
lower part of the articulation is covered in anteriorly, jHwteriorly, and externally 
by a thin independent membranous layer, which passes fmni the li)wer edge of tlie 
annular ligament tu the neck of the radius, elrengtheJied un the outer side by those 

Fio. 271. — Annuuah I.i«uuent. 
(The bcftd of th« radius removed to nhon* th<? mrml>ranou8 connection of thla ligament 

wilh the nulitu.) 



OapiuUofelboir-JalDl 

Coaliloa of fUiy llMO* 
■iMnbraiiavt tlHua joinuuc th« 

ol ttiB radtui 

Humus 

' Annul u Ucsaiaal 



Cipial* ofalbov 






fibres passing down from the capsule. They are loose enough to allow the bone tu 
rotate upon its riwu axia (fig. 271). Internally and below the cavity is closed in 
by a loose membrane, the ligHme-ntuin tguadratum, which paases from the lower 
bonier of the radial notch to the neck of the radius. 

The synovial membrane is the sitme as that of the elbow, and, after lining the 
annular liganient, pa.s.vt!» on lo the ueck of the radius, and tlience up to the lower 
iiiar>;in of the articular carlihme. 

The arterial and nerve-supply are the same oa those to the outer part of the 
el bow- joint. 

Relations. — Behind lies I he anconeus and in front the outer border of the 
brarhialis. 

ffi) TiiR Mm RADifi-uLNAR Union 

Class.— .S.yrMirMr<w(s. Subdivision. — Syndesmoais. 

There are two interosseous ligaments which pass between the shafl.8 of the 
bones and unite them firmly together, viz.: — 

Oblique ligament. Interosseous membrane. 



The oblique ligament I'chorda obliqua) (figs. 26'J and 272) is a fairly strong, 
naiTow band, which pas^s from the lower em] of the rough oulpr border of the 
coronoid pmces-s, downwar^b and outwards to be attached to the posterior edge of 
the lower end of the tuberosity of the radius and the vertical ridge running from it 
to the inner Iwrder of the bone. Some of its fibres blend with the fibres of insertion 
of the biceps tendon: behind, it is in close contact wilh the supinator; beloM-, a 
thin membrane ]>afises off from it to the upper edge of the interosseous membrane; 
the posterior interosseous vessels pas-s in (he spmre Iwtween it and the inteixisseoua 



202 



THE ARTiCULATlOSS 



membrane; nccaaionally a slip is continued into the annular ligament of the8U|H»riar_ 
radio-uliifir arliciihition (sn? fij;. 272). 

Tlic interosseous membrane (fiK. 269) is attached to the ulna at the loi 

f)art of the ritige in front of the depression for tlie supinator, and along the whole 
Giiph of iho internsseous border us far as the inferior radio-ulnar articulation, 
approacliing tlie front of the boiie in the lower part, of its anachnicnl. To the 
radius it is attached along the interosseous border, from an inch (2*5 cm,) below 
the tuberosity to the ulnar notch for the lower end (if the ulna. It \a strongest 
and broadest in the cenire. wliere the fibres are dense and closely packed; it is 
also well marked beneath the pronator quadratu^. and thickens considerably at 
the lower pnd. fnyniing a siruiig band of union between the two bones. Its fibres 
pass i-hielly downwanlH and inwards, from the radivis to the ulna, though some 
take the opposite direction; at the lower end some are transverse. On the posterior 
surface are one or two bands, which pa.ss downwards and outwards fr*im ihc ulna 
to the radius, and frequently there is a strong bundle as large as the oblique liga- 
ment ; this, which should be called the iof ehor oblique ligament (fig. 276), stretches 

Fia. 272. — ITprEH Portioks or Ltft I'lna .*vo U idivs with OBLiqu* and Aivkular 

].l(i\M£.VT»: TO .'■HOW AS OCCASIONAL Sl-IP FHOM TBB ( )Bl.rgfe LiCIAMEVT TO THE 

I^jWkr I'art ok the Ax.VTlar l.KJAMKNT- Thin condition i» present in the spider monkiry 
{Alrlrji), wliit'li had ik> exteraid tii'itnb but only nidimniUiry bniins uf nntt. 

(From a ilinecUon by Mr. W. P'-xraon, Royii) College nf Hurgvoii«, ^iiglatid.) 



ABBoltr Uf aseai 



OooaUOD*! *11D (torn obltqn* lli*- 
•onL to aaiiblu IMAcocut 



Ul«* 



n? 



uen* 



li^t-" a 




ODllqua 1 !«■■•» 



from the ulna, an inch and a lialf above it« lower extremity, downwardB and out 
wants to tlie ridee above and behind the ulnar notcfi nf the radiutj. 

At its attaciinifini to the bones, the intero-sseous membrane blends with the 
periosteum. Its upper border ia connected with the oblique ligament by a thin 
membrane, which is jiicrced by itte posterior iniei-osseous vessels: and the lower 
Iwrder, wliich stretcHea acroBS between the two bones just above the inferior radii»- 
ulnar articulation, assists in completing the capsule of that joint. Its anterior 
surfiice Ls in relation with the ^«.ror digUorum profundu* and /frjor jioUina lonyns 
in the upper three-quarters, the lower fourth l>eing in relation with the pronator 
quadratu^. The anterior interosseous vessels and ner^'e desceitd along the middle of 
the membrane, the artery lieing iKiimd donTi to it. About an inch from the l^^^-(!r 
end it is pierceil by the (interior interoaaeous arter>*. The [Misterior surface is in 
relation witli the supiruitor. oMuctor pollicis tongun (rrtmsor ossin melacarpi finUieis), 
ertrnsor pojliets tonguit and hreris, and the e.rteiisor indicis ^wo/wi't/s; at it.'^ lower 
part, also with the posterior branch of tlie anterior interosseous arlerj*, and the 
deep branch of the radial nerve ^posterior interosseous). 



(C) ThK LvfERIOR RADIO-tTLNAR JoiNT 

CiASi.^Diarthrosis. Subdivision. — Trochoides. 

This a. in one respeet, the reverse of the superior; for the rndius, inBtead of 
presenting a circular head to rotate upon the facet on the uhia, presents a t-oncave 



RAOIO-ULXAR 



203 



» 



facet which tvlls round tlte ulna. The articulation may b« said to conei&i of two 
parts at right anglet^ (u each ullior: oni.> Lietwei-n ttie radius and ulna, and the uther 
Lvtwceu th« ulna and the trianf^lur fibru-cartilagc. 
The ligaments are: — 

Anterior radio-ulnar. Posterior radio-ulnar. 

Triangular fibro-cartilage. 

The triangular fibro-cartilage (articular disc) (figs. 276 and 277) ovists the 
rodiuH in forming an arch umler wiiicU is received the first n»w of carpal hones. Ita 
Ijase is attached to the marein of ihe radius, separating the ulnar notch from the 
articular surface for the carpus, while its apex is fixed tu the fossa at the base of the 
styloid process of the ulua. It gradually and uniformly diniintslus in width from 
ba^e \n apex, hecominK rounded where it ia fixed to the ulna; it is joined by fibres 
of the internal lateral ligament of the wrist. It ia about three-eighths of an inch (1 
cm.) wide, and the same from base to apex; thicker at the circumference than in the 
centre; smooth and concave above to adnpt itself to the ulna, and smooth and 
slightly concave bflow to fit over the tritiuetral bone. Ita anterior and posterior 
borders are united to the anterior and posterior radio-ulnar and radio-carpjil lijra- 
inents, It is the moat ini|Hirtant sinicture in the inferior radio-carpal aniculation, 
as it is a very firm bond of union between the lower ends of the bones, and serves 
to limit their movementa upon one another more than any other structure in either 
the upper or lower radio-ulnar joints. Ita structure is fibrous at the circumference, 
while in the centre tliere ia a preponderance of cells. H differs from all other fibro- 
cartilagea in entering into two distinct .irliculationa; and acparatca entirety the 
synovial membrane of the r.idio-iilnar joint from that of the wrist. 

The anterior ntdio-ulnar ligament (fi^. 273) is attached by one end t« the 
anterior edge of the ulnar notch of the radius, and by the other to the rough Imne 
above the artinilar surfju-o nf the ulna a« fnr liiwanls ils the notch, aa well as into 
the anterior margin of the triangulnr cartilttge from base to apex. 

The posterior radio-ulnar ligament (fig. 274) is aimilarty attached to the 
posterior margin of the ulnar notch at one end, and at the other to the rough bone 
above the articular surface of the extremity of the ulna aa far mwarda aa the groove 
for the cjf<^sor carpi uinaris. with the sheath of which it is connected, as well as 
into the whole length of tlie posterior niiirgin of (he triiuigvilar fibni-curt.ilage. Both 
the radio-ulnar ligaments consist of thin, almost scattered, fibres, but they sen'e 
to form a capsule for the sup|Mirt aii'l protectitm of the s>Tiovial membrane. 

The lower end of the interosseous membrane extends between the ulna and 
radius immediately nbove llieir iJoitits of contact, Transverse fibres between the 
two hones form a .sort of arch above the concave articular facet of the radius, and, 
joining the anterior and posterior radio-ulnar ligainenta, complete the capsule of the 
inferior radioulnar joint. 

The synovial membrane, sonietimea cal1e<] the membrana saccifonnis, is 
large. lind Ukmw in pmportion In the size of the jtiint. It is not ojily interposi'd 
between the radial and uhiar nrtiruhir surfacw. but linea the terminal articular 
surface of the uhm and the upper surface of the triangular fibro-cartilage. 

The arterial supply is derivol from the anterior interoesst-ous arter>' and 
braiiclifs of tlif anterior carpal arch. 

TIk! nerve-supply cumcK from t)ie anterior ititeroeaeous oi the median, and the 
deep branch of the nidial (posterior interoweeous). 

Relations.^Hehinil lien the tejidon of the extentmr di^ti quinii pmprius and 
in fn>nt the flexor digitonim profundus. 

The movements of the radius. — The upper end of the radius rotates upon 
an axis drawTi through its own head and neck witliin the collar formed by the radial 
notch and the annular ligament, while the lower end. retained in pwition by the 
triangular cartilage, rolls round the head of the ulna. This rotation is ealletl pro- 
nation, when the radius from a position nearly parallel to the ulna tunis inwards 
so as to lie obliquely across it; and .tttpttiatiim, when the radius turns back again 
from n-ithin outwards, so aa lo uncn>es and lie neariy parallel «'ith the ulna. In 
these niQvcmenta the nulius carries with i( the hand, which rotates on an axis 
passUig a little to the inner side of the miihlle tine: thus, the hand when pronated, 
lies with it.< dorsum npwanis, as in pinying the piano, while when supinated, the 
palm lies upwanis— the altitude of a l>cggar asking alms. Ward thus expressft* 



264 



THE ARTICULATIONS 



the rclatinna of the two extremities of tlie nuliu8 in pronation mul supiimtioD: 'The 
head of the radius is sn disposed in relutiori to the si);nu)id ravity at the lower end 
thai the axis tif the former if proIongp<l fulls uprm the oontre nf the cirrlo nf which 
the latter is a seprnetil;' Ihe axis thus passes through the lower end of the ulna at 
a iMJint at which the triangular fihro-cartitae;e is attached, aiut if proJoiiiu;ed further, 
pauses thmijgli the ring foigor. Thus the radius describes, in rotating, a blunt- 
poinictl cone whose apex is the fientro of the radial liciid. and whow^ Uai* is at the 
intIsi; piiriiiil rol4ition of the bone being unac(;(inij>anied by any liinge-Hkc or 
aiilero- posterior motion of its head, and pron»fion and supination occuiTinp with- 
out disturbance to the parallclisni of the hones at the superior radio-uhiar joint. 
Associated "itli this n>taliori in the onlinary way, there ia some rnlation of the 
lujmcn»-uhmr shaft, which causes lateral shifting of the hand from side to side; 
thus, with pronation there w some abduction and with Knpiioii inn tnoriie adduetion 
combined, ^o that the hand can keeji on the same su|H>rficie.s in bolh pronaiioii and 
supination. The power of .-lupinalion in man is much greater thiui pronrttinn. 
owing to the immense power and levenige obtainerl by the cur\'e of i)ie radius, 
and by tlie attachn)ent of the bicei>s tendon to the back of thi tuberosity. For this 
reason all our screw-driving and boring tools are made to be used by Ruptnaiion 
inovenients. 

In the undissected state, the amount of rotation it is possible to obtain l*" about 
135**, so that neither the ]):i!m nor the fore p.irt of the lower end of the radius can 
be turned completely in oi>po»ite diix-ftions; yet in the living suljject this amount 
can be greatly increased by nilalion of tlie humero-uluur shaft at the shoulder-joint. 

Pronation is checked in the living subjpi't by (a) the posterior inferior radio- 
ulnar ligameni. which isKtreiiptheneii by theconnertion nf the sheath of the extensor 
tendons with it; (b) the lowermopt fibres of the interosseous membrane; (c) the 
back part of the intenial and adjacent lilires of the posterior ligament of the wrist, 
and (d) the meeting of Ihe soft parts on the front of the forearm. 

Supination is checked nniinly (a) by Ihe uHcrnal lateral ligament of the wrist, 
but partly also by (b) (lie oblique radio-ulnar ligament; (c) the anterior inforieir 
radio-ulnar ligament, and (d) the lowfwt fibres of tlio itit*rossiM)Us rnenibriiiie. 

The intenw.-«eons membrane servea, from the direction of its fibres doxMiwards 
and inwards from the radius to the ulna, to transmit the weight of the body from 
the ulna to the radius in the extended po-sition of the elbow, as in pushing forwards 
with the arms extended, or in suppfirting oiie's own M'eighl on Ihe hands, the ulna 
being in intimate contact with the humerus. l>ut not al all with the carpus; while 
the area of contact of the radius with the hnmenis in small, and that of the nulius 
with the cariam largr;. Hence the weight transmitterl by the ulna is commnnicatcd 
to the radius by the tightening of the interosseous membrane. Conversely, it falls 
Upon the hand with thie ann extendwl, the interosseous nienpbrane at-ting :is a sling 
to break (he violence of the shock, and preventing tiie whole force of the impact 
from ex|X>nding itself directly upon the capttulum. 

Muscles which act upon the radto-ulnor joints. — Pronalors. — Pronator teres, pmnatoj 
qitadnita-i. Hcxor rnrpi ratlialit, palniiuiiw Ir-ngiis. 

t^upiruilara, — Rjci-jw, xupiniitot. abductor poQicia loiipw (extenaor om» metlicarpi polliets). 
exteiiNuruulliciK luiieus. 

Thii hrdrliio-riKlrnliis jp chirfly a flexor nf the tlbow-joint, but it takes i«»rl in the iiiitiiilion 
nf the nm\-<-iiiiint of ;<up)nation wlien the liaml i» fully praiiated and of proiiutioii nhen titc liaiid 
is fully mpiiuited. 



6. THE RADIOCARPAL ARTICULATION 
Class. -Diorlhnsin. Subdivision. — Conditlarihrotn't. 

The wrist-joint is formwl by the union of the radius nnd triangular (ibro-cart ill 
above, articulating %iith the navicular, lunate, and triqiierntl IwinM lielow; t1 
ulna iK'injr 4'xclu(!eil by ihe inter^'eiition of the triangular fibrtKcnrtihige. The 
railiuK and triangular cartilage together present a smooth Aurfare. filightly concave 
both from before backward.-;, nnd from side to side, whilst the tliree bones of the 
enrpun prrj*ent a smooth, convex surface, made uniformly even by the interossecius 
ligfiments which bind them together. 

The eapsule of Ihe wTisI-joint hiw Iwen usually descriltod as four separate liga- 



Tiih' witisT-JOiyr 



205 



Tnenta, and it will be cfmvenleni for the »ake of a complete tteecriptioii la fdltnw 
this method; bin it must he undorstonrl that these four portions are coniirinoua 
around ihe jriiiit, exteniUng frtmi styloid pmccas to styloid proccas on both its 
aspects. 

The four portions are: — , . 

Volar (anterior) radio-earpal. Ulnor lateral. \ 

Doraal (posterior) nulio-carpal. Hadiat lateral. \ ^ 

The volar radio-carpal (liR. 273) is a thiek slnmn liyiiinf-iit, iittached supe-'- 
rioriy to the r;uhus itiinnHlijilely above the anlx?nor rimrKin of the feniiitml artirutur 
facet, lo the curved rid^ at ilie mot of the sryloid jinx-es-s of ilip radius, and to th* 
anterior nuirjiin of the trianKiilarcarlihise, hlondine with some fibres of the capsule 
of tlie inferior radio-ulnar joint. It j)!U*»e.i (hnvnwanls arul inwanls to be attached 
to Ixith n)«"s iif carpal bout's, especially the second, and to the volar intercarpal 
ligament. The strojimwl and most nbli)]ii(j libre« arise fnim the root of the styloid 
prorcss of the radius, and pass ohliouely over the navicular, with which otdy a few 
fibres are connect erl, to Ik- itiwrred nit^ the Iun:ile (semilunar), capitate (mognuiu), 



Fro. 273. — .Asramon View or Waiar. 



miuir niillo-ul>Br 

Uaanirai 



tnwraat UMnI llca- 
naivr oarpl ulnarM 



v^. 



i.*" 



/ -. 



Badikl UMra) tif amani 
olvriMi 

Volar rwdio^u-p*] 

liciuiiant 
Vandon of <l*ior aarpa 

radtaUa 



CaiwiUr IiRsmmt at Snt 
OiupO'iiiauoani*! JOinc 



and triquetral (cuneifomi) bones. Another set, less oblique, passes from the margin 
of the fivcct. for the lunate to be attached to the adjacent parts of the capit.ite, 
hamate (uneifonn), and triquetral t>ones. Between the twoaetsof fibres, small ves- 
sels pass into I lie joint . 

The dorsal radio-carpa! ligament (fi^r. 274) is attachc<l above to the dorsal 
edge of the lower end of the radius, ihe buck of the styloid proeees.and the poste- 
rior margin of the fibro-cartilage. It pa.'we.s downwards and inwords to be con- 
nected with the first row of the carpal bone3, chiefly with the hmate and triquetral, 
and the dorsal intercarpal liparneni. Thi-s litianient '\s thin and meml)ranoii8, 
and is strengthened by (i) strong fibres passinc from Ihe back of the fibro-carlilaKe, 
where they are Ijli-ndod with Ihn posterior inferior radio-ulnar Hj-anient, and, frotn 
the edpe of the mdiuf* just Iiehind the ulnar iintrh, to the triqnetnd biHie; (ii) fnirn 
the ridge and groove for the e.xtrn.sr)r pollir-is lonfjus to the bark of the lunate and 
triquetTfll bones; and (iii) from the groove for the radial extensors to the back of 
t^ie navicular and lunate- It Is in relation with, and strengthened by, the extensor 
tendons which pass over it. 

The ulnar lateral ligament ffip. 274) is fan-^hapefl. with itjt apex al>ove, at 
the styloid iJixieess of the ulna, to which it is attached on all sides, blending with 




206 



THE ARTICULATIONS 



the apes of the fibro-partilape. Some of the fibres poss forwanls and outwnrrljs to 

the ba.se of the pisiform bone and to the inner part oi the upper he irrlernf the trans- 
verse cftrpal ligament, where it is attached to the pi;jiifomi Vwne; Ihey form a thick, 
roundetl fajtcicuhw wi the front of the wrist. Other libres- tltwceiu! vertically to 
the inner side of the triiiuetrul bone, and others again outwards to the doi-sal sur- 
face nf tlie trltjueirftl. The lentlon \>{ the e-jcietifior carpi tdnaris is posterior to, 
and pusses over, part nf the fibres of the liganieiit. 

The radial lateral ligament (fig. 273) eonsist.s of fibres which radiate from 
the fore part and tip of llie styloid process of the radius. Some pass dywiiwards 
and inwanis, in front, to the navicular itnd adjacent edfse uf the capitate; some 
downwards, a little forwards and inwards, to the tubercle of the navicular and rid^e 
i)f tlieK"'^(<^r inuttaugulur (tnip/.(!iuin); and oLhen^ downwajxlsiuid uutwurds tu the 
rouph dorsal aurfacuof the navicular. Tlie fibres of this ligament aienot soltingaiid 
strong, nor do they ra<tiatp so much as those of the ulnar lateral ligament. It is 
in relation with the radial arttrxf, and the abductor itoUici* longus {extmtnor ossis 
tnttacnrpi polUcii) and extensor pollici^ brevls, the artery separating the tendons from 
the ligament. 

The synovial membrane is extensive, hut does not usually conmrnnitate with 

¥10. 274. — P^JSTEnioR View op Wrjst. 



FoaunoT ladiv-aliuf lliai 



OotmI mdl»-awi>«) liiamost . 



Dinar lM*talll«aiiiaDl vtwMM f 



jout «(tkann 



\ 



the nynnvial inetnbrane of the inferior rodio-ulnar joint. Wing shut out by the 
triaiiguhir cartilage, ll is also excluded, in ainiu^t every iMr^[a^ce. from that nf the 
carpal joints by the interdiseQUs ligaments between the first row of carpal bones. 
The styloid process of the radius is cartilage-covered internally, and forms part of, 
the articular cavity, while thai of the ulna does not. 

The arterial supply is derived from the anterior and poeterior carpal arches, thi 
IKwterior division of tlie ant^nor interosseous, fnmi twigs direct frtmi the radial unt' 
ulnar arteries, and from recurrent braiu-heH from the liwt dorsal iiilenKSsfiMis. 

The nerve-supply is derived from the ulnar and median in front, and the deep 
branch of the radial dxwterior int<rmssena>i) behind. 

Relations. — In front uf the radio-carpal joint are the tendons of the f1e\o| 
muscles of the wrist and fingers, the synovial sheaths ai»<ociated with litem, H 
radial and ulnar anerii.!s, and i.be median and ulnar nervas. 

Behind the joint are the majority of the tendons of tlie exter)in>r muscles 
the wrist and fingers, with their synovial sheaths, the lemiinal [rnri of the inlerit 
and posterior interosseous arteries, and the deep branch of the radial ner\'e (| 
tenor interoswKiUA). On the outer side liethetendonsof the.-\bductorpoIlicislanj^ 
(extensor u»8i«i melacarpi fKiiiicis) lUid the extensor pollicis brevis. On the inner skle 



THE WRIST-JOIST 



267 



the joint is subcutaneous and it is crosseci by the dorsal cutaueous brimcb nf 
ihe iiiii:ir nervy. 

Movements. — The wrist is a condyloid joint, the carpufl forminft the condyle. 

It allow.s of nmvenirnrs upon a tninsverse axis, i. e., flexion and extension; iind 
an>und an an tero- posterior axi.i, i. e., abduction and adduction; toget^ier witii a 
oombination of these in quick succession — cirt-umduction. Laciiing only rotation 
on a vertical axis, it thus possessses most of the movements of a liiill-and-8ocke& 
joint. withniJi ilie weakness and liBbility lo diwiocaiion whirh are peculiar to these 
joints. Thia deliciericy of rotation is coin|M!fis)iied for by the movements of tlie 
radiiirt at themdio-ulnar joints, viz., supination and pronation. Itsslrenj^li depends 
chiefly upon the numl»er of tendons which pass over it, and the close connection 
which exists l«5l Aeen the fibrous tissue of their shcatlw and the capsule of ilie wrist : 
alf-o upon the proximity of the me^lio-carpai and carpo-nietacariial joints, whicli 
pcnnitfi ishockii and jora to be shared and distributed between them: another source 

Fw. 275 — Fhoxt oi- Wkist wrm Aktbrior Annclab LlGAKtEXT. 



■i^, 



t'l 



A' 



i 



Uffaaaaat 



, Volar ndio-oarpal Ucvmim 



Vinai Ui«nU ligsmvni at 
wvui wlUi *i\ti to uUKitar 

miraiiH ' 



Tfudaii «ru>* n«ior c«iT> 
TatfMtM 



Aaiarior ankftUr IttkOMai 



ofatreogth i:; iheabeenreof any long bone on the distal side of the joint. In ilexion 
and extension the carpus rolls backwards and forwards, respectively, tjenealb the 
arch formed by the radius and fibro-cartilage; flexion being limited by the dorsal 
li^rament and dorsal portions of the lateral; extension by the volar, and volar por- 
tions of the lateral iiganientii. In adduction and abduction iha carpal bones 
glide from within outwards aJid from without inwards respectively. Alxluction is 
more limited than iidduclion, and is elieckcd by the ulnar lateral ligament and by 
contact of the styloid [(rocess "f the radius with tlie greater inultanirular; adduction 
is checked by tlicnulial lateral ligament alone. One reason for ud<liicti<iM lieing more 
free than abduction is that the ulna docs not reach so low down as the radius, and 
the yielding fibro-cartilaKe allows of j^reater movement iipwanls of the inner end of 
the carpus, in circumduct ion the hand moves ao tut to describe a cone, the apex of 
which is at the wrist. These movem«its are made more easy and extensive by the 
slight gliding of tlie carjiai lames upou one anoiher, and the comparatively free 



26S THE ARTICl'iATlONS 

motion Ht (lie ine>Jii>carpiil joint. The oblique direction of the. fibres nf the lateral 
lij^^uneiila prtveiiUi any rotation at the mdioH'arpal joint, wliile it permits conwidcr- 
able freeduni of abduction and adduction. 

MukIki which act upon th« radio-carpal joint. — Flexors. — The ll«xon of the curnus 
and llie long Bexors of ihi^ fingers aiid thi> thumh. luid tlie palniaris longus. £<l«iuor«.— -'llie 
cxteniHtrw of the carpus and finders. Abtlucturx. — Flexor i-jirpi radtalis and exteoaorcaqM radinlia 
lonKUK and brevU Holini; fiimultaiieniiNly; tiie iittiliiiptor |>r>l)tfi>i lonRua (exteimor owis met-nCArpj 
polticiii). cjcleniioree poUii-is longiu aad brevis, .lij//Mrtors.— Flesor carpi ulnaris. cxtcn»or curpi 
ulnarie. 

7. THE CARI^AL JOINTS 

The joints of the carpus may ho subdivided into — 

to) The joints of the first row. 

(6) The joints of the second row. 

(c) The medio-carpal, or jiuiction of the two ro^^'s with each other. 

(a) The Union ok the Fihst Row ou Carpal Bonim 

Class. — Diarthro»is. Subdivision. ^Arf/trridia. 

The bones of the first tow, the pisiform excepted, are united by two sets of 
ligantent^ and two intoroj^euuij libru-cartila^tti. 

Dorsal. Volar. 

Inierosseous- 

The two dorsal ligaments exlciul tnmsvereely lu'tween the bones, and connect 
the navicular with tlie lunate, and the lunate with the triqueiral. Their poste- 
rior surfaces are in r(>ni:n'| wilii the poslerior lifcaniciit of the wri.'it. 

The two volar ligaments extend nejirly Iriuisverscly between the bones con- 
necting the uavicuiitr with the tuniite, and the lunate with the triquctnil. They 
arc stronger than the dorsal ligaments, and arc i>laced beneath the anterior liga- 
ment of file wrist. 

The two interosseous ligaments (fip.. 277) are interposed l)etween the naviculiir 
and lunate, and ihe luiiau- and triquetral bone:;, reaching fnvrn the dorsal to the 
volar surface*, and Ix-mi; connected with the doiynl and volar URanientB. Tliey 
are narrow lil>ro-fartilages wliieb extend l)elweeii small puilitms only of the osseous 
surfaces. They help to fortn the convex carpal surface r)f the radio-carpal joint, 
and are somewhat vvrdye-shapoti, their bji«cii \mn^ towards the wrist, and their 
thin edpes Ijetwt^n the adjacent articular surfaces of the bones 

The synovial membrane is a pmlong;ition from that of the rncdio-earpal joint. 

The arterial anil nerve-supplies nre the same as for the medio-carpal joint. 

TuF, Union of thi: PisiKonM Honk with tiii-; Triqi'kthal 

Thit) is an arthnMlial joint which has a loose fibrous capsule attached to iKith 
tlie pisifonn and triquetral bones ju.st beyond the margins of liieir an icular surfaces. 
It is lined by a sepanil.i- .synovial nietnbnuie. Two strong roundeti or flattened 
bonds pass downwanis from the pisiform, one to the process of the hamate, and 
the other to the Iwise of the fifth metacarpal Ixme; the.se may be regarded as pro- 
lon^alions of the tendon of the flexor mrjii tdnnrix. and tlie pLsifrmn^ bone iimy 
be looked upon in the tight of a sesamoid bone devehtped in that tendon. 

(b) TiiK Union ok the Sf.co.\d Row of Carpau Wtsvs- 
Class. — Diorthr^t's. Subdivision.— ArfArorft'a. 

The four bones of thb row are united by throe doraalrthrre palmar, and two 
inien*sswiua lignmentt*. 

The three dorsal ligaments (fig. 270) extend tr:uisver>iely and connect the 
jtreater with the te«ier muliannular (trapezoid), the lesser nmltangular with the 
capitate, and the cupilale with llie baniate. 



THE CARPAL JOIXTS 



269 



The three voUr ligameots are stronger tliaii ihe dorsal, and are deeply placwl 
beiiemh i-he mass of flexor tendons; tliey extend transversely Iwtweeti ilie bones 
in a similar niiiiiiier In ilu' dniviil Itgamentu. 

Three interosseous ligaments cotinept ihc bones of the lower row frf the car- 
pus together. Two iire cnimecied with the cHjjittitc, one luiitmg it with the hnmale 
(fig. 277) and the oilier binding it to the leswer miiltanji^lar. The thin! linjiineiil 
joins the grtater and lesser tnull angular. 

The synovial membrane i& a prolongation of that lining the medio-carpal joint. 

The arterial and nerve-«upplies are Ine same as for the medio-carpal joint. 

(c) The MKDio-CAnpAL Joint, or the Union of the Two Rows of the Carpus 

WITH KACH OTIIRft 



(I) Class. — Di'trfhroftix. 
(II) Cl&ss.—Diarlhrosis. 



Subdivision. — Arthrodia. 
Subdivision. — Comiylarihrosis. 



The inferior surfaces of the bones of the firat row nrr adHpted to the aupcrior 
articular surfaces of the lM>nej) of the second row. The line of this articulation is 
coneavo-coiives from side to side, and is sometimes deacriiwd aa having the course 



FlO. 270. — POSTEHIOK ViKW OF THE WmIST. n ITH CaPSULB CUT TO SHOW AllTICl^t^H StnFACES. 



Lowar •«(! ot intaroaMwiia 
UgBinaitc 



' tnCvrlor ob1iqu« llB&CMQt 



TmiBVana rfonal llKaBi«al ■- 



wTiBt Uit la kaaii aoaa* Id 

UEII 



M, 



T«GdoD Dasar Okryl BlAuH 



of a Roniim S pluceil hcinxontally, 0) a nsemhlonce by no means strained, (i) 
The outer part of Ihe first- row consista or the navicular aJone; it is convex, and l>earB 
the greater and lasscr muUangulars. (ii) Then follows a transversely elongat^ed 
socket formed by the inner part of the navicular, the lunate, and triquetml, into 
which are rcLcived— (h) the head of the capitate, which articulates with the nnvioular 
and lunate: (&) the upper and outer angle of the hamate, which articulates nntU 
the navicular; and ic) thfs upper eonve.\ portion of the internal surface of the hamate. 
which articulates with the external a:id concave portion of the inferior surface uf 
the triquetral, (iii) The innermost purl, of the inferior surface of Ihe triquetral 
bone U convex, and tumwi a little hnckwarrf-s (o fit into the lower portion of the 
internal surface of the hamate, which is a little concave and turned forwards to 
receive it. The ceutrtJ part, which forma a socket for the capitate and hamate, 
has somewhat the character of a condyloid joint, the capitate and hamate being; 
the condvie, to fit into the cavity formed by the navicuhir, lunate, and Iriqueind; 
the other portions are typicully (irthrodinI. The lipaiO'enlK are: — (1) radiate or 
anterior medto-carpal; (2) posterior medio-carpal; ci) transverse dorsal. 

The radiate, anterior or volar medio-carpal \^ a ligament of considernhle 
slrengtli, consisting inosily uf tiba-s wliich nidiatc from the capitate to the navicular, 



270 



TUB AHTlCULATfONS 



luoatc. and triquetral; some few fibres connect the greater wid lesser multangular 
wit!) the navicular, and others pass betw-eeii the hamate and triquetral. It iscovcnd 
over and thickeiieil liv fitmms tissue derived from the sheaths of tlie flexor tendons 
and the hhna of origin of the small muacles of the thumb and little fuiRer. 

The posterior or dorsal medio-carpal ligament consists of fibres passing 
obliquely from the bonps (jf the first row to tho^c nf the second. It is stronger on 
the ulnar side tJiHTi on the rmlini, but is not so strong as the volar ligKment. 

Tlic transverse dorsal ligament (h^. 27ti) 'is an additional bond, well marked 
and often of considerable strength, which passes across the head of the capitate 

Fio. 277. — SiTfOviAL MiiMURAfiRii UP WaisT, Uamo, ako Fixoms. 



■yiMvlal M«e( IM MM- 



*%1 



•tmtUI MV Of thi mwi -iMBt 



■ynovul ■«] et tbs oarpua 



Sf aoTt&l iui).c4ouian>illv 
»»p*miK far Uie faui-iR 
luiil nnli nigiAoarpkl. 
baan 



fi 



, Byaovul MO or ih« onw-nMiaoarpal 
Joint ol Uia UiuiDO 



m 



m. 



f^i 






I 



I'lu'' 




LMCI«1 llt«IB*Dlll o( Itlll ■T.VIWUUpO'pllSlKBgaAl 

u-d )uwrptialanc«4l jotata 



fiwm the na\icular tn the triquetral bone; besides binding do^^-n the head of the 
capitate, it serves to fix the upper and outer angle of the hamate in the socket 
formed by the first row. 

The donwil ligaments, like the volar, are strengthened by a quantity of fibrous 
tissue bolnnning to the sheathe of (he extensor tendons, and by an extension of 
some of the fibres of the r!i|)s-ule of the wrist. There are no proper huenil medio- 
carpal lipamonf.s; thry an> but prolongations of the lateral ligamenls of the WTift. 

The synovial membrane itisr. 277) of the faq»us is common to all the joints of 
the corpus, and extends to the bases of the four inner metacari>a1 bones. Thus, 
besides lining ihc intcr-or mcdio-rarpal joint, it sends two prviccsscs upwards 



THE CARPO-METACARPAL JOISTS 



271 



between the three Ixmes of the first row, an<i three downwanls Iwiween tlie con- 
tiguous surfaces of the lesser aiid greaier iiiultuit^ular, the lesser tnultaugiil.ir 
and capitate, and capitate and hamate, Krom these latter, pn>longations extend 
to (lie four inner cnrpo-nietacarpal joints and the three intermetacarpal juiiits. 

The arterial supply is deri ve<l from — (a) t he anterior and puat trior carpal branches 
nf ihe radial and uhiar arteries; (6) the carpal branch of the aiitenor iiilen)swe<iii»; 
(c) the recurrent branrhc-H frrun the dtrep palmar arch. The terminal tnigs of the 
anterior and posterior intenisieous artentw supply the joint on its doreal asjjcct. 

The nerve-supply pomes from the ulnar on the ulnar aide, the median on the 
radial side, and the deep branch of the radial (posterior interonseoum) Ijehind. 

Relations. — The relations of this joint are practically tlie same as those of 
I lie radio-carpal joint, except that the flexor carpi ujnaris docs not cross the front, 
the ulnar artery in aeiiarated from it by the transverse carijal ligament, and the 
radial artery passes across its outer bon.k'r instead of in front. 

The movements of the carpal articulations iK'fueen bones of the same row are 
ver\' limited and consist only of slight jrlidinjc upon one another; but , slight as they 
are, they give elasticity to the carpus to break the jar* and shocks which result 
from blows or falls upon the band. 

The movements of one row of bones upon the other at the meilio-oiirpal joint 
ore more extensive, esiwcially in the diretrtion of Hexion and extension, so that the 
hand cnjoj-s a greater range of those movements than is permitted at the wri.'?l-joint 
alone. At the wr'wt, extension U more free than flexion; but this is balanced by 
the greater freedom uf Jlexion than of extension at the medio-carpal joint, luid by 
flexion at the carpo-mctaeariKtl joint, so that on the whole ihe range of flexion of 
the hand is grejiter than that of extension. 

A slight amoimt of lateral motion accoinpiuiie<l by a limited degree of rotation 
alio takes place; this rotation consists in the head of the capitate and ihe superior 
and outer angle of the hamate bone rotating in the sncket formed by the three 
bones of the upi>er row, and in a Rliding forwards and backwards of the greater 
and lessser multangular upon the navicular. 

In addition to the ligaments, the undulating outline and the variety of shapes of 
the apposed facets render this joinr very socure. 

Bearing in mind the mobility nf thi.s medi*>-carpal joint and of the carpo-meta- 
carpal, we see at onee the reason for the radial and ulnar ficxorji and extensors 
of the carpus being prolonged dowTi to their in.sertion into the base of the meta- 
carpus, for they produce the combined effect of motion at each of the three trans- 
verse articulations:— (I) at the wrist; (2) at the medio-carpal; (3) at the earfift- 
metacarpal joints. 

BIu8cl«s which set upon the mid-carpal iolnt.^Tli« muH<rW nliirh act upon rhis 
joiol are tliu «]i>ti>* ax cIiikw M'hii-K ncl ii|^>ii t.hti miiio-ctrpiil jo'iitl, ^xrept th« fli^xnr cHrpi ulDaris, 
which JH iiiscned iiitu the pjiiifomi bone. 



S. THE CARPO-MET.\CARPAL JOINTS 

ThtM nmy be di\Hded into two sets, namely: — 

(a) The carpo-metacarpal joints of the four inner fingers. 
(6) The carpo-metacarpal joints of the thumb. 

The inferior surlacefi of the Uines i»f the second row of the carj'us present a 
composite surface for Ihe four inner metaeanml bones: the greater multangular 
presents in additinn a dUrinct and separate saddle-shaped surface forthe base of the 
metacarpal bone of the thumb. 



(a) Thk Foctr Ixner CARpo-M>rr.\f arpai. Joists 
Class. — Diarthrosii. Subdivisioa.^.4r/Arodtd. 

These joints exwt between the greater and lesser multangular, capitate, and 
hamate bone-i above, and the four inner metacarpal bones below. The ligaments 
which unite them are, dorsal, volar, and interosi^eous. 

The dorsal ligaments (fig. 275).— Three dorsal IlgamcJits pass to the second 
metacarpal Ume: one from each of the carpal bones with winch it articulates. 



272 



Tits ARTiCULATlOSS 



viz., tiie greater and lesser iimltaii^lnr, atul capitate. Twci rlurtuil hands paa 
from ibe capitate to the tKiM mctacarpuj Loni!. Two dowul butLds pasa to the 
fourth bone: vIk., one from tho hamate, luid luioiher fnitn the capitate; tholutter 
is someliiiies wanting. The fifth bone hns only one band passing to it from the 
hamate. 

The volar Jigameats (fig. 273). — One strong baud pusses from the second 
nicUii.^ur)>iil lioiie to tiie gi'eiitt^r niidtatifriilur iniernal to the rid^ fur the Lmiisvereo 
carptil lit^iuiieiit; il id covered by the sheatlt df the flvsor CAirjii nuliaiis. 

TIircR bund-s pass fn>tn the third inc'tac:ar])ul: imp oiitwank to the prpatcr niull- 
angiiliir. a middle one upwards to the capitate. luid a third inwards over the fourth 
lo reacli the fifth metacArpid imd the hamate hones. 

One ligiiment curmectH the fourth bone lo the hamate. 

One hganiont counccts the fifth bone lo the hamate, the fibres ©.\lending inter- 
nally, and euntiecting the <]i>i-»d and vohtr ligHineiits. The lif^ainent to tlie fifth 
bone is strengthened in fnait by the prolonged fibres of the flexor carpi idnaris 
anil the .strong inner .slip of the lipamcnl of the third inetaearpnl bone; and poste- 
riorly, by the tendon of the ej^irnxor carpi tdtuiris. 

The interosseous ligament (fi^. 277) is Hinited to one p.trt of the articulation, 
and consi^ls of short tibres cnrinecting the contiguous luiglcs of the hamate and 
rapitate with I he thir(! ajifl founh nietararpfd bniiea towards their volar aspect. 
There is, however, a thick strong ligament connecting the edge of the greater mult- 
angular with the outer border of the base of the ssetond metacarpal bone: it helps 
to separate the carpo-met-acarpal joint of the thumb from the c-onuuon carpo-meta- 
carpat joint, and to close in the radial side of the latter joint. 

The synovial membrane is a continuation of the mcdJo-curpal joint; neea- 
sionally ther*' is a separate membrane tietwecn the hairiaie and fourth and fifth 
metacarpal bonea (fig. 277); while that l^etween the fourth and capitate is lined 
by the s\TioviaI sac of the common joint. 

The arteries to the four inner cjirpo-nielacarital joints are as follows: — 

(1) For the index tinger: twigs are supplied by the trunk of the railial on the 
dorsal and volar as^rectH. and by the llon^a] and volar metaciirpal branches. 

(2) For the middle finger; the fiist dorsal raetanariial by (he branch which 
passes U[>wartls to join the dorsal i-arpal arch, and a branch from the deep volar 
areh wlueh joins the volar carpal arch. 

(3) For the ring finger: rlie deep volar arch and recurrent twigs from the second 
doisal metacarpal in the same manner as for the middle linger. 

(4) For the Utile finger; the ulnar and its deejj branch; also twigs from the 
second dorsal metacarpal. 

The nerves an' supplieil lo tliiise joniis by the dee[> volar branch of the ulnar, 
the deep branch of the radial (praterior interosseous), and the median. 

Relations. -In front of the inner four carpo-meiaeariial joints are ihe flexors 
of the fincere with their synovial Nheath. The flexor carpi radialis crossing in front 
of (he outer part of the joint and the fibres of the oblique adiliu'lor ij<illicl'^ which 
spring from the capitate and lesser miillatigular are also anterior relations. Hehind 
the joiiits are the extensors of the wrist lUid fingers with their sjiiovial sheaths and 
the dorsal metacarpal arteries. At the outer border of the joints between the 
index and les-wr multjuigular lies the radial artery. 

The movements [K*rmitte(,l at tliese joints, though slight, serve to increase those 
of the medio-carpal and wrist-joints. The joint l>etween the fifth mctaear|>ai and 
the hamate iKines ajppnwu-fies somewliat in shajie aini tnobilily the first carjKi- 
mctaearpal joint; it has a greater range of flexion and exterision, but its lateral 
movement is neariy as limited as that of the throe other metacarpal bone^; the 
process of the hamate bone limits its flexion. lateral motion towards the ulnar 
side is cliecke<i by the strong pahuar band which unites the baw of the fifth meta- 
carpal to the base of the third, and the strong transverse ligament at the head 
of tlte bom's- The mobility of the second, thinl. and fourth mei.arar])al bones 
is very hmitefl, ami conswts alm»»;l entirely i)f a Klight gliding upon the carpal 
bones, i. e., flexion and extension : ihat of the third and fourth bones is extremely 
slight, as there is no long flexor attached to cither; but, owing to the close connec- 
tion of the ba»«« of the metacarpal bones, the radial and ulnar flexors and exten- 
MiTu of the carpus act on all by their pull on the particular bone into which tfaf 
are iu-sejled. 



THE INTERMETACARPAL JOISTS 



373 



Abduction, or movement toward the radial side, is prevented by the impaction 
uf tiie setwiid bone aKuiiist (he greater luultaii^lar; a little adduction ia pemiilled, 
and is favoured \>y the jiiiijie given to the hamate and hfth metauarpal banes. 

There is also a slif^hl ^lidiii^ between the femTlli and hfth boucs. when Ihf) ^on* 
cavity they present, towards the paini is deepened to form the 'cup of iViopenes.' 

Mutcles which act upon the four inner carpo-metacarpal joinis ure Uic llcxun< and 
irxH:ii«on« of lliu «ri«t Hi»d nnRerv.exrepI I he flexor '-jiriH iiIiinriK 



Class. 



(&) Thb Carpo-mf-tacarpal Joint of the Thumd 
DiartkroAia. Subdivision.— S(widfc-«Aa;>rti A rthrodia. 



The bonett enteriii;; into tbia joint are the baae of the first metacarpal and the 
greater muhanpular. The first metacarpal bone divergew fnim the oilier four, 
contrasting verv' sin>nRly with the position of the preat toe. It is due to this diverg- 
ence that the rhumb is able to lie opposwi to each and all the fingers. The liga- 
ment wlwh unites the bones is the 

Capsule. 

The articular capsule iRgs. 273 mid 27-1) constt>tij of hbrcs which piiss from 
the manf^in of the articular fai-et on the greater multuiigular, to the margin of tlie 
articular facet at the base of the first metacarpal bone. The fibres are stronger on 
the dorsal than on the palmar aspect. They are not tense enough to hold the bones 
in close contact, .so that while they restrict Cbcy do not prevertt motion in any 
direction. The intenud fibres are stri-jnger than the external. 

The synovial membrane is lax, lUid distinct from the other synovial mem- 
branes of the carpus. 

The arteries nf the carpo- metacarpal joint of the thumb ore derived from the 
trunk of the rtidial, the iiret volar mctarnrpal, and tbt; dorsalis pollicia. 

The nerves are .supplie*! by the branches of the median to the thumb. 

Relations. Itehind arc the long and short exten.s«>r tftndons of the thumb, 
auti behind and exteniiilly the tendon of the alxlnctor pollicia !ougu« (e.\ten«ir oasis 
nietacarpi pollii;is). T lie tendon uf the fie.vor pollicis hmgus ii> in front and fibres 
of the flexor polHcis brevi» and opponeus p4>Uicis muscles are also anterior relations. 
To the inner side is the radial artery as it piis.ses forward-s into the palm uf the hand. 

The movements of this joint are re^lat<iil by the shai)e of the articular :^ur- 
faces, rather than by the ligaments, luul consist of flexion, cxtcn.sion, «bduction, 
adduction, and circumduction, but. not rotation. In ficxinn and extension the 
metacun^al bone slide.'* In ajid fro upon the multangular; in abducliori and adduction 
it alidea from side to side or, more correctly, revolves upon (he an tero- posterior axis 
of liie joint. The power of opposbig (he thumb to any of the fingere is duo to the 
forward and inwaiil obliquity of its flexion movement, which in by far its most 
extensive motion. Abduction is very free, wlille adtluction is limited on account 
of the proxiriuty of the second metacarpal bone. The movement of the greater 
mulianfailar upon the rest of the carpus aomewliat increases the range of all the 
niiivemema uf the thumb. 

MuBclc! which act upon the carpo-metacarpal joint of the tbmnb.— F;«wr«.— Flpxot 

pnlliHfi brcvi.%. tlcxi>r [lolliris InncuK. dp^WDf^n^ pnlliriM. KxP<*n*»M.— Exieneopp* l>oUii'iw hrr^-in 
Utd InnfEii^ And .-ilidui^Ior [loJIit'i!! loiifciu. Aifluriarii. — Abiliii'l'tirpj* polliciM liinfri.i» ntid Itri'viit. 
cxteafiorL-!> u»llidK lijnci'i.'i uiid brevis. .{({Jitelvn, — 'Ilm tnuisvcTM) luid ubljque ouductor iHillicic, 
opponcn*. nrdt ilomiU int^roweouti. Mvgrict proitannff oppoindOTi.— Opponent, flexor brevw, 
OoJJqiM' Hiltdii'tor. 



9. THK INTKR.Ml-rrACARPAL ARTiriT-ATIONS 

diss.— Diarlhrosis. Subdivision.^^ nlArorfid. 

Tlie metacarpal nf the thumb i-i not connected with any other metacarjjal bone. 
The second, third, fourth, and fifth metacariKi! bones are in actual contact ai their 
bases, and are held firmly together by the following ligaments: — 



Dorsal. 



1ft 



Interosseous llgamcnta. 



Volar. 



274 THE AliTICVLATlOXS 

The dorsal ligaments (fig. 275) tire layers of varinblo t-lucktiesM of stronfc. short- 
fibres, whirli pass trains voi-sely from hone to bone, lilling u]) the irreKulurities on 
the dorsal tiurfiiL-es. 

The volar ligaments an- tran^vcrMi'* layers of Itgnmentouti liw^ue paiwiiig fnini 
Ixine l« l>f)ne: llioy catitint. lie well different interf from the nthrr liBametils and 
fibrous tissue i-nverinp the hnnos. 

The interosseous ligaments (fijt, 277) pass Ix-lween tlie npposod surface"* of 
the Itone.s, and art- attached to the distal sidi^ "f the articulai- faceti*, so an tu cirwe 
in the synovial cavities on lliis asiJerl; where (here are two articular facets, tlie 
fibres extend upwanis between them nearly aa far as their carpal facets. That 
between the fourth and fifth is ihc weakest. 

The arteries to the intennelacHrpal joints are Iwikb from the volar and dorsAl 
melacarpnl arteriL's; the twigs pass upwards between the interosseous mu-scles. 

The nerves are derived from rhe ulnar ai]d the deep branch of radial (posterior 
interosseous). 

The synovial membrane i» prolonged downwards from the common carpal sac. 

The UtnoN or the Hkads of the MtTACARPAt. BoKQa 

The distal extremities of these bones are connected togettier on (heir palmar 
aspects by what it* called the transverse ligament. This consists of three short 
bonds of fibrous tisane, which unite the second and third, third and fourth, and the 
fourth and fifth bones. They are rather more than 6 mm. (J in.) deep, and rather 
lees in width, and limit the distance to which the metacarpal bones can be f«parated. 
They are continuout) above with the fascia covering the interosseous muscles; below, 
they are connected with the subcutaneous tissue of the web of the hand. They 
are on a level with the fmnt surfaces of the bones, and are blended on either side 
with the edges of the glennid li^imient in front, with the l(i(or«l ligHnii-nt.s of the 
mctacarpo-phalangcal joint, and alpo with the sheaths of the tendons. In front, 
ii hinihrieai miwcle passes with the digital arteries and nen-es; while behind, the 
ini^oisti muscles pass to their injiertions. 



10, THE MErrACARPO-PHALANGE.\L .lOINTS 

(a) TlIK METArAttl'n-MIALASaEAL JoiNTS DF THi: Foi'R ISNKH FlNOEHS 

Class. ^Oi'uri/irosM. Subdivision.— Cwirii/Ajf^ArMi's. 

In these joints the puf»-sliaped extremity of the b.i.sc of the first phalanx fits 
on to the rounded bead of the n^etaca^pal bone, and is united by the following 
ligaments:^ 

Lateral. Olenoid. 

The glenoid ligament (Gg. 278) is a fibro-cartilaginous plate which f<eeins more 
intendetl to tncnaae the depth of the phalangeal articular facet in front, than lo 
unite the two bones. It is much more (irutly attachefl to the margin of the phalatix 
than to the metacarpal Ixiue, being only loosely eonneeled with the j>a!mar surface 
of the latter by some loose areolur tissue which covers in the synovial membrane, 
here prxdonged upon the surface of the bone some little distance. Laterally, it is 
connected with the lateral ligaments and the transverse melacaqjal ligament. U 
curiT!»pon(h^ to the sesamoid bonijs of the thumb; a sesamoid bone sometimes exists 
at the inner border of the joint of tlie little finger. 

The lateral ligaments (277 and 278) are strong and finnly connect the borw 
with one another; each is attached above to the lateral tubercle, and to » depreesit 
in front of the tubercle, of the nietacarpal txuic. From this point the iibrcs spread 
widely aa they descend on the side of the base of the phalanx; the anterior fibres 
are connected with the glenoid liganient; the posterior blend witli the tcndinoua 
expansion at the bock of the joint. 

The joint is covered m posteriorly by the expansion of the extensor tendon, and 
Bome loose areolar lis.sue passing fnjui its under surface to thf- bnncK (fig. 278). 

The synovial membrane is lootw and capacious, and invesis the inner surface 
of the ligaments which connect the l»on<». 

The arteries come from the digital or volar metacarpal vessels of the deep arch. 



METACARPO-PHALANOEAL 



275 



The nerves un; derived fmni ihe digital branches^ or from iwigs of the branches 
of the uhiiir to the tnt^rosMous muscles. 

Relations.— 1. The niet.iLcarp(vphiilan(!;cal joinf.s of the middle three digits. 
In front, the tendons nf the flexor prnfumliis and flexor subliiiiis diftiloruiii. Later- 
ally, oil the radiitl side, a lunibrical, un intenwHeous muscle, aiid digital nerves and 
vessels; on the ulnar side, iin interasseous muscle and digital vessels and nersiai. 
Behind, Ihe eomiium extensor teudon and iu the eaiic of Ihe index digit the tendon 
of the extensor iiidiiris. 

H. The mctacarpo-phidanfieal joint of the little finder. In front, the flexor qiiinti 
diRiti brevis and tiie tendtms of the Hcxor profundus and sublimis digitorum muscle 
which go to this dipt. IHehind, the extensor diftili quinti to a Hlip of the extensor 
digitorum cominunia sonietimes. On the radial ttide. a lumbrical, Ihe thinl ]>alniar 
interosseous musde, digital vessels and nerves. Ou the ulnar tjide, <ligilHl ve-st^els 
and nerves. 

The movements permitted at theee joints are flexion, extension, abduction, 

Fk). 27S. — AxTRKioie and Puhtemioh View of Lioauektb op tiig Finqbrb. 



e€ I he lueUfiUtial 

bollHl 



Ar««lar ItoHW 
eapsMla 

lAWMi ti|«aBiit 



l.*Ianl li|t>iii*at 
FUxflr iaKd«n 



Arselav tiMV* 

04PMUa 

Bitciuar teadoB 



- rteior wadoo 



BlipaoftliBaiMciBcir 

MUdOD 



adduction, and oircunidnction. Flexion ia the most free nf all and may be eontinued 
until the phalanx is at a right anple with the mptar'arpal bone. It is on this aceoimt 
that the artinilar surfat-e of the head of the bone \» prolonged so niut-li further on 
the palmar lisjject, and that the synovial ineinbnine is here so loose and ample, 
lixtejision is the niOHt limited of the movements, and oaii only In- carrio*! to a lillle 
IjeyiMid theatraiplit line. Aiidudion and adduetton are fairly free, but not so free 
as flexion. Hexion is asaoeiated with adduction, and extension with abduction. 
ThLi may be proved by opening the hand, when tlie fingejs involuntarily separate 
as they extend, while in closing the fist they come together again. The frw abduc- 
tion, adduction, ami circumduction which arc permitted at these joints are due 
to the fact that the long axes of the arlicutar faceln are at right angles to one another^ 

Hu&cles actinK on ttie middle three dif^its. — f'/.-iroi'*.— nexordiffiloruai jjivfuiidiw, flc.\or 
diicil'tnttniiiihlmii-'', F.iUnxnrn. — Kxlcii.'oriliKiloriini roniiiimibunclon inriiidf-.vdigitlhcfxttnsor 
iiidici.i. AbduetfiT*. — Drtrsjil intciottwei. .liWuc/ors.- I'aliiifir iiit«ro«uJ. 



h-L 



276 



TIIK ARTICULATIONS 



HuBcles sctiag oa ths mctacarpo-pbalangeal Joint of the Httle fiager. — Fitxori. — Flsxor 
numti digili brevii, flexor digitonun Humimi-<,fl<>xur(Ugtlurumpn>{imtJiis, Ertenmr*. — Extensor 
aigitoniin communij', *xleni«or quiiili digili. Ainiucmr. — ALfdurLur ijiuiiti djgiti. A'Ultiriur. — 
Ttiird pidmar iuterutiscciuii. 

(b) Thk Mktacaspophalasoeal Joint of the Thumh 

Class. — Diarthrogis. Subdivision.— Coiuij/UirOirosis. 

Tlie heail of Ihn nieljirarpul Ijone of the thumb difTers confiidoralily fnitn tlie 
corrfcipondiiig cmU of the melucarpai hunm i)f tin; (ingcra. It is less convex, wider 
from side to side, the pulmar edge of the urticulur surftice U rnispd imd irregular, 
and here on either side of the mefiiftii line ure the two fjifeta for the sesamoid bonee- 
Thebrtseof tlie first plialaiix of the llmnib, too, is more like the base of the second 
phalaax of ooe of the other firigere. The ligaments are; — 

Lateral. Dorsal. 

Setiamoid bones in place of a f^lenoid ligament. 

The lateral ligaments are short, strung baiuU uf fibres, which radiate from 
depressions on cither side of the head of the metacarpal bone to the base of the 
&r8t phalanx and sesamoid Ixmes. As they descend Ihey pass a little forwards, so 
that llie greater number mv iiiaerlcd in front of tlie centre of motion. 

The dorsal ligament mnsists of e^eattered fibrt-s uhieh pas.s across the joint 
frotrt omi lateral ligamtsit to the other, completing the capsule and proteiMing the 
^tiovial i*ac. 

The sesamoid bones are two in number, situated on cither side of the middlo 
line, and connecteii together by strong transvorsR fibres wbieh form the floor of tbe 
gn:K)ve for llie lon<i jksor Irruion; they are connected with the base of the phalanx 
and head of the'inetacarpal bone by strong fibres. Atileriorly they give attueh- 
inonl to t he short mm^rles of ( he thumb, and posteriorly are .-imoot li for t he pur|ioaB 
of ghding ovi-r tlie faeeis. Tlie laiern! Itgament.-i are partly itusertefl into tlieir sides. 

The arteries and nerves come from the digital branches of the thumb. 

Relations. Of the nictiicarpo-phal;ingcal joint of the ihiimb: In front and ex- 
leniully, abductfr pollicis brevis and superficial head of fle.tor pollicia breviw. 
In frimt and internally, ciblique and trunsvei-se addu(rtor>> and deep head of flexor 
[Ktllicis brevis. Directly in front, flexor pollieis longus and terminal branches of 
first volar metacarpal artery, linliind, o-vtenwir piilliris brevis aJid longus tendons. 
Laterally, the dorsal digital vessels luid the digital ner^'es. 

The movements are ohiefly fle.xion and extension, ver>' little lateral movement 
lieiiig pennitted, and that only when the joint is slishlly bent. Thus (his joint 
more nearly appn)achcs tbe simple hinge eharacter tluui the curn^JsjHtuding articu- 
lations of the fingers. The thumb gets it-s freedom of motion at the carpo-incta- 
carpal joint; the fingei^ get theirs at the motaiiirpo-phalangeal, but they are not 
endowed with so much freedom as the thumb enjoys. 

Muscles which Met upna the inetacarpo-phnljin|[«al joint of the thumb. — Flerort. — 
FJexur i)olLk-i8 brvvi)<, Mvxor pullii'is luiigns. ExUnsars. — ExtoiiM>r pollicis brevis. extenflor 
poUtcifi (ongiut. 



11. THE INTKKPHALAXGEAL ARTICULATIONS 

Class. — Diarthrosis. Subdivision. — Glntfli/mus. 

The ligaments whirh unite the phalanges of the thumb and of the fingers are: — 
Glenoid. Lateral. 

Tlie glenoid ligament [fig. 278), Bomelimes called the sesamoid body, is very 
firmly eonneete*! with the base of the distal bone, and loonely. by mttuis of fibro- 
aroolar tissue, with tlic lieail of the pnixintal one. It blends with the liiteral liga- 
ments at the .'^idf's, wid over il pass the flexor tendons, Oecasionally a sesamoid 
hone is deveh>pe«l in the cirtilage of the interph;ilangeal joint of the thumb. 

The lateral ligaments {fig. 277 and 27.S) are stnmg bands wliich are fttiachcd 
tothe roughdeprc'i-'ionsnn the sides of the upper phalan.\, and to the projecting 



THh' HIP-JOINT 



•277 



laierfll margins of the lower phalanx of each joint. Tliey are ten«e in e\'er.v poni- 
tion, and entirely prevent any lateral motion;they are connectwl poaierioriy with 
the expansion cif tlie extensor tendon. 

Dorsally tfifj. '27H) the joint is ciivereii in l>y tlip lieep Hurfiire of the extensor 
leiiiion. ajid u little libro-anvilur tissue extends from the tendon, and thickeoit the 
posterior portion of the (^\^loviHl sac, completing iho capsule. 

The synovial membrane is Ino^-e and ample, nnd extends upxi'arcls a little way 
nlonp the shaft of the proxinial hone. 

The arteries iukI nerves mnie from their res|>ective diiiilal brunches. 

The relations nf the iiiterphalaunea! joints are the flexor and extensor ten- 
dons and Ihc diglral vessels and nervtM. 

The movements an- liniite<l lo flexion and extension. Flexion is more free, 
Ainl citii Iw fontiiuied till one Ixme is at a riplir angic to the other, and is most free 
at the junction of the first and sef^onH Unties; the second phalanx can be Hexed on 
the first throu({h I H)° to 1 15* when the latter is not flcxeil. The Krealer freedom 
of flexion is due to the grealer extent of the artJt-ular surface in front of the lieatla 
of the proximal buries, and to the direction of the fibres of Ilie laicral li^itinents, 
which pass a tittle forwards to their iiiMenicin into the distid Lione. 

The muscles which let upon the interphalangeal jointa Arc Oic fxtenwn and flexors 



TIf£ AltTWULATWNS OF THE LOWER LIMB 

The articulations of the lower limb are the following: — 

I. The hip-Joint. 
2 The knee-joint. 

3. The tibio-fibular union. 

4. The ankle-joint. 

5. The tarsal joints. 

6. The tarKo-metalarsal joints. 

7. The intermetatarsal joints. 

8. Thcmetatarso-phalangeal joints, 
il. The interphalangeal joints. 



I. THt; Hir-JOIXT 



Class . —J5 lort/irotis. 



SubdivisioQ.^EnarMrodia. 



The hip is the nwwt typieal example of a ball-and-sorket joint in the Ixidy, the 
round head of the femm- winj^ rerpived into the cup-Kha|»ed cavity of llie acetab- 
ulum. Hoth .-irtimihir surfaces are coatt^d with cartilage, that covering the head 
of the femur being thicker above wlierc it has to licar the weight of llio body, and 
thinning out to a mere edge tielfiw; the pit for the ligatnejituni teres is the only 
part unriialed. but the rartilape is somewhat heaped up aroimd its margin. Cov- 
enng the acetabulum, the cartilage is ht)rseshf»e-shHperi, ajid thicker above than 
below, being deficient over the deprp-'ssinn at the l>oltom of the acetahuhim, where 
a niH-is of fatty tbwiie— the .so-called synovial or Haversian gland— la lo<igo<l. 

The ligaments of the joint are: — 



Articular capsule. 

Transverse. 



I..iga.mentum teres, 
Glenoid lip. 



The articular capsule is one of the strongest ligamenta in the body. It ia 
large and stntiewhat loose, .so that in every position of the body some portion nf it 
is relaxwi. M the pelvis it l«i atlJirhed, superiorly, lo the base of the anterior 
inferior iliac spine: onr\ing barkwarfls. it l)econies IjJendetl with the deep surfnce 
of the rcflecteti tendon of the rtciuji iemori». posteriorly, it ia atlaehcd a few lines 



278 



THE AHTWULATloyS 



from the acetabular rim; and below, to the upper edge of the pnxive Iwtweeti (be 
acelabuluui aiid tuberosity of tho isfkium. ThuH ii reachcB the transverse lipn- 
niMil, boiug liriiil_v bltsntied with ilH outer surface, and frequently sends fibro» t»evond 
the notch to blend with the obturator membrane. Anteriorly it is attacbeti Iw 
the pubis nwirthcuotph.tothe ilio-pectinenl eminence, and thence backwarls to tho 
base of the inferior iliac spine. A thin strong atraluni is given off from itfi suiioi-f irial 
aspect behind; tliis extends beneath the gluteus miniraus and sniidl rotfttore. to 
be attached above to the dorstun of the ilium higlur than the re(Jectod tciidoa of 
the rectus, and ptwt^iriorly to the ilium imd iscOiiuni nearly iw far as the sciatic 
notch. As this expansion passes over tlie [onti Lendon of the rrctus, the tendon 
may Iw do-'wrilKd as bcinj? in pjirt Mintaincil within the substance of the capsule. 

At the femur, the capsule 'at fixeil to the anterior portion of the upp(;r Ijonler 
of the tTBat tiTichanter and to the superior cervical tubercle. Theiu*e it runs 
down the spiral line as far as the inner border of the fetuur, where it is oo a level 



Pio. 279. — Antcrior Virw or trb Camitlk of tb» IIii>-joint. 




VcBAoB •trMHu »til]*d ap 



TMIdtne-tPoahanlarM basil paaWBR IwravMk 
rMtii> ■nd rsniu laMrmll* 

PUMd OLD tt* wcKti aiKii 01 eapwl*. wttMb t* 

•aOvrpaoM ioODttiBusl««t««rtibi»tat 

tIM-4aaioT«l Mail 
VuM-aapsaUr baail 



with the lower part of the lesser troclianter. It then runs upwards and backwunlf: 
along on obli(|ne line HtK)Ut 1.6 crn. (^ in.) in fmnt of ihe ie.>«er(.r(>rliiuiter. and euti- 
ttnuca its ascent aloriR the back of the neck nearly parallel to the intertrochanteric 
crest, and from 12 to 16 mm. () tn j in.) above it; finaUy, it passes along the inner 
side of the tmchanteric fossa to reach the anterior superior angle of the jcreat tro- 
chanter. 

On laying open the capsule, some of the deeper fibres are seen rcflecte<l upwards 
along the neck of the femur, to Ih> aitachi>il much iicuiyt the h»ttl: thc;<e are the 
retinacula. One crtrrcspond.'t to the up)>er. untl another to the lower, |>art of the. 
flpir.ll line; a third is .seen at the upjXT and buck part of the neck. Tliey form flat 
tiAnds, which lie on the femoral neck. 

Superadded to the capsule, and considerably strenglhening it, are three auxil- 
iary bands, whose fibres arc intimately blended witli, and in fact form pari of, the 
capsule, viz.. tlic ilio-femonil. iHchio-capsulur, and pubo-cupsular bands. 

The Uto-femoral (fig. 27!)) is the longest, widest, and strongest of the bands. 



Tlit: HIP-JOIST 



279 



II to of triuiigulur shape, with the apex attached above to s curved line (ui the ilium 
inimfvlialely below aiid Ijrhint! the luHuriiir inferior spuie, aild \\s Ixiae below (o tlic 
i»nterioredge aft he greater tmcliaiiter and to the spiral line a-s far as tlip inner border 
of the shaft. The highest or outejmost fibre-s are roarse. almost straifiht, and shorter 
than the rest; the innem^osl fibres are also thick and strcmg. but oblique. This 
varying oblitguity of the hbres, and their accumulation at the bordeis. explain why 
this band has been licscribod as the Y-6haped ligament. About the centre of it.s ba.'^, 
near the femoral atta«hnieiit. is an a]>erturc transmitting an articular twig from 
the ascenHing hraru-h of the external clrcumJlex arter>*. 

The iscbio-capsular band (fig. 28^1) L-i forme*! of very strong fibres attaclied all 
along the upper Imrdvi- of the groove for the external obturator, and to the isriiiul 
iimrgiu of the acetabulum aU»ve the groove. The hithest of these incline a little 
upwawls as they pa^s outwards to be fixed to the gre:iter trochanter in frtiiit of the 
insertion of the piriformis tendon, while the other Jil)res eun'e more and more 
upwards as they pasa outwards to their insertion at the iimer side of the t rorhan- 



Fiu. 2S0.— PoftTKiiioK ViBW or tob Capbi'le or thb Hir-JoiNT. 



MMdoo oi III* raotaa mi4 
111* triuunlw ■ utoMt** 





bcblo-ciiitiaular tHud 
Tkli la placet] oa Uia wsak 
VOttkXi of Ifea aapanls 



teric fossa, blendinje; with the insertion of the external rotator tendons. When the 
jnmi is in flexion, these fibrea pass in nearly straight lines to their femoral attarhmpjit. 
and spread out uniformly over the head of the femur; but in extension they wind 
over the back of the femur in a /.oiiular nmnner, embracing the ponterior aspect of 
the neck of tlie femur. 

The pubo-capsular (pectineo- femoral) band iTig. 27!)) is a dii^'tincl. but nar- 
row set of fihnw wliich are individually les marked ihan the fibres of the other Iwii 
bands; they am fixed above to the oliturator rrest and to the antorior bonier of 
the ilio-pectineal eminence, reaching as far down as the pubic end of the ace- 
tabular notch. Below, they reach the neck of the femur, and are fixed abo\'eand 
behind the lowermost fibres of the ilio-fonioral band, witii wliich they blend. 

In thirhn««! anil strength the cfl|>Hule varies greatly; thus, if two lines Iw 
dran7i, one from the anterior inferior spine to the inner border of the femur near 
the le-wer trochanter, and the other from the anterior part of the gmove for the 
external obturator to the trochanteric fossa, all the ligament between these lines on 



280 



THE AHTICULATIONS 



the outer and upper aspects of the joint is very thick nnrt strong, while that below and 
to the inner side, except at tlie narrow pubo-capsular hand, is Ifiin an(i weak, so 
th»t the hejid of the borie can be seen throiifrli it. The capsule is 1hi<*ke.st m the 
course of the ilio-fiatiiom.! band, towards the outer purl i>f uhirh it ine!itiiin» ovt 
6 mm. (l in.). Iictwe«n the ilio-feiiioral atid iHcliio-r«|wuhtr li!ind.s ihe capitule) 
is very Ktmn;!;, and with it iiere, neiir the acciuhulum. is incorporated the reflected 
tendon of the rectus, and here also a tri an pilar Iwind nf fibres runs downwards 
and forwards to be attached by a narrow insertion to the mdge on the front bor- 
der of the creater trochanter near the gluteus minimus (the itio -trochanteric 
band) (lip. 2N4)K 

The capsule is sirengtheiied jiJho at this jxiiTU V»y a ntruii(r liund from the under 
surface of the gluteus iiiiniinus. and by the tendino-trochanteric band which 
passes dowii from the ret5ectp<l tendon of the i-eetus lo the vnstus lalcrali» (ex- 
temuji) (iiir. 279), Ttiis i.-* ckisely blended with tlie capsule near the outer edge of 
the ilio'femural ligament. 

The thimid part of the; i'ap.<ule is lielwecn the puUcM-apwular and ilio-femoral 
bands; this is sometimes pei'furated, allowing; the bur^i under the psoas to conmiu- 

Fia. 2S1.— Section tkr«h:«h tiik HtP-jniST. Rnownsci the OijtNotii \.w. Lioamk-ntcm 

Tkkks, and HmwAm-A. 



LifkaioD I u ta tare*, 
plan^il cin 1 ho ram* 
IhsuoliiKl.kiiuik* 



m 



^\i\'y 



'r< 






<">:.^ 



j^^^& 



>/■•; 



■:% 









:;sv: 



fi 



aieaoM Up 

Arttoular eapsul* 

&a4lci)i*d fll>rM of 
oapinii* I tvun- 






'a fl''* 



nioale with the joint. The capsule is also very thin al tl« attuchnienl to the lioek 
of the femoral neck, anil a^ain opposite the acetabular notch. 

The ligamentum teres [iipi. 2Sl and 2S2) is an interarticular flal hand which 
extends from the .icetahular fossa to the head of the femur, and is usually abotJl 
37 cm. (14 in.) lonp. U \m» t wulmny attiic-limenljf. one on either side of thescclab-j 
ular notch immediately Iwlow the articular cartihifre. while intermediate fibres »prin|^ 
from tlK" under f^urface of the tnuiMvenK-liKanienl. The iM-hial portion Ls the stronger, 
and ha:^ sevend of its fibrw arisinp outside the cavity, below Hn<l in connei'lion with 
the origin of t lie transverse li^iamcnt, where it is also continuous with the caiisule and 
periosteum of the Uchiutn. .At (he femur it is fixed to the front part of the depres- 
sion on the h«ul, and to the cNrtilage round the marjtin of the depression. It is 
covered by a prolongation of synovial membrane, which also covers the cushion of 
fat in the itwess of the acetabulum; the |>ortion of tlie membrane rcHectfid over the 
fatty tissue <I(H'S not clinc riosely to the ntund liftament. but forms a triangidar 
fold, the apex of which is at the femur. 



THE HlV~JOJST 



281 



The transverse ligament ifif,. 2K3) passes acroe^ tkp' acdtahular notch ami con- 
vens it inin a fnraiiiL'ii; it sujiportw \»\.n of llic (ilennid tibro-rartiltme, mid is coii- 
neclod wiili the lignmentutn tore:* hikI vhe ciipsuk'. It ii^ conipor^d of decussutiiig 
fihrps. which ari«e from the margin nf thf juTtabtilum on cither sirlc nf the notch, 
thoise coming from the pubis Ijeing more superficial, antl passing to fonn the deep 



Fio. 282. — njF-joi.vT Arnut oividimo tht. Airnctn^n Capsclb a.vo DiaAirncvLATi.-4o 

TUE l-'CUl'K. 



Jii\ 



ArtlcalBT mp»n]«, oat 
0(»IMI4 lip 



AnIeuUr oapanl* 



Ugamanlua tnr** 



Anloular earaal* 



:>->.■- 



part of the lipament at the Ifchium, while those superficial at the ischium are deep 
at the pubis, tt thus roriij>letc;< the rim of the aectubulum. 

The glenoid lip (cotyloid fibro-cartilage) (fi>p*- 2S1 and 282) is a yellowish-white 
structure, which deej^ns the acelabuluni by suruiouiilinji ilu uiargiii. It varies in 
ritrength atiil t iiickiicss, hul is .stronger al its ihtw and ischiul portions tlmn nlsewhero. 
Ita Iwae is broad and fixed to the Uiiiy hni aa well as U.i the articular cartilage of the 

Fia. 283. — Portions of iKCHlt'M a.vd PrBi». BMi>wrNtj thk CtiTYuuii Notx-h a»d tbb 
LtOAUKNTCU TctUM ATTACafID OlfWlDB THB AcETADrUTIil. 



■r«» Il(«tii4nt 




BknoM lip 



Xi«iMvorM UiKaMut 



llBBiDtatvia torn ■*• 
lB«ll*d to iMkliua Ma- 
•14a Ua aoaUbuIan 



i acetabulum on the inner, and the periosteum on the outer, side of it. and blends 

U inftepariiMy with the tran-svcrse liganienl which supports it nv^r the acrlahular 

notch. Its free margin is thin; on sertion it is somewhat lunated. having its outer 
surface convex and it«« articular face concave Hmf very smixith in adaptation to the 

kheadnf the bone, which it tightly einlmtces a little beyond its crearest circumference. 
Itaomewhat contracts the ajiertiire uf the acetabulum, and retainti the head of the 



282 



THE .[RTlCVL.VnOSS 



femur within it« grasp aUer division of the muscles and capsulur lig&n>eut. U is 
covered on both H*pecis by (-ynovial inenibraiie. 

The synovial membraDe lincK. ilu- cupsulo and both surfaces of ihe glenoid 
lip, and passes over the border of the Bcetaliiiiuiii to reach and cover the fatty 
cushion it contains. The part covering the fatty cushion is unusually thick, and is 
attached round the edges of the rough l^my surface on which the ctiahion reaU. 
The nieTabmue is IrKweiy rellecKd off this on to the ligamentum teres, along which 
it is prolotiib^ to the head of the femur; thus the fibres of the round ligamont iltb 
shut out from the joint cavity. From tlie capsule (he synovial metiibrane is also 
refle<!tod below on to the neck of I be femur, whence it pasfief over tlie retiiiiicula to 
(he margin of the artiouUir cartilage. A fold of synovial iMornbr.itic on the under 
aspect of the neck often conve>*s to the he;id of the femur a branclj of an artery — 
geiierally a brauL-h of flie internal circumflex. 

Tlie arterial supply comes from — (a) the transveiBe branches of the internal 
and external circumdex arteries; ib) the e.xternai branch of the ipbturaior sends a 
branch 1 hrough the acetabular notch beneath the transverse ligament, which ramifies 
in the fat at the l>ottoni of the acctjihuhim, and travels down the round ligament 
to the heaxl of the femur; (r) the inferior branch of the deep division of the su[jerior 
gluteid; and (d) the inferior gluteal (sciatic) arteries. The branch from the obtur- 



FlO. 2S4. — hHlAUETTTirM TrRRS, UiX I.V Kl.RXION. 



ator to the lii;anientuni teres is tunnetitnefl very large when the branch from the 
internal circuiiiHe,\ dues not also supply the ligament. 

The superior and inferior (jlulcitl send .several branches ihrnugh the innominate 
attachment of the articular cafwiile: thase aniL-^tomose freely l>cncath the rap.sule 
around the outer aspect of iIk* acetabulum, and supply some brjinehes to enter the 
bone, and othere which enter the substance of the glenoid lip- J'here \s quite an 
arterial crescent upon ihe posterior aud post on»-suporior portions of the acetabulum; 
but no vesseU are to Ix; seen on the inner aspect of the glenoid tip, 

The nerve-supply comra from (a) foniora! (anterior crural), (6) anterior diviaion 
of the obturator, (r) the acces-sinrv obturator, and {d) the sacral plexus, by a twig 
from the nerve to the quadratus femoris, or fmm the upf>er part of the great sci- 
atic, or frotn (lie lower part of the sacnd plexa-s. 

Relations. —In iroiil and iu contact with the capsule are the psoas bursa, the 
tendinous pjirt. of the psoa^i magnum?, and tlie iliacu». Stilt more anteriorly ami 
not in contact are the femoral arter>'. the femoral (anterior crural) ner\'e, the rectus 
fctnorts. the sartorius, and the ten.sor fiL<iciH^ tatir. 

.-iftoivand in clofle relation with the capsule arc the piriformis, the obturator inter- 
nus and the gemelli, and the reflected hea^l of the rectus femori*. whilst nnrre super- 
ficially lie the gluteus minimus and medius. 

Behind and in close relation with the capsule are the obturator extemus, tha 



THE HlP-JOlNT 



283 






li and obturator ititemus, and the pirifnmiia. More superficially lie tlie quad- 
ratus femoris, ihp scintir iifT\'es. and the jrlutotis nmxinms. 

Hthnc the obturator extenius, the iiectiiious, and the inlemal circumflex artery 
are in close n*hiiinn witli the rapsule. 

The movements. — The hip-joint, like the shoulder, is a i>ull-aiKl-finRkoi joint, 
■ut with a. much more complpte socket jiiid ;i rorreBpoiKlinp limitation of move- 
ment. Each variety of movement is j>ermitied. vik.. flexion, extension, abduelion, 
adduction, circumduption, and rotation: and any two or more of those ir.nvenipnis 
not Iwin^ antaironLstic cjin 1* rnmhined, i. e , floxion or extension associated with 
abduction or adduction ran be comhineil with niliUioti in or out. 

It resulli* from the oijliquity i>f the neck of thn fetnur that Ihe movements of 
the head in the arctabulum are always more oi less of u rotatory character. Thtrt 
is niore esi«H.'ially the cai^e during ilexi<)n and extension, and two resulis follow 
from it. First, the l»earint; surface." of ihe femur auil acetabulum preser\'c their 
apposition to each orlier, so that the amount of articular surface of the head in the 
acetabulum does not, sensibly diminish fnri fxinsu with the transit of the joint 



FB^. 285. — LlOAMBVTtTM TkHEB. very lax tS COMPLXTE ExTKSSIQN. 



u 



from the extended to the flcx«d position, as wmiM necewarily he the case if the 
movement of the femnml head, like thai of the thiRh itself, wns simply angular, 
instead of rntator>' an»l ariffulur. Secontlly, as mtatiou of iho head can continue 
Until the liRaments are tight without Iwin^c checked by contact of the neck of the 
thigh bono with the rim of the acelabulum, flexion of the thigh so far as the joint 
is concerned is practically unlimited. Hexion is the iiiowt important, most fre* 
quent. and most extenfivo movement, and in the dLsscetcd limb, before the lipa- 
mcnus are disturbed, can he carried to ]G(i'. and i.*i then checked by the lower fibres 
of the Lschio-capsular lisiainent. In the living subject simple flexion ran continue 
until checked by the contact of the soft part-s at the gnnn, if the knee he Ijenl; if 
tlie knee Ije straicht. flexion of the hip is checked in most pers<jiis by the hamslrinj; 
muscles at nearly a riKht- ruigle. Thin is very evident on Irj'ing lo touch the cround 
with the fmj^rs without bending the knees, the chief struin Ijeinj; fell at the pop- 
liteal space. This is due to the shortness of the hamstiings. Kvtcnsion is limited 
by the ilio-femond ligament. 

Abduction and outward rotation ran be perfomied freely in every position of 
flexion and extension — abduction being limited by the pubo-capaulai ligament; 




2S4 



THE ART!CULAT!ONS 



imtward rotation by the iHo-femoral ligament, especially its inner portion, during 
exteiisiun; but by llie outer portion, as welJ na by ttie Uf^inerttuni l«reb, during 
flexion. 

Addiifitifin U \'ery limitwl in the pxtcndcd thigfi im anroiinl of the <-ontact wth 
the opposite limb. In the sliKhtly flexed poi^ition adrlurtion is more free than in 
extension, and is then limited by the outer fibres vi the ilio-femoral band and the 
superior portion of the capsule. In flexion the range is still greater, and limited 
by tlte iiJchiiMrapsiitar liganiont, the lit^'ameiituni tercM l^ing also renilered nearly 
light. Inward mtjition in the exl^mleij jioaition is limited by the lower fibres of the 
ilio-femoral ligament ; and in flexion by the ischio-eapeulur ligament and the portion 
of the capsule Iwtween it and the ilio-femoral band. 

The ilio- femoral band also preveiils the tendency of the tntnk to roll backwards 
on the tlugh bones in the erect posture, and so does away with the nevessity for 
niuisculaj [low'er fur this pur^iose: it is put on stretch in the stand-ut-<.'a.sG p<wition. 

The ligaroentuni teres is of little use in resisting violence or in imparting strength 
to the joint. It assists in cheeking rotation outwnrd-s, and adduction ^luring Hexion- 
A ligament can only be of iwe when it is tight, and it w.%s found by trephining the 

Fio, 2M. — LiGAHBNTt'M Tere!*. nwAWv TioHT IN FtBXios oiuniKED wmi Rotation 

■ ii;TWAHI>f>. ANU AUDITITION. 



^ 



bottxim of the aeetabulum, removing the fat. and threading a piece of whipcord 
round the ligament, that the ligament wa=i slack in simple flexion, nnd very loose 
in complete extenaion, but that its most slack condition was in nltduclion. It in 
tighteist ill flexion combined with adduction and rotation outwardfi, and almost 
as tight in flexion with outward rotation alone, and in flexion with adduction alooe 
(figs. 284-'iS6). 

Muscles which act upon the h.ip-}oitit.—FlfxoTa. — Tliv peons and iUuc-ue, the nn>lus rimioris, 
ih* pfHiini-ijn, (he itdiliirtors, iliP iwrtonufi, th« UTinor fAooiic lal*. ikntl the nhtunitor extrmiis, 
RrtenMiTK. — lln> rIiiUmih rii(txmiu>, llir iHwIt-rirar filHTX of tinr glul*') fiiMiiiw am! minimiw, lh« 
bi<K|M. tlic *c>llit«l|<lillO!nl^, \\\i: KCtiiirnvniUraiiu^us. aiid th« uclitiil fibrvti u( lliv uitdnctur iiia^iiiu. 
AbdurlnT*. — Oliileuii innxiintix (upixr film-.'* I , lenwir fiwciB" liitw, gliiU')t.-( rncdiu.-'. duti'iui mimmiia, 
and. wh<>ii tlio iniiit i« fli-xt-d (lie, pirituniii^, iilittimUir iitlrrtiiDi, iImt 2(-[iii''IH, ikuI Uitr snrtoriiis 
abtij t>eixiini> uiKiiii'turn, AiUitict"**. — .\dductiirw« diakiihk, It'iiRus. hrevi.i, and minimus, (he 
obttir.itornxtemim. iheitninliK. ihf p&plinpu-t, i)ipquiiilrutu.-< fcmoris. and llic Inwer fibres of Die 
gtiiti*!!^ muctmu.-. inirriuii Itolalont. ^I'saa^. urd^d^ the jmnt is flexed, Ihc iintrrinr filima of Uie 
|tIiit«UH nwxljus and miniinuii, and the ten»ot fiwciv Iniip. h'xirmni Hdul'im. — (iliiteu!' mo-xitnuv, 
pOHlerior fibres of itluteUH modius and miniiuus. the H(Idt]ctor<>a maKiniA. niodiu!', anil intnJMius. 
the aartoriuA, the hii-ops, and the ijuatlmtm f«nwria: the jwdus mni^niiH wiitn tlie joint Lh flexed; 
the obturnlnr ifilemus, ItiD gemelh, and the piriformifi whi>n the jntnl U extendivl. 



THE KNEE-JOINT 



2. THE KNEE-JOINT 



28& 



Class. — Diarthroai*. 



Subdlvisioa. — Gittglytnut. 



The knee is lite liirjtest joint in the body. It is rightly descriljcd us a pngly- 
nioid j<)int, but th<-'rc \s also an iirthrfydiol elfimeut; for, in addition io flexion and 
extension, there is a sliding backwards and forwards of the tibia upon the femoral 
condyles, lu wdt a» sUuht mtation round a vertical axi:j. It i» uiie uf the most 
superficial, and, as far oa adapution of the bony surfaces goes, one uf the weakest 
jninU, for in no position are tbe bones in more than partial contai-t. Iik strength 
lies in ilie nunitwr, size, and arrangement of tlie ligaments, and the powerful mus- 
clos and fascial expansions which pass over the articulation and cnanle it to with- 
stand the le>'erftge of the two lonj^-st bones in the body. It may Ite said to con- 
sist of two articulations with a common syno-ial membrane— tbe pa telh>- femoral 
and the tibio-feiii<)nil, the tatter being double. It is composed of the condyles 
rnifl trochlear surface of the femur, the tuberosities of the tiliia, and the patella, 
united by tlie foUuwing ligaments, which may be divided inlu an external and 
internal sot: — 



EXTEHNAl. 

(1) Fibrous expansion of the extensors. 

(2) Articular capsule. 

(3) Oblique popliteal ligaiuent. 

(4) Fibular lateral. 

(5) Tibial lateral. 

(6) Ligamentum patells. 



IVTKRN'Al. 

(1) Anterior crucial. 

(2) I'osterior rrurial. 

(3) Internal uieuitscus, 

(4) E.\t«mal nieniticus. 

(5) Coronary. 

(6) Transverse 



External Lio.\Ait;N*« 



^H Superficial to tbe 5brous expansion of the ciuadriceps extensor tendons tlie 
^■fascia lataof the tliigh covers the front and sides of the kneu-^Mnt. 
^^ The deep fascia of the thigh, as it descends to its attaclunent to the tuberoNity and 
\ oblique lines of ttie tibia, nut only o\'vrlie8 but blends with the (ibmus cxpimsion 
of the extensor tendons. 

The oblique lines of the tibia curve upwards and backwards fron\ the tuberosity 
on each side tu the poslero-latoral part of tlie condylea. The process of fascia 
Hltachod to the outer ridge of the tibia and to tlie head of the fibula dcfirends from 
I the tensor fasciae latsc and is very thick and Htmng. It is finnly blended with 
tbe tendinous fibres of the vastus lateralis. Tlie fascia lata. on the inner side of the 
I patella, besides being attached to the inner oblique ridge of the tibia, sends some 
^H longitudinal fibres lower down to become blended with the filirous eJCpansion of the. 
^^Bartorius. The fascia is much thinner oti (he inner side of the patella than on the 
^ outw, and blemls much less with the tendon of thi' vastus niedialis than the outer 
^^ part, of the fascia does with the vastus !ateruli.s. A thin layer of the fascia lata in 
^Bthe form of transverse or arriform fibres pjis.-^es over the front of the joint. These 
^'fibres are !ji>eciaUy well marked over the Ugamentum patella, and blend here with 
tbe central portion of thequadrioeps extensor fibres. 

The fibrous expansion of the extensor tendons i-onsit4ts~~fl) of a centra) por- 
tion, detLsely thick and strong. 37 cm. (IJ in.) bmad, which b inserted into the 
anterior two-thirds of the upper iKtrder of the j)atel1a, many of its superficial 
fibres passing over the subcutaneous surface of the bone into tbe ligamentum pa- 
tellDD; (*2j of two lateral portions thinner, but strong. Tlie laleral |Xinion« are 
inserted inlu the patella along its upper border on either side of the central [wrtion 
1 and also into its lateral borders, nearer the anterior than (he powterior surface, fas 
^_^low down as the attachment of the ligamentum polellie; pas.>^ing thence along the 
^■eidci) of the ligamentum pate1la> to the tibia, they arc attached to the oblique tines 
^^ which extend laterally from the tuberosity to the inner and outer condyle.^, and 
reach as far as the tibial and fibular lateral ligaments. On the outer side, the 
fibres Mend with the ilio-til)iaI band of the fascia lata, and on the inner they extend 
below the oblique line to blend with the [wriosteum of the shaft. Thus there ia a 
I large hood jipread over the whole of l he fmnt of tlie joint , investing the patella, and 



2S6 



THE ARTICULATIONS 



below to the til>ia, anrl separated everjinrhere from the sj-nwial membrane l>y a 
layer of fatty tiwue. 

The Ugamectum patells (Hg. 289) is the coiitiiiuatiun in line oi the central 
portion <if the coujoinuil lendoii, some fibres of which are prolonged over the front 
of the i>atellii into ihe lijiaiiieiit. It i» sin extremely Hiniiig, ftiit. bmni. attached 
above in the lo%ver bunJer of ihe patella; helow. it ^ fixed to the Inwer parr of t-hc 
tuberrwiiy and upjier part of the crfst of the tihia, snmewh.it nbIir)Uely. Ivtng pro- 
kiiitfed (hnvti%v:»nU further on the outer side, wi that (his horder is fully 2* .5 cm. 
(J in.) lon}rer than the inner, whi^-h nieaaures 67 cm. (2i in.) in length. Behind, it 
is in contact with a maiss of fut which separate* it from the synovial membrane, 
and a small bursa intervenes Ijetweeii it and the head of the tibia. In front, a 
large bur»a separates it from the subcutaneous ti^ue, and latemily it is continuous 
with the fibrous expansion of the eMensors. 

The tibial (intemail Lateral ligament (fig. 2S71 is a strong, flat band, which 
extenda from the depne-Won i»n the tuhcrrlo on the inner side of the internal epicon- 

Fio. 2S7. — roBTBKioR View or the Knbe-joikt. 






■ \ 



TindoB of *id4tiM»r uuwoai 



Pluitulk 
Oaurr tMMl of (•■iraoiMialiia 



.V N 



lanar Iwad or(wlra«D«mlNa 



Fibular l*I«r*l liumniaiit t 
»uunot parlion 



Foaieiitir turl ot nbular 
lateral llKi men 1 
Tendac at BcpltUua 



T«a4oBorbliMD* — ; 
flupcrto* poatorior UMa- ^ 



n 



TondoD D( ••maisBbra- 
&o«u» wtib lu slip to 
Uilokan Uu oMiaueiMp- 
UtDKllwawMil 



TIOMl Ul«m tl|»n«DI 




dyle of the femur, la Ihe inner border and internal surface of llie shaft of the libia, 
3'7 cm. (IJ in.) below the condyle. It is S'7 em. (34 in.) long, well defined ante- 
riorly, where it blends with the expjinsion of the rnnjoined extensor tendons; but 
not so well defined posteriorly, where it merges into the nblic|ue po])liteal ligament. 
Some of the lower fibres blend with Ihe descending portion of tlie srpumfmbranonus 
tendon. Its deep surface is firmly adherent totlmeilgeof the internal meniscus and 
coronary ligament, while part of Ilie semimcmltratmifus teridon and in/trior internal 
articular tes^rts and wtTt-e pnsa between it and the bone. Stiperfirially, a bui^a 
separates it from ihe tendons of the gracitin and nemitendinosus muscles and from 
the aponeurosis of the anrforim muscle. 

The fibular ferternal) lateral ligament (fig. 287) consists of (wo portions: the 
anterior, wliich b the lonuer and letter marked, is a strong, rounded mrd. about 6 
cm. (2 in.) long, attached aUive to tho lulferrle on (he outer .';idp of the exlemiJ 
pjjicondyle of the femur, jvi.-*i below and in frrmt of the origin of the outer head of 



THE KNEE-JOIST 



287 






the gwttrocntmtus, whilst the tendon of the poplUeus arises from the (jrwove below 
and in front of it. Below, H is fixed to the middle of the outer surface of the head 
of tlie fibula, 1'25 cm. () in.} or more anterior to the ajrex. Su])er1icially is the 
t«ndon of the biceps, which splim to embrari; its lower extremity; while beueath it 
pass the pojilUeus tendon in ila sheath, ami the inferior external articular ce&aets and 
nertv. Some fibre« of the pcmneus longus occasionally arise from the lower eiiU of 
the ligament. The posterior ixirtion is S mm. (J in.) behind the anterior, h iS 
broader and leaa define<.!; fixed below to the apex of the fibula, it inclines upwards 
and Bomewhat backwards, and tic8 down the jtoplUcus ajiaiiiKt tlie outer condyle of 
the tibia, blending Iwneath the outer head of the tjastrocnemius with the oblique 
popliteal ligament of the knee, of which it lh really a portion. 

The oblique popliteal posterior ligament or ligamenttun Winslowii (fig. 
287) is a broad den.-<e structui-e of mterlacing fibres, with large orifices Tor vessels 
imd ner\"e8. It is attached above to the femur close to the articular margins of the 
condyles, Htretchin^ arrows the upper margin itf tlie interc(HidyIoid fossa, to which it 
is oonnectod by fibro-fatty ittBue; it thus rcjiches across from the tlliial xa the fibular 
lateral ligaments, [ii^lnvv. it i.*; fixed to the l>ftrdpr of the outer condyle of the tibia, 
to the bone juat below the jjosterior intercondyloid notch, and to the shaft of the 
tibia [jolnw the inner condyle, blending with the descending slip of the semimem- 
bmnoeus and tibial lateral ligament. Superficially, an oblique fasciculus from 
the Memimembranosiis runs acnwa the centre, pa.saing upwards and outwards from 
near the back part of the inner tuberosity of the tibia to the external epicondyle 
of the femur, where it joins the outer liead of the gostrocnemius, a seiHimoid plate 
IwinE sometimes developed at Ihe point of junction. Tins slip greutly Htrenpihens 
the oblique popliteal ligament, of which, if not the chief constituent, it is at IcasS a 
very important part. 

Its deep surface is closely connected with the semilunar menisci (especially the 
inner) and coronary ligaments, and in the interval Itetween the cartilages with 
the posterior crucial ligament and fibro-fatty tissue within the joint. Superficially 
it forms part of the lloor of tiio popliteal wpace. 

Tlie articular capsule or anterior ligament (lig. 28S) is thin but strong, cov- 
ering the synovial membrane under the quadriceiis extensor tendon, and looking 
like a loose sac. It is attached to the femur near the articular marinn on the inner 
side, but further away on the outer; it pa-sses beneath the fibular Literal ligament to 
join the sheath of the pojiiiteuf. Internally it joins the tibial lateral ligament. 
Below, it is fixed to the upj*r and lateral borders of the patella and the anterior 
Ixmler of the head of the tibia. It is strengthened superficially lx:tweeti the femur 
and patella by an expansion from the artiruUirimjeiiu (suh-erureue) and is separated 
from the fibrous expansion of the extensor tendon by a layer of fatty tJAsue. The 
synovial membrane lines its deep surface, and holds it again.<it the borders of the 
aemiiunar menisci; it is also attached to the coronar>' ligaments. 



Internal Jjcaments 

The anterior crucial ligament (figs. 288 and 289) is strong and cord-like. It 
b> attached to the inner half of tlie fossa in front of the intercondyloid eminence of 
the tibia, and to the outer tKinlrr of the inner articular facet as far back as the 
inner intercondyloid tubercle, ft passes upwards, backwards, and outwards to 
the hack part of the internal surface of the external condyle. To the tibia, it is 
fixed l)ehind the anterior extremity of the internal .^lemiliniar menisrus. Hebind 
and to the outtjr si«lo it haa the anterior extremity of the external meniscus, a few 
fibres of which blend with the outer edge of the ligament. Its anterior fibres at the 
tibial end are stnmgf.sl and longest , twing fixed hipheBt on the femur; while the 
posterior, springing from the intercondyloid eminence, arc shorter and more oblique. 
Near the spine, a slip i^sometimesglvenoff to the posterior crucial ligntnent. 

The posterior crucial ligament (figs- 28S, 289. and 290) is stronger and less 
oblique than the anterior. It is fixed l>elow to the greater portion of the fossa 
liehind the intercondyloid eminence of the tibia, especially the outer and p<js(erior 
portion, and then inwanls and upwanlw along the iiiten-ondyloid notch: being 
joined by fibn\s which arise between the intercondyloid IuIktcIcs. it a.scends to the 
anterior part of the outer surface of the inner condyle, having a wide crescentic 
attachment 1"5 cm. (^ in.) in extent just above the articular surface. Behind. 



283 



THE ARTICILATIONS 



it is connected at the tibia directly with the posterior ligament, and a little lugher 
up by me:i.ns of a quantity eif irner|>(jtt<!<] amoltir tissue. In front it rests upon the 
])0!(t«rior liorn of the iuternal semilunar meniscus, and receives a large slip from 
the external tneniieus, which ascemls along it, either in front or behind, to the femur; 
liighcr up in front it ts connected witli the anterior crucial lieainent 

I'litil thi'y rise above the itiu^n'oiidyloid eminence uf the tiliia the tw» crucial 
ligameiiU iire chwely bound lofwlher, «> lliiil no interspitce exists lx?tween their 
tibial attachments and the point, of doeusdiir ion ; the only spare lwtT,\t*cn them U 
tlicreforc a V-sha|ie<I one corn^jwinclinfi To the upj'irT hsilf of their X**^*I^ arr-inge- 
ment, aiid thijj i» a more rhiritc in the uiidissccted stale, autl can Ix* seen frr.»ni the 
front only, owing to the fatty tiissue beneath the aytiovial membrane which sujv 
rounds Uieir femoral attachment, 



Pro. 28S.— Antebiur View or thb IwnfnNAi, I.igauents of the Kneb-joint. 



Apvrlar* iMdlnc iato tka 
burubeuutb Iba suiAn- 



S! 



,y 



AttuliMont or artlaolw 
Mpml* lo l«iniiT 



TMir IImim « Ufa in oul cdc« 
«f 111* Hl«]l«r ■iraovtftl 
told 



ToaMnor eruoiil U| 



AjUvHcw orueial lltuoaal 



Cora nary ll||miBvnt 



Tho intcrarticular menisci or semilunar fib ro- cartilages (figs. 288 and 

2K!)) are twn crosceiilic plates resting upon the circuinrerciitial portions of the artic- 
ular facets of the tibia, ami moving with the til>ia u|Km the fejnur. They some- 
what (ipe|>eti the tibial articular surfiice??, and are dense and compact in structure, 
beriming looser and nuire fibrous near their extrcniitie«, where tWy are firmly lixed 
iu front of and behind the intercondyloid eminence of the tibia. The circumfer- 
ential border of each is convex, thick, and spmcwhat loosely attached to the 
borders of the condyles of llie tibia by the coronary lipainetUs and the rctlexion 
of the synovial membrane. The inner border is concave, thin, and free. Half 
an inch (I'S cm.> broad at the wide.st part., they taper somewhat towards their 
extr*^milips, iind rover rather less than two-third.s of the articular facet.s of the 
tibia. Their upper surfaces are slightly concave, and fit on lo the femoral condylea, 



THE Ki\EE-JOi.\T 



289 



rhile Itie lower are flat and real oa Ibe head of tbe tibia; both gurfaces arc smoolh 
id covered by svDovial meiiibraiie. 
TIiu external meniscus (lig. 'i&9) is nearly circular in form aiid less tirmly 
fixed than the internal, luid consequently 8lid(» mure freely upim the tibia. Il» 
iterior e«mu is altjicliefl t« a narrow depresaiuii aJuug the outer articular facet, 
ist in front of the extemiJ iiiien-nndyloid tubercle of the tibia, clf>se to, and on 
le outer eide of, the anterior crucial ligament; a small slip from the comu is often 
ted to tlie tibia in front of tlie crucial ligament. Tlie ]>osieji<'r cornu is tirmly 
attuohwl to the tibia behind the external intercondybid tubercle, blending willi 
the posterior crucial lipainent, and (living o(f a well-inarkcd fasciculus, wliicli runa 
up along the anterior border of the ligament tu'l>e attached tu the femur (liKiuneat 
of Wrtsbetg). It alao acntU a narrow slip into the bock part of the anterior crucial 
ligament. 

Ha outer border is groovetl towards iUj poeterior part by the poptitaa tendon, 
which iH held to it by fibrous tissue and synovial niembrane, and t>eparates it from 
tlie fibular Intend ligaiiieni. From itti anterior border la given off the tranaver»e 
_lig)iment. 

The internal meniscus (%. 289) l<; a segment of a larger circle than the ex- 
anial, and has an outline more oval than circular. Us anterior cornu is wide, and 
has a broad and oblique attachment to the anterior margin of tile head of the tibia, 
roaches backwarrls and outwards from the margin of the condyle towards Iho 



Fid. 289. — STHutTuim* ltimo on tub Hbju» or the Tibia. (Ki^t knee.) 



tilcknanlaat palalla 






Vr9iaa*«n« I«udmii 



BitoniAl meououa 



F eni«l>l UB*B»al- 



iBtBRIttl nW&lKTIW- 



FOaMrlor eruolal II^Mataiit . 



Trndon of bl««p« 
flbuUr Ui«i*l lUMuiiant 



Bii'ut 



tfh.' 



liddle of the fossa in front of the intereondyloid eminence, being altogether in 
front of the anterior crucial ligament. The prtstcrior oornu is iinnly fixed by a 
broad msprtion in tin aiitero-poMt^-rior line along the inner .lido nf the posterior 
intercondyloid fossa, from the internal l.ul)ercle to the posterior margin of the Iieati 
ii the tibia. It^j convex border is connected with tlie tibial lateral ligament and 

sttnimvmbfQnosus tendon. 

The traasTerse ligament (fign. 28S and 280) is a rounded, slender, short cord, 
which exteiid-f from the convex bonier of the external meniscus to the concave 
border or ant<yri(>r comu of the intenial, nfar which i( Ls sometimes attacherl to th(* 
bono. It is an at^cfrisory band of the external cartilage, and is situated Itcneath 
hit synovial ineni))r:uif- 

The coronary ligaments (fig. 288) connect the margins of the semilunar men- 
isci witli the Ii0!ii| of tlie tibia. The cxtctrnal i.s niuiili more lax than the iiitcmalr 
jKinnitling the outer curtilaee to change \\.» position mure fn%ly than the inner. 
They are not in reality .sj'parate structures, but consist of fibres of the several 

Sirwmnding ligaments of tite kne<vjoint which become attached to, as they pas.i 
ver. the inanrin* of (he fibro-cartilages. 
The synovial membrane (fig. 291) o( the knee forms the largest synovial sac 
in the body. Huljriiig upwards from the patella, it follows the capsule of the joint 
ini« a large cul-dt-mc beneath tlie tendon of the extensor mu.sclcs on the front of 

Cr. It reuclics etomc distance bevund the artioular surface of tbe bone, and 
: . 






290 



THK ART ICUIAT loss 



oommunicates very frwiuently with a larRe bursa iiiterpneed betu-een the tendon 
anil the femur above the line of attachment of the articuJar capsule. After iav«et- 
ing the circumference of the lower end of the feniur, it U i-eQected upon the fibrous 
envelope of the joint formed by tlie capsular, pusteriur, and lateral tigamentii. It 
c(»vers a ^reat poi'tion of tlte cruciul ligamouls, tnit k'uvcti uncovered the Imck of thi! 
p<wtcrior crUKial where the latter is t-onnected with the poeterior ligament. Jind the 
lower part nf ixilh crucial lipuneuts where they are united. Thus the ligaments 
are oomplelely shut out of the syno\nal cavity. Alonp the fibrous envelope the 
synovial manbrane is comlucled down to the semilunar menisci, over both aur- 
faees of which it pa.'ses. and is reflected off the under surface on to the ruronary 
ligoraeatd, and tlienre down to the head of the tibia, around the circumference of 
which it extends a short way. It dips down between the external canilage and the 
head of the tibia as low as the superior tibin-fihular lipiment, reiichinp inwards 
nearly Mf far »» the int«rcondyloid notch, and fonninft a bursa for the play of the 
poplileul tendon. 

Km:. 290, — Antrrior View of thk KNCc-jnixT, shi:>wixh tmk Synovial l.iGAMKvra. 
(Anterior portion uf rap!<ii1<> with the cxl«iiBor tcndtni tlirowu duwiiwuRls.) 



PtMUrlOT OTUoMl UsMsant 



PMoIlM- ISM 



.^' 



Alar told 






l«6 VtllHr MDdOK Dt 



At the buck of the joint two pouches are prolonged beneath the mnscles, one on 
each side between the eondyle of the fcnmr and the origin of the easimcncmhis. 

Largo procft-wft* of synonal membrane also project into the joint, and heinfc 
occupietl by fiit ser\'e a- pudding I" Oil up spaces. The chief of these pn>reiwes. 
the patellar fold fltgamentum mucosum) (figs. 290 and 291). spiings from the 
infrapatellar fatty mass. Thii4 Ho-culled ligament ii4 the c^mtral portion of the 
large procpHS of synovial membnuie. (rf which the alar folds form the lateral free 
mnrEins. It extends from the fatty mass. Mow the patella, backward-t and upwards 
to the intorcondyloid not.<'h of the femur, where it ii» attached iri front of the ante-rior 
crucial, and to the ont^r side <rf the posterior crucial ligament, Near tlie femur 
it i» thin and transparent, consisting of a double fold "f synovinl menibrarie, but 
near the patella it coniairis some fatty tissue. Its anterior or upper ed^e Ls froe. 
and fully 'let cm. (an inch) InriK: the iKW^ierior i»r lower edge is hidf the lenj^h, and is 
atlncliL-d to the crucial ligaments alK>ve, IhjI is free Ijclow. 



THE KSEEJOIST 



291 



Passing bockwarcls from (lie capsule on each Hide of the (Hitella ts a prominent 
croRoenttc fold formed by redujilicaliona uf the synovial membrane— lliosc are the 
alar folds (fip. 2iH)). Their free marginfi are concave and Ihin, anil aru lost below 
in the p;itolliir fold, Thcrt? is a slight f(>.ssa ubovu and another l>elow earh ligament. 

The arterial supply is dcrivetl from ilie art. genu suprema (ann-stomotica) ; 
the aujierior and inforior medial imd lateral artir-ular; the medial articular; Ilie 
deswiidiini; branch of the external circumllex; the anterior recurrent branch from 
the anterior tibial; and the iweterior tibial recurrent. 

The nerve-supply comes fr<>m the great sciatic, femoral (anterior cniral), and 
obturator sourcea. The great sciatic Rives off the iiitemaJ and external popliteal; 

Fio. 281.— VBiiTicAiy SetTioN or the KMEB-jomr in the A.NTi:»u-n»iTRiiinR Oibkctiok. 
(Thp bones Kte »Htipn-hst flra«-ii apart.) 



■iuaoBlur 



Bbna or i|uailric*pa 
taXVLaot 



JsN 



|iS 



m 



I: 



.1-' 



■ion a» araoTlal aM M IMMI 






rally Umd* 

OHMnglaivnavUl bwib* 
blSBB tMblod •nolKl 
tUamaat laatfiBi Inla 
MMBrMUallMBt 

BnorUl isAinknB* '•- 
n»M»i «a enMUl lies- 
maau 

Oat nwt of *aM(Mr uuotal 
IUmuoI 

OBll«M voplMMl im- 
aant 



fe 



i^W^^ 



:^\T% 



f 



'ItllU 
Vrp.palvUkp Mm* 



rally Uwiaa »>M«*n Uc>- 
nentuiD v«i«U« and 



:'-:^ 



^? 



tW.! 



^ 



paMlls 



the internal popliteal sends two, sometimes three branches — one with the medial 
articular arter>-; one with the inferior medial, and sometimes one with the superior 
medial anitrular artery; the Mteriud iwplitcal give.s a branrti which acpouipaniea 
the superior, and anotlier which arc*}m[>anies the inferior Hrticular arter\', and a 
rcRurn^nt branch whioh foilown ihc course nf the acferior recurrent branrh of the 
anterior tibial artery. The femoral (anterior crural) .sends an articular bnmch 
from the nerve to the vastus lateralis (extemus); a second from the nerA*© to the 
vastus medialis (inlemua); and sometimes a third from, that to the vastus inter- 
niediua (crureus). Thus there arc three articular twigs to the knee derived fruin 



292 



THE ARTICULATIONS 



the muscular branches of the femoral (anterior crural) . (Roger Williams, Journ. 
Anat. Physiol., 1879.) The obturator by its deep division sends a branch through 
the adductor magnus on to the popliteal artery, which enters the joint through 
the posterior ligament. 

Relations. — Anleriorly and arUero-laleraUy the knee-joint is merely covered 
and protected by skin, fascia, and the tendinous expansions of the quadriceps 
extensor muscle. Externally and ■posteriorly it is crossed by the biceps tendon. 



Fio. 292. — The Lateral Lioaments of tub Knee ly Flexion and Extension. 







Internally and posteriorly lie the sartorius and the tendons of the gracilis and aemi- 
tendiiiosus muscles. Posteriorly it is in relation with the popliteal vessels and 
nerve.s, the semimembranosus, the two heads of the gastrocnemius, and the plantaris. 
The tendon of the popliteus pierces the capsule behind and to the inner side of the 
biceps tendon. 

The movements which occur at the knee-joint are flexion and extension, with 
some slight amount of rotation in the bent position. These movements are not so 
ample as the corresponding ones at the elbow, for the knee is not a simple hinge 



THE KSEE-JOIST 



293 



joint. The movements of rotation inwarda and outwarda are the tibia willi the 
fibula upon the condyles of the femur. 

Thr ktK« differ!} from a true liinge joint, like the elbow or ankle, in iJie following 
partic-ulars: — 

1. The points of eontanl of the femur with the tibia are ronstantly changing. 
Thus, in the ftexed posiiion, the hinder parr, of the articular surface of the tibia is 
in ixmtact with the rounded back part of the condyles; in the semiflexed position 
ttie middle ports of the tibial faoeta articulate with the anterior rounded part of the 
rondyleii; while iti the fully extended (Kisition the anterior and midtlle partf" of itie 
tibial facets are in I'ontat-t with the aiit«rior HallPiieil ptirtiori of the condyles. So 
with the patella; in oxtreme flexion the inner articular facet rests on the outer part 
(if the internal condyle of the femur; in flexion the upjjcr pair of facets i-est on 
the lower p.^rt tif the tnichlear surface of the femur; in nxid-llexion t}ie niidille pair 
rest on the middle of the trochlear surface; while in extension the lower pair of 
facets on the patella ifwi nn the upiM-rjxirtionof the trochlear surface of the femur. 

This ililTerence may be deHcribed as the shiftinff of t)ie jioinU of contact of the 
articular surface. 



FiQ. 293.— Seltiok'df Kkee. khowixo CHrriAUt in CxTBNstoN. 



^h 






i{ 



If.-'.: 



AOMrlw CTOolal ll«>Ba9t 
ailCMo«mai[i wmivcc of nen 



ilisunwai cl Wtiftffifi 
FMleilor cTuolkl IUi4ui«iil 



. ADlarloT tlbtO-nbuUrhSBBMBl 



2. It differs from a true hinge in that, in pasainp from a state of exiension to 
oneof llexion. the tibia does not revolve round a sin;ile transverse axis drawn through 
the lower end of the femur, as the ulna does round the lo%*er end <if the humcnis. 
The artjcular surface of the libia slides forwanU in exlennion and backwards in 
flexion; thus t-he axis round which the libia revolves upon the femur is a shifting 
one, as is seen by reference to tig. 292, H, (.', ]J. 

3. .\nother point of difference izt that extension Ih at^eumpaiiied by rotation out* 
wardt*, and flexion by rotation inwards. This rotation occurs rmmd a vertical axis 
drawn through the mifldle of the out^r condyle of the femur and the outer condyle 
of the tibia, ;md is most marked at the termination of extension and at the com- 
mencement of flexion. This rotation of the legal the knee 'i» a true rotation about 
a vertical axis, and thus differs from the obliquity of the flexion and extension 
movetnent-s at the elbow which is due tu the oblique direction of the articular sur- 
faces of tlie bones. 

4. The antero-posterior spiral curve of the femoral condyles is such Jhat tiie 
witerinr part is an arc of a plater circle than the posterior; hence certain ligaments 




294 



THE ART ICC L.\r JOSS 



which are tishteneij during extension are relaxed during flexion, and thereby a con- 
eiduruble amount of rotat^^ry movement is pc-xinittcMi in Ihc HexeiJ jKusiliun. The 
axis of this rutatiiin tb vertit-al, and iMUities thnmj;h (he inner intercondyloid tubercUi 
of the tibia, bo thai the uutcr condyle moves in the viTu of h larger circle than dc 
the inner, and is ihereff>rc require<l to move more freely and easily; hence tb*l 
8ha|)e uf the external articular facet and the looae connection uf the external men- 
iscua which \s adapted lo it. 

In extension, all the LiKaments are on the stretch with the exi-eiJlJon of the 
ligamentuin paleila; and front of tlip eapaule. Kxteniiion is checked by both the 
crui-'ial lieanients and the lateral li/ranients (fiRs. 292. A, B, and 29;i). 

In flexion the Upiment lun puteilic juid anrerif)r portion of the capsule arc on 
tlie atretfli; ■»> aW> i^ the posterior crucial in extreme tlexion, tliough it is not quite 
tight in the semiflexed state of the joint. All (he other ligaments arc relaxed {fig. 
292, C, !->). ahliougli the relaxation of the anterior crucial ligament is slight in 
extreme flexion (Hg. 2114). Flexion Ls mdy checked during life by the contact of 
the 8oft parts, i. e., the calf with the back of the thigh. 

Fia. 294. — CavaAL Liqauekts in FvsaAOK. 



roMmor antolBt - 



ABt«tler«nal*l 



^.:^ 



■ jf •■' 



Slip rroin cttcmal <«rtil*s» 10 UaBT 






-^ 



y/ 



y 



Inward rotation is cheeked by the unterior crucial Hpament; the lateral liga- 
ment.* Iieingiimse. 

Outward n;»ia(ioti ia checked by the lateral ligaments; the crucial liganicnts hftV< 
no controlling effect on it. as they are untwisted, by Jl. 

Sliding movements are checked by tlie crucials and lateral ligaments— sliding 
forwards esiwcially by the nnterifir. and sliding backwards by the posterior crucial. 

ICdkIbs which act upon the \aitz-yo\at.—FUxor». — Biceps. scjinineuiliranoHtis. aemU 
tendinosus, siutorim, kiliI nKnciuiii.->, ]>luntttrM, and |ioplit<?«« Frtrnmr. — QiindrirRpa 
evt«tuior. tnltrnal Holotorv. — Hiartoriu<i, grncjIiH, sen)itendin<MiM, iiptnimi-mbnuiCNU!*, poplJCcua. 
Ettanal Rotator. —Hicvpn. 



3. THE TiniO-FIBULAn tH^'ION 

The fibula ia connected with the tibia throughout its length by an interoeseoui 
membrane, and at the upper an<l lower evtremities by means of two joints. V« 
little movement is permitted lieiween the two bones. 

(a) The superior tiblo-flbular joint. 

ib) The middle tibto-fibular union. 

(c) The inferior tibio-fibular joint. 




TIBIO-FIBULAR 



(«) The Superior Tikio-muular Joint 



305 



Class. — Diarthrtuiis. 



Sy^hdiviiioD.— A rthrodia. 



I 



mi^terkir libitvlibular joint ui aUmt 6 mm. Ci in-) Iteiuw, anil quite di:ttitict 
from, the knee at its up|)er and anterior [^tart ; but at its p(>stcrior and superior 
A»poct, where the borrier of the outer condyle of the tibia is l^evelled by tiie pt>i>- 
liLeus musrle, the joint i» in th« closest proximity to tho buiva beneath the tcndou 
iif that muselc, and in only !:<epara[ed from the knee-joint by a thin sejitum of 
arculiir tissue. Tiiere is oium a raininmnii-aiion beiween the synovial cavities of 
the two joints. The ligiunenitj uniting the bones are:— 

.\rticular capesule. Anterior tibio-fibulur. 

Posterior tibiofibular. 

The articular capsule is a well-marked fibro-areolar structure; it is attached 
clu»e round itir> articular nfurginN of the tibia an(i hbula.- In front it is shut off 
completely from the knet^ji'iini by the capsule of the knee and the comnju-y liga- 
ment; but lw>hind, ii Is often very thin, and may communicate with the bursa 
underthcpopliteua tendon. 

Tlie anterior tibio-tibular ligament (fig. 393) consists of a few fibres wkirh 
pass upwanl-i and inwiinl-^ from the tibula to the tibia. It liea iK-neath the aiilorior 
portion of the tendon of ihe biceps. 

The posterior tibio-fibular ligament (fig. 287) consists of a few fibrw whichr 
pass upwards and inwarvln l*tween the adjacent l>ones, from the head of the fibula 
to the outer tuberosity of the libia. 

The superior interosseous ligament consists of a mase of dense >'eUow Bbro- 
areoLir tissue, bintUng the opposetl surfaei« of the !>onefi together for 2 r.m. (j in.) 
below the articular facets. It is continuous with the interosseuus membrane along 
the tibia. 

The biceps tendon ia divided by the long external lateral ligament of the knee; 
of tlie two division;} the anterior is by for the stronger, and is attached to tlie ex- 
ternal tubertKity of the tibia as well as to the front of the head of the fibula, and 
thus the muscle, acting on both Ixincs, tends to brace them more tightly togetlier; 
indeed, it holds the bones sirnngly together after all other connections have Iwen 
severed. 

The synovial membrane which lines the joint sometimes communicates with 
the knee-juint tliaiUfiii the bursa Ijeneatb Ibe^wpliteus tendon. 

The arterial supply is from the inferior lateral articular and recurrent tibial 
artorie-j. 

The nerve-supply is from the i;iff!rior lateral articular, and also from the re- 
current brunch of the external p()pliteal. 

Relations. — In front, the upper ends of the libialiii anterioivthe extensor dtgi- 
lonini' longus, and the peroneus longus. Bthiiid, the tendon rnlhc poplilcus over- 
lapped by the lateral lifad of the gaalrocneinius. Kxternailrj, the bice|)S tendon atid 
the externul [wiplilenl nerve. Below and \nUmnUy. the anterior tibiiil vessels. 

Thfl movements Jire but slight, and consist merely of a gliding of t he two bones 
U|>on each other. The joint is so constructed tli.it tho fibula gives some support, 
to the tibia in trananiitting the weight to the foot. The articular facet of the tibtn 
overhangs, and is received upon the articular facet of the head of the fibula in an 
oblique plane. This joint allows of slight Nneldiiig of the external malleolus during 
flcxkin and extioision of the ankle-joint, tiic whole filmla gliding slightly upwards 
in flexion, and downwards in extcntuon. of the ankle. 




(h) The Middlb TiBio-ptnt'iJMi rxioN 

Class. — St/narthrnitis. Subdivision, — Syndctmosii. 

The interosseous membrane is attached along the outer border of the tibia 
and the inberoeseous border of the fibula. It t^ deficient aI>o%'e for about 2*5 cm. 
(I in.) or more, measured from the under aspect of tho superior jmnt. Its upper 
borfler is concave, and over it ijass tlie anterior tibial vessels. The menibr.'ute 
oon.'fists of a thin aponeurotic and translucent lamina, formed uf oblique line fibres, 



296 



THE ARTICULATlOyS 



flome of wKich run from the tibia to the tilmla, and snine from the fibula to the 

tibia, but ftll are inoline<"l downwards. They are best marked «t their at (iirhmonl 
to the bone», and gnuJually urow denser and thirlter as they approjirh ihc inferior 
intenifiseous ligament. The cliief use of the membrane is to afford & surftice for the 
origin of muscli9>. It is continuous Ijelow with the inferior inlcfswecius Ugamwit. 
In front of the tntcnraseous membrane of the ligament lie the tibialis anlerinr, 
the ext«nsor dijjilonim longus. the extensor hallucis hjiigus, and Ihe anterior tibial 
vewselu and nerves. tlcKind it is in relmitui with the tibialis posterior, the flexor 
hallucis longus, and the peroneal artery. 

(c) The Inferior TiBio-FiDfLAR Ahticui-atios 
Class.— f>wrtfcft)8i«. Subdivision.^.'! rtArtHfifl. 

This junction is formed by llic lower ends of tlie tibia and fibula. Tlie rou^ 
triangular .-(urface on eueh of llietie bones fonncd by the bifurcation of their inters 
osseous lines is cIo«cty and firmly luutBl by the inferior inlenisseous ligament. 
The libulft is i[i actual contact with the tibia hy un articular farel, whinh is t<niaU 
in 8i?c. crescentic in sliape, and continuous with the articular facei of the malleolus. 

The ligamenia which unite the bones are: — 

1. Anterior lateral nmlleolar ligament. 

2. I'oBteriiitr later.il malleolar ligament.- 

3. TniiLsverse ligiuiient. 

4. Inferior iiitero)<8eous ligament. ; 

The anterior lateral malleolar ligament {figs. 295 and 299) ]& a Ktrong trian- 
pilar hand about 2 cm. (j in.) wide, and is alt.ichrd to the lower extremity of 
Ihe tibia at it.-* anterior and avtemal angle, close to the margin of the facet for 



Flo. 395.— Lower Evm np I.bpt Timv and Fiui-'i.*, siiomNo the l.iiiAueN-rs. The 

■ynovi«IfoU1 ln'iwfcri tlii-su- Imatnlia^beon reniov*d to show thr tmrisvprsc ligiunenl fanning 
part of tlif ca]K<uK< of i\k joint, and the deeper 6ljrvH oi the luitiirior Utcnl malleolar Uj(i^ 
niMil which coflfnt into rontaot wifh the Ijilus. 

{fmn a diMection by Mr W. P«*raon, of tltp Roy»l College of Rurgranff' MuM-iim.) 



IMMM IICBW«B 




)ABt«nor laMtvl i— ll»i 



XatanMl iMaral IiMm«n 






Ihe talus (a.'<lra2alus), an'l pa.sses downwards and outwards to the anterior iHirder 
and rcmtigunUH surface i»j the lower end of the fibula, some fibnes pa.-tfiinfi: alon^ 
the e-lfjie nearly as far a.s the origin of the anterior fafleiculu.* of the exlvmal latt^nil 
ligament. The fibres increase in length from above downwards. In front it is 
in relation with the peroneus tertiua and deep fascia of the log, and gives origin to 
libres of Hie aniermr ligrunnnl of the ankle-joint. Behind, it lies in contact with 
Iho inten)as«ous ligament, and comes into contact with ll»c articular surface of the 
lalufl (iLftrriguluH) i^.i- fi>;s. Lft.i and 206). 

Tije posterior lateral malleolar ligament (figs. 295 and 2Wl) is very niinilar 
to the anterior, extending from (lie jfosterior and external angle of the lower end of 
the Libia downwanl^ and outvvanLt to the lowest ITi cm. i ^ in.) of the bnnler scfui' 
rating the internal from the jxisterior surface of tlie shaft of Ihe fibula, ami to the 
upper part of the [xwlerior border of the external malleolus. It is in relation in 
front with the intonwscous ligament; l)elow, it tottchefi the Tran8\-erpe ligamait. 

The inferior interosseous ligament is a denfie mass of short, felt-like fibres. 
j»a*sing transversely l>e{ween and fimily uniting the opposed rough tnangular 



THE AhlKLK-JOIST 



297 



_ iifaces nt the lower ends of the tibia and fibula, except, for 1 cm. i% in.) at the ex- 
tremity, whpro I here isasynovijd gravity. Ir eMerifU from the (interior to the jKiste- 
'rior laiera! mallenUr iJKamenta, reaching upwards 4 cm. (I J in.) in front, but only 
half this heijiht U'hind. 

Tlie transverse ligament (fig. 298) is a strong rounded bond, altiiched lo nearly 
the wblJe Uyigili of the infi-rinr Imnler of the [losteriorsurrsce of the libia, juat above 
the articular facet for the talus (astraKH-'us). It then inclines a little forwards 
am! downwards, to Iw attached to the internal surfaee of the external malleolus,' 
just above the fivfwi, uni) into the upper part, nf the fossa itself. 

The synovial membrane 'a cunlinuous with that uf (hi:; ankle-joint; it projects 
upw:irds between the bones beyond their articular fac«ls as high ha the inferior 
ini.eniKS(4>Ut> ligamenL. 

The nerve-supply is the tuaine as that nf the ankle-joint; the arterial i^upply 
is from the pcrotieul and the anterior pemnctLl, and sumetiinc^ fmm the anterior 
tibial, or it.s exicrnnl mikl1er>lar branch. 

Relations.— In fmnt of the inferior tibiofibular joint are the anlerior peroneal 
artery and the tendon of the penineus tertius, and behind it are the ^xMitcrior per- 
oneal anery andlhe paJ of fat which lies in front of the tendo AoliilliB. 

The movement pfrniiitwi ;Lt this joint is a men,- plidinj:, chiefly in an upward 
and fiowiiwnnl direction, of the fibula on the tibia. The bones are firmly braced 
together ami yet form a slightly yieliliriK arch, thus allowing a slight lateral ex- 
pansion during extreme flexion, when the broad part of the talus \s brougUi under 
the arch, by the upward gliding uf the fibula on the tibia. To this end the direction 
of the fibres of the lateral nuilleolar ligaments \s <l<)wnwnrd3 from tibia to fibula. 
This mechanical iirrungenient seeunw fjerfect w)ntact of tlie articular surfaces of 
the ankle-joint in all positions of the foot. 



4. THE ANKLE-JOINT 

Class. — r>inrUiro»ia. Subdivision. — Gingt^mua. 

The ankle is a perfcwt ginglymug or hiugo joint. The bones whi<*b enter Into 
\\8 fonnatinn are: the lower extremity and internal malleolus of the tibia, and 
the external iinilli'niu.s of the fibula, above; and the upper and lateral articular 
surfaces of the talus (nslragjilus) beluw. Tlie Ugamentj;' uniting the bones are: — 



Anterior. 

Posterior. 



Deltoid. 

Kxtemal lateral. 



Pig. 20'^. — Right Anklr-joint. sauvriW) tkb LiGAUBNTni. 
(From diwwL-tion by Mr. \V. Pearwm. of ttie Royal Ci>IIe«e of Surueons' Museum.) 



■■parlM*! Hbroi of aatarlM f 
M«rft1 mtllroLM IMunital 1 



AnMrlar ramlmlna | otrttrr 



aciddl* fUvleuluu I 







' SaltoM l)c«a«iil 



The anterior ligament (lie- 2991 is a tliin, memhranous structure, which 
exteiKls !x!tween the lateral ligaincntfi. Ii is atlnched alinve to the anterior bor- 
der of the internal mallenlus, to a crest of Iwine just almw the tninsverse grrwve at 
the lower end of the tibia, to the anterior lateral malleolar ligament, and to the 
.anterior border of the external malleohw. Below, it ia attached to the rvugh upper 



398 



TUB ABTWULATfOSS 



Kurfooc nf tho neck of the tii!ii$ (iistrugaliis). Internally Jt ts thicker. And is 6xed to 
the tiiluH close to the facet for the inner malleolus, Ijeinp conlinuouji with thedeUoid 
liganioul, and pacing furwarUs to blend with Ibe tai<)-navicular li^unient. Kxier- 
nillly it is itttached to the talus, just below and in front of the angle l)etweeti the 
fiuperior und lutenil fjice(»p cloMe to their eiijie^, tind ]<iiim theHiil«rior fat-rieuluaof 
the exteniuJ tuteral liiitiinent. It is in relittion, in front with rhe tibialis avirrinr 
muscle, the anteiior tibial vcstscls and nerve, the cxtaisor tetidons of the toe*, and the 
penmeus teriiiu; luul beKind with a mass of fat and synovial membrane. 

The posterior ligament (tig. 29(>) ia a verj- thin and disconnected membranous 
struclui'e, connected above with the external malleolus, internal to the jwnmciil 
gmove; to the [jostoriur margin of the Inwer end of the lilna external to the proove 
for the tibialis pfjeterior; and to the posterior lateral malleolar ligament. Below, 
it is atta(^hed U* the fKisfcrior surface of the talus (astragalus) fmni the deltoid lo 
the external lateral lifiaments. The passafje of the flexor hsilucis longus tendon 
over the back of the joint sen'ea the purpose of a much stronger posterior ligam«it. 

Fia. 287. — iKXBft Vuw of trk Anki^b amd the T.iRsua, AnowiNa tab (iitoovs for trb 

TeKCON or THE TlBULIS PomSKIOR. 



^ 






Infaitor eil- 



Hiavt plMilBrUvmanl I^ma pLuttar bcaiBCOl 



The deltoid or internal lateral ligament (fig. 297) is attached sufteriorly to 
the internal malleolus along its. lower Iwrnter, and to itn anterior surfju-e superficial 
to the anterior li.canient ; some \-ery strong fibres are fixed to the notch in the lower 
border of the malleolus, and, getting attnchnient l>elow to the rough depression on 
the inner side of the talus (astrognlus), form a deep portion to the ligament. The 
ligament radiates; the pcwierior fibriw are shnrt. and incline a little haekwonls to 
Iw fi-Xwl to tlie rough inner surface of the talus, close to the superior artirular 
facet, and into the tubercle to the inner side of the fle-xor hallueis lonpis groove. 
The fibres next in front are numerous and form a thick and strong mass, filling up 
the niugli depnwsion on the inner surface of the talu», whilst. i?ome pass over the 
Ijilo-caleaneal joint to the upper and inner Imrder of the sustentaculum tali. Tl 
fibres, which are connm-ted atxfve witli I he anterior surfaee of rlie malleolus, 
downwards and Miuiewhat forwards lo \ie atluche<l to the navicular and to the 
margin of tlie ralc/inen- navicular ligament. 

The external lateral ligament Mtgs. 'J96 and 200) cnnniiits of three distinct slips. 
The anterior fasciculus, the anterior talo-fibtilar ligament, is rihbon-like and 
jiasses from the anterior border of the externnl malleolus near the tip to the rough 



THE ASKLB-JOfNT 



299 



surface of the talus in front of the cxremal lateral facet, and overhanging the ainiia 
pedis. Tliemiddle fasciculus, tlic ca I caneo- fibular ligament, is u)jtruni£ roundish 
buiidle.. wjiit-h extends downwards and stjinewhat bat-kwanls from the aiili*riur 
border of the exUtriuU malleolus cluse to the attmdinieni of iIk anterior fa»rictilus, 
and from the outer surface of the intilleoiut<, ju^vt in front of the apex, to a tulier- 
cle on the middle of the outer surface of the caleaneum. The posterior fasci- 
culus, the posterior talo-fibular ligament, is almost horieontal: it is a stronir, 
thick band attachetl at one end to the posterior lx»rder of the niaHe<)hi«. and siiglitly 
to the foesa on the internal surface; and at the other end to the talus. Iwhind the 
articular facet fur the fibula, as n^ell as to a tubnrclc on the outer Hide of the ^niuve 
for the ficxoT kalhieis lonijus. The middle fasciculus is covered by the tendons of 
the prronri Inmjus atui hrevla; and in exlenaicn, the poKtcrior fasciculus is K^ccived 
into the pit on the inner surface of the external malleolus. 

The synovial membrane is very exleosive. Be«ides lining the ligaments of 
the ankle, it extends upwards between the tibia and fibula, forming a short adniv- 

Fio. 29S.— LiuAUum siaN ntOH tbs Back or nu Amklb-jqikt. 



y P 



TB* lawtr pari of tba l>Mra^*aaa 



VeaUMor Usiaant a( aDKJs^Mot 



PiMKiar MTt M IM aatlotd 
unuiwui 



^\'J^v 



Traiurctae ti 



rmt tUaMOBi of niI*not 
UUa-atutai >otal 



PoatartoT talo-Abalarlmmaot 



Oaloaooo-flbulai IIcbuicuI 






soA as f ar as the interoascous lit;a:nent. Upon the anlfirior and posterior ligaments 
it Ls very loose, and cxtrnds beyond the limits of the articulation. It is said to 
contain more synovia than any other joint. 

Tlie nerre-supply \n from the saphenous, posterior tibial, and the external 
division of the antciior tibial- 

The arterial supply rnmc8 from the anterior tibial, the antenor peroneal, the 
external Tiialleolar, the jKjatenor tibial, arnl [xij^teritirpenmeal. 

Relations.— /n jroiU and in contact with tht? anterior ligament, from within 
outW;ird.s, are the tcndorLs of the libi:ilirf anterior, the tendon of the extenrsor hallucis 
lon^us. the anterior tibial vessels, the anterior tibial nerve, the tenHon.s of the ex- 
lerwor dixitoruin longus, and tiie tendon of the iwroneus lertius. To the inner side 
of tlie tibialis anterior and to tlie outer side of the peroneus tertiua the joint Is sub- 
cutaneous unterioriy. Behind and ejienuxllit are the tendons of the peroneus 
longus and brevis. Behind and iniermdtv. from within outwanls, are Ibe tendon 
of the tibialis posterior, the tendon of the flexor digitorum Umgus, the posl'Orior 




3(K» 



THE ARTICVLATIOSS 



tibial vessels, the posterior tibial tierve. and the tendon of the flnxor lialiuois longiis. 
More mtMjiully Ijcliind ia a \y.u\ af fat whi^h inlervcnps between the tendo Acliillis 
imd the joint. Bdow and on thr oidrr side, cmssiiiK the niidtlle fast-iculus of tJit &\- 
tenial iaterul ligataeiit, ai% the tenduti.s of the peroneus hitiuiis and brevis. Btiotc 
and on the inner side, crossing the deltoid ligament, are the tcndijns of the tibialis 
poHt«rIr)r anil tho ilexor dijiitoruin liingus. 

Movements. — Tiua being a true lunge joint, flexion and extension are the only 
movements of which it is capable, there Ixiing no lateral motion, e-xcept in extreme 
extensioQ, when the narrowest, part of the talus is thnist forfli'ards into the widest 
part of the tUjio-fibular arch. In llexion the talus is lightly embraced by t he malleoli, 
and lateral movement is Impossible. Flexion is limited by: — (i) nearly tho whole 
of the fibrt's of (lie deltuid ligament, none but the most aitieri(»r Ijeing relaxed; (ii) 
the posterior and middle portiona of the external lateral ligament, especially the 
posterior: (iii) the posterior ligament of tlio ankle. It is also limited by the neck 
of the talus abutting on the edge of tlie tibia. Kxtension is limited by: — (i) the 
anterior hbres of the deltoid ligament; (ii) the anterior and juiddle [wrtions of the 
externa] lateral ligament; (iii) the inner and stronger fibrxs of the anterior ligament. 
It ia also limited by the posterior portion of the talus meeting with the libia. Thus 
the middle portion of the external lateral ligament is always on the stretch, owing 
to its obliquely backward direction, wliereby it limits flejsion; and its attachment 
to the fibula in front of tlie malleolar apex, whereby it prevents ovei'-ex tension a» 
soon as the foot Ixjgtna to twist inwards. This inwanl twisting, or adduction of 
the foot, is partly due to the greater posterior length of the inner border of the supe- 
rior arliciilar siirf;iMe of the tjdijs, anil to the les.s pmporti<iniLte height posteriorly 
of the external border of that surface, but chiefly to the lateral movement in the 
talo-caleanea! joints. Flexion and extension take place round a transverse axis drawn 
through tlie Ijody of the tahis. The movement is not in a direct antero-poet^rior 
plane, but on a plane inclined forwanls and outwards from the middle of the as- 
tragalus to the intermetatarsai joint of the second and third toes. 

HiMclei which act oo the ankle-joint. -F/wcrw.— Tibialis antprior, extensor hallnrblongua, 
extensor dinltiimm Ifinpi*. pcrvnifiis tertiii.s /■.■.r/ruA.'m.— TitiiatiR pnslprior. flexnr i^ieilnrum 
lan([uii, He.tur linlluvw lugi^fus p(!riJiiKii)> l>ii)]|;ii.s, p«:niiwiu( l»r«vis, aulvus, KatitJTtoneniiua, pl&ntAria. 



.•i. THR TARSAL JOINTS 

These may be divided into the following sub-groups: — 

(a) The talo-calcaneal union. 

(6) The articulations of the anterior portion of the tarsus- 

(c) The medio-tarsal joint. 

(n) Thr T-M/>-rAi-<UNKAL Union 
There at« two jnints which oJiter into this union — viz,, an anterior and a posterior. 



(i) The PoMrriar TaUy-calcnnatl Joini 
Class. — Diatihrosuf. Subdivision.- -Arlhrodia. 

Tho calcaneus articulators with the talus by two joints. The anterior and posterior: 
the (oraier communicates with the niedio-tansal; the ptwierior Ls seiwimto and 
complete in itself. The two bones are united by the following ligaments: — 



Int erf isseous, 

Piisteri'T talo-calcaneal. 



External tnlo-calcanenl. 
Internal talu-<',-ilcanejd. 



The interosseous ligament (Hps. 2^9 and 300) is a strong band coimerting the 
appascd surfai-es of thf- falcjuieiLs and tahw along their oblique groirt-es. ll is 
composeil of twveral vertical laminir of fibres, with some fatty tissue in between. 
It is l»etter inarke<l. deeper, and broader externally. Strong laminie extend fmm 
the rough inferior and external surfaces of the neck of the talus to the rough su|)e- 
rior surface of tlie calcaneus anteriorly, forming tho posterior boundary of the 




TALO-CALCA.\EAL 



3Ul 



anterior tato-culcaneal joint; these luive been described as tlic anterior interos- 
seous ligament. Tlu> po»t'erior lunilDne extend from the roof of the sinua pedis 
tu the culcuncus iiiunediately in front uf the (Eternal facet, thug foniiing the anie- 
rior part uf the rajwule of the [Mjeteiinr joint. 

The external talo-calcaneal ligament (fip. 209) extends from the gronve 
just below and in front of the ('xrnrmil artifiuljir fiicct of the tfthis, to the calcaneus 
tivine litlle distance from the articular mwrpin. Its fibres are nearly parallel with 
tbotte of the middle fasciculus of the cxternut lateral ligament of the ankle, which 
pasaes over it and add^ to hs strength- It tills up the inter\'al between i1h> niiii- 
ale and anterior fasciculus of the oxtcnial lateral lijfamont, a c<>u.si4ierablc bundle 
of ita Hbres blending with tlte anterior border of tlie middle ftuficulus. 

The posterior talo-calcaneal ligament po-s^cd from the external tubercle 
€>f the talus and lower edge of the proove for the flexor hallucis lonpU3 to the cal- 
caneuij, a variable tlistaiue fnun the artlculnr nijtrgin. 

The internal talo-calcaneal ligament is a narrow band of well-marked fibres 
paf<tiine u|}liquoty dovMiwardg and backwards from the depression on ilie talus, 
just behind the inner enil of the sinus pedis, to the calcaneus behind the siisten- 
tacuhim tali, thus completing the floor of the groove for the flexor halluci^ longus 
tendon. 

The synovial sac is distinct from any other. 
^m The nerve-supply is from the posterior tibial or one of it-s plantar branches. 

^^m The arteries are, a branch from the poeterior tibial, which ent^^rs at the inner 
^^^ end of the sinus pedis; and Iwi^s from the taraal, external malleolar, and the per- 
1 oneal, which enter at the outer end of the sinus. 

W an 

I bo 

I tal 



Class. 



(ii) The Anterior Tato-calaineal Joint 
-Diarthrosis. Subdivision.— .-1 rUirodia. 



This joint Is ft)mied by the anterior facet on the upper surface of ttie calcaneiia 
and the facets on the lower surface of the neck and head of the talus; it la 
bounded laterally and behind by liKamentrS, and communicates anterioHy with the 
talo-navicular joint. The ligaments ore : — 



Interosseous. 



Internal (or antero-intcmal) talo-calcaneal. 
External calcaneo-navicular. 



The interosseous ligament by its anterior l&mime limits this joint poeteriorly. 
It has been already descrilwd I p. 300). 

The antero-internal talo-calcaneal ligament consists of short fibres attached 
above to the rough defircs-siuii <in the internal surface of the neck of the talus, and 
below to the upper edge of the free border of the sustentaculum tali, blending poste- 
riorly B-ith the inner extremity of the interavseous ligament, and ameriorly with 
the upper border of the plantar cat caneo- navicular ligament. It is strengthened 
fay the deltoid ligament, the anterior fibres uf which are al»o attached to tlie plantar 
calcaneo-navicular ligament. 

Tlie external calcaneo-navictilar (superior c&Icanco-scaphoid. Gray) (figs. 299 
and 300) limits this, as well as the Udo-navicular joint, on the outer side. It Is a 
stmng, well-marked band, extending from the rougli upper surface of tlwr calcaneus, 
external to the anterior facet, to a .slight gnMive on tho outer surface of the navicular 
near the posterior margin. It blends below with the plantar calcanw>-iiavicular, 
and above with the talo-navicular ligament. Ita fibres run oblicjuely forwards 
and inwards. The internal lateral and middle fjwscifulug of (he external lateral 
ligaments of the ankle-joint also add to the security of tliese two joints, and assist 
in limiting movements l«twocn the bones by passing over t he talus to the calcaneus. 

The movements of which these two joints arc capable are adduction and abduc- 
tion, with some amount of rotation. Adduction, or inclination of tlie sole inwards, 
in combined with .some nrtation of the toes inwards, and of the heel outwards; 
while alwiuctiou. or inclination of the foot outward.^, is assnoJalod with tyming of 
the toes outwards and the hwl inwards. Thus the variety and the range of move- 
ments of the foot on the leg, which at the ankle are almost limitcl to lle.xioii and 
extension, are increaK(>d. The cuboid moves with the calcaneus, while the navicular 
rovolvos on the head of the talus. 



302 



THE ARTlCCLATIOm 



tn walkitiK, the heel is first placed on the ground; Ihe foot b> slightly adducted; 
but as the body snin^ forwards, first I he outer then i he inner toes touch the ground, 
the lulus presses against the navicular and sinks upon the plantar cjdrftnor)-nttvipular 
ligament i tho foot then becomes slightly alxiucled. When Ihe foot is firmly placed 
on the ground, xhe wyight Is transmitted to it obliquely downuartls and inwards, 
^o that if the ligiuiicnts between the calcaneus and talus did not dieck abduction, 
inward displacement of the talus from thetibio-libulararcti would only be prevented 
by the tendons passing round the innrr ankle (esi>eciidly the tibiaits poitttnor). 
if the ligaments be too weak to limit abHuriion. the weight of the liody increases 
it, and forces tlie inner tnalleotus and talus dowTiwards and inwards, giving rise 
to fiat foot. 

The advantflgei of the obliquity and peculiar arrangemrait o( the posteiior 
talo-caicaneal articulation are serai in walking :— (i) for the piieterii>r facet of the 



Fig. 299. — Extkunal View of thb LioAsreN-re op t«k Foot akd Ankle. 






UEiimeBt «( aakte 




AaWrtar l»l«r«) «mUMlM Usa 



Ksl«n«l aBl«aaao-aB«i«ul>r 






DDt««l oal>e4dao-a**lcular 



ll|i»B«nl 



Middla (uoMulMB ol uMmal latMBl 



enlcaneufl ret^eives the whole weight of the body when Ihe heel is first plared nn 
the gnamd; in) by the upward pressure of this facet agiiiiiht the lalus it transfers 
the weight to the ball of the toes as the heel is raised, the hinder edge of the sus- 
lentflculnni tali and the anterior and outer part, of the upptT surface of tlie cal- 
caneus preventing the talus from being displaced too far forwards by the &uper- 
incuml>ent weight; and fiii) the calcaneus serves to suspend tlie talus when, with 
the heel raised by muscular act ion. the other foot is beinR swung forwards. 

The synovial membrane is the same as that of the talo-navicular joint. The 
arteries and nerves jin> dcrivofj from the same sotirres .is those of the modio-tarsal 
joint:«. 



(6) The AR-nrui-.^Tio^rg of the Antkrior Hart of thk Tarsto 



These include (i) the • 
cuneiforuii and (iv) CU( 



navicular; (ii) navieulari-cuneifomi; (lii) Inter- 
I joints. 



THE TARHAL JOtSTS 



303 




(i) The CuboidiQ-nuvicular OnUm 
ClAis.—Diarthrogis. Subdivision. — Arthrodia. 

The ligautcnt« wlurh trnite the cuboid and tuviculur are: — 

Dorsal. Planlfir. In(^ot&>«(iU». 

Tlie dorsal cu)>oideo*aaTiculax ligament (ftg. ^00) runs forwnnk aiid oiil wunls 
fnim the outer end uf the dun;iil HUrface of the niivicular to the middle rhinl itf the 
inner border of the euboid on iia dorsal uspcct. pii-siiinp over the posterior external 
iinjjio of the third cuneiform hone. It is widej exiemally. 

The plantar cuboideo-navicular ligament i^ a well-mnrked strop): band, 
whieh runs fonviirds and outwards, from the plantar surface of the navicular lo the 
depresMoii on I lie inner surface of the cuboid, and slightly into the plantar aurface 
just beJow it. 

The interosseous cuboideo-navicular ligament b? a Ktronfr band which pas*e.s 
between the apfMwcd .surfaces of the.sc bones from the dorsal to the plantar Hganienls- 
Sontoof its p^Bilerior fibres reach the plantar surface of I he foot behind the cuboidett- 
navicular ligament, and radiate outwards and backwards over the inner border of 
the euboid to blend with the anterior extremity of the pttuitar catcaneo-cubold liga- 
ment. 

(ii) The SaviciUari'Cuneijarm Arlicuiatiott 

Class.— /)wir//iro»i*. Subdivision.— .-iW/trVK^iVi. 

The ligaments uniting the navicular with the three cuneiform bones are:— 

Dorsal. Pluntur 

Internal. 

The dorsal naviculari- cuneiform ligament is very stnmg. and .^itWrhe;? a-s a 
continuous !<l nu-ture on the dwrsal siirfaci- <if tlie riavicular. I>elweeit the luLjerck- of 
the navicular (»n the inner side, and llie don^al cuUiideo-navicular ligament ex- 
lernnlly, passing furwarda and u little outwards to the dor&al surfaces of the throe 
cuneifonn hone^. 

The internal navicular! -cuneifonn ligament is » very strong thick band which 
connecl-i ihe iul>crcle of the naviculnr viih the inner .turfitce of the fiwt cimei- 
forra Ixine. It is coniinuoii.s with the d<ir>*Hl and plantar lignnientj*. Its lower 
hurdur touches llw tentlnn uf tliu fibiaiis /rnstcriitr. 

The plantarnaviculari -cuneiform ligament f')nn.s. like the don<jd, a continuous 
slru<:(un' exteiidiiif; iHMwcen the plaiilar .surfactv of ihe bones, lis (ilmti |)a.ss 
fomardH and outwards. It is in relation below with t}ie tendon of the tibialis 
poUerior. 

It nmut Im notired that thp oxpHDdml tvndnn of iin*riioTi of the tAutlis paxtrruir, and thtt 
iijiaiiii-iilH unit ilia; tliu Daviculur with the cuboid and cunvifunu Ixiiiw, p«u«furwunlsuiiduulwiiniF, 
while the prronru^ hn<tu« ton<lr>n and I ho lienmrntA tiniting the fin*t and i»crniid rows o( boiit», 
f-xcfipt lli«> intiPT h.tlf nl tilt- (jorvn] (:il(>>ii)ivtciil)ir ligiimpnli'. piuui forw.inlK and initrinti. Thin 
arnui(f*^ni>nt is iidniinibly itdapUsI (u jjrrfcrvv div archm- i>f Ihv fuol. and raprnally lliu lraip» 
versp arrh. Ilnil thiyic t<>ndon« and lifcammt^ nin <lirwtly forwnrd*. oil tlir rtniiii on thi* lr»t»- 
vtT»; nTfh wfiiil'l liiivi> r,'i!li'n itti titc inlcriuvapoiMi li^nmrnt!*, hiil tut it in, the iirch in br.ir4*d tt|i hjr 
the sbovc-uwiitiotiiAl tilruiturw. 



(iii) The Intercuneiform and (\v) The Citneo-ciHfoid Articidations 
Class.— DiVir/ftcnAi'j*. Subdivision.- .4 rMr^uj. 

The uniting ligaments of these bones arc divided into three sets: — 

fJorsal. Plantar. 

InterosseouA. 

The dorsal ligaments ate three in numlier, two, the dorsal intercuneiform, 
eonnectinn the three cuneiform bones, and a third, the dors;il cuneo-cuboid, 
uniting tlio third euneiform with Itie cuboid. They pass beluc^^n the contiguous 



304 



THE ARTiCULATinSS 



margins of the bones, and iire blended beliind with llie donal ligaiiier>ts of the 
ciilmi'lofi-iijivinilar and navicular!- cuneiform joints. 

T\k plantar ligaments ure two in iiuniiK-r: a very nlrongeine.tlte plantar mter- 
cuneifonn, passes outwai-da iind forwards from the outer side of the base of the 
first cuneiform to thp iiix'x of the second cunoifoniv, wimling snmeivhat to its outer 
aide. The second, the plantar cuneo-cuhoid, connecls the apox uf the third cunei- 
form with the anterior haif of llic inner surface of the cuboid along its plantar bor- 
der, joining with the pUinlar culwideo-niiviculajr ligament beliind. 

The interosseous ligaments iire tlinw in number. They are Blmnjr and deep 
miissps of ligamentous tist^iie which connect the t^cond cuneifnnn witli the first 
iind third runeifnnn l)onc,s. Hn<l ihc third cunoiforni with the ruboid: occupying 
all the non-articular portions of the apposed surface* of the bones. The ligaments 
extend the whole verticjil depth between the second cuneiform and the third, 
and the third cuneiform and the culioid, and blend with the dorsal and plantiir 
liframenTH; they artt situated in front of the arlicular facets, and completely shut 
off the synovial cavity l»ehind fiuni that in front. Tlie Hpanient between the first 
and second cuneiform l)ories occupies the inferior and anterior two-thirds of the 
apposed surfaces, and does not generally extend high enough to separate the syno- 
vial cavity of the anterior tarsal joint fnnn that of the ee<:ond and tliird metatar- 
Hal and cuneiform bones. If it dt)es extend to the dorsal surface, it dividfs the 
facets com[)letely fnim one another, making a seventh synovial sac in the foot. 

The synovial cavity mil be described later on. 

The arterial supply is from the metatarsal and plantar arteries. 

The nerves are derived from the anterior tibial and internal and external 
plantar. 

The movement permitted in these joints is very limited, and exials only for 
the purpofie of adding to the general pH.ancy and elrwlieity of the tarsus without 
allowing any sensible alteration in the position of the different parts of the foot, aa 
the meilio-l:irs:»l and talo-^-alcaneal joints do. It is simi>ly a gliding motion, and 
either deepens or widens the transverse arch, The third cuneiform being wedged 
in between the others is less movable, and so fomis a pivut upon which the rest 
can move. The movement is more produced by the weight of the body than by 
direct muscular iu'^tion; and of the muscles attached U> this part of the tatsuSj 
all deepen the arch save the tibialis anterior, which pulls the first cuneiform up, 
and so tends to widen it. 



(c) Thh Mkdh>-t.*rs.\l or Traxbvehsk TAnsAL Joints 

The articulations of the anterior and posterior portions of the tarsus, although 
in the same transverse line, consist of two wparate joints, viz., (i) an inner, the 
talo-navicular, which pommunicntes with the anterior talo-ealcjineol articulation; 
and (ii) an outer, the calcane(»-euboid, which i.^ complete in itself. The move- 
ments of the anterior upon the posterior portions of the foot take place at these 
jaiuts simultaneouKly. It wilt be most convenient to deal with the joints sepa- 
rately as regards the ligaments; while the arteries, nerves, and movements will 
be considered together. 

(i) The Tafo-navkuiar Articulation 

CIms. ^nitiiihrosis. Subdivision.— Knar/ftrwrfi'a. 

This is the only l>all-and-«oclcet joint in the tarsus. It communicates with the 
anterior talo-calcaneal articulation, and two of the ligaments which cUiwe it in 
do not touch the talus, but pas.^ from (he calcaneus to the navicular. The unitini; 
Iigamenl8 are: — 



Elxtemal oalninco-navicular. 



Plantar cnlcaneo-navicular. 



Talo-nawular. 

The external calcaneo-navicular has been already descril>ed {p. 301). 

The plantar calcaneo-navicular ligament (figs. 3ti0 and 301) is an esew 
ingly dense, tliirk platf of fibro-ela'itic ti,«sue. It extends from the ■nistentaeulum 
tali and rhe under surface of the calcaneus in front of a ridge curving onlwari'ls to 
tjie aatcrivT tubercle of that bone, to the whole width of the under surface of the 



THE T^RSML JQIXTS 



305 



na^'icula^, and aJso to the inner surface of the naWcular beliind ibe tubeix-le. In- 
temully it ia blended with the amerlor portiua of the deltoid ligament of the ankle, 
and externally with the tower border of the external calcajico-navicular li^iuiieut. 
It is tliickpsi nloiiK the inner border, its upiwr surface loses the wcU-nmrkcd 
fibrous appearance which the hgamont lius in the sole, and becomes smcwifh and 
faceted. In contact with the under surface of the liRament. t he tendon of the iHnalU 
pMterior passes, giving considerable support to the head of the talus by asaiating 
the power and protecting the »prin»; of the ligament. The fibres of the ligameut 
run fon\'ards and inwards. On account of lis elajiticity it iu sometimes tenued 
the spring ligament. 

The talo-navicular ligament is a broad, thin, but well-marked layer of fibres 
which passes from the dorital and external surfaces of the neck of the tains to the 

Fra. WO. — View or tub Foot from \novK wmi thb T*tfB mtitovro to saow the Plantar 

AXD EXTCK.NAL CAt<CA?IKO-NAVlCVl.AJt LlOAJUUm. 



I Mboldaci-iik*l««lir , 



Uwrw « 



Ilgunaot 



i-cndon of u bMU ponmor 



.\4 



:km''^ 



whole length of the dorsal surface of the navicular. Many of the fibres converge 
to their insertion on the navicular. The fibres low down on the outer aide blend 
a little way from their origin with the upijer edge of the external calcaneo-navicular 
ligament, and then [«iss forwards and inwards to the navicular; those next above 
puia obliquely and with a distinct twL<4t over the upper ancl outer side of the bead 
of the talus to 1 he centre of the dorsum of the navicular, overlapping tibrwi from 
the inner ^de of the talus as well aa some from the anterior ligament of the ankle- 
joint. 

Synovial membrane.— The tato-nnvicular is lined by the same 8>'novlal mem- 
brane as the anterior talo-cuicaneal joint. 



(ii) The Calcaneo-ciOtoid ArtictUatian 

Class. — Diorfhrosis. Subdivision. — Saddle-shaped A rthrodia. 

The ligaments which unite the bones forming the outer part of the medio-tareal 
joint are: — 

Internal or Interosseous calcaneo-cuboid. 
Long plantar. 
an 



Doreol calcaneo-cuboid. 
Plantar calcaneo-cuboid. 



306 



THE ARTICULATIONS 



The internal or interosseous calcaneo-cuboid ligament (fi^. 300) i^ a stmng 
band of fibres nttached in the cah^uiious nlonK tiip inner part of the n<in-artirular 
ridge above the articular facet for the euUnid, and ;i]f<« to the upi>er part of the 
iiiternai surfsue clutie to the articular margin, and passes forwards to Ije attached to 
the dopn*;4ion on the iniernai surf^ice of the cuboid, and also to the rougli aiiglo 
between ihu ititeniul .ind inferior suKaecs. At the calcaneus this liguinenl is i-iii»iely 
connected with the exlenial eiilcuneo-tiaviinihir ligtunent. Towards the sole it 
is connected with the plantar cnJcanco-cuboid ligament, and superiorly with the 
dorsal calcaneo-cubftid. 

The dorsal calcaneo-cuboid (fig. 300) is attached to the dorsal surfaces of tlie 
two bones, exiendiag low down externally to blend with the outer part of the plantar 
ealraneii-iTuboiil liiiaineiit. Over tlic inner half, or more, tlie ligament slrelehes some 
distance beyond the niai^ins of the articular surfaees, reacfiins well forwards upon 

FlC. SOl.—LlGASlENTB OF TUE SoLt OT THE LeIT FoOT. 



tM 



L«af plAOtsr or loni lotariar 



Tentfoa orp«T«a«Ba lonciu 



' si4avt Fwi naw Huutii uwavs 



Sborl plKQtar ar ahoFi itmcior 
Oiioanao-aubotd llgamcst 



lUKfiai or NATicuuii 



[HT(RN«i. cuHriniiitt 



tMMrtloa ar pcroiMiu loaciu 



the cuboid t<i be attached about midway between it« anterior and posterior borders ; 
but Ixjwards the outer side, the liganiont is much ehorler, and is attached tu the 
nuboid behind its tubercle. 

The long plantar ligament (fig. 301) is a strong, dense band of fibres which 
are attached poateriorly to the wimie of the tmder surface of i he oalrnn^is between 
the posterior tubercles and the rounded eminence (the anterior tubercle) at the ante- 
rior end of the bone- Most of Its fibres pass directly forwards, and are fixed to ihe 
outer twiv-thirds or more of the oblique ridge Ix-liind the penmeal prnove on the 
cuboid, while some patv fun her forwards and inwards, expandinjr into n broad ln\*er, 
and are inserted into the ba«cs of the second, thin!, fourth, and inner lialf of the 
fifth metatftrsal bonca. This anterior expanfled portion complete? tlie canal for 
the pfToneus loiujun teiuion, and from its under surface arise the obliqut adductcr 
kalltiriit and the (tcxnr quinli di'jiti brevis muscles. 

The plttatar calcaneo-cuboid (short plantar) (fig. 301) is attacbod to the 



THK TAHSAL JOINTH 



tSUunence (anterior tulwrclc) at t.he anterior end of the under surface of 
eus, and to the hone in fmnt of it, and then lakes an oblique course f<ir- 
fiards and iri\vanl». and is attached to the whole of the deprewetl iiiferiur surface 
of the cuboid behind the oblique ridge, except its outer an^e. It is strongest near 
its outer wigc. and is formed by deiteo strong fibres. 

The synovial membrane is diintinfM from that of any othertarsal joint. 

The arterial supply of ihc mcdio-taisal joints is from the anterior tibial, from 
the tarsal aiui metatarsal tiranches of the dorsalis pe<]i«,and from the plantar arteries. 

The nerve-supply of the medio-tarsal joints is from the extermil division of 
the anterior tibial, and Ofca^ionally from theyui^erlicial peroneal or external plantar. 

Relations.— On ihe dorsal aspect of the mid-tarsal joint lie the tendons of the 
tibiulLi anterior, ext-eiisor liallueis longus, extensor digitoruni lonjtus. and i>ero- 
neus tcrtius. the muscular part nf the extensor digitoruni brcvis. the dorsulis pe<iis 
arterv*. and the anterior tibial ner\'e. On its planiar aspect arc the tpndnna of the 
flexor difiitorum lonpis and lialluria longus, qua^lratus plants (arcrssorius) , and the 
internal and external plantar vessels and nerves. It is crossed extenially by tl»e 
londons of the peroneus longus and brevia and internally by the tendon of the tibialis 
posterior. 

The movements which take place at the medio-tarsjil joints are mainly flexion 
and extension, with su[x>radded lateral and roiator>' movements. Flexion at these 
joiuts is simultaneous with ext«ii.^i(>n of tlie ankle, and i-ier itrsa. Flexion and 
extension do not take place upon a transverse, but round an oblique. a.x.is which 
pasaes from within outwards, and somewhat baekwarda and downwards through 
the talus and cahnuicus. 

Combined with flexion and extension la also some rotatory motion round an 
antero-pa-iterinr axis which ^ums the inner or outer border of the foot upwards. 
There is also a fair amount of lateral motion whereby the foot can be inclined 
inwanls (i. e.. adtiucted.) oroutwurda (i.e., abducted). 

These movements of the niedio-tar*ial Joint occur in conjunction with those of 
the ankle and lalrnmlcaneal joints. Rotation at Ihe talo-calcaneal joint is, however, 
round a vertical axis in a horizontal plane, and ao turns the tnesi inwanls or outwards; 
whero.'w at the mcdio-tarsa! union the axis is antero-posterior and the inner or 
outer edge of the foot U turned upwards. Gliding at the talo-calcaneal joint elevates 
ur depresses the edge of the foot, while at the mediotarsal it adducta or abducts 
the Kws without altering the relative position of the calcaneus to Ihe talus. 

Thus Hexitm at the medio-tarsal joint is associated with adduction and inversion 
of the fool, occurring sinuiltanoously witli extptwion of the ankle: and extension 
at the medio-taraal joint is associatetl with abduction and eversion. occurring simul- 
taneously with flexion of the ankle. 

Flexion and inversion are far more free than extension and eversion, which 
latter movements are arrested by the ligaments of the sole as soon as the foot js 
brought into the position in which it rests on the ground. 

Although the talo-navicular is a ball-and-socket joint, yet, owing to the union 
of the navicular with the ouljoid, its movement-^ are limited by the shape of the 
calcaneo-cuboid joint; this latter being concavo-convex from above downwards. 
prevent.'* roiatiifti round a vertical axis, and also any side-to-side motion except 
m a direction iii>li<iuely downwardii and inwanU, and upwards and outwards. This 
is also the direction of freest movement at the talo-navicular joint. Movement 
is a1»> limited by the ligamentou.H union of the calcaneus with the navicular. The 
twisting movement of the foot, such as turning it upon its inner or outer edge, and 
the increase or diminution of the arch, take place at the tarsal joints, especially the 
medi(»-tari>al and lalo-ealcancal articulations. Here too those changes occurwhich, 
owing to paralysis of some muscles or contraction of others, result in talifies e(|uino- 
vanis, or valgus. 

HuKl«s which acl on the mld-tarsal ^aiut.—Inveiiera. — TibSnlit nnt«rior nnd po-sterW 
arting 9imultaiintii>.1y: rhvy arr tudful hy the flexor diiitiiriini lon^in luii! Hexor hMlliiri* Iniiguit. 
Etvrtcri. —Thf.' prroiitfi loiiKui, bre\'ii. «nd t«rliu8, acting simultaneously. Tliey hpc aided by 
Ihe extcaitfor digitoruni longiiit. 



308 



THE ARTiCULATlOSS 



6. THE TARSO-ilETATARSAL ARTICULATIONS 

There may be said to be throe articulations between the tarsus and metatarsus, 
via. : — 

(a) The Interoal, between the first cuneifonn and firat metatareal boDes. 

(&) The Middle, between the three cuneiform and second aiid third metatareal 
bones. 

(c) The Outer, or cuho-imialars(d, between the cuboid and fourth and fifth 
metatarsal bones. 

The arteries for the tarso-metatarsal joints arederive<l:— {!) for the internal, 
from the dorsalis i>edis and iuteraal pJantar; (2) for the rest, twigs from the arcuttt« 
and deep plantar arch. 

The nerve-supply comes from the anterior tibial and plantar iier\'e8. 

The movements (lennitted at these joints are flexion and extension of the 
metatarsua on the tarsus; and at the inner and outer divisions, .slight addurtion and 
abduction. In the outer, the laieml motion is freer than in the inner joint, and 
frecat between the fifth metatarsal bone and the cuboid. In the inner joint, flexJon 
is combined with slight abdurtion. and extension with adduction. 

There is also a little eliding, whicli allows the traiu^iverse arch to be increased 
or diininishwl in ilepth; the inner and outer two bone-s sliding downwards, and the 
two middle a little upwards, when the arch is increased; and viix versd when the 
arch is flattened. 

(«) The Internal Tab8o-mrt.\t.\iisai. Joint 

Class.— Dwrf/iroswt. Subdivision. — Arthrodia. 

A complete capsular Hgament unites the first mciaiarsal with the firet cunei- 
form, the fibres of wliich are very tliick on the imder and inner as]>ects; thuse 
on the outer side pitss from behind forwards in the inter\'ul bol.ween the interosseous 
ligaments which connect the two bones fonning this joint with the second meta- 
tarsal. T\ic. iiganient on the plantar a.'iiiect is by fur ihc strongest, and blends 
at the cuneiform bone with the naviculari-cuneiform ligament. 



(6) The Middle T.^rso-metataimal Joint 
Class.^/>iarTt/iro,iij. Subdivision.— ^./IrtArodw. 

Into this union there enter the three cuneiform and second and third metatarsal 
bones, which are bound together by the fallowing ligamenta: dorsal, plantar, inter- 
osseous. 

The dorsal ligaments. — 1. Some short fibres cross obliquely from the outer 
edge ol the firwt cuneifunn IwinH to the inner border of the base of the second meta- 
tarsal bone; they take the place of a dorsal metatarsal ligament, which is wanting 
between the first and second metataraal bones. 

2. between the second cuneifonn and the base of the second metatarsal bone 
some fibreiS run dirertly forwards. 

3. The tliird cuneifonn is connected with (I) the outer corner of the second 
motatarssl bone by a narrow band passing obliquely inwards; (2) with the third 
metatanuil by fibres passing directly forwards; and (3) with the fourth metatarsal 
by a short, band passing obliquely outwards to the inner edge of its base. 

The plantar ligaments. — A strong ligament unites the first cuneifonn and 
the bases of the second and third metatarsal hones. The tibialia jtosterior is inserted 
into these bones close beside it. Other slender ligaments connect the second cunei* 
form with the second, and llie third cuneiform with the third metatarsal bones. 

The interosseous ligaments. — (1) A strong broad interosseous ligament extends 
between the outer .surfac*: of the firat cuneifonn and Ihc inner surface of the base 
of the second metatarsal bone. It is attached to both Iwnes below and in front 
of the articular facets, and separates the middle from the internal tarso-rnetatarsal 
joint. (2) A seeond biind is attached behind to a fowa on the anterior and outer 
edge of the third cuneiform and to the interosseous ligament between it and the 
cuboid, and passes hurixontally forvv'ards to be attached to the whole depth of tho 
fourth metatat^ bone behind its internal lateral facet, and to tiie opposed sur^ 



TARSO-iJETA TA RSA L 



30fl 



laces of the third and fourth below their tuieral articular facets. It soparat(» 
the middle tarso-metiitarsal, and in(«rmet«taraa] between thp thiiv] and foiirih 
bones, from the cubo-nictatareol juint. It ia more firmly connected wiih the third 
bone than with ihe fourth. (3) \ slender hganient composed only of a few fibres 
often pojutes from a nmul) tul:>eiTle no the inner and anterior edge of rhc ihint i-unpi- 
form to a groove on the outer edge of tlic second meutaraal bone between the 

two InttTll fiU'Hl.S. 

The synovial membrane is prolonged forwards from that of the navicular!- 
cuneiform and inter-ciineiform articulations. 

(c) The Cudo-ketatarsal Joint 
Class. — Diarthrosis. Subdivision.. — ^-4 rihrodia. 

The bones pomprising this jiiint are the fourth and fifth metatarsal and the 
anterior surface of the cuboid, finnly connected on all sides by 

Dorsal. Plantar. Interoeseous ligamenta. 

The plantar cubo-metatarsal ligament is a broad, well-marked ligament, 
which cxten<is from the cuboid l>ehind to the bases of the fourth and fifth meta- 
tarsal l>oncs in front. It is continuous along the groo\'e at the base of the fifth 
metatarsal bone with the dorsal ligament, and as it passes round Ihe outer border 
of tlic font it Is somewhat thickened, and may be de!>cnl)ed ats the external cubo- 
metatarsal ligament. On its inner side it joins Ihe inlemswous ligamenl^s, thua 



Flo. 302. — Section Tn mnv tub Svnotial C^viTiEa or nrc Foot. 




1. PtMWrlor UIockUaoMl. 
4. Tuul. 



S. CAlcanco-fiubold. 



I'liaiiuulu. 



completing the capsule below. It is not a thick structure, and to see it the long 
plantar ligament, the peroneus tongue, and external slip of the tibialis pouteriur 
must iw removed; the attachment of those structures to the fourth and fifth meta- 
tarsal boiRw coiLniiienibly a*si.Ht.-< to unite them with llie tarwus. 

The dorsal cubo-metatnrsal ligament is composed of fibres which pass ol>- 
liquely outwari!^ and forwards from the cuboid to the bases of the fourth arid fifth 
metatarsal b-mes. They complete the capsule above, and are continuous exlemally 
with the external cubo- metatarsal ligament. 

The interosseous ligament f^huts olT the cubo-metatarsal from the middle tanso- 
metataraaL joint, It is attached to the third cuneiform behind, and to the whole 
depth of thft fourth metatarsal behind its internal lateral facet, and to the apposed 
mirfaccs of the third and fourth bones below their articular facets. It is continuous 
below with the plantar lijEament. 

The synovial membrane is separate from the other synovial sacs of the taisua, 
and is cfmiinued lielwwn the fourth and fifth metatarsal bones, 

Relations. — ^The line of the tarso-metatanial joints is crowsetl dorsjilly by the 
tdons of the long and short extensor muscles of the toes and the tendon of the 



310 THK ARTICVLATIONS 

peroneus tertius. On the plantar aspect it is in relation with the oblique adductor 
of the Kreat toe, the short Hexor of the great toe, the external plantar arter>', and 
the t^nduu of the peroneus Iodjkus. Its inner end is subcutaneous except timt it 
U orosscd, near the plantar surface, by a slip of the tendon of the tibialis miteriur, 
and its outer end La crossed b^ the tendon of I ho ix^mneuH brevis. 

7. THK INTERMETATARSAL ARTICULATIONS 
Clsss. — DiartkrosU. Subdivisioo. — Artkrodia. 

The bases of the metatarsal hones are firmly hehi in position by dorsal, plantar, 
and interosseous ligaments. The first occasionally artlculatea by ineausof a distinct 
facet with the second metatarsal (figs. 222 and 223). 

Tiie dorsal ligaments are broad, uicmbrauous luindi: passinf! between the four 
outer toes on their dorsal asfwct: but in place of one between the first and second 
metatarsal bones, a ligamcjit extends from the first cuneiform to the bjuse of the 
second metatarsal bone (p. 3US). 

Tlie plantar ligaments are stroug, thick, uell-marked ligaments which connect 
the bones on their plaiilar aspect. 

TIic interosseous ligaments are three in numlier, very strong, and are situated 
at the points of imion of the shaft with the bjuses of the bones, and fill up the sulci 
on their sides. They liniit the synovial cavities in front of the synovial facets. 

The common synovial membrane of the tarsus extends between Ilie necimd and 
third, and third and fourth bones; that of the cubo-metatarsal joint axtending 
betAveori the fciurlli and tiflh. 

The arterial and nerve-supply is the same as for the tarso-metatarsal joints. 

The movements consist merely of gliding, so as to allow the raising or widening 
of the tniiisver>ie arcli. Considerable tiexibility and elasticity are thus given to the 
anterior part of the foot, enabling it to become moulded to the irregularitiesi uf the 
ground. 

The Union of the Hkads op Tun Metatarsal Bones 

The heads of the metatarsal bones arc connected on their plantar as]x;ct by 
the transverse ligament, onnsistiiig of four bands of fibres pa.sKing transversely 
from bone to bone, blending with the fibro-rartilaginons or sesamoid plates of the 
mctatarso-phalangeal joints, and the sheaths of the flexor tendons where they are 
connected with the fibro-cartihiges- It differs frr>ni the corresponding ligament 
in the hand by having a band from the lirat to the second metatarsal bone. 

8. THE >tETATARS(>-niALANCJ[!:AL AKTICILATIONS 

(a) TnK Metatarro-phalangeal Joints of titr Faun Oi'ter Toes 

ClftSS. — Diarthrnsia. Subdivision. — Condnlarthrosit. 

These joints are formed by the concave proximal ends of the first phalanges 
articulating with the rounded heads of l>ic metatarsal bonea, and united by the 
following ligaments:^ 

Two lateral. Dorsal. Plantar sesamoid plate. 

The two lateral ligaments are strong bands pa.*sinp from a ridge nn each side 
of the head of the metatarsal bone to the sides of the pmxinial end of the first pha!an.\. 
and also to the sides of the sesamoid plate which unite* the two Ixmes on their 
plantar surfaces. On llie dorsal aspect they arc united by the dorsal ligament. 

The dorsal ligament consists of loose fine fibres of areolo-fibrous tissue, extend- 
ing between the lateral ligaments, llius completing a capsule. It is counected by 
fine fibres tu the under surface of the extensor tendons, whieh pass over and con- 
sldenibly stren^hen this portion of the rajwule. 

The plantar sesamoid plate helps to rieepen the shallow facet of the phalanx, 
for the head of the metatarsal bone, and corresponds to the glenoid ligatnenti 
the fingers It is fimdy connected to the lateral ligaments and the traaifveise Ii| 
ment, and is grooved inferiorly where ttic flexor tendons pass over it. It ser^-es to 
prevent donuit ciisiocation of the phalanx. 



/A' TEHPIiA LA SGEAL 



3U 



The second loetatarso-phalaiigeal joiul is 6 mm. {\ in.) in froot uf buth the Gist 
and thii'd inetaturM>'pliuliuij:eat joints. 

The tlilrd niettiiai^i-plmlaiigeal joint is 5 turn. {\ in.) in (rani of the fuurth, 
and the futinh 9 mtn. (| In.) in front of the fifth. 

The head of the fifth mctalursal is in line with the neck of the fourth. 

Thus the outer side of the longitudinal arch of the foot is shorter than the inner; 
it is also distinctly shallower. 

(6) ThF. -UfrrATAHSO-PHALANGEAL .rO!NT OP THE GrkaT ToE 

The metAtars4>-phalangeal joint of the great toe differs from the rest in the 
following particulars: — 

(1) The boneu are on a larger scale, and the articular surfaces are more extensive. 

(2) Tlicre are two grooves on the plantar surface of the nieiataiyal U)ne, one 
on each siile of the median line, for the sesamoid hoiie;^. 

(3) The sesamoid Imne-s replace the fibro-cartilaginous or sesamoid plate. They 
are two small heniispherinal bones developed in the tendons of the flexor hallucis 
brevis, convex below, but flat above wltere they play in grooves on the bead of 
the nietatiir$al bone; they are united by a atrcaig transverse lijcamentoua band, 
which is smooth below and forms part of the channel along which the long liexor 
tendon plays. Tliey are firmly uniie<i to the bui*c of the phalanx by strong short 
fibres, but to the metatarsal bone they are joined by somewhat looser fibtts. Lat- 
erally they are connected with the lateral ligaments and the sheaih of the flexor 
tendon. They provide shifting leverage for the fiexor hallucin brevis as well as 
for tlie fiejar hnitucU longut. 

The arteries i^ome from the digital and metatanaal branches; and the nerves 
from tliecutant-itii.'r digital, or from small twigs iif the nerve-s to the inten>s.se! muscle-S. 

The movements permitted are: flexion, extension, abduction, adduction, and 
circumduction. 

Flexion is more free than extension, and is limited by the extensor tendons and 
dorsal ligaments; extension is limited by the Hexor tendons, the plantar fibres of the 
latoral ligaments, and the sesamoid plaies. The lateral motion Is possible from the 
sliape of the Iwny siirfaccH. but is very liniitpd. Ijeing mttst marked in the great toe. 
U is limited by the lateral ligaments and sesamoid plates. 



9. THE INTERPHAL-WGEAL JOINTS 
Class. — Dutrihrosia. Subdivision.— Ci'nj^ymus. 

The articulations between (he fitst. and second and second and tliird phalanges 
of the toes are similar to those of the fingers, with this important difference, that 
the Iwjnes are smaller and the jtiint^. especially between the .leeund and thinl pha- 
langes, are often ankyloscd. The ligaments which unite them are:^ 

Two lateral. Dorsal. Glenoid ligament. 

The two lateral ligaments are well marke*!. and psiss on each side of the joints 
from a little nmgh depression on the head of the proximal, to a rough border on 
the aide of the base of the distal phalanx of the joint. 

The dorsal ligament is thin and membranous, and extends across the joint 
from one lateral ligament to the other beneath the extensor tendon, with the deep 
surface of whirh it Ls I'niinccted. and by which it is strengthened. 

Tlie glenoid ligament covers in the joint on the plantar surface. It is a fibro- 
cnrtilaginnus plate, connected at the sides with the lateral ligaments, and wilh the 
bones by short ligamentous fibres: the plantar .surface is smooth, and gn»o\cd for 
the flexor lendons. 

The arteries and aerves are derived from the corresponding digital branches. 

llie only movements |>enmitled at these joints are flexion and extension. 

At the interphaiangeal joint of the great toe there is very frequently a small 
sesamoid hone which plays on the plantar surface of the first phalanx, in the same 
way as the sesamoid bones of the metatarso-phalangeal joint play upon the plantar 
surface of the hend of the metatarsal l>one. 

Relations of the muscles acting on the metatarso-phalangeal and inter- 
phaiangeal joints of the foot. — If the student will refer to the accounts given of 



312 



THE ARTICULATIONS 



. 



the relations of the correepondinK joinLB in the hand and of the actions of the muscles 
ujwn those joinw, and if he contrasts und compares thft mu.«WTlp« of the hand with 
those of the foot, he will readily be able to construct tables of the relations of the 
niotatarbo-phalaniieAlaiidinterphaliingeal joiiilsof tlie foul, and tableful the muijclea 
acting upon the joiuttf. 

Morphology of l.igammlti 

Tbe vnriouM li||tnni«t)t« of the humao body ha\-c, in very many inslancn, been e\-olved u tlie 
r«fiuh »f Kouuiiclary changes in musrlt^ tKljarent to iojnt«. In a {»\v mstanc««, ligament* repre- 
sent llic (k'^ciiemle remnsatd or cartilaginouii and horn rlenients. Artinilar capsuliw are io 
moft jrnrils til-rived from the perio«toum, but tbcy oulj' be strengtlietiod by tbe iiieorporalioa ol 
teiidoaji d«lai.iit'd from uilj.-M-«nl ni(ii^<-le«. 

MiL'<('1w< arising fmiii, ur iu»ertoil iato, bouea in tbe inunedjate vicinity of a joint tend lo 
beixime iTiptwrnirpliosed into tendon near their attachments, and a comprehensive windy of 
inyologT iti low vertebrate fortn* iiidic«(e«i that there i* awfociated with thi« ti«sue-<-htiiige u 
t«nileiicy for the mtiH'te to alter tl« point uf attuc-hment; licnce a mUHcle originally inF^erted below 
H iotnl may ii\-e»toally come to have its iuM^rtion above the joint. Iti the «i»nie wny, ft muscle 
aruiing alwve a joint may, a^f a result of altered environniPiU. nlilft ilt^ urigiii to wjme |)oint below 
tbe joint. To tbici change of petition tbe tenn migration of muscles ha.*) bee.n npplied. In 
many inifanr-rw » portion of tlie miwcle eiiuivnieiit l« Ibe di.-ljiniv Iwlweeii the firi^iiinl and Un- 
aequirvd rittHL'hmfnt pen-ist^ ttn a tibrou'* band and fulfills the fiiiivtjon of a liKAnient. Tbi* » well 
!>ccn in the knee-joint, where the internal lateral ligament 18 derived from the adductor magnus. 
ibiis imiiti'le liikviiiK shifted its itinertion frxmi the lilmi to the fi'imir. In llie Hiiiiie wny th« extvrti.il 
lateral baiunent reprewnta the tendon of the peioaeus longus, nbich bu» migrated from ibo 
femur to the head of the fibula. 



Fig. 303. 





C D 

One of the most remarkable examples of a tendon divorced in this way is the ligamentum 
teres m the tiip-juinl. Thie curious structure was in all probabihty the tendon of llie pectineus, 
which has Imm'h detached from the miisele in oonaequence of the profound niterationsi whieh have 
taken place iii the limb durine itH evolution. 

(Vmon^ other Ugamente uenve<l in a similar way from mUErle-t miiy l>e mentioned the ftacro- 
lu)>eroii!i hgament. This was origimdly the tendon of oririn of the l)icep9 femoris. (H, Mon-u>, 
"A Note on Three Pointa in Anatoniv," Med. Times and tJa/elte, April 7, 1877, p. 301.) 'Hie 
saero-spinous iu derived from tlie fibroiui retrogre^iiiion of nortioUA of the coccygeus. llic 
aacro-corcygeti) ligiuncnta represent the muscles wliich lift, depress, and wiig tin? tail in llmse 
mammals fiimiKbed with mieh an appendage; indeed, the^e Ugaments are occasionally replaced 
by inuscle-titMUD. 

The cotaco-humcral ligament in deri^-ed from the original tendon of in-sertton of the pectoralis 
tDiDor,nndnot tmfreqiioDtly tbe muM-le in inserted into ihe leiMer tuberonily uf the IninieriL'', the 
ligament iH-inc then replaced by the lendonof iliemu^ele. Thecoraeo-clitvieidar. rlmitdKiid.aiid 
gWno-humer.ll li^rimentts are probably derived from modtticationa of the subclavius nimrle. 

Tbe itTtrbral colimm contnins M>veral tigamentoUH KtriictureH of great mo ri>l to logical hitereiit. 
The pulpy flub^tajicw in the centre of each inten'ertebral din? ii^ derived from tlie notoehord; ihe 
eutipcn-ooT},' lig;mient passing from the tip of the odontoid pnx-eitf) to the .interior margin of t)i« 
foramen mKgn'im i« n remniinl of the cneath of the notocnord. and indicatct it« potiltion as it 
pUMd from Ihe x-ertehml column into the base (rf the cnuii'im. The lmni*A*er»e ligament of the 
alloB (OA pointed out by i'rofAwor Clelnnd In 1S59 .'uid mf>l 1 in a pemi^lent and functionid fonn 
aS tlie posterior conjugal ligament uniting the rib-heiidH in wals and many other muiinnala. wlUUt 
tbe intercMPous ligament of ttte head of a rib in man ia the feelite repratrnlative of tht.-t ^intrtnrc 
in the Ihor.icio region of the spine. The lignmentum conjugale eo-itaruni wjm deAcrilie*) by M.iyer 
in IS34 (SfOller'n Arehiv fnr .\nntnmie;. .\roording to f.n>>chka'§ aceount vi tin" iiciuneni it 
would veein a^ tbuuiih tbe puvteriur .luperior fibrcti of the captmle of the eosto-eentnd jomt repre- 
MBted it in nuui, niihcr than the intcrosAeous ligament. 



MORPHOLOGY OF LIGAMENTS 313 

Many of the subcutaneous tracts of faecia and many aponeuroses in the human body are 
derived from the metamorphosis and retrogression of muscle-tissue. 

Development. — In the case of bones ossifying in membrane the articulation will be a suture, 
the ossifications from neighbouring centres extending until they practically come into contact. 

With cartilage bones the articulation may be either a syndesmosis, a synchondrosis, or a 
diarthrosis. The embryonic tissue in which the cartilage is to develop is at first continuous; 
centres of chondrification, corresponding in number to the bony elements which are destined to 
be formed, appearing in it. As the chondrifications approach each other a small portion of the 
primary embryonic tissue persists between them (fig. 303, A), and it is the subsequent fate of 
this intermediate tissue that determines the nature of the articulation, 

(1) When the ossification of the cartilage occurs to form the articulating bones, the inter- 
mediate tissue may undergo transformation mto cartilage (fig. 303, B), a synchondrosis being 
thus produced. (2) Or the intermediate tissue may be converted into fibrous connective-tissue 
(fig. 303, C),the result beit^ a syndeBinosis. (3) Or, finally, the central portion of the inter- 
mraiate tissue may degenerate, so that an articular cavity is produced, the peripheral portions 
being converted into connective tissue, forming a sleeve-like capsule surrounding the cavity, 
continuous at either extremity with the periosteum of the articulating bones (fig. 303, D), 
This is the articular capsule, and the connective-tissue cells arranging themselves in a layer upon 
its inner surface give rise to a synovial membrane. As the result of tliese processes a diarthrosis 
is produced, and from its mode of formation it is clear that the cavity of such an articulation is 
completely closed. The appearance which some diarthroses present of ligaments traversing 
the cavity, as in the cases of the ligamentum teres of the hip and the crucial ligaments of the 
knee, is fallacious; these ligaments are really outside the joint cavity, the articular capsule and 
synovial membrane being folded around them so aa to exclude them from the cavity. 



INDEX TO PART I 



Abduction, 209 
Abnormalities of sternum, 132 
Accessory band of lateral atlanto-axoidean 
joints, 217 

process, 26 

tarsal dements, 19o 
Accommodation curvatures, 32 
Acetabular foramen, 169 

notch, 169 
Acetabulum, 168 

Acromial (scapular) extremity of clavicle, 135 
Acromio-clavicular articulation, 249 

ligaments, 250 

movementa, 250 

relations, 250 
Acromion angle, 138 

J)rocess, 13S 
duction,'209 
Adductor tubercle of femur, 176 
Afi^ger nasi, 78 
Air-cells, mastoid, 60 
Abe, 48 
Alar folds, 291 

(lateral occipi to-odontoid or check) liga- 
ments, 218 

process of ethmoid, 72 
All-sphenoid centre, 55 
Alveolar canals. 77 
posterior, 77 

point, 100 

process of mandible, 86 
of maxilla, 79 
Anmiotic cavity. 4 
Ampulla of semicircular canals, 70 
Anapophysis, 26 

Anatomical neck of humerus, 140 
Anatomy, definition of, 1 
Angle, acromion, 138 

cranio-f arial , 104 

of lower jaw, 87 

of maxilla, 78 

of pubis, 168, 

of rib, anterior, 121 

sacro-vertebral , 171 

of scapula, 138 

of sternum. 128, 133 

subcostal, 133 

subscapular, 139 
Angles of occipital bone, 41 

of parietal bones, 45 
Angular motion of joints, 209 
^ process, external, 48 
internal, 48 
Aneulus Ludovici, 133 
Ankle-joint, 297 

arterial supply, 299 

ligaments, 297 

movements, 300 

muscles acting upon, 300 

nerve-supply, 299 

relations, 299 
Annular ligament, superior radio-ulnar joint, 

261 
Anterior alveolar canal, 77 



Anterior angle of rib, 121 

atlanto-axoidean ligament, 216 

atlanto-oceipital ligament, 213 

ctinoid process, 53 

condyloid foramen, 41 

costo-oentral ligament, 239 

cranial fossa, 105 

crest of tibia, 181 

crucial ligament, 287 

ethmoidal canals, 49 

gluteal line, 165 , 

mferior spine of ilium, 164 

lateral malleolar ligament, 296 

ligament, ankle-joint, 297 
of knee-joint, 287 
of symphysis pubis, 236 

longitudinal ligament of intervertebral artic- 
ulation, 223 

medio-carpal ligament, 269 

nasal aperture, 98 
spine, 77, 79, 103 

oblique (lateral occipito-atlantal) ligament, 
215 

radiate sterno-costal ligament, 243 

radio-carpal ligament, 265 

radio-ulnar ligament, 263 

region of skull, 98 

sacro-coccy|sal ligament, 234 

sacro-iliac hgnment, 231 

stcrno-clavicular ligament, 247 

superior spine of ilium, 164 

talo-calcaneal joint, 301 
arteriai supply, 302 
ligaments, 301 
movements, 301 
nerve-supply, 302 

talo-fibular filament. 298 

tibio-fibular ligament, 295 

tubercle of calcaneus, 191 
Antcro-inlemal talo-calcaneal ligament, 301 
Antero-posterior diameter of pdvic inlet, 171 
Anti-clinal vertebra, 23 
Antrum of Highmore, 77, 79 

mastoid, 60, 62, 67 

maxillary, 102 

tympanic, 62, 67 
Apertura pyriformis. 98, 102 
Aperture, anterior naaal, 98 

of pelvis, inferior, 171 
superior, 171 

superior thoracic, 133 
Apex of fibula. 185 

of patella. 180 
Apical odontoid (suspensory) ligament, 220 
Apophysis of femur, 179 

Appendicular elements (bones of visceral 
arches). 114 

elements of skull, 113 

set of bones, 13 

skeleton, 13. 133 
AcjuBeductus vestibuli, 61, 108 
Aqiieduct of Fallopius, 61 
Arch, costal. 133 

of vertebnp, 17 

pubic, 172 



315 



H^ 316 ^^V INDEX TO PAltr I ^^ 


^^M Arch. Eupt^rcilituy, 47 


ArtLCiiliirdisvof Ufuiporo-iuaudibuEiu- joint, 210 M 


^^m .\rchc4 ot utlA», 'M 


proccM of vertcbnr. IS ■ 


^^H bnuir-hial, 7. 9 


of nalfbra-, li)tainpn|jtcuiiii«cliiig, '.32!> ^^J 


^^H Ardioplasiii, 1 


aurfti(.«of tibia, 180 ^^H 


^^M Arrtiuio ligMiricni of Aymp1iy«s pubis, 237 


lubttn'lc of teitt]M>rn) bone, 5d ^^^| 


^^H Anil I>nii<r, 10 


.\rtirulN.ti<i4), anxMitio-claviculjir, 249, 250 ^^^| 


^^M Aruiruil "Ujjply t>( uriklv-iuinl, ^t) 
^^^^_ of ntbintn-iixuiiitvin joiut. 'ilS 


ankle, 297 ^^^| 


atlunio-nxoidiMkn, 2l.i ^^^| 


^^^^^k of cj«l(-ni)tM-criiljcii(l juint, 3t}7 


Atlud with iicdpur, 'J\lt ^^^M 


^^^^H of <-tiIcancu>, 191 


arlvrial !>U|i]ily. 215 ^^^| 
movcinviit^Hf. 2ir> ^^^H 


^^^^^1 of capiluliir }oiiiL. 2i)i 


^^^^^M nf ciu-|H)-]iit'l;u :ir[Mtl joint of thumb, 273 


muwiefi actiri); uixm, 215 ^^^| 
nerve-Mipjily, 215 ^^^H 


^^^^^1 of CariK>-niftHC:irniU^<>inl!>, 272 
^^^^^1 of coraco-rlavic-uLir )uint. 2.'>1 


colcaneo-caboid, .it)5 ^^^| 


^^^^^H of coHto-tnut.ivcf^ joiut, 241 


tofiUi-tTaiiftVi^rMi. 211 ^^^H 


^^^^^1 of elbou-joiot, '2^ 


cuboid-imvicular, 'J()3 ^^^M 


^^^H of fibula, ISb 


cubo-metu.Carsal, 309 ^^^| 


^^^^H of hip-juint, 2S2 


cuneo-cuboid, :{03 ^^^| 


^^^^^H of hunioruA, UO 


eJbon-. 25S ^^M 


^^^^H of inferior radio-ulnnr joint. 203 


^H 


^^^^^1 of interior tihio-lihiUnr joint , 'J97 


intercuneiform, 303 ^^H 


^^^^^H uf intpr['hon<irnl joints, '^4.'i 


int«roal tarso-me la tarsal, 308 ^^^| 


^^^^^1 of intLri'inivifonii joiiiU, liOA 
^^^^^M of intvrmct:icarpHl joiiilK. 274 


kneo, 'i&o ^^H 


medio-rnrpnl . 2tXi ^^H 


^^^^^1 of iiiU'nni.-tiit.'irsiil j'litil.*. lilO 


mediu-tarsiil. 30-1 ^^^| 


^^^^^1 of liilvrp]iiUai)g(.M] juiiitH, ntigiTM, 277 


mctarar|to-i>hulfUigciiJ. 276 ^^^| 
mid -radio- ulnar, 2fil ^^^H 


^^^H toc.t. Ull 


^^^^^H of Incltryniiil lioue, 75 


navirulari-ouncifonn, 303 ^^^| 


^^^^H of lower jttw. 67 


0€cipilu-axni4cHn, 218 ^^^| 


^^^^H <if malAr bone. 84 


radio-rarpa] . L1i4 ^^^| 


^^^^^1 cif iiittxilln. 


KUCTO-i:aH-l-^'|r(nil , 234 ^^^H 


^^^^H of inedtiMiurpnl joint. 271 


nhouUlcT. 2i>3 ^^H 


^^^^H of mr>lArnrpt>-ph.ilanKOAl jcants of fingers, 


t.iio-niivinilar, :(0*l ^^^H 


^^^H 


teiii|Hin.>-ii>iuiililiutar, 210 ^^^H 


^^^^1 27t} 


Cibjo-ribultir, 294 ^^M 


^^^^H of metal Afso-phalanjieal joints of toen, '41 1 


ulna, 15U ^^H 


^^^^^1 niis.ll lioiies, 71} 


ArticutatiunK. 207 ^^H 


^^^^H of occipiui-iiiUnlul joint. 21S 


of aiitorior part of t»rNU)>, 302 ^^H 


^^^^H of palalt^-bonp, Kt 


betwocn atlns and n\i.-<. 'Jl.S ^^^| 


^^^^^H of jietvir 'jLi'.i 


IwtwKeti nkull uiid Hpuiiii roll! tun, 213 ^^^H 


^^^^^ft of posleriur talt>-ciU«ui«:iI joint. 301 


uf lioditM of viTiebra*. 221 ^^^| 


^^^^^K of radiiri-nirptiL joinl. 2lyt\ 


of rnlran<^un, ^^^| 


^^^^^M of mxcru-coccy^iun] ji>in(. 233 


ofciipitalc (oMiiaKCium}boi>e, 15S ^^^| 


^^^^^1 of •ucro-vvricbral jmnt, 230 


carpal 26S ^^H 


^^^^H of Kht>u)d<<r-joiiit, 2.'>tt 
^^^^^1 of xphcnoid, Ti^ 


rarj-io-metararpai . 271 ^^H 
cciiu<tituantA o . 207 ^^^H 


^^^^H of xlenio-rostail joint. 243 


oott to- chondral, 243 ^^^H 


^^^^^B uf stertio-Ftiritu-elnviciilnJ' joint, 248 


at ouboiii. 105 ^^^| 


^^^^^1 of :tiipiTior mdiu-iilimr joint, 2<il 


of etbmoid, 74 ^^^H 


^^^^^1 of Hyni{>liy!iis [nibi'*, 2JS 


ofcKtcrnal cuneifonu bone. 104 ^^H 


^^^^^H of t.iitu^ or iinlrB(;»lLU, in;) 


of frontjil Imiie, 50 ^^^B 


^^^^H of tttr-'O' 011.-1 iirarvil joints, IMS 


at. front of tliomx. 242 1 


^^^^^H of t<'mjM>ral l!4 


of KTcator mullanguliir (trnwtium) boce, ^_H 


^^^^H of t^niporo-miuitlibular joint, 212 


^H 


^^^H oftiliin. 104 


of iinmale (unciform) honei, 158 ^^^| 


^^^^H of tilii' I- fibular juitil. 20,'> 


of iiilvrnal L'uiicifumi biine. 103 ^^^| 


^^^^H of vertebral jointt. 22^ 


intcrt'hondral . ^^^| 


^^^^^^ of vonirr, 


intifrmvlamrpid, 273 ^^^H 


^^F Artbrcdial dtmrlhron-}!. 200 


inl«-nnetatar»il . 31(1 ^^^^ 


^^H Articiilnr rApriiilc (arroniio-HAvicuIar joinl).2^ 


intorphaliin^al . 273,311 ^^^| 


^^H of arUculalton ot ntliis witli iKrdput, 214 


tntfrxlvrniil, 242 ^^^H 


^^^^^ of allaiK'XMlofitoi'i joint, 217 


of inrliryinal bone, 75 ^^H 
of leiwrr multnncilar (trapesoid) bone, 157 V 


^^^^K of cupituliiT joint. '2:t9 


^^^^H of rnrpo-metacarpitl joint of thumb, 273 


of lowrrlirnli, 277 ^^^H 


^^^^^B of ro'to-tmnxverse articulation. 241 


of tuiiatv bone-, 1 55 ^^^| 


^^^^H of tup-jojpit. 277 


of mnxillu.SI ^^^H 


^^^^^1 of knro joint. 'J87 


m«l.-ii-:ir|)(>-plia]an;tr>al. 274 ^^^H 


^^^^^H of Ul<-i-»l atl.-«nlo-axoiiJeao joints. 2tS 


mfta(iir~i>-|))iHlnnKi>Hl, 310 ^^^H 


^^^^^1 of sliouldLT -joint. '23A 


of niidfllf* cunrifnrm Ikihr. 104 ^^^H 


^^^^^M of 0t4>mo-poi<1o-claviru!iir joint. 247 
^^^^^1 of l«m[iorv>-mitoilibi]lar jomt, 210 


ofnaaal honr, 713 ^^^H 


of naWcularlKiiie, 155, 192 ^^^H 


^^^^H of libio-fibular joint . 205 


of ocnpitul bone, 44 ^^^f 


^^^^B of vftrlobml joinla, 22^ 


of p.ilate bone. tSi ^^^^H 


^^^^^ cartilafip', 2U7 


of parietal bones, 47 ^^^^H 


^^M of ahould«r- joint . 255 


of pclvifl, 23 1 ^^^^M 


^^M dine ''arromiti-dnvi (nil.tr jointV 250 


tit pelvL4 with f^inc, 220 ^^^^^H 

radio-ulnar. 200 ^^^^^^H 


^^H o/ inferior rtulio-ubcir joint. 2K3 


^^^^^ of ftvmo-coaio-ciuvicular ivuA, 'ii& 


of rib6 with vcrtobne, 33S ^^^^^H 



INDEX TO PART I 



317 



ArticulatioDS, ascro-vertebral, 229 

of ukull, 210 

of sphenoid, 55 

stemo-costal, 243 

of talus or astragalus, 188, 190 

tarsal, 300 

tarso-metataraa), 308 

of temporal bone, 64 

tibio-tibular, 295 

of triquetral (cuneiform) bone, 156 

of trunk, 220 

of typical metacarpal bone, 159 

of upper extremity, 246 

various kinds of, 208 

of zygomatic (malar) bone, 84 
A^terion, 91 
Asternal ribs, 121 
Astragalus, 187 
Atavistic epiphyses, 14 

Atlanto-axoidean uticulatioc, arterial supply, 
218 
ligaments, 215 
movements of, 218 
muscles acting upon, 218 
nerve-aupply, 218 

joint, central, 215 

joints, lateral, 215 
Atlanto-odontoid articular capsule, 217 

joint, 215 
Atlas, description of, 19 

and axis, joints between, 215 

development of, 34 

oblique ligament of, 214 

with occiput, articulation of, 213 
Attic, 67 
Auditory apparatus, measurements of, 71 

foramen, 119 

meatus, external, 64, 95 

meatus, internal, 60 
Auricular tissuro, 63, 95 

point, 91 

surface of ilium, 170 
Axial set of bones, 13 

skeleton, 13, 16 
Axis, b&fli-bregmatic, 104 

baei-cranial, 104 

basi-facial, 104 

of pelvis, 172 

of scapula, morphological, 139 
Axis, description of, 20 

development of, 34 



Bands of capsular ligament of hip-joint, 207 
Bars, hyoid, 113 

nmnoibular, 113 

metamorphasis of branchial or visceral, 113 

thyreoid, 113 
Base of tirst metatarsa) bono, 196 

of metatarsal bone, 196 

of scapula, 137 

of second row of phalanges, 199 

of skull. 94 

of typical metacarpal bone, 159 
Basi-bregniatic axis, 104 
Basi-cranial axis, 104 
Basi-facial axis 104 

Basilar bones developed in cartilaginous crani- 
um, 113 
Basion, 95, 104 
Basi- pharyngeal canal, 51, 56 
Basi-sphenoid centre, 55 
Bertin, bones of, 56 
Bicipital groove, 141, 144 

hollow of ulna, 151 

rib, 127 



Bicuspid t«eth, 110 

Birth, peculiarity of bones at, 116 

skull at, 114 
Bodies, Pacchionian, 45, 49 

of vertebne, 23, 221 
Body cavity, 6 

of astragalus, 188 

of axis, 20 

of capitate bone, 157 

of femur, 173 

of hyoid, 89 

of ischium, 167 

of lumbar vertebne, 24 

of pubis, 167 

of radius, 147 

of rib, 121 

of scapula, 136 

of sternum, 128 

of typical metacarpal bone, 150 

of ulna, 151 

of vertebne, 16, 18 
Bone, breast, 127 

calcaneus, 190 

capitate, or os magnum, 157 

collar (clavicle), 133 

coxal (OS innominatimi)i 164 

cuboid, 194 

etiuiioid, 71 

external cuneiform, 194 

femur, 172 

fibula, 185 

fifth metacarpal, 162 

fifth metatarsal, 198 

first metacarpal, 159 

first metatarsal, 196 

fourth metacarpal, 162 

fourth metatarsal, 197 

frontal, 47 

greater multangular (trapezium), 156 

hamate. 138 

humerus, 140 

hyoid, 89 

inca, 45 

inferior turbinate, 74 

interparietal, 39 

lachrymal, 75 

lesser multangular (trapezoid), 157 

lower jaw, 85 

lunate (semilunar), 155 

malar. 83 

maxilla, 77 

navicular (scaphoid), 155, 191 

occipital. 39 

patella, 170 

pisiform, 1 56 

pre-interparietal, 45 

scapular, 135 

second metacarpal, 160 

second metatarsal, 197 

shin, 180 

sphenoid. 50 

styloid, 163 

suprasternal, 248 

talus or astragalus, 187 

temporal. 57 

thigh, 172 

third metacarpal, 161 

third metatarsal, 197 

tibia. 180 

triquetral (cuneiform), 156 

ulna, l.")0 

vomer. 75 

Wormian. 45 

zygomatic, S3 
Bones, appendicular set, 13 

axial set of, 13 

basilar, developed in cartilaginous cranium, 
113 



318 



INDEX TO PART I 



Bones of Bertin, 56 

carpal, 153 > 

compound, 14 

of cranium, 39 

cuneiform, 192 

development of, 14 

epipteric, 57 

of face, 39 

of foot as a whole, 202 

of forearm, 146 

of limbs, homology of, 202 

of lower extremity, 164 

metacarpal, 159 

metatarsal, 196 

nasal, 76 

of nasal region, origin of, 113 

nuclei of, 14 

of orbit, 100 

palate, 81 

parietal, 45 

peculiarity of, at birth, 116 

phalangeal, 162, 199 

roof, developed in membranous cranium, 113 

sesamoid, 164,202 

of skull, 39 

of skull at birth, 116 

sphenoidal turbinate, 5d 

spongy, of nose, 73 

supra-sternal, 130 

surfaces of, 16 

tarsal, IS6 

of thorax, 120 

turbinate, 52, 72 

of tympanum, 68 

of upper extremity, 133 

varieties, 16 

Wormian, 50 
Borders, bony, 16 

of clavicle, 134 

of abula, 185 

of frontal bone, 49 

of humerus, 142 

of hyoid bone, 89 

of ilmra, 164 

of ischium, 167 

of lachrymal bone, 75 

of nasal bones, 76 

of parietal bones, 45 

of patella, 180 

of pubis, 16S 

of radius, 147 

of sphenoid, 54 

supra-orbital, 48 

of temporal bone, 61, 62 

of tibia, 181 

of typical metatarsal bone, 196 

of ulna, 151 

of vomer, 75 
Brachvcephalic skull, 109 
Brancnial arches, 7, 9 

bars, metamorphosis of, 113 

grooves, 7 
Branchiomere. 8 ^ 

Branch iomerism, 7 
Breast bone, 127 
Bregma, 91, 104 
Brim of pelvis, 170 
Buccal surface of teeth, 109 
Bulla ctbmoidalis, 102 



Calcaneal pillar, 202 

oH.sification of. 191 
Calcanco- cuboid articulation, 305 
liffameiUs, 306 
Calcanco-Gbular ligaiaent, 299 



Calcaneo-navicular ligament, external, 301 
Calcaneo-scaphoid ligament, superior, 301 
Calcaneus (os calcis), description of, 190 
Calcar femorale, 179 
Calcification of bones, 14 
Canal, 16 

basi-pharyngeal, 51, 56 
carotid, 62, 95 
external semicircular, 67 
facial, 61, 66, 68 
Fallopian, 66, 68 
Huguier,63,67,95 
incisive, 102 
infra-orbital, 77, 93, 120 
mandibular (inferior dental), 86, 120 
pharyngeal, 54, 93 
posterior palatine, 78, 82, 120 
pterygoid (Vidian), 54,93,95 
pterygo-palatine, 82, 93 
sacral, 29 
Canoliculi, carotico-tympanic, 62 
Canaliculus cochleae (ductus perilymphattcus), 
62,71,95 
innominatus, 53 
mastoid, 62 
tympanic, 62 
Canalis musculo-tubarius, 66, 9S 
Canals, alveolar, 77 
ethmoidal, 49, 73, 101, 120 
gubemacular, 94 
palatine, 82, 93 
posterior alveolar, 77 
semicircular, 70 
zygom at i co-facial, 120 
zygomati co-orbital, 84 
Cancellated tissue of femur, 179 
Canine fossa, 77 

teeth, 110 
Capitate (os magnum) bone, 157 
Capitular (cotito-central) articulation, 239 
arterial supply, 240 
movements, 240 
ner\'e-8upply, 240 
Capitulum of humerus, 144 
Capsular ligament of elbow-joints, 258 
Capsule, articular, of capitular articulation, 239 
carpo-metacarpal joint of thumb, 273 
of cost o-t ran s verse articulation, 241 
of hip-joint, 277 
of interchondral joints, 245 
of knee-joint, 287 
of shoulder- joint, 253 
of tibio-fibular joint, 295 
of vertebral joints, 225 
periotic, 58. 112 
Carotico-clinoid foramen, 53 
Carotico-tympanic canaliculi, 62 
Carotid canal, 62, 95 
groove, 52 
ridge. 62 
tubercle, 19 
Carpal bones, ossification, 158 
union of first row of, 268 
second row, 268 
joints. 268 
Carpo-metacarpal joints, 271 
four inner. 271 
of thumb, 273 

arterial supply. 273 
movements, 273 
mu.scles acting upon, 273 
ncr^'e- supply, 273 
relations, 273 
Carpus, description of, 153 
Cartilage, 207 

articular, of shoulder- joint, 255 
epiphyseal, 14 
Meckel's, 87 



INDEX TO PART I 



319 



C&rtilage, parachordal, 112 

periotic. 112 

sphenotic, 113 

varieties, 207 
Cartilages, costal, 124 

Cartilaginous cranium, basilar bone developed 
m, 113 
remnants of. 1 Id 

plate (pelvic joints), ear-sbaped, 232 
Cavernous groove, 52 
Cavity, amniotic, 4 

body, 6 

floor of cranial, 105 

lesser sigmoid, 151 

medullary, 16 

pleuro-peritoneal. 6 

of radius, sigmoid, 149 

of scapula, glenoid, 138 

tympanic, 67 

of ulna, greater sigmoid, 150 
Cell mass, inner, 4 
intermediate, 6 
Cells, 3 

ethmoid, 72, 74, 102 

mastoid, 60 

posterior ethmoidal, 102 
Central atlanto-axoidean joint, 215 

portion of intervertebral Sbro-cartilages, 222 
Centres of ossification of scapula, 139 
Centrosomes, 4 
Centrum of vertebrae, 16 
Cephalic index. 109 
Cervical ligament, 227 

rib, 22 

ossification of, 126 

tubercle of femur. 173 

vertebrae, description of, 18 
development, 35 
peculiar, 19 
Cervico-basilar ligament, 21S 
Characters of foetal skull, 1 14 

of a typical rib, 121 
Chassaignac's tubercle, 19 
Choanie. 103 

(posterior nares), 94 
Chondral stage of skull development, 112 
Chondro-cranium , 112 
Chorda obliqua, 261 
Chromatin, 4 
Chromosomes, 4 
Cingulum of incisor teeth, 100 
Circumduction, 209 
Circumferential cartilage. 207 
Classification of joints, 208 
Clavicle. 133 

ossification of . 135 

structure of, 135 
Cleft, middle car, 67 
Clinoid process, anterior, 53 
middle, .'>3 
posterior, 51 
Cliviia, 51 
Coccygeal cornua, 29 , 

vertebne, 29 

development of. 36 
Coccygeus, attachments uf, 27 
Coccyx, 29 
CocUea, 70 
Collar-bone. 133 
Column, vertebral, 16. 30 
Compensation curA-atures, 32 
Compound bones. 14 
Conchse, nasal. 72, 73, 74 

sphenoidal, 52. 56 
Conchal (inferior turbinate) crest, 77, 82 
Condylar foramen, 42 

fossa, 42 

process of lon-er jaw, 87 



Condylar tubercle of lower jaw, 87 
Condylarthroses, 209 
Condyle, 16 
of femur, 177 
of lower jaw, 87 
Condyles of occipital bone, 41 
third occipital, 43 
of tibia, 180 
Condyloid foramen, anterior, 41 
Conjugate diameter of pelvic inlet, 171 
Connecting Qbro-cartilage, 207 
Conoid tubercle, 135 
Constituents of articulations, 207 
Coraco-acromial ligament, 252 
Coraco-clavicular articulation, 2fi0 
arterial supply, 250 
ligaments, 250 
movements, 250 
muscles, 250 
nerve-supply, 250 
Coraco-humeral ligament, 264 
Coracoid ligament, 252 
process of scapula, 139 
(conoid) tubercle, 135 
Comua of hyoid bone, 89 
Coronal suture, 45, 91 
Coronary ligament of knee-joint, 289 
Coronoid foHsa of humerus, 144 
process of lower jaw, 87 
of ulna, 150, 151 
Costal arch, 133 
cartilages. 124 
grooves, 121 
processes, 25 

tuberosity of clavicle, 134 
Cos to-central ligament, anterior, 239 
CoKto-chondrnl joints, 243 
Cos to- clavicular ligament, 248 
Costo-transverse articulation, 241 
arterial supply, 241 
ligaments, 241 
movements, 241 
nerve-supply, 241 
Costo-transverse foramen, 18, 21, 121 
ligament, middle, 241 
posterior, 241 
superior, 241 
Costo-vertebral articulations, 238 
ligaments of, 239 
groove. l.'iS 
Costo- xiphoid ligament, 243 
Cotyloid bone, 169 

fibro-cartilage, 281 
Coxal bone (os innominatum), 164 

os.sifiration, 170 
Cranial cavity, floor of, 105 
fossa, anterior, 105 
middle, 105 
posterior. 108 
Cranio-facial angle, 104 
Cranium, 39 

measurements of, 109 
membrjuious, 112 
remnants of cartilaginous, 119 
Crest, 16 

conchal. 77. 82 
ethmoidal, 82 
frontal, 48 
uf ilium. 164. 165 
inferior turbinate, 82 
intertrochanteric. 173 
lachrymal, 75, 101 
nasal , 79 
obturator, 168 
of pubis. 168 
of scapula. 138 
sphenoidal, 51 
superior turbinate, 82 



^t 320 ^^^F / ^^^^^^^^H 


^^1 CiVKt of tibi«, anterior, 181 


Develupmenl of vonmr. 73 ^^^^^| 


^^H tranKve-rf«, Qi 


of sygotnatic (malnr) bone. 85 ^^^| 


^^H Orilirirurm plate of ethmoid, 71 


Diiunrler of |mJ vk- inlri ,171 . ^^^| 


^^M Crulu CMpituli. i2l 


DiapliniKin tuid lieuri . rcvcstiou of, 10 ^^H 


^^M Criflta rolli irifnrior. 121 


DiApby.iirt, 14 ^^^H 


^^^^^H Mi]icri<>r, 121 


DinpopbyaeM, 39 ^^^H 


^^^^B 


Diartbmww. 208 ^^M 


^^^^^r v(usiit)LLli, 70 


heteroniorpbie. 2fKI ^^^| 


^V Cmwn »f T.(»?lh, 109 


^^1 Cronn^, rclatioa of upper and lower teeth. 111 


DitTerencc i» peLvea aecordin); to wx, 172 1 


^^M Criirial liK»niRnl of atlajito-udontoid joinl, 217 


DilTerencftt in eitemum arrording to aex. 130 I 


^^B f>f knetvjoint. 2ii7 


Digastric foasa, tjO, S.^ M 


^^H of occipit^o-axMl joint, 218 


iJi|{e«tiv« tract, development of. 9 ^^^B 


^^M Cubdid. duucrip'tioii of. 194 


Digital foma of femur. 173 ^^H 


^^M CiibnidCD-iuiviruIar ligtuoonU. 303 


of fibuln, ISfi ^^H 


^^H Uiiiri[t, !t03 


Disc, articular {acroiTita-rlavicular joint), SSO 1 


^^M Cuboid'QHse'CoiidHnucii, 105 


sterno-cu6lo-c]ai'icu]iir joint, 24ii M 


^^M Outio-metatursal joint . 309 


Doliciiopellic fielviA, 172 1 


^^H Cuneiform bone, l.JO, Itl'J 


iJoliocepbalic. 109 ^^J 


^^M exiVTiial. 194 


Duriiai colcaueo-euboid lifnimc'iil . 306 ^^H 


^^H second or middle, 193 


cuboideo-navirulur ligament. MA ^^^H 


^^H Cuneo-4:iibc>i<l urtiniiiition, 3<)3 


Cubo-met.tt^irMil ligtmicnt. IMM ^^^H 


^^H Curvatures of the upinui culuniii, uormal, 30 


cuni'u-eubuid Iii:uiui''iit.303 ^^^H 


^^M C;^opin.sm, -( 


intercuneiform li^imontK. 303 ^^^| 




tigametitx. fin-t row of nirfxtl Imjiics, 268 ^^^| 




iiitermi;liii'ar{Pitl juini«, 274 ^^^M 


^^V 


intermctiitnr^hl jointn. 310 ^^^| 


interpbulaiiKi'id joiiitu of tocK, 31 1 1H^| 


^^^^ Deciduous (toUk) Iwl h, 1 1 1 


mt>tacur|Mi-|>baluneeitl ioini-N of finseix. 274 V 


^^M r imc of eruption .111 


meWtArfto-phftlnnpcal joinli* of toc-'«. 310 1 


^^1 IWii '<n(!rO'-corcyK>'-il t-*i>P>'-'>-<XMiiual) ligament, 


■iiiddit! lar!vt>-inclMlHrsnl joint, 308 ■ 


Sd'ond MMV of (urpjd bunoii. '2GS m 


^^1 D<-lr<>id lintomnl Intcml] ligament of aiikle- 


naviPulAri-rimnform lifnnient, 303 ^^^| 
(|XMlerior> iiifdio-ritrF-^t liK^uiient. 270 ^^^| 


^H iiiiiit.2^ 

^^M tubvrclc of clfurivle, 13.^ 


radio-carptil UKaiiient, 205 ^^^H 


^^M DRntJtl rnnal. inferior, 120 


vertebra-. desTriptioa of. 23 ^^^| 


^^H U^ntnry enntre, S7 


Dorauni epbippii. 21 ^^^t 


^^H IJeiitiilc .4uturct>, I'OK 


of ilium. 10-5 ^^^M 


^^H Devi^opmont of ralraneue. 191 


wUk, ^^^H 


^^^^^B of carpal bonca. lo8 


Duct, lachrymo-naflol, 102 ^^^H 

Ductus perUymphaticuc, 71 . 05 ^^^| 


^^^^B of da vide, 13A 


^^^^H of roxal bone, 170 


^^^H 


^^^^^H of cuboid. 195 


^^^H 


^^^^H of cuneiform boncn, t9U, 194, Ida 


^H 


^^^^H of ethmoid. 71 


^^^^^H femur. 17U 


Ear-bonei nt birth. 117 ^^^| 


^^^H fibulu. 


Kar. miildle. ftfi ■ 


^^^^H of lirKt. or inierool. cuneiform bono, 103 


Kiu--shu[%d curiilaiiiuous plate (pelvic loitiu), 1 


^^^^H bune. 51) 


-212 ■ 


^^^^^H 


Rctndfrrm, .'i H 


^^^H byui'l. 90 


Elbow-jnini, 258 ^^^^ 
urtenal siippLy. 2S0 ^^^M 
liguiii(?nt!)u , 2,!>S ^^^^ 


^^^^^M of inferior turhin&te, 76 


^^^^^1 


^^^^H of Ithctiryrnnl bone, 75 


movement^) of, 200 ^^^| 


^^^^^M ItinKi. 202 


miucles aetinf; upon, 2f}n ^^^H 


^^^^^H of mnndiUlo iluiver jaw). S7 


oerve-«upp1y nf, 2o9 ^^^^^H 


^^^^H mikxilla. 


relation.^ 2.'>9 ^^^^^| 


^^^^H of i»crar-urpua. 1G.3 


Hlemenl^t, ac«^s.<ory tarsal, 195 ^^^^^H 


^^^^H melatunats, 199 


bUeventb rib. 124 ^^H 


^^^^^1 of nuiiol bonea. 77 


tbomcic vcrtebni. 23 ^^^H 


^^^^H of occipital, 44 


Blliplieal retyvfw ifovea hcmiclliptjca), 70 V 
Rmbryolngj', 1.3 ^^^B 


^^^^^H of palsie Imne, S3 


^^^^H of piuietiil lN>ra>s, 47 


Eminonec. froiiUil. 47, 08 ^^^| 


^^^H of patella. IMU 


ilio- pectineal. 165 ^^^| 


^^^^^M of phidHtige" , 16D, 201 


na>al,47 ^^^H 


^^^^^1 rndiui^. loO 


pariclal, ^^^H 


^^^^H xrapiilii. 139 


{nTamidal of lem mral bone. 66 ^^^^H 
of tibia, inlc-miiiuyloid. IKO ^^^^^H 


^^^H 


^^^^^1 i<t.>luri"jid. it5 


Eniinentin amiatii, 02 ^^^^H 


^^^^^M of rtjilienoidnl concKiK, 58 


ll^nrtlirodtiil diiirtliroMej. 209 ^^^^^| 


^^^^^1 of AterriuiM, 


Kudoderm, a ^^^^^^ 


^^^^H of taluH.nr a^truxidus. IBO 


ICndofinat hion centre, 81 ^^^^ 


^^^^^1 of temporal bone. 64 


Kndoadceleton. 13 ■ 


^^^H 


Kn-ufarm process (mclHKtemum), 127. 130 H 


^^^^P of iTinpaDum. G9 
^^^^"^ of ulna, I.S:i 


r%phipptal diarthroffev, 'J()!l M 


Kpteuiidylesof humpruM. 144 ^^J 


^^V of vertohra^. 33 


i'ipiotic nucleus of temporal bone, 06 ^^^| 


^^^^^ of viscera, 9 


IClNphyoeiil cnrtilnge*, 14 ^^^H 



INDEX TO PART I 



321 



Epiphyseal lines, 14 
Epiphyiies, unossified (ribs), 124 

varieties, 14 
Epiphysis, 14 
Epipteric bones. 57 
Epistropheus, description of, 20 
Epitrochlea, 144 
Epitympanie recess, 67 
Erector splnae, attachment, 28 
Eruption of teeth, times of, lU 
Ethmoid, articulation of, 74 

at birth, 118 

description of, 71 

ossification of, 74 
Ethmoidal canals, 49, 73, 101, 1^ 

cells. 72. 102 

(superior turbinate) crest, 82 

notch, 49 

process. 75 

spine, 51 
Etnmo-vomerine region of skull, 112 
Eustacliian tube, 62 
Exoraiathion centre, 81 
£x<»keleton, 13 

Expiration, muscles which effect, 246 
Extension, 200 
External angular process, 48 

auditory meatus. 64, 95 

calcaneo-navicular (superior calcaneo- 
scaphoid) ligament, 301. 304 

cubo-metatarsal ligament, 309 

cuneiform bone, 194 

lateral ligament of ankle-joint, 298 
of knee-joint, 286 

ligaments of knee-joint, 285 

malleolus, 186 

meniscus (knee-joint), 289 

pterygoid plate, 54 

semicircular canal, 67, 70 

supracondylar ridge, 142 

t^o-calcaneal ligament, 300 
Extremities of clavicle, 135 

of femur, 173 

of fibula, 185 

of humerus, 140 

of tibia, 180 

of typical metacarpal bone, 159 

of typical metatarsal bone, 196 
Extremity, bones of lower, 164 
of upper, 133 

lower, of ulna, 152 

upper, of radius, 146, 149 
of ulna, 150 



Face, bones of, 39 

Facets of fifth metacarpal bone. 162 

of fifth metatarsal bone, 198 

first metacarpal, l.')9 

first metatarsal, 196 

of fourth metacarpal bone, 162 
metatarsal bone, 198 

second metacarpal, 160 

of second metatarsal bone, 197 

third metacari>al, 161 

of third metatarsal bone. 197 
Facial bones, origin of, 1 14 

(Fallopian) cantd, fil , 06. 68 
Falciform process of great sacro-sciatic liga- 
ment, 232 
Fallopian canal, 61 . 66, 68 
Fallopius, aqueduct of, 61 
False peUis, 170 

ribs, 121 

aynehondrases, 209 

vertebriE, 16 
21 



Fascia. Sibson's, 123 
Femur, description of, 172 

ossification of, 179 

structure of, 179 
Fenestra cochleff , 62, 66 

vestibuli. 62, 66 
Fibro-cartilage, cotyloid, 281 ^ 

interpubic, 237 

intervertebral, 221 

semilunar, 288 

triangular, 263 
Fibrous cartilage, white, 207 

expansion of extensor tendons, knee-joint, 
285 

ring of int«r vertebral fibro-cartilages, 221 
Fibula, description of, 185 

ossification of, 186 
Fibular (external) lateral ligament, 2S6 
Fifth metacarpal bone, 162 

metatarsal bone, 198 
First cervical vertebra, 19 

cuneiform iKtne, 193 

metacarpal bone, 159 

metatarsal bone, 196 

phalanx, 162, 201 

rib. 123 

row of carpal bones, union of, 268 
of phalanges, 199 

thoracic rib, 127 

thoracic vertebra, description, 23 
Fissure, auricular, 63, 95 

Glaserian, 59, 66 

inferior orbital (spheno-maxillory), 92, 101, 
120 

jjetro-tympanic, 59, 66, 95, 120 

ptery go- maxillary, 93 

pferj'go- palatine, 93 

sphenoidal. 53. 100. 119 

spheno-maxillary, 92 

superior orbital (sphenoidal), 53, 100, 119 

tympaiio-mastoid, 60, 63, 95 
Fixed vertebrse, 16 
Flat bones, 16 

Flattened portion of clavicle, 134 
Flexion. 209 
Floating ribs, 121 
Floccular fossa, 61 
Floor of cranial cavity, 105 
Foetal skull, general characteristics, 114 
Folds, alar, 291 

patellar, 290 
Fontunelle. sagittal, 47 
Foramen, 16 

acetabular, 169 

auditory, 119 

ca-cum, 48 
of ethmoid. 72 

carotico-clinoid. .'>3 

cent rale cochleare. 61 

condylar, 42 

cast o-trans verse, 121 

Husclikc,63 

hyi»oglosNJiI, 41,95, 119 

infra-orbit ul, 77 

jugular. 63, 95. 119 

lacenim, 51. 62, 95 

magnum. 39. 43, 95, 1 19 

mandibular (inferior dental), 86 

ma.stoid, 60,95 

mental. S5 

obturator (thyreoid), 169 

optic, 51. 5:i, 101, 119 

ovule, *J, 119 

I)arietal.45 

I)etro-.'iphenoidal, 119 

pharyngeal, 120 

posterior condyloid. 42 

rotundum. 53. 93. 119 



322 



INDEX TO PART I 



Foramen, scapular, 137 

tsiiigulurf. m 

±<!>heiio-ij:hlHtijie, 82, 93, 102, 120 

tpinosuni, 5^] 

sternal, 128 

stylo-mRHtoid, fi:2, 95, 120 

Bupru-orbil39,-l6 

supra trochlear, 144 

triifeiiiijiiil. 119 

verWliniJ. IB 

Vesalii, 53 

ayRoinalico-l^mpotaJ, 120 
Foi^raiitft. anterior cniidyloid, 41 
cranial fossa, 105 

for facial nen-e, 120 

^^rejilcr jjjtlaline, S4 

of humoni.'i, !4ti 

lesMcr jMJfitiiiP, 94 

middle mlutiiie, 94 

of miiiJle LTiinial fossa, 106 

of norma facialis, 99 

fii postcnnr cruiiijil fossa, 108 

Scarpa's. 7^.9-4, 20 

of skull, norve 1 U 

of Stensoii,79,94 
Fossa, 16 

anlcrior crunia.1, 105 

canine, 77 

condylar, 42, 95 

digastric, 60, 85 

digital, of Sbuta, 186 

of femur, intercondylar, 177 

floccular, 61 

glenoid, 16 

of humerus, coronoid, 144 
olecranon, 144 
radial, 144 

hypoglossal, 51 

iliac, 166. 170 

incisive. 77, 79 

incisor, 85 

infraspinous, 136 

i£ifr»teniporal,92 

i'liguhtr, fi'2, 95 
3L-hryinnH9.I00 

mojiaihijlnr, 93 

CLiastoid, 60 

middle craniiil. 105 

posterior cntniwl, 108 

pterygoid. 54, 95 

pcerj-gfi'palalifte (spheno-maxillary), 93 

scaphoid. 4>t. cVI. !)5 

apheno-mfixil]ary,93 

subarcuata, 61 

siibscfLputiir. 136 

suprjii^V'iiiona, lliC 

temporal, 91 

trochanteric, 173 

trooliiear, 49 

vermiform, 41, 108 

zygomatic, 92 
Fow>B>.nu.s;,l,9n, 101.102 
Ffi>!ill^l rni"!il[?ttri.-., 61 

petrosa, 62 

vestibularis, 61 
Four inner carfxvicielacarpnl joints, 271 
Fdur inner GngenB, iJK'iacarpo-phalangeal 
joint a. 274 

outer toes raetfltar,KO-pliaIangeal joints, 310 
Fonrlli nieJararpal bone, 162 

nielalarsallioiM? 197 
Fovea oE femUr, 173 

fipinicl]i|itit'ii,61. 70 

henii'^plupni'u.fil. 70 

FtiDnl;ill>(.rl[;iI Inrtli. 118 

description of, 47 

ossifir.ition of, 50 

crvst. -is 



Frontal eminences, 47, 98 

notch. 48 

I)rocess of maxilla, 78 

sinus, 47, 49 

spine, 48 

suture, 47 
Fronto-ethmoidal cells, 74 
Fronto-nasal plate, 113 
Fronto-sphenoidal i»-oce86, 84 
Furrow, 16 



Ganglion, location of Gassetian, 61 

of hi.>niilun;ir, 61 
GaKtuTinn ganglion, location of, 61 
General niorphogeny, 3 
rn-niiil (iiben'les, 8,5 
Germinal layers, 4 
Ginzlymi diarthroses, 209 
Girdle, pelvic, 203 

shoulder, 203 
Glabella, 47, 91, 99 
Gladiolus (mesostemum), 127, 128 
Glaserian fissure, 66 
f;ieno-iiurT!t'nil ligament, 253 
Glenoid cavity of scapula, 138 

fossa, 16 

ligament, 255 

of iiiterplialan^al joints;, fjngers, 276 

of loew, 311 
of HLetacarpo-phulangr-nl joints, 274 

lip (colyloiil libro-cartilugct, 281 
Gliding 111'ifiiiTi of joint.s, '^iXi 
Gluteal line, antenor, 165 
inferior, 166, 170 
post prior, 165 

tulwroeily of femur, 173 
Gluteus muxiniuf!, attachment of, 28 
Coniphosia suture, 208 
Gonion, 104 
Great eacro-sciatic hcament, 233 

[tcapuliir notch, 13/ 

itciutic Olio-sciatic) noteh, 165 

toe, inctatuniO'ptialangcal joint of, 311 

1 rtichantcr of femur. 173 
Greater multungiilar (trapezium) bone, 156 

puliitint' fonmiina, 94 

wigtnoiJ ctivity of ulna, l,W 

lulit'rnsify of humerus, 140 
(Jnioyi' of atlas, 20 

basilar, 43 

bony, 16 

carotid, 52 

cavernous, 52 

costal, 121 

eosr.t>-\i'delir,'il, 133 

of cuboid, peroneal, 19S 

of femur, 178 

for radial nerve. 142 

inrrn-yrbitat, 77 

tntt-rtulwrcular (l>icipita]), 141, 144 

lachrymal, 77, 101 

medullary, 5 

tnu^culo-ppinil, 142 

mylo-hyi>iii, SO 

(iljl.uratnr. 167 

occipital, 60 

optic, 51 

sigmoid, 60 

vertebral, 32 
Grooves, branchial, 7 
Gubcmaeular canals, 94 



Hamate (unciform) bone, 158 
Hamular process, 54 



INDEX TO PART I 



323 



Hamulus, 70 
Honnonic sutures, 20S 
Head of axis, 20 

of bone, 16 

of c&pitate bone, 157 

of femur, 173 

of &bul&, 185 

of fifth metacarpal bone, 162 

of fifth metatarsal bone, 199 

of firat metacarpal bone, 160 

of first metatarsal bone, 107 

of humerus, 140 

of radius, 146 

of rib, 121 

of scapula, 138 

of talus or astragalus, 189 

of tibia, ISO 

of typical metacarpal bone, 150 

of typical metatarsal bone, 196 

of ulna, 152 
Heart, development of, 10 
HeUcotrema, 71 
Heteromorphic diarthroses, 209 
Hiatus canalis facialis, 62 

sacralis, 28, 29 
Highest nuchal line, 40 
Highmorc, antrum of, 77 
Hip-joint, 277 

arterial supply, 282 

ligaments, 277 

movements, 283 

muscles acting upon, 284 

nerve-supply, 282 

telatioQs, 282 
Histolog}-, definition of, 1 
Homologioal comparison of bones of arm and 
thigh, 203 
of forearm and leg, 203 
of hand and foot, 203 
of limbs, 202 . 

of pelvic and shoulder girdles, 203 r 

Homomorphic diarthroses, 209 ' 

Huguier, canal of, 63, 67, 95 j 

Humeral ligament, transverse, 255 j 

Humerus, arterial supply, 146 

description of, 140 i 

ossification of, 146 

tuberosities of, 141 
Huschke, foramen of, 63 
Hyaline cartilage, 207 
Hyoidbars, 113 

at birth, 118 

bone, description of, 89 
ossification of, 90 

tubercle, 89 
Hypoglossal foramen, 41, 95, 108, 119 
Hypomalar, 85 

Hypophyseal fossa (sella turcica), 51 
Hypotympanic recess, 67 



Iliac fossa, 166, 170 
Iliacus, attachment of, 28 
Ilio-femoral band, 278 
Ilio-lumbar ligament, 229 
Ilio-pectiaeal line, 167, 170 
Ilio-sciatic notch, 165 
Ilio-trochanteric band, 280 
Ilium, description of, ltV4 

tuberosity of, 167 
Immovable joints, 208 
Inca bone, 45 
Incisive canal, 102 

fossa, 77, 79 

sutures, 94 
Incisor crest, 79 

fossa, 85 



Incisor teeth, 109 
Incisura, 16 
Incus, 69 
Index, cephalic, 109 

pelvic, 172 
Individual bones at birth, peculiarity of, 116 
Inferior aperture of pelvis, 171 
or arcuate ligament of symphysia pubis, 

237 
articular procesees of axis, 21 
conchse at birth, 118 
dental canal, 86, 120 

foramen, 86 
extremity of femur, 177 
gluteal hne, 166, 170 
mterosseous ligament, inferior tibio-fibular 

joint, 296 
interstemal articulation, 242 
meatus of nose, 102 
nasal conchse, 74 
nuchal line, 40 

orbital (spheno-maxilUry) fisBure, 92, 100, 120 
radio-ulnar joint, 262 
arterial supply, 263 
ligaments, 262 
nerve-supply, 263 
relations, 263 
region of skull, 94 
sacro-iliac lisainent, 232 
stemo-costaT ligament, 243 
temporal ridge, 48 
tibio-fibular joint, 296 
arterial supply, 297 
ligaments, 29/ 
movements, 297 
nerve-supply, 297 
relations, 297 
transverse ligament, 252 
turbinate bone, 74 
articulations, 75 
ossification, 75 
Infra-gknoid tubercle of scapula, 138 
Infra-orbital canal, 77, 93, 120 
foramen, 77 
groov^, 77 

firocess, 84 
ra-spinous fossa, 136 
Infra-temporal fossa, 92 

ridge, 53 
Infundibuhim, 49, 102 

of ethmoid, 73 
Inion, 91 

Inlet, pelvic, diameters of, 170 
Inner carpo-metacarpal joints, 271 

cell mass, 4 
Inspiration, muscles which effect, 246 
Interarttcular cartilage, 207 

ligament, capitular articulation, 230 

stcmo-costal joint, 243 
menisci, semilunar fibro-cartilagcs, 288 
Interchondral articulations, 244 
arterial supply, 245 
ligaments, 245 
movements, 245 
nerves, 245 
Interclavicular ligament, 247 

notch, 127 
Intercoccygeal joints, 236 
Intercondylar fossa of femur, 177 
Inter condyloid eminence of tibia, 180 

notch of tibia, posterior, 180 
Intercostal spaces, 133 
Intercuneiform articulations, 303 
Interior of skull, 104 
Intermediate cell mass, 6 
Intermetacarpal joints, 273 
arterial supply, 274 
ligaments, 273 



^Mf ^ INDEX TO PART I ^^^^^^^H 


^^■r <itvrni«(acnrpiLl jnintA, nn-vc-«uppiy, 274 


Joint, aommio-T-lftvicLilftr, 24fl, 250 ^^^| 


^^V IntiTiiK'imimul juioto, 310 


nnkle, 2t>7 ^^^H 


^^H an<>nul siip|>ly, 310 


anti'riur talo-mlmnpal, 301 ^^^H 


^^V ligximiii-v, ;iO<t 


allanlo-oilontoui, 21.^ ^^^H 


^^m movvmeni^, ^10 


calcaiieo-cuboid, 305 ^^^| 


^^V m'rv'c-Mupply. •'ilO 


carpo-nif tat'arpial, of thumb, 273 ^^^| 


^^K- Inlcnial luiKukr proecM, 48 


central at lanto-AXoidean, 216 ^^^| 


^^B auditory meatus, 01 


ca!(to-trnn«vprse, 241 ^^^H 


^^ft cuIcjuiL'U'rulwid ligooKint, 305 


_cu]x)'ni(.'latarsa1, 300 ^^^H 


^^M dinpilomi bone, 193 


CTibonnxicular. 303 ^^^| 


^^H lateral lifraiiu'nt of ankle-joint, 298 


<-uni-'>-mltoid, 3U3 ^^^| 


^^H of kiifC'juiiit , 2HU 


vllxiw, 25S ^^H 


^^H lifpimonttt ot kDc-f-jotnt. ^87 


hip, 277 ^^^1 
infiTior rudio-iilnar, 262 ^^^H 


^^H iiibIIgoIiu. ISl 


^^H iiK'iiitieii», kuL'i'-Juint , 280 


intorc-uiirifonii. 303 ^^^| 


^^H o&nculDri-ciiiiPirorm ligament, 303 


ini^'mol tanw-rneiatntsnl. 30S ^^^| 


^^^1 Orr-ipit:il rri-nt, W 


knn-, 2.S.i ^^H 


^^H pruluK-nUKV, 41 


n]«<lio-i<arpfil. 209 ^^^| 


^^1 p(er>')C<ii>) iibto, 54 

^^H Klip ni -run clybir IJnf of Tcniur, 176 

^H Mvf.: 113 


tnidillp tiirsn-nK'latarHal, 306 ^^^| 


mid-railiii-uUinr, 2^1 ^^^H 


na^'imlari-cuneifonn, 303 ^^^^ 


^^H inlo-calranpn] lieomeni, 300, 301 
^^H tann-mtlatamul joinl. 30K 


of iinterinr purtH of taniUfi. 3n2 ^^^H 


of thumb, i)>otaoarpo- phalangeal, 276 ^^^| 


^^^^^ lutcrosseoiLf liorder of nulius, 147 


poftterior talo-rfil nines 1, 3(X} ^^^H 


^^^K 


mdio-rarpal. 2M ^^^| 


^^^^H of ulnar. 


Mtcro-rotryp^al, 234 ^^^H 


^^^^H «filcuieo-7uV>otcl liffanu-ut, 30(1 


sliouldcr, 252 ^^^| 


^^^^H cuboideo-navinilur ligaiin-nt. M)A 


stcmo-ro^o-rlaviciilur, 240 ^^^H 


^^^^^H ligBtntnt, nntrrior tulo-ritli-jinciil jouit, 301 


raln-niivioulnr. 3(M ^^^H 


^^^^^H cubo-niptatnn.ll jitint, 'M*J 


tihio-KbviIur. 2!t4 ^^H 


^^^^^B first row rurpu] lx)iii-s, 'Jii» 


Joititx br-tw^Tii alias and azi>, 216 ^^^| 


^^^^^H fottr inner rarpo-miirta'-urpitl joints 372 
^^^^^H^ infrrinr f ilno-hlmlar joint, 2^ 


carpal. 20S ^^H 


rariio-iDi'tacnrpal, 271 ^^^H 


^^^^^^^ JliLtKs, 301 


eluKsifioulion of, 208 ^^^| 


^^^^^^^V intMTnctnrarpnl joints, J74 


Costrwlion<lra1. 243 ^^^H 


^^^^^^r ijifmriclatiir^al joiiitn, 3ID 


caHtit-vi-rlcliral, 238 ^^H 


^^^^^H nuiUllc tarso-mcialnrsul joints, 308 


intrrctiDndrQl, 2-14 ^^^^ 


^^^^^H pelvic jnintA, '£.i2 


imrrroocyRcnl. 2^in ^^^H 


^^^^^H jHMttrnor tulo-calruiK>al joint, 300 


inlfi-iiietacarpHl. 273 ^^^^| 


^^^^H fieconti row carpal Exinc-s, 200 
^^^^H Huprrior tibio-fibular joint. £M 
^^^^^f niptnbranc. miit-rudio-ulnar uuiou, 202 


intemiPlaiarsnl, 310 ^^^H 


int^rphabneraJ, 270, 311 ^^H 


intrr^itirnnl. 242 ^^^| 


^^^^^ mid'lk (ibk)-lil>tilar joint, 21)5 


latcntl atlaiito-iucoidcnn, 215 ^^^^ 


^^H riflgnof liltiiiLt. IS5 


mrdio-larval or tniiif^vrrse tftrail, 304 ^^^| 


^^H Intrrparictiil bono, 3U 


RittncnqMMpbalnii^ttl. 274 ^^^H 


^^H^ Inlrr])hiilnnK<-al jointit, fiofciTs, 270 


niutnt.irMi-plinl.-uigeal, 310 ^^^H 


^^^^_^ urti-rial s<i)>|]|y, 277 


of pflvj.s, ^^^H 
mciiO'ulnnr, 260 ^^^| 


^^^^^^m iiKivi<in>*nt», 277 


Micit)-viTt4-liral, 229 ^^^^H 


^^^^H muiiclea aninR upon, 277 


Ktcn]o-<?i>$Iii], 243 ^^^1 


^^^^f nen-e-aiipplr. 277 

^^^^^ Interphalaajtcal joint:), toi>i«, 311 


taisal. 300 ^^H 


|nrM>-i!U!t<itarHal, 30R ^^H 


^^H arterial !<uppl)-, 311 


tibiu-tiliuUir, 205 ^^^^ 


^^^^^^^ liKumL-nt-i. 311 


upper pxtn'inily, 246 ^^^| 


^^^^^^^^H 


various movcm^nU of, 200 ^^^H 


^^^^^^^ ni-n-c-supply, 311 


vprlpbral. 225 ^^^H 


^^^f rrlntion~. 


JuffuUir foramen, 03, 95, lOS, 119 ^^^^1 
ossa, 02, ^^^^1 


^^H Int^rpuhic lihro-'-aHilagp, 237 


^^H lutcnpinuiiAt tiiianicnia, 227 


notch (tnt«n-tavirular), 137 ^^^^H 


^^H Inlcntfmal jomi.-', 2-12 


prooMs. -12. 05 ^^^^^H 


^^^1 Inlenraii«\fnu- li)(anirntN, 227 


Jugum Kphfnoiflalt', 50 ^^^^^H 


^^H luU-rtnH'ljaiitvrit! i'r\«t, 173 


^^^^^H 


^^1 lino of fwnor, 


^^^1 


^^H InlTtiilH'rriil^ir (liit-initnll cnxtiiv 141, 144 
^^H Idtvrvi-'rtt'tmtl arlioiitatioii, ligaincnU. 221 


Kinds of articiiktioDs, 208 ^^^H 


^^H fihro-rartilaKT. 221 


KnM^joint, 285 ^^^^^H 


^^H iiacro-ct>c4-y|^al joint, 234 


Brt«-nal suppK-. 291 ^^^^^| 
ligaitientE, 285 "^^^H 


^^H Intn>duction. 1 


^^B Irrcipilar bone. 10 
^^H IndiiOH^psiilar band, 2T0 


movcmrntA. 292 ^^^H 


musck-a acting upon, 294 ^^^^| 


^^^1 Ii4<r))iuin, 1 07 


nervf -supply, '201 ^^^| 


^^B Itvr rbordo; antrriua. 120 


notation!). ^^^H 


^H postcritu. Wi, 120 


Kn«e-pan, 179 ^^^H 
Labial surfarr nf ttvth, 109 ^^^| 


^^P 


^ Jaw, lower, 85 


Labyrinfh of etbmoid, 72 ^^^H 


^^R uftpiT, 77 


oswous, 00 ^^^H 



INDEX TO PART I 



325 



Lachrymal bones at birth, 118 

description of, 75 

ossification of, 75 
crest, 75, 101 
fossa, 49, 100 
groove, 77, 101 
process, 74 
sulcus, 75 
tubercle, 78 
Lachrymo-etbmoidal cells, 74 
Lambda, 91 

Lambdoid suture, 45, 01 
Lamioa cribrosa, 61 

papyracea (os planum), 72 
spheno-petrosai, 53 
spiralis, 70 
I^amioffi of axis, 20 
of vertebne, 17, 18 

ligaments uniting, 225 
Laminar portion of intervertebral fibro-carti- 

lage, 221 
Lateral atlanto-axoidean joints, 215 
ligament of ankle-ioint, 298 
ligaments of knee-joint, 286 

interphalangeal joints of fingers, 276 
of toes, 311 

metacarpo-phalangcal joints, 274, 276 

metatarso-phalangeal joints, 310 

radial, 259, 266 

temporo-mandibular joint, 210 

ulnar, 259, 265 
malleolar ligament, anterior, 296 

posterior, 296 
masses of atlas, 19 
occipito-atlantal ligament, 215 
or short vertebral ligaments, 224 
region of skull, 91 
sacro-coccygeal (intertran/i verse) ligament, 

235 
Layers, germinal, 4 
somatic, 5 
visceral, 5 
Lesser multangular (trapezoid) bone, 157 
palatine foramina, 94 
sigmoid cavity of ulna, 151 
tuberosity of humerus, 141 
Ligament, annular, of superior radio-ulnar 

joint, 261 
anterior, of ankle, 297 

atlanto-axoidean, 216 

atlanto-occipital, 213 

of knee-joint, 287 

oblique (lateral occipito-atlantal), 215 

radiate stcmo-oostal, 243 

sacro-coccygeal, 234 

sacro-iliac, 231 

talo-fibuiar, 298 
antero-intemal lalo-calcaneal, 301 
apical odontoid (suspensory), 220 
calcaneo-fibular, 299 
capsular, of elbow-joint, 258 
ccrvico-basilar, 218 
conoid, 2-tO 
coraco-acromial, 252 
coraco-clavicular, 2.50 
coraco-humerai, 254 
costo-clftviruiar, 248 
costo-xiphoi<l, 243 

deep sacro-coccygeal (supra-cornual), 235 
dorsal cubo-iiictatarsal, 309 
dorsal radio-carpal, 265 
external calcaneo-navicular (superior cal- 

caneo-*traphoid). 301. 304 
external lateral, of knee-joint, 286 
gleno-hiimeral, 253 
glenoid, 25.'> 

great or posterior sacro-sciatic, 233 
Oio-lumbar, 229 



Ligament, inferior interosseous, inferior tibio- 
fibular joint, 296 

sacro-iliac, 232 

stcmo-costal, 243 

transverse, 2.52 
interarticular, 239 
intercla\-icular, 247 
internal lateral, of ankle-joint, 286 
interosseous, cu bo -metatarsal joint, 309 

of pelvic joints, 232 

of posterior talo-culcaneal joint, 300 
lateral sacro-coccygeal (intertransverse), 235 
neck, 241 
oblique (niid-radio-ulnar union), 261 

popliteal, posterior, 287 
occipito-cervicat, 218 

of intervertebral articulation, anterior longi- 
tudinal, 223 
of posterior longitudinal, 223 
plantar calcaneo-navicular, 304 

cubu-metatar«al, 309 
posterior, of ankle-joint, 298 

atlanto-axoidean, 216 

at lanto-ocopital, 213 

cervical, 227 

(dorsal) medio-carpal, 270 

radiate stemo-costal, 243 

sacro-iliac, 232 

talo-fibular, 299 
radiate (anterior costo-ccntral or stellate), 
239 

lateral, 259, 266 

of medio-carpal joint, 269 
sacro-lumbar, 229 

sacro-«pinous, or small sacro-sciatic, 233 
sacro-tuberous, 233 
spino-glenoid, 252 
spring, 305 

Ktylo-mandibular (stylo-maxillary), 212 
supi'rficial posterior sacro-coccygeal, 235 
superior interosseous, tibio-fibumr joint, 295 

sacro-iliac. 231 

stcrno-costal, 243 

transverse (coracoid or suprascapular), 252 
supraspinous, 226, 235 
talo-naA-icular, 305 
temporo-mandibular, 210, 212 
transverse of central atlanto-axoidean joint, 
217 

dorsal (medio-carpal joint), 270 

humeral, 255 

(inferior tibio-fibular joint), 297 

of heads of metatarsal bones, 310 

of hip-joint, 281 

of knee-joint, 289 
trapezoid, 2.50 
ulnar, lateral, 259, 265 
volar (anterior) medio-carpal, 269 

radio-carpal, 265 
Ligamenta flava, 225 

Ligaments of acromio-clnvicular joint, 250 
alar (occipito-odontoid or check)) 218 
ankle-joint, 297 
anterior talo-calcancal joint, 301 
connecting articular processes of vertebra, 

225 
of articulation of atlas with occiput, 213 
of atlanto-axoidean joint, 215 
attachments of sacro-iliac, 28 
unitins l»odies of vertebrae. 221 
of cakaneo -cuboid joint, 305 
of capitular (cost n -centra I) articulation, 239 
calcaneo-cuboid, 300 
of carpo-melacarpal joints, 271 

of thumi), 27.1 
of coraco-clavicular joint. 250 
coronarj-, of knee-joint, 289 
of costo-trans verse articulation, 241 



^^^Kr ^^^r ^^ ^ ^l^^^^^^l 


^^B Li^iununbi of cnwto-Trrtvbral arlimlittioiu, IMU 


I.ins of f«nur, spiral, 173 ^^^H 


^H crucial, of atlanlixKlvatoiti juiiit. 217 


of fibula, eccuudary ubti(|iie, ISO ^^^H 


^H of kuw-joint, 2S7 


ilio-pPctinf«l. 167. 17U ^^^| 


^^1 of rtihiiiilMi-rus'iciilikr union, .303 


infrrior gliit'-nl, 106, 170 " ^^H 


^H of cubu'inetatanuil juini. .300 


jnylo-livoid. $0 ^^^| 


^^^^^ of vuiuKHOubnid articiiiatioii. 30.1 


olitiqut'. of fibula, 18.^ ^^M 


^^^^L deHcriptJun of, 207 

^^^^f dorsal, of intermetatarsal jomU, 310 


ofulnit. lUl ^^^M 


po»t<;rior^lutpal, 105 ^^H 


^^^^^ middle tunn-int'Catanal joint, SOS 


of radium, 148 ^^^M 


^^H of i.-IIk>w •joint, 2^ 


uf iif^apiila. 136 ^^^| 


^^M of union of lirbt row of <'&rpii1 bonpd, 369 


Irnpezoiii, 13S ^^^| 


^H of four curpo-motaou^l JoiaU. ;£72 


IJnea aapera, 173 ^^^| 


^H of hip-joint, 277 


[}ocIinca of foinur, 173 ^^H 


^H of iiuerior r&ilio-ultiar joinl. '2Syi 


• luadrala of femur, 176 ^^H 


^H tibio-fibukr jaint, i^Q 


LuiDH, bony, 16 ^^H 


^H of interchondrul joint. 2-14 


epipfayimtl, 14 ^^H 


^^M of intercuneiform ioint, 'ilXi 
^^M of ioUTinL-tiurarpul juinU, ifTS 


aupra-eondylar. of femur, 176 ^^H 


Buprema Oiighmt uuebal line), 40 ^^H 


^^1 of mtcrmclAtarHal juinU, 310 


Lingual suKacr of treth, 100 ^^H 


^^M tati'mal, of knMviiiiiil, 247 
^H of iutcrpliularjgwii jutttlii, 276 


Lincula, €2 ^^H 

(a lower jaw, 86 ^^H 

Lip. glenoid, 281 ^H 

Liiilninc-, tubTrkt of, 123 ^^M 


^H of loot, 311 


^^B int4Tii<u<i.i]iM, intiTriincLroriii joml, 304 


^H of iiiti.-nnctHluriiU Joint , 3 10 


LouK bonit>, 16 ^^^| 
plantar ligamr^nt, 306 ^^H 


^H midilk- tAmo-mctataraal jomt, 30S 


^^1 inU-rxpinoiLK, 227 


IKMlfnor larnxilmr liganii^nt, 232 ^^H 


^H of ini<-i>t<'rnul Joinls. 212 


Lonptudiiial Ueainent uf inl ervertebr«I joint. ^^| 


^^1 int<-rtr.-kii.-<vi^rse, 227 


anlf-rinr, 2'J.I 1 


^H of knfH.<tr>iiil , 2.V> 

^H^ unititif; unitnte uf vertebra, 223 


jHMtirior. 223 ^^^^ 


IjOngU;* oolli, atlactiment of, 20 ^^^| 


^^^^ lateral, of lcnM>-ininr., 29S 
^^^^K malleolar, '29(1 


Lower extrfmity, Iwncs of, 164 ^^^| 
of fibula, ISO ^H 


^^^^V or Hlion vertebral, 224 


of rai.lius, 140 ^^H 


^ of mfviify-rarpBl joint, 2tK) 


of tibia, IRI ^^M 


^^L of met Mcarpo- phalangeal joinU, 274, 276 


of ulna. ]Ii2 ^^H 


^^^^^ of inetatarso-phalangeal joiaU. 31(1, 311 


limb, art ifrutat ions of, iU ^^^^H 


^^^^P of midc])e rurso-metatarwU juiitt, 30S 


^^^^^ of niid-radio-iilnar joint, 2IJI 


Lumbar nb«, ossification of, 127 ^^^H 


^^V roorplioloKy of, :tl2 


vcrtebrie, 23 ^^H 


^H of naviculariK-unDifonn joiot, 303 


dcacription, 23 ^^H 


^H oMirjue, of atlas, 214 

^H uniting occiput and uxii, 218 

^H of pclvir articulatinn, 231 


dcvc-lopmcnt, 35 ^^^| 


Lunat« (semilunar) bono, 155 ^^H 


^^^H 


^M plantar, 306 


^^^M 


^^1 of int'.'niii-latuniat jotntt, 310 


^H 


^^M iniddlt.- Uirso -nielalarstil joints, 308 


lUarbooe, 8S ^^H 


^H of poatcrioT taio-oalojineal joint. 3U0 


tubercle, 84 ^^M 


^H propvr scapular, 252 

^^M at nulio-uu'pal joinlK, 20 


tulK'aiKity, S3 ^^^| 


Mulk'ular if^nt-tit, onlerior lateral, 3Q0 ^^H 


^H of m<lio-ulnnr joints, 260. 263 
^^1 flacni-cncn-gi-ttl iirtia lint tun, 234 


posterior lateml. 206 ^^| 


Malk-olux, cxtcnial, ISC ^^M 


^H of BBcro-v('rt(>bml nrciculadond, 220 


intenutl, 181 ^^H 


^^M at 8eoon<l row of rArpnl bono, 2fiA 
^H erf sliouliJiT- joint , 2^2 


Mallcti-t. 60 ^H 


M&nuniUarv process, 24 ^^H 


^H betnvcn Kkiill And spinal column. 213 


Mandibln, M5 ^^M 


^^1 cnnnrHiiiK "piitou^ proreanen uf verl<-hnR, 226 


arterial nupply, 87 ^^^| 


^H stvniu-i-1uv)<-nlar, 217 


■t 118 ^^H 


^^1 of 9l«rno-roHt.Al joints, 213 

^^M of ntvruii-coHto-ctavtcuIar joint, 246 


oiwifimtinn of, 87 ^^H 


Mandibular bars. 113 ^^H 


^^M of cymphyHiH pubU, 2^ 


inferior dental) canni, 80, 120 ^^H 
nramen, 96 ^^H 


^^M talo-ralrnnpal, 300 


^^M of (»)i>-naneular joint, 301 

^^1 of tpmixtrf-mandiDular artieuIfttioD. 210 

^H tibio-libular. 205 


fossa. Oil ^^^1 


(iiii;moid) notch, 87 ^^^^H 


premolai?, 110 ^^^^^| 


^H connccliiif; tma'n'VTa? proccaa/^ of vertebne. 


Kfunc. ^^^^H 


H 227 


Manubrium, 127 ^^^^H 


^H Lijcaincntum tuucosum, 200 


stemi (prD-eteroum). 127 ^^^^H 
Ma.«toid air-crllfi. 60 ^^^^^H 


^H nuchiT. 227 


^M patvUa-, ZSli 


atitrum.eo, 62, 07 ^^^^H 


^M tvrofi. 2S0 


ranuliculuf, 62 ^^^H 


^1 Wltkslovii. 387 


for&mMi, 60. 95 ^^^M 


^^M Lioib, artirnlntinnM of low^r, 277 


(aupra-mcatal) foma, 00 ^^^^H 


^^1 LirulNxim HUtiin-ii. 208 


notch (digactric foimi), 60 ^^^^H 


^H ),imK*, drvrlopnu'iU of, 11 


proc«'N<. 60. 05 ^^^^H 


^^M l.imbiin .'•plionoiilnlix. 51 


dt>v<'1oi>mi-nr. (in ^^^^^H 
Uaxillu, n ^^^^^H 


^H lAu*!. unlrrior kIuU'uI. 165 


^H of femur, tmertmchantcrir, 173 


niticuliition nf, 81 ^^^^^H 


^^K^^ pectiaivU, 173 


OMilirAtioii ^^^^^^1 



INDEX TO PART 1 



327 



Maxillary molare, 110 
premolar teeth, 110 
process, 74 

of palate bone, 82 
ainiw (antrum), 79, 102 
MaxiUo-ethmoid celln, 74 
Measurements of component parts of auditory 

apparatus, 71 
of cranium, 109 
of pelvic diameters, 172 
Meatus, external auditory, 64 

internal auditory, 61 
Meatuses of nobo, 102 

inferior, 102 

superior, 73 
Meckel's cartilage, 87 
Mediastina, development of, 10 
Medio-earpal joint, 269 

arterial supply, 271 

ligaments, 269 

movements of, 271 

muscles acting upon, 271 

nerve-eupply, 271 

relations, 271 
Medio-tarsal (transverse tarsal) joints, 304 
Medullary cavity, 16 
groove, 5 
ridgep, 5 
Membrana sacciformis, 263 
Membrane, Interosseous, mid-radio-ulnar union, 
262 

middle tihio-fibular union, 295 
synovial, 207 

acromio-clavicular joint, 250 

ankle-joint, 299 

anterior talo-calcaneal joint, 302 

calcaneo -cuboid joint, 307 

first row of carpal bones, 268 

second row of carpal bones, 269 

carpo-metacarpal joint of thumb, 273 

four inner carpo-metacarpal joints, 272 

costo-sternal joint. 243 

costo-transvor^e ^oint, 241 

cubo-metatarsal joint, 309 

elbow-joint, 2.59 

lup-joint, 282 

inferior radio-ulnar joint, 263 
tibio-fibular joint, 297 

intermetacarpal joints, 274 

intermetatarsal joints, 310 

interphalangeal joints, 377, 311 

knee-joint, 287 

medio-carpal joint, 270 

metacarpo-phalangeal joints, 274 

metatarso-phalangeal joints, 310 

radio-carpal joint, 266 

shouldor-joint, 255 

stemo-costo-clavicular joint, 248 

superior radio-ulnar joint, 261 

talo- navicular ^oint, 305 

tibio-fibular joint, 295 

vertebral joints, 225 
Membranous cranium, 1 12 

roof bones developed in, 113 
Menisci, interarticular, 288 
Mental foramen, 85 

protuberance, 85 

tubercle, 85 
Mcsaticephalic, 109 

pelvis, 172 
Mesentery, development of, 9 
Mescthmoid, 72 
Mesoderm J 5 
Mesodermic somites, 6 
Mosognathion centre, 81 
Mesopalatinc suture, 79, 94 
Mesoscapula, 139 
Mesostemura, 127 



Metacarpal bone, first, 159 
second, 160 
third, 161 
fourth, 162 
fifth, 162 
bones, union of heads of, 274 
Metacarpo-phalangeal joints, 274 

of thumb, 278 
Metacarpus, ossification of, 163, 199 
Metacromion, 138 
Metamerism, 5, 6 
Metamorphosis of branchial or visceral bars, 

113 
Metapophysis, 24 
Metastemum, 127 
Metatarsal bone, first, 196 
second, 197 
third, 197 
fourth. 197 
fifth, 198 
bones, union of heads of, 310 
pillar, 202 
Mctatarso -phalangeal joints, 311 
arterial suppr^, 311 
tigaments, 310 
movements, 311 
nerve-supply, 311 
of four outer toes, 310 
of great toe, 311 
Metatarsus, description of, 196 
Metopic sutures, 47, 91 
Middle alveolar canal, 77 
clinoid process, 53 
costo-transverse (neck or interosseous) liga- 

ment, 241 
cranial fossa, 105 
cuneiform bone, 193 
ear, (>6 

cleft, 67 
meatus of noiie, 102 
palatine foramina, 94 
tarso-metatarsal joint, 308 
tibio-fibular union, 295 
Mili-radio-ulnar union, 261 
Mid-tarsal joints, 307 
Milk teeth. 111 
Mixed bones, 16 
Modiolus, 70 
Molars, mandibular, 110 
maxillary. 110 
third, 111 
Morphogeny, general, 3 
Morphological axis of scapula, 139 
Morphology, definition of, 1 
of^ ligaments, 312 
of skull, 112. 
of vertcljra-, serial, 37 
Movable vertebra;, 16 
MovcmentJi of acroniio-cla^icular joint, 250 
of ankle-joint, 300 
of atlanto-oxoidcan joint. 218 
of capitular articulation, 240 
of carpo-metacarpal joints, 272 
of coraco-clavicular joint, 251 
of co.-ito-transvpiNe articulation, 211 
of ellx)w-joint, 260 
of hip-joint, 283 

of inferior tibio-fibular joint. 297 
of inner carpo-metacarpal joints, 272 
of interi'hondral joints, 245 
of intercoccygoa! joints, 236 
of intercuneiform and cuneo-cuboid joints, 

.104 
of intermetatarsal joints, 310 
of interphalangeal joints, fingers. 277 
of inteqihalangeal joints, toes, 311 
of medio-carpal joint, 271 
of metacarpo-phalangeal joints, 275, 276 



^M 328 LVDEX TO PART I ^^^^H 


^^M MovaaioDts of mid-larsal joiuts, 307 


Muscles BclinK upon rmlio-vurpal jotut, 368 ^^H 


^^H of ocripilo-atluntitl nrtiouliition, '.{IS 


mrlio-iiln»r joini, 264 ^^H 


^^H of occip:ti»>}txi.-tl joint, 'J'M 


oh ouiilcr- joint. 257 ^^^| 


^^H of pclvio arCivuktiuiis, 233 


loTiipory-iimiKiibiilar itrliniliition, 213 ^^^ 


^^B of ni>lio-r:irp9il joint. 267 


affpclinK iv)mro-<'ltivinjli>r joint, ;;51 1 


^^H of rHittiiH, 2fVS 


<-x|iinil ion, 24li ^^^H 


^^H uf sucru-txiccyKL-nl iirtk-ulutiou, '235 


iiu<[jinition. 240 ^^^| 


^^M of .'4a('rr>-^-i>rr.r)>ru.l nrtirtilationtt, £10 


movf'inrnrft of Hpiniil column, 229 ^^^| 


^^H of xlioiiLili^r-jdirif , 2.'il!i 


(tU'riiOH'nsto-clHvirular joint, 249 ^^^H 


^^M of »(<:•( iio-*^)^^! iirtk-utiniua, 243 


in orbit, 103 ^^^| 


^^H of Kt<>rni>-ciMioH'lB\*u'iiIiir joint. 219 


of peK-if! artiRiiIalioRii, 233 ^^^| 


^^H a{ .lynipliv.Hi.H i^ibi.i, '23fi 


poHt.-iutiitl, ^^^H 


^^H of titlo-cuLfr»iii>al joiiiU, 301 


prs-a.\ial. ^^^| 


^^H of tttrHO-riietuliir^iil jivjur^, 308 


of sB<?rt>'ror('\f;ea1 nrlirulntinn. 235 ^^^H 


^^H of tnut>c)m-niiuiililiiibr artirulntinn, 212 


of sacro-vtTlcbnil lulirulatiotis, 21)0 ^^^H 


^^H of ihofim an u nholc, 21-'; 


of vPTli^hnil jniat-4, 22i> ^^^H 


^^H of libio-fibiilar juini, 29'* 


Mu.spiilo-dpiri|l Krouve, 142 ^^^M 


^^M of vertobral juttilH, 228 


Mylii-liyoid groove, 86 ^^^H 
line, m ^^H 


^^M MultADKiibr (trapi-ziimi) Wnp, Ereater, 156 


^^M OrapoKoid) boae, Inttscr. IA7 


^^^1 


^^B MulttKdtis mii-irlo. airtkclimr'nt . 28 


^H 


^^H Muaclp-ntt.ti-hmcntx of a^traKalus, 1S9 


^H of atlus, 2U 


Nanw, uiitdrior, 94. 103 ^^| 


^^M axLs. 21 


NmaI :i|v>nurr. anterior, 98 ^^^H 


^^M of culnmcus, 190 


7A ^^^B 


^^M of rapitftto (m iiiugnum) Uuav. 158 


aCbinb, 118 ^^H 


^^B of dHX-trlr, 133 


OM^itinition of, 1 1 ^^^H 


^^H of rnrcyx, IVi 


n>m'hii- (turbinate boiirit), 72, 73, 74 ^^^| 


^^H of mxtii tmnf, 104 


^^^1 


^H of ciirioM. I!t5 


emjncn<v,47 ^^^| 


^^H of <-xliTii:il runrnfonii bun«, t!M 


fiwui-, •lfM-n|rtionof,9R, 101, 102 ^^H 


^^M of fniitir. 173 


meatiiHi*''. I(i2 ^^^| 


^H of tibulA. ISA 


^^^1 


^^^1 of fn>tii 111 Ikiiic , '17 


r^Kiun. oriitiii nf boniM of, 1 13 ^^^H 


^^M ul crt'utor tnuliniiKtiUr (tropvzmiu) Ixuiv, IS? 


sTKne. 4^, 77, 79, 103 ^^H 


^^H of h^niittr (unrifnmi} bone, IAS 


poKi^rior, 81 ^^H 


^^H tif 1i)iiucriu>, 141 


Niunan, 99 ^^^1 


^^M of hyoid liiitii?, 110 


NiLMi-lHcbryinal durt, 102 ^^^B 


^^H of iburn, \(t\ 


NuvicTulnr (ffrnphnitl} bntvr, 155, 191 ^^H 


^^H «( ivdiiiiin. Hi? 


Na^-ic-iibri-cimDifonti arti<MiIatioD, 303 ^^^| 


^^H (tf mabir Imni-. -S3 


Ni-ekuf axtx.'JO ^^^1 


^^H of inanilihle, 85 


of L'upituto bone, 157 ^^^| 


^^1 of mnxilla. 


of femur, 17^1 ^^^| 


^^H nf mi't iic-tirpnl bonm, 159 


of buniiTiifi, anatoniica). 140 ^^^H 


^^H of riu-lutaniiit IwcirA. Ifltl 


i«)i Weill, ^^^1 


^^M nf midiltf' •-•incironn boix-, 194 


licamont, 241 ^^^| 
of nuliiiH. r40 ^^^^1 


^^H «tf riaviriiliir. 192 


^^M of oi'<-tpitul iioiif, 40 


^H 


^^H of piil^ri' bono, 81 


of <irapiila, lltS ^^^H 


^^H uf |i:inpt»l liDjiOH, 45 


of tu.lii- iir )L-<t rixhIus, 189 ^^^1 


^H of patflla. 171> 


of Ceuib, 109 ^^H 


^H nf pbat-inftoH. Ilkl. 201 


Nrn'p-fnrnminn'^f .ikiill, 119 ^^^H 


^^H of pUifortii boiii^, 160 


Nerve-»iU|>ply i>f Hiikle^joiiil , 299 ^^^H 


^H of pubU, IAN 


of Btlanto-«!coiilr-an iininjlHtion, 318 ^^^H 


^^1 of ratlJiH, 147 


of oalean'KiH'Litkfiiit jninl. ^1)7 ^^^| 


^M of rib.. 121 


ofcapitularariimlalioii, 210 ^^^| 


^^M of isntTiitn, 27. 2S 


of i-arpit-niutiimrTiiil jointK. 272, 273 ^^^H 


^^H of K^ripboid, I.U 


of roraro-olarir-ular jninl, 2.'>I ^^^H 


^^H of ''i-iipub. 130 


of (volo-t mniivi^ntr arlirulatioii, 211 ^^^H 


^^M of rwvoiuli cvrncal vtrtobra, 23 


of clbuw-joiul , 2T& ^^^1 


^^H of ^phrnoid, A2 


of hip^ joint, 'JS2 ^^^H 
of infrrinr rsdio-uloar joint. 263 ^^^| 


^^H of HlortKitn, 137 


^^1 of t'.>ruponLt bono. S8, 00, fl4 


of inferior libiu -fibuliu' joint. ^>7 ^^^H 


^H of libiu. IHI 


of Jnnrr oarpo-milacarpfU joints, 272 ^^^^| 


^^M of iiiii». I'lO 


of iiil<-rr!i(iiiiir.il joint*, 245 ^^^^^^| 


^^M of T>-)c<iiiiiiiJv iHtrie. 83 


. of intert-itn'-ifnriii ji>tn(.v. 304 ^^^^^| 
of itit<.>m)etnenr|iaf joint.<, 274 ^^^^H 


^^M UuMlt'it arting tipoti imkir Joint. 3(X) 


^^H fttl.iiilo'ii.xiiiili-jut .ifliritLtlion, 21S 


of tnt^Triiii-hiturxnl joinU, .'110 ^^^^| 


^^^^^ curp>.>-<iK>turur|wl joinlj', 272. 273 


of intvrpbiLtaiiB'-ul joinls. 277. 311 ^^^| 


^^^K elbov'inint. 204) 


of medii>-r;»rpal joint. 271 V 


^^^^H bip-j<Mnt, 2AI 


of m('tiirar|Hi'{ib:i)HiiKfal jr>irit<t, 275, 27fl ^^^B 
of mefatano-plinl.'uiin'iil jointi^, 311 ^^^| 


^^^^^1 Intior ntr^o.i-nit-tni-un.iul juioia, 273 
^^^^^H intiTiibnliiiic-al joitit.H, tingem, 277 


of orc-ipito-atlnninl artirulntion, 215 ^^^B 


^^^^^^ 


of |vlvn- aHii-iilalion, 2:):! ^^^| 


^^^^^^H medio-mrpal jotnl, 271^ 


of (nstofiiir t»li>-ta]i-nn'til joint. 310 ^^^| 


^ inptncitr|X)-|)balnTiici'al jtiuiU, 275, 27i} 


of rxlio-t-iiffHil joint. 2tUi ^^^H 


^^^^^V mi<Miin.-il 


of Rnrm-cori-yfpvil iirtinilnlinns, 235 ^^^| 


^^^^^^^^ PM-rfuio-afJauUl jouit, 215 


of sacTo-vertebi-al urtk-ulatiotut, 330 ^^^| 



INDEX TO PART I 



329 



Nerve-supply of shoulder-joint, 256 

of steriioKx>stal articulatioos, 243 

of stemo-coeto-clavicular joint, 248 

of superior radio-ulnar joint, 261 

of symphysis pubis, 238 

of tarso-mctatarsal joints, 308 

of tibio-fibular joint, 295 

of vertebral joints, 228 
Neural canal, 18 
Neuro-central suture, 33 
Ninth thonicic vertebra, description, 23 
Norma basilaris, skull, 94 

facialis, skull, 98 

lateraHs, skull, 91 

occipitalis, skull, 91 

verticalis, skull, 90 
Nose, meatuM» of, 102 

spongy bonea of, 73 

superior meatus of, 73 
Notch, 16 

acetabular, 169 

ethmoidal, 49 

frontal, 48 

great scapular, 137 

great sciatic, 165 

Hio-sciatic, 165 

jugular (interclavicular), 127 

mandibular (sigmoid), 87 

mastoid, 60 

nasal, 48, 77 

popliteal, 180 

pterygoid, 54 

radial (lesser sigmoid cavity) of ulna, 151 

of Rivinus, 06 

scapular, 137 

semilunar (greater sigmoid cavity) of ulna, 
150 

sphenopalatine, 81, S3 

supra-orbital, 48 

of tibia, posterior intercondyloid, 180 

r panic, 66 
r (sigmoid cavity) of radius, 149 
Notochord, 5 

Notochordal region of skull, 1 12 
Nuchal liner highest, 40 
inferior, 40 
superior, 40 
Nuclei of bones, primary, 14 

of bones, secondary, 14 

of calcaneus, 191 

of carpal bones, 158 

of clavicle, 135 

of coxal bone, 170 

of cuboid, 195 

of external cuneiform bone, 194 

of femur, 179 

of fibuU, 186 

of first cuneiform bone, 193 

of humerus, 146 

of metacarpus, 163 

of metatarsus, 199 

of middle cuneiform bone, 194 

of phalanges, 163, 201 

of radius, 150 

of scapuU, 139 

of sternum, 131 

of talus or astragalus, 190 

of tarsal bones, 190, 191, 192, 193, 194, 195 

of temporal bone, 64 

of tibia, 184 

of uloa, 153 



Obelion, 91 

Oblique diameter of pelvic inlet, 171 

ligament of atlas, 211 

ligament of mid-radio-ulnar union, 261 



Oblique ligament, popliteal posterior (ligamen- 
tum WinslowiO, 287 
line of clavicle, 135 
of fibula, 185 
of fibula, secondary, 1S6 
of radius, 148 
of radius, posterior, 149 " 
of scapula, 136 
of uba, 152 
Obturator crest, 168 
(thyreoid) foramen, 169 
groove, 167 
Occipital bone, 39 

articulations of, 44 
at birth, 116 
development of, 44 
ossification of, 44 
condyle, third, 43 
condyles, 95 
crest, external, 39 

internal, 41. 
groove, 60 
point, 91 
protuliorancc, external, 39 

internal, 41 
suture, 91 
Occipito-axoidean articulation, 220 
Occi pi to-cervical h^ament, 218 
Occiput and atlas, hganients uniting, 218 
Odontoid process of axis, 20 
Olecranon fossa of humerus, 144 

process of ulna, 150 
Ophryon, 99 
OpLsthion,95 

Opisthotic nucleus of temporal bone, 64 
Optic foramen, 51, 53, 101, 119 

groove, 51 
Orbital fissure, inferior, 120 
superior, 53, 54 
plate, 49 
process of malar bone, 84 

of palate bone, 81,82 
wings of sphenoid, 52 
Orbito-sphenoid centre, 55 
Orbits, 98 

description of, 100 
Organs, 3 

Origin of appendicular elements (bones of vis- 
ceral arches), 114 
of basilar bones of skull, 113 
of facial bones, 114 
of roof bones of skull, 113 
Os caicis, 190 
centrate, 158 
innominaturo, 164 
Jaix)nicum, 85 
lingua;, 89 
planum, 72 
sacrum, 27 
trigonum, 190, 195 
Vcsalianum, 159, 195 
Osseous labyrinth, 69 
Ossification of hones, 14 
of calcaneus, 191 
of carpal bones, 158 
of clavicle, 135 

of coxal bone (os innominatum), 170 
of cTiboid, 195 
of ethmoid, 74 

of external cuneiform bone, 194 
of foiiiur, 179 
of fibula, 186 

of first or infernal cuneiform bone, 193 
of frontal Ijone, 50 
of humenifi, 146 
of hyoid Iwnc, 90 
of itifrrior tuV>erclp, 75 
of lachrymal bone, 75 






r.\7>5:.V TO PAHT I 



■.,1.; ->. .-:': . . -.: ;>.-CK 1«*4 



,YVU . Tvv.>. V- 






ri-.-,-.-.-,. ..:■., >;-.>'):-T<=rf=.T «"- 10 



'"...N *^ r^ i:» ^'- 









■-— *- ■_-_^-'- ~-^ "rij:-^ri-=i:«»i *"- «li™<"^ 



.;.!»*.* > ■;•: S." 



-!;:'.ri- :..cii 5^ ^J 



:■=:> 3>: 



ji4« 



- - ~-~ ^' ■» 



INDEX TO PART I 



331 



Posterior cemca! ligament, 227 

clinoid process, 51 

condyloid foramen, 42 

cost o -transverse ligament, 241 

cranial fossa, 108 

crucial ligament, 287 

ethmoidal canal, 49 
cells, 102 

gluteal line, 165 

inferior spine of ilium, 165 

interconuyloid notch of tibia, 180 

lateral malleolar ligament, 296 

ligament of ankle-joint, 298 

of knee-joint, oblicjue popliteal, 287 
of symphysis pubis, 236 

longitudinal hgament of intervertebral joints, 
223 

medio-carpal ligament, 270 

nares, 94, 103 

nasal spine, 81 

oblique line of radius, 149 

palatine canal, 78, 82, 120 

pctroHal process, 51 

radio-carpal ligament, 265 

radio-ulnar lieament, 263 

regionof skull, 91 

sacro-coccy^ieal ligament, superficial, 235 

sacro-iliac bgamcnt, 232 

sacro-sciatic ligament, 233 

eemicireular canal, 70 

stemo-clavicular ligament, 247 

Bupcrior spine of ilium, 164 

talo-calcaneal joint, 301 
arterial supply, 301 
ligaments, 300 
nerve-flupply, 301 

talo-fibular ligament, 295, 299 
Post-glenoid process, 59 
Post-malar, 85 
Post-scapula, 139 
Post -sphenoid centre, 55 
Prae-axial muscles , 1 1 
Prejflenoid tubercle, 59 
Preinterparietal bone, 45 
Premalar, 85 
Prem axilla, 79 
Premolars, mandibular, 110 
Prescapula, 139 
Presphenoid centre, 55 
Pressure epiphyses, 14 

lamelke, 179 
Presternum, 127 
Primary curvatures of spinal column, 30 

foramina of skull, 1 19 

nucleus of bones, 14 
Prismatic portion of clavicle, 133 
Process, acromion, 138 

alar, of ethmoid, 72 

alveolar, 70 
of mandible, 86 

angular, 48 

anterior rlinoid, 53 

condylar, of lower jaw, 87 

coracoid, of scapula. 139 

coronoid, of lower jaw, 87 

ensifonn, 130 

ethmoid, 75 

frontal, of maxilla, 78 

fron to -sphenoidal, 84 

of great sacro-sciatic ligament, falciform, 2:j:i 

hamular, 54 

infra-<irbiral, 84 

jugular, A2 

lachrymal. 74 

mastoid, 60, 05 

maxillary, 74 

of palatP hone, 82 

middle clinoid, 53 



Process, olecranon. 150 

orbital, 81 
of malar bone, 84 
of palate bone, 82 

palate, 78 

paramastoid, 43 

posterior cUnoid, 51 
petrosal, 51 

post -glenoid, 59 

pterygoid, 50, 54 

pyramidal, 81 
of palate bone, 82 

of scapula, 138 

sphenoidal, of palate bone, 81, 82 

styloid, 58, 62, 64, 95 
of fibula, 185 
of radius, 149 

of third metacarpal bone, 161 
of ulna, 152 

supracondylar, 144 

temporal, of malar bone, 84 

of ulna, 150, 151 

uncinate, of ethmoid, 73 

ungual, of third phalanx, 163 

vaginal, of sphenoid, 51, 54 

of vertebrro, 18 

xiphoid, 130 

zygomatic, 58, 78 
Processus cochlearifonnis, 62, 66 

dentatus, of axis, 20 

FoUi, 69 

gracilis, 69 

margin alis, 84 

tubarius, 54 
Promontory of cochlea, 70 

of temporal bone, 62 
Pronator ridge of ulna, 152 
ProStic nucleus of temporal bone, 65 
Proper scapular ligaments, 252 
Protoplasm, 3 
Protuberance, mental, 85 
Pterion, 92, 105 

Pterotic nucleus of temporal bone, 65 
Pterygoid (Vidian) canal, 54, 93, 95, 120 

fossa, 54. 95 

notch, 54 

plate, external, 54 
internal, 54 

processes, 50, 54 

tubercle, 54 
Pterygo-maxillary fissure, 93 
Pterygo-palatine canal, 82, 93 

fissure, 93 

(spheno-maxiUary) fossa, 93 
Pubic arch, 172 
Pubis. 167 

symphysis, 236 
Piibo-capBular (pectineo-femoral) band, 279 
Pulpy nucleus of intervertebral fibro-cartilages, 

222 
Pyramidal eminence of temporal bone, 66 

process of palate bone, 81, 82 
Pyramids, vertebral, 32 



Radial fossa of humenis, 144 
lateral ligiimcnt. 239, 2(15 
groovi' for, 14 2 
I not rii {lesser .-iiginoid cavity) of ulna, 151 
I (anterior costo-central or stellate) ligament, 
I 239 

j Ttadiate ligamnit, 269 

stemo-costal liganicnts. 24,'^ 
Radio-carpal articulatiim, 2(i4 
arterial supply, 206 
ligaments, 205 



332 



INDEX TO PART I 



Radio-camal articulation, movements, 267 
muscles acting upon, 268 
ner\'e-eupply, 266 
relations, 266 
ligament, dorsal, 265 
volar, 265 
Radio-ulnar jointB, 260 
inferior, 262 
ligaments, 263 
union, mid-, 261 
Radius, description of, 146 
moveniuits of, 263 
ossification of , 150 
Rami of pubis, 167, 168 
Ramus of Uchium, 167 

of lower jaw, 86 
Recess, elliptical, 70 
epitym panic, 67 
hypo-tympanic, 67 
spherical, 70 
Recessus ellipticus (fovea hemielliptica) , 61 

sphiericus (fovea hemisphsrica), 61 
Region of skull, anterior, 98 
ethmo-vomerine, 112 
inferior, 94 
lateral, 91 
notochordal, 11 
posterior, 91 
superior, 90 
trabecular, 1 12 
Relations of acromio-clavicular joint, 250 
of anklp-joint, 290 
of calcaneo-cuboid joint, 307 
of carpo-metacarpal joints, 272, 273 
of cron'mi of upper and lower teeth to each 

other. 111 
of cuho-metatarsal joints, 309 
of elbow-joint, 259 
of hip-joint, 282 
of inferior radio-ulnar joint, 263 
of inferior tibio-fibular joint, 207 
of inner carpo-metacarpal joints, 272 
of interphalangcal joints, 277,311 
of medio-carpal joints, 271 
of metacarpo-phalangeal joints, 275, 276 
of pelvic articulations. 234 
of radio-carpal joint, 266 
of shoulder-joint , 255 
of stemo-costo -clavicular joint, 248 
of superior radio-ulnar joint, 261 
of symphysis pubis, 238 
of temporo-mandibular articulation, 213 
of tibio-fibular joint, 295 
Remnants of cartilaginous cranium, 119 
Retinacular fibres. 278 
Rhomboid ligament, 248 
Rib, bicipital, 127 
eleventh, 124 
first. 123 
second, 123 
tenth. 124 
twelfth, 124 

typical cliaracters of, 121 
Ribs. 120 

asternal or falsr, 121 
floating. 121 
ossification of, 125 
peculiar, 122 
sternal or true, 121 
vertebral. 121 
vertchro -chondral, 121 
vertcbro-stcmal. 121 
Ridge, carotid, 62 

external supracondylar, 142 
infra-temporal, 54 
internal supracondylar, 143 
intrm:':-fon^. of fibula, 185 
Jfj'dgcs, uioJiiliaiy, 5 



Ridges, superciliary, 98 

temporal, 45, 48, S9 

of ulna, pronator, 152 
Riviniis, notch of, 66 
Roof bones developed in membranous cranium, 

113 
Root of teeth, 109 
Rostrum of sphenoid, 51 
Rotation, 209 
Row of phalanges, first, 163, 199 

second, 163, 199 
Rules governing epiphyses, 14 



Sacral canal, 29 
comua, 28 
foramina, 28 
groove, 28 

vertebne, development of, 36 
Sacro-coccygeal articulation, 234 
arterial supply, 235 
ligaments, 234 
movements of, 236 
nerve-supply, 235 
ligament, anterior, 234 
deep, 235 

lateral (intertransverse), 235 
superficial posterior, 235 
Sacro-iliac ligament, anterior, 231 
inferior. 232 
posterior, 232 
superior, 231 
ligaments, attachments, 27 
Sacro-lumbar ligament, 229 
Sacro-sciafic ligament, great or posterior, 233 
small. 233 
notches, 165 
Sacro-spinalis (erector spmie), attachment of, 28 
Sacro-spinous or small sacro-aciatic ligament, 

233 
Sacro-tuberouB (great or posterior sacro-sciatic) 

ligament, 233 
Sacro-vertebral angle, 26, 171 
articulations, 229 
arterial supply, 230 
ligaments, 229 
movements of, 230 
muscles, 230 
nerve-supply, 230 
Sacrum, descnption of, 27 
Sagittal fontanelle, 47 
sulcus, 48 
suture, 45, 91 
, Scala tj-mpani, 71 
vestibuh, 70 
Scalene tubercle, 123 
Scaphoid bone, 155, 191 

fossa, 43, 54, 95 
Scapula, angles of, 138 
torders of, 137 
description of, 135 
morphological axis of, 139 
nuclei of, 139 
ossification of, 139 
processes of, 138 
surfaces of, 135 
Scapular foramen. 137 
ligaments, proper, 252 
notch, 137 
Scarpa, foramina of, 79. 94, 120 
Schindylesis sutures. 2C® 
Sciatic notch, great, 165 
Second cen'ical vertebra, description of, 20 
cuneiform Ixtnc. 193 
metacarpal bone, 160 
metatarsal bone, 197 



INDEX TO PART I 



333 



Second phalanx, 163 

rib, 123 

row of carpal bones, union of, 268 
Secondaiy curvatures of spinal column, 32 

nerve-foramina of skull, 119 

oblique line of fibula, 186 
Segmentation of ovum, 4 
Sella turcica, 51 
Semicircular canals, 70 

canals, external, G7 
Semilunar bone, 155 

fibro-cartilages, 288 

ganglion, location of, 61 

notch, greater sigmoid cavity, 150 
Septum, nasal, 102 

sphenoidal, 51 

trans^'ersum, 10 
Serial morphology of vertebrae, 37 
Serrate sutures, a)8 
Sesamoid bones, 1&4, 202, 276, 311 
of thumb, 276 
of great toe, 311 

plate, plantar, 310 
Seventh cervical vertebra, description of, 21 
Sex, difference in »tcmum accoraing to, 130 

in pcKis according to, 172 
Shaft of bone, 16 

of femur, 173 

of fibula. 185 

of humerus, 141 

of metacarpal bones, 150 

of metatarsal bones, 190 

of fifth metatarsal bone, 199 

of first metatarsal bone, 197 

of radius, 147 

of