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Full text of "The comparative anatomy of the domesticated animals"

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1 be I 
.ED. I 



THE 

COMPARATIVE ANATOMY 

OF THE 

DOMESTICATED ANIMALS 



THE 

COMPARATIVE ANATOMY 

OF THE 

DOMESTICATED ANIMALS 



BY 

A. CHAUVEAU, M.D., LL.D. 

MEMBER OF THE INSTITUTE (ACADEMY OF SCIENCES); INSPECTOR-GENERAL OF VETERINARY 
SCHOOLS IN FRANCE; PROFESSOR AT THE MUSEUM OF NATURAL HISTORY, PARIS 

JElctiiseli antJ IBnlargeti, toftl) ti)e ©o^opcratfon ot 
S. ARLOING 

DIRECTOR OF THE LYONS VETERINARY SCHOOL 
PROFESSOR OF EXPERIMENTAL AND COMPARATIVE MEDICINE AT THE LYONS FACULTY OF MEDICINE 



SECOND ENGLISH EDITION 

TRANSLATED AND EDITED 

By GEORGE FLEMING, C.B., LL.D., F.R.C.V.S. 

LATE PRINCIPAL VETERINARY SURGEON OF THE BRITISH ARMY ; FOREIGN CORRESPONDING MEMBER 

or THE SOClETfe ROYALE DE MfeDKCINE, AND OF THE SOClfiTfi ROYALE DE mSdECINE PUBLIQUE, OF BELGIUM 

FOREIGN ASSOCIATE OF THE SOClllTfi CENTRALE DE MfeOECINE VfiT^RINAIRE OP FRANCE 

HONORARY LIFE MEMBER OF THE ROYAL AGRICULTURAL SOCIETY OF ENGLAND 

FOREIGN MEMBER OF THE SOClfiTfi NATIONALE D'AGRICULTURE OF FRANCE, ETC 

EXAMINER IN ANATOMY FOR THE ROYAL COLLEGE OF VETERINARY SURGEONS 



WITH 585 ILLUSTRATIONS 



NEW YORK 

D. APPLETON AND COMPANY 

1905 



IN COMMEMORATION OF THE CENTENARY 

OF THE 

ROYAL YETERINAEY COLLEGE, LONDON; 

THE PARENT OF VETERINARY SCHOOLS IN ENGLISH-SPEAKING COUNTRIES. 

AND IN MEMORY OF 
CHARLES VIAL DE SAINT-BEL, 

EQUERRY TO LOUIS XVI. OF FRANCE, PRINCIPAIi OF THE LYONS ACADEMY, 

PROFESSOR IN THE ROYAL VETERINARY SCHOOL OF THAT CITY, 

AND 

DEMONSTRATOR OF COMPARATIVE ANATOMY AT MONTPELLIER ; 

WHO, WHEN A REFUGEE FROM THE GREAT FRENCH REVOLUTION, WAS 

CHIEFLY INSTRUMENTAL IN ESTABLISHING THE FIRST ENGLISH VETERINARY SCHOOL, 

IN WHICH HE WAS THE FIRST TEACHER, 

1791. 



PEEFACE TO THE SECOND ENGLISH EDITION. 

Since the translation of this work into English, seventeen years ago, it 
has been several times reprinted, the last occasion being in 1889. Cir- 
cumstances had, however, for some time indicated that there was need 
for a revision of the work in order to bring it up to the requirements 
of the present day, and the issue of a fourth French edition last year was 
considered a favourable opportunity for undertaking the task. 

In preparing this second edition, the necessities of advancing veteri- 
nary education in the English-speaking schools was kept in view, and this 
entailed considerable amendments, alterations, and additions, in order 
to adapt it more perfectly to the conditions it should fulfil as a text- 
book and standard work of reference on the subject. 

The high esteem in which the first edition has been held for so many 
years in this country, in our Colonies, and in the United States of America, 
amply testifies to the value of the work ; and in this new edition every- 
thing has been done to render it still more comprehensive, complete, and 
useful. The anatomy of the Ass, Mule, and Eabbit has been added, as 
well as that of the Camel — that animal being utilized not only in our 
army in different parts of the world, but also in some of our Colonies. 
The number of illustrations has been increased by more than one hundred 
and thirty, the pages have been enlarged, and the letterpress so modified 
as to make reading and reference much easier. 

A copious index — there is none in the French edition — has also been 
added, with the view of enhancing the usefulness of the book as a work 
of reference for students and practitioners. 

With these alterations, additions, and modifications, I trust the work 
may continue to be accepted as in every way worthy of the position 
accorded to it as the best on the subject. 

The editorial remarks — for which, as well as for the translation, I 
assume the entire responsibility — are included in brackets, as in the first 
edition. 

GEORGE FLEMING. 
London, 

April, 1891. 



TABLE OF CONTENTS. 



Dedication 

Preface to the Second Edition 

Table of Contents 

Table of Illustrations 



Vll 

ix 

xxvii 



GENERAL CONSIDERATIONS. 



Definition and Division of Anatomy ....... 

Enumeration and Classification of the Species of Domesticated Animals 
General Ideas of the Organization of Animals, and the order followed in studying the 
various apparatuses ........ 



BOOK I. 




IiOCOMOTORY APPARATUS. 




[RST SECTION.— THE BONES 


7 


Chapter I.— The Bones in General .... 


7 


Article I. — The Skeleton ...... 


8 


Article II.— General Principles applicable to the Study of all 


the Bones 11 


Name, Situation, Direction, and Configuration of Bones 


12 


Internal Conformation of Bones. Structure of Bones 


15 


Development of Bones ...... 


19 


Chapter II.— The Bones of Mammalia in Particular 


24 


Article I.— Vertebral Column . . . . 


24 


Characters Common to all the Vertebrae .... 


24 


Characters Proper to the Vertebrae in each Region . 


26 


1. Cervical Vertebrae ...... 


27 


Differential Characters ...... 


30 


2. Dorsal Vertebrae ...... 


32 


Differential Ciiaracters ... , . 


35 


3. Lumbar Vertebrae ...... 


36 


Differential Characters ...... 


37 


4. Sacrum ....... 


39 


Differential Characters .... 


40 


5. Coccygeal Vertebrae ..... 


41 


Differential Characters ..... 


41 


The Spine in General ...... 


42 


Varieties in the Vertebral Column .... 


43 


Comparison of the Vertebral Column of Man with that of the 1 


Domesticated 


Animals ...... 


45 


Article II.— The Head . . . c . . 


46 


The Bones of the Cranium ..... 


46 


1. Occipital ....... 


46 


Differential Characters ..... 


48 


2. Parietal ....... 


49 


Differential Characters ..... 


49 


3. Frontal 


49 


Differential Characters ..... 


52 



TABLE OF CONTENTS. 



4. Ethmoid . 
DiflTerentiiil Characters 

5. Sphenoid . 

Diflferentiiil Characters 

6. Temporal . 
DiflFerential Characters 

The Bones of the B'ace . 

1. Supermaxillii . 
Diflferential Characters 

2. Premaxilla 
DiflFerential Characters 

3. Palatine 
Differential Characters 

4. Pterygoid 
Differential Characters 

5. Malar . 
Differential Characters 

6. Lachrymal 
Differential Characters 

7. Nasal . 
Differential Characters 

8. Turbinated 
Differential Characters 

9. Vomer . 
Differential Charaeters 

10. Inferior Maxilla 
Differential Characters 

11. Hyoid 
Differential Characters 

12. Wormian Bunes 
Of the Head in General . 

1. General Configuration 

2. Conformation of the Cranium in Particular 

3. Relations between the Cranium and Face . 

4. Modifications due to Age . 
Comparison of the Head of Man with that of Animals 

Article III. — The Tuobax 

The Bones of the Thorax in Particular 

Differential Characters 
Ribs ...... 

Differential Characters in the Ribs of other Animals 
The Thorax in General .... 

Comparison of the Thorax of Man with that of other Animals 

1. Sternum 

2. Ribs 
Article IV.— Anterior Limbs 

Shoulder 

Scapula . 

Differential Characters 
Arm 

Humerus 

Differential Ciiaracters 
Forearm 

1. Radius 

2. Ulna 
Differential Characters 

Anterior (or Fore) Foot, or Hand 

1. Carpal Bones . 
Differential Characters 

2. Metacarpal Bones 
Differential Characters 



TABLE OF CONTENTS. 



that of the Domesticated 



AND THEIR PARALLELISM 



8. Bones of the Phalanges or Digital Region .... 

Differential Characters ...... 

Comparison of tJje Thoracic Limb of Man with that of the Domesticated Animal 
Article V. — The Hand in General ..... 

Article VI. — Posterior or Pelvic Limb 
Pelvis .... 

A. Coxa, or Os Innomatura 

B. The Pelvis in General 
Differential Characters 

Thigh .... 

Femur .... 

Differential Characters 
Leg ..... 

1. Tibia 

2 Fibula, or Peroneus . . 

3. Patella 

Differential Characters 
Posterior Foot . 

1. Bones of the Tarsus 
Differential Characters 

2. Bones of the Metatarsus 
Differential Characters 

3. Bones of the Digital Region 
Differential Characters 

Comparison of the Abdominal Limb of Man with 
Animals. 
Article VII. — The Foot in General 
Article VIII. — The Limbs in General, 
Chapter III.— The Bones in Birds 
Chapter IV.— Theory of the Vertebral Constitution of the Skeleton 
SECOND SECTION —THE ARTICULATIONS .... 

Chapter I.— The Articulations in General .... 

General Characters of the Diarthroses ..... 

General Characters of the Synarthroses ..... 

General Characters of the Amphiarthroses, or Symphyses . 
Chapter II. — The Articulations in Mammalia in Particular . 
Article I. — Articulations op the Spine ..... 

Intervertebral Articulations ...... 

Differential Characters ....... 

Article II.— Articulations of the Head 

1. Atlo-axoid Articulation . . . . . . 

2. Occipito-atloid Articulation ..... 

3. Articulations between the Bones of tlie Head .... 

4. Temporo-maxillary Articulation ..... 

5. Hyoideal Articulations ....... 

Article III. — Articulations of the Thorax .... 

Extrinsic Articulations ....... 

Costo-vertebral, or Articulations of the Ribs with the Vertebral Column 
Intrinsic Articulations ....... 

A. Chondro-sternal or Costo-sternal Articulations 

B. Chondro-cdsta! Articulations, or Articulations between the Ribs and their 

Cartilages ... .... 

C. Articulations between the Costal Cartilages 

D. Sternal Articulation peculiar to the Ox and Pig 

The Articulations of the Thorax considered in a General Manner, with respect to 
their Movements .... 
A.RTICLE IV. — Articulations of the Anterior Limbs 

1. Scapulo-humeral Articulation 

2. Humero-radial Articulation 

3. Radio- ulnar Articulation 

4. Articulations of the Carpus . , 



xii 



TABLE OF CONTENTS. 



5. Intermetacarpal Articulations .... 

6. Metacarpo-plialangeal Articulations 

7. Articulation of the First Phalanx with the Second, or First 

Articulation .... 

8. Articulation of the Second Phalanx with tlie Third, Second Interphalangeal 

Articulation, or Articulation of the Foot 
, \bticle V. — Articulations of the Posterior Limbs 

1. Articulations of tlie Pelvis 

2. Coxo- femoral Articulation . 

3. Femoro-tibial Articulation 

4. Tibio- fibular Articulation . 

5. Articulations of the Tarsus, or Hock . 
Chapter III.— The Articulations in Birds . 

THIRD SECTION. -THE MUSCLES 

Chapter I.— General Considerations on the Striped Muscles 

The Striped Muscles in General ..... 

Structure of the Striped Muscles .... 

Physico-chemical Properties of Striped Muscles 

Physiological Properties of Striped Muscles 

Appendages of the Muscles ...... 

Manner of Studying the Muscles 
Chapter II.— The Muscles of Mammalia in Particular 
Article I. — The Muscles of the Trunk 

Subcutaneous Region ...... 

Flesliy Pannicuius (Panniculus Carnosus) 

Cervical Region ....... 

A. Superior Cervical or Spinal Region of the Neck 

1. Rhomboideus ...... 

2. Angularis Muscle of the Scapula (Levator Anguli Scapulae) 

3. Splenius ....... 

4. Complexus (Complexus Major) .... 

5. Trachelo-mastoideus (Complexus Minor) 

6. Spinalis or Semispinalis Colli .... 

7. Intertransversales Colli ..... 

8. Great Oblique Muscle of the Head (Obliquus Capitis Auticus or Inferioris) 

9. Small Oblique Muscle of the Head (Obliquus Capitis Posticus or 

Superioris) 

10. Great Posterior Straight Muscle of the Head (Rectus Capitis Posticus 

Major) ........ 

11. Small Posterior Straight Muscle (Rectus Capitis Posticus Minor) 
Differential Ciiaracters ....... 

B. Inferior Cervical or Trachelian Region 

1. Subcutaneous Muscle of the Neck (Cervical Panniculus) . 

2. Mastoido-humeralis (Levator Humeri) 

3. Sterno-maxillaris ...... 

4. Sterno-thyro-hyoideus ..... 

5. Subscapulo-hyoideus ...... 

6. Great Anterior Straight Muscle of the Head (Rectus Capitis Auticus 

Major) ........ 

7. Small Anterior Straight Muscle of the Head (Rectus Capitis Auticus 
Minor) ....... 

8 Small Lateral Straight Muscle (Rectus Capitis Lateralis) 
9. Scalenus ....... 

10. Long Muscle of the Neck (Longus Colli) 

Differential Characters ...... 

Spinal Region of the Back and Loins 

1. Trapezius ....... 

2. Great Dorsal (Latissimus Dorsi) 

3. Small Anterior Serrated Muscle (Seiratus Anticue) 

4. Small Posterior Serrated Muscle (Serratus Posticus) 

5. Ilio-spiualis Muscle (Longissimus Dorsi) 



TABLE OF CONTENTS. 



6. Common Intercostal Muscle (Transversalis Costarum) . 

7. Transverse Spinous Muscle of the Back and Loins (Semispinalis of the 

Back and Loins) ...... 

Differential Characters ..... 

Comparison of the Muscles of the Back, Neck, and Cervix in Man with 
analogous Muscles in tbe Domesticated Animals 

1. Muscles of the Back and Cervix .... 

2. Muscles of the Neck ..... 
Sublumbar or Inferior Lumbar Region .... 

1. Iliac Fascia or Lumbo-iliac Aponeurosis 

2. Great Psoas Muscle (Psoas Magnus) .... 
3 Iliac Psoas Muscle (Iliacns) .... 

4. Small Psoas Muscle (Psoas Parvus) .... 

5. Square Muscle of the Loins (Quadratus Lumborum) 

6. Intertransversales of the Loins (Intertraiisversales Lumborum) 
Differential Characters ...... 

Comparison of the Sublumbar Muscles of Man with those of Animals 
Coccygeal Region ...... 

1. Sacro-coccygeal Muscles .... 

2. Ischio-coccygeus (Compressor Coccygeus) . 
Region of the Head ...... 

A. Facial Region ...... 

1. Labialis or Orbicularis of the Lips (Orbicularis Oris) 

2. Zygomatico-labialis (Zygomaticus) 

3. Supermaxillo-labialis (Levator Labii Superioris Proprius, or Nasalis 

Longus) ...... 

4. Maxillo-labialis (Depressor Labii Inferioris) 

5. Mento-labialis, or Muscle of the Chin (Levator Menti) 

6. Intermediate Posterior Muscle .... 

7. Alveolo-labialis (Buccinator) .... 

8. Supernaso -labialis (Levator Labii Superioris alaequi Nasi) 

9. Great Supermaxillo-nasalis (Dilatator Naris Lateralis) 

10. Small Supermaxillo-nasalis (Dilatator Naris Superioris) . 

11. TransversalLs Nasi (Dilatator Naris Transversalis) . 

B. Palpebral Region ...... 

1. Orbicularis of the Eyelids (Orbicularis Palpebrarum) 

2. Frouto-Palpebral, or Corrugator Supercilii 

3. Lachrymalis Muscle ..... 

C. Auricular or Conchal Region .... 

1. Zygomaticus-auricularid (AttoUens Anticus) . 

2. Temporo-auricularis Externus (Attollens Maximus) 

3. Scuto-auricularis Externus .... 

4. Cervico-auriculares (Retrahentes Aurem) 

5. Parotido-auricularis (Abducens, or Deprimens Aurem) 

6. Temporo auricularis Internus (Attollens Posticus) 

7. Scuto-auricularis Internus .... 

8. Mastoido-auricularis ..... 

D. Masseteric or Temporo-maxillary Region 

1. Masseter. ...... 

2. Temporalis ...... 

3. Internal Pterygoid (Pterygoideus Internus) 

4. External Pterygoid (Pterygoideus Externus) 

5. Digastricus (Stylo-maxillaris) .... 
Z. Hyoideal Region ..... 

1. Mylo-hyoideus . . . ... 

2. Genio-hyoideus ..... 

3. Stylo-hyoideus ...... 

>. Kerato-hyoideus (Hyoideus Parvus) . , , 

J. Occipito-styloideus ..... 

6. Hyoideus Transversus .... 
Differential Characters ...... 



PAGE 

265 



jdT 



TABLE OF CONTENTS. 



1. Facial Regrion . > . . 

2. Palpebral Region . « . . . 

3. Masseteric or Temporo-maxillary Region . 

4. Hyoideal Region . . . . . 
Comparison of the Muscles of the Human Head with those of the Domesticated 

Animals . ...... 

1. Epicranial Muscles ..... 

2. Muscles of the Face ..... 

3. Muscles of the Lower Jaw . „ . . 

4. Hyoideal Muscles . . , . . 
Axillary Region ... , . 

1. Superficial Pectoral (Pectoralis Anticus and Transversua) . 

2. Deep Pectoral (Pectoralis Magnus and Parvus) , 
Differential Characters ...... 

Costal Region .... . 

1. Serratus Magnus ...... 

2. External Intercostala . . . 

3. Internal Intercostuls o . . . . 

4. Leva tores Costarum ..... 

5. Triangularis Stemi ..... 
Differential Characters ..... 
Comparison of the Thoracic Muscles of Man with those of the Domesticated 

Animals ...... 

Inferior Abdominal Region ..... 

1. Abdominal Tunic (Tunica Abdominalis, Tunica Elastica) 

2. White Line (Linea Alba) ..... 

3. Great or External Oblique of the Abdomen (Obliquus Abdominis 

Externus) .... ... 

4. Small or Internal Oblique of the Abdomen (Obliquus Abdominis 

Internus) ....... 

5. Great Straight Muscle of the Abdomen (Rectus Abdominis) 

6. Transverse Muscle of the Abdomen (Transversalis Abdominis) 
Differential Characters ...... 

Comparison of the Abdominal Muscles of Man with those of Animals 
Diaphragmatic Region . . o . . 

Diaphragm . . . . . . = . . 

Differential Characters ....... 

Comparison of the Diaphragm of Man witli that of Animals 
Article II. — Muscles of the Anterior Limbs . « . o 

Muscles of the Shoulder . . .... 

A. External Scapular Region ..... 

1. External Scapular Aponeurosis ...... 

2. Long Abductor of the Arm, or Scapular Portion of the Deltoid (Teres 

Externus) ..... . . 

3. Short Abductor of the Arm (Po.itea Spinatus Minor), or Teres Minor 

4. Supra-spinatus (Antea Spinatus) . . . . 

5. lufra-spinatus (Postea Spinatus) ..... 

B. Internal Scapular Region ....... 

1. Subscapuliiris ..... 

2. Adductor of the Arm (Teres Internus, or Teres Major) 

3. Coraco-humeralis, Coraco-brachialis, or Omo-brachialis 

4. Small Scapulo-humeralis (Scapulo-Humeralis Gracilis, Scapulo-Hume- 

ralis Posticus) ....... 

Differential Characters ........ 

Comparison of the Muscles of the Shoulder of Man with those of Animals . 
Muscles of the Arm . . , . . . 

A. Anterior Brachial Region ... . . 

1. Long Flexor of the Forearm (Flexor Braehii), or Brachial Biceps 

2. Short Flexor of the Forearm (Humeralis Obliquus, Brachialis Anticus, 

or Humeralis Externus) ...... 

B. Posterior Brachial Region , o ... 



PAGE 

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292 

292 
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296 
296 
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297 
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299 
299 



300 



305 
305 
307 
307 
308 
308 
310 
310 
310 
310 
310 
311 

311 
312 
312 
313 
314 
314 
315 
315 

316 
316 
316 
316 
317 
317 



319 



TABLE OF CONTENTS. 



1. Large Extensor of the Forearm (Caput Magnum) 

2. Short Extensor of the Forearm (Caput Medium) 

3. Middle Extensor of the Forearm (Caput Parvum), luternal portion of the 

Triceps ....... 

4. Small Extensor of the Forearm, or Anconeus 
Dififerential Characters ....... 

Comparison of the Muscles of the Arm of Man with those of Animals 
Muscles of the Forearm ....... 

Antibrachial Aponeurosis ...... 

A. Anterior Antibrachial Region ..... 

1. Anterior Extensor of the Metacarpus (Extensor Metacarpi Magnus) 

2. Oblique Extensor of the Metacarpus (Extensor Metacarpi Obliquus) 

3. Anterior Extensor of the Plialanges (Extensor Pedis) 

4. Lateral Extensor of the Phalanges (Extensor Suffragiuis) 

B. Posterior Antibrachial Region ..... 

1. External Flexor of the Metacarpus (Flexor Metacarpi Externus, or Pos- 

terior Ulnaris) .... 

2. Oblique Flexor of the Metacarpus (Flexor Metacarpi Medius, or Anterior 

Ulnaris) ........ 

3. Internal Flexor of the Metacarpus (Flexor Metacarpi laternus, or Pal 

maris Magnus) ...... 

4. Superficial Flexor, Sublimis of the Phalanges (Flexor Pedis Perforatus) 

5. Deep Flexor of the Phalanges (Flexor Pedis Perforans) . 
Dififerential Characters .... 

Muscles proper to the Forearm in Carnivora . 

1. Proper Extensor of the Tliumb and Index 

2. Long Supinator .... 

3. Short Supinator .... 

4. Round Pronator .... 

5. Square Pronator ...... 

Comparison of the Muscles of the Forearm of Man with those of Animals 

1. Anterior Region ...... 

2. External Region .... 

3. Posterior Region .... 
Muscles of the Anterior Foot or Hand . 

A. Muscles of the Anterior Foot in Carnivora 
1 Short Abductor of tlie Thumb 

2. Opponens of the Thumb 

3. Short Flexor of the Thumb 

4. Adductor of the Index 

5. Cutaneous Palmar (Palmaris Brevis) 

6. Adductor of the Small Digit 

7. Short Flexor of the Small Digit 

8. Opponens of the Small Digit 

9. Lumbrici ..... 
10. Metacarpal Interosseous Muscles 

B. Muscles of the Anterior Foot in the Pig . 

C. Muscles of the Anterior Foot in Solipeds 

D. Muscles of the Anterior Foot in Ruminants 
Comparison of the Hand of Man with that of Animals 

A. Muscles of the Thenar Eminence . 

B. Muscles of the Hypothenar Eminence . 

C. Interosseous Muscles .... 
Article III.— Muscles of the Posterior Limbs 

Muscles of the Gluteal Region, or Croup 

1. Superficial Gluteus (Gluteus Externus) 

2. Middle Gleuteus (Gluteus Medius, Gluteus Maximus) 

3. Deep Gluteus (Gluteus Internus) 
Dififerential Characters ..... 
Comparison of the Gluteal Muscles of Man with those of Animals 
Muscles of the Thigh .... 



PAGE 

319 
320 



rvi TABLE OF CONTENTS. 



A. Anterior Crural, or Femoral Region .... 

1. Muscle of the Fascia Lata (Tensor Fascia Latae, Tensor Vaginae Femoris) 

2. Crural Triceps ....... 

3. Crureus, Rectus Parvus, Anterior Gracilis 

B. Posterior Crural Region ...... 

1. Biceps Femoris, Triceps Abductor Femoris 

2. Semitendinosus Muscle (Biceps Rotator Tibialis) . 

3. Semimembranosus (Adductor Magnus) .... 

C. Internal Crural Region ...... 

1. Great Adductor of the Leg (Sartorius) .... 

2. Short Adductor of the Leg (Gracilis) .... 

3. Pectineus . ... 

4. Small Adductor of the Thigh (Adductor Parvus, Adductor Brevis) . 

5. Great Adductor of the Thigh (Adductor Maguus, Adductor Longus) 

6. Quadrate Crural (Quadratus Femoris, Iscliio-Femoralis) 

7. External Obturator (Obturator Externus) 

8. Internal Obturator (Obturator Internus) .... 

9. Gemelli ....... 

Differential Characters ....... 

1. Anterior Crural Region ...... 

2. Posterior Crural Region ...... 

3. Internal Crural Region ...... 

Comparison of the Muscles of Man's Thigh with those of the Thigh of Animals 

1. Anterior Muscles ....... 

2. Muscles of the Posterior Region ..... 

3. Muscles of the Internal Region ..... 

Muscles of the Leg .... . . 

Tibial Aponeurosis ........ 

A. Anterior Tibial Region ...... 

1. Anterior Extensor of the Phalanges (Extensor Pedis) 

2. Lateral Extensor of the Phalanges (Peroneus) . 

3. Flexor of the Metatarsus (Flexor Metatarsi) 

B. Posterior Tibial Region ...... 

1. Gastrocnemius, or Gemelli of the Tibia (Gastrocnemius Externus) . 

2. Soleus (Plitntaris) ...... 

3. Superficial Flexor of the Phalanges (Flexor Perforatus, Gastrocnemius 

Internus) . . ..... 

4. Popliteus ....... 

5. Deep Flexor of the Phalanges (Perforans, Flexor Pedis) 

6. Oblique Flexor of the Phalanges (Flexor Accessorius) . 
Differential Characters ...... 

1. Anterior Tibial Region ...... 

2. Posterior Tibial Region ...... 

Comparison of the Muscles of the Leg of Man with those of Animals . 

1. Anterior Region ....... 

2. External Region ....... 

3. Posterior Region ....... 

Muscles of the Posterior Foot 

Pedal Muscle (Extensor Pedis Brevis, Extensor Brevis Digitorum) . 

Differential Characters ....... 

Comparison of the Muscles of the Foot of Man with those of Animals 

\. Dorsal Region ....... 

2. Plantar Region ....... 

3. Interosseous Muscles .... 
Chapter IIL— The Muscles in Birds ..... 
Chapter IV.— General Table of the Attachment of the Muscles in 

Solipeds ....... 



^^ 



TABLE OF CONTENTS. 



XTii 



BOOK 11. 



THE DIGESTIVE APPARATUS. 

Chapter I.— General Considerations on the Digestive Apparatus 
Chapter II.— The Digestive Apparatus in Mammalia 
Article I.— Preparatory Organs of the Digestive Apparatus . 
The Mouth ....... 

1. Lips ........ 

2. Cheeks ....... 

3. Palate ....... 

4. Tongue ....... 

5. Soft Palate ....... 

6. Teeth ....... 

7. The Mouth in General ..... 
DifiFerential Characters in the Mouth of the other Animals 

Comparison of the Mouth of Man with that of Animals 

Table of Dentition ...... 

The Salivary Glands ...... 

1. Parotid Gland ...... 

2. Maxillary or Submaxillary Gland .... 

3. Sublingual Gland ...... 

4. Molar Glands ....... 

5. Labial, Lingual, and Staphyline Glands 
DiflFereutial Characters in the Salivary Glands of the other Animals 

Comparison of the Salivary Glands of Man with those of Animals 
The Pharynx ....... 

DiflFereutial Characters in the Pharynx of the other Animals . 
Comparison of the Pharynx of Man with that of Animals 
The (Esophagus ...... 

DiflFereutial Characters in the (Esophagus of the other Animals . 
Comparison of the (Esophagus of Man with that of Animals 
Article II. — The Essential Organs of Digestion 
The Abdominal Cavity ..... 

DiflFereutial Characters in the Abdominal Cavity of the other Animals 
Comparison of the Abdominal Cavity of Man with that of Animals 
The Stomach ....... 

1. The Stomach of Solipeds .... 

DiflFereutial Characters in the Stomach of the other Animals 

1. The Stomach of the Rabbit . . . . 

2. The Stomach of the Pig .... . 

3. The Stomach of Carnivora ..... 

4. The Stomach of Ruminants ..... 
Comparison of the Stomach of Man with that of Animals 
The Intestines ....... 

1. The Small Intestine ..... 

2. The Large Intestine ...... 

A. Csecum ....... 

B. Colon ....... 

0. Rectum ....... 

Diflferential Characters in the Intestines of the other Animals 

1. The Intestines of the Rabbit .... 

2. The Intestines of Ruminants .... 

3. The Intestines of the Pig .... 

4. The Intestines of Carnivora . .... 
Comparison of the Intestines of Man with those of Animals 
General and Comparative Survey of the Abdominal or Essential Portion of the 

Digestive Canal ...... 

Organs Annexed to the Abdominal Portion of the Digestive Canal 

1. Liver ....... 

2. Pancreas ....... 

8. Spleen ..... 



TABLE OF CONTENTS. 



Diflferential Characters in the Organ8 annexed to the Abdonainal Portion of the 

Digestive Canal in the other Animals ..... 508 
Comparison of the Organs annexed to the Abdominal Portion of the Digestive 

Canal of Man with those of Animals ..... 510 

Chapterlll.— The Digestive Apparatus of Birds . . . .511 



BOOK III. 

RESPIRATORY APPARATUS. 

Chapter I.— Respiratory Apparatus in Mammalia ... 517 

The Nasal Cavities ...... c . 517 

1. The Nostrils ....... 518 

2. The Nasal Fossae .... . . 519 

3. The Sinuses ..... , . 524 
DifTerential Characters in the Nasal Cavities of the other Animals . . 526 

Comparison of the Nasal Cavities of Man with those of Animals . 527 

The Air- tube succeeding the Nasal Cavities ..... 527 

1. The Larynx ........ 527 

2. The Trachea ....... 536 

3. The Bronchi ........ 539 

Differential Characters in the Air-tube succeeding the Nasal Cavities in the 

other Animals ........ 541 

Comparison of the Larynx and Trachea of Man with these Organs in the 

Domesticated Animals ....... 542 

The Thorax ......... 542 

Differential Characters in the Thorax of the other Animals . . 545 

The Lungs ......... 546 

Differential Characters in the Lungs uf the other Animals . . 552 

Comparison of the Larynx, Trachea, and Lungs of Man with those of Animals . 553 

The Glandiform Bodies connected with the Respiratory Apparatus . 554 

1. The Thyroid Body or Gland . . . . . .554 

2. The Thymus Gland ....... 555 

Differential Characters in the Glandiform Bodies annexed to the Respiratory 

Apparatus in the other Animals ...... 556 

Comparison of the Glandiform Bodies annexed to the Respiratory Apparatus 

in Man with those of Animals ...... 557 

Chapter II.— The Respiratory Apparatus of Birds . . .557 



BOOK IV. 
URINARY APPARATUS. 

1. The Kidneys 568 

2. The Ureters ........ 574 

3. The Bladder 575 

4. The Urethra . . . . . . . . 578 

5. The Supra-renal Capsules ...... 578 

Differential Characters of the Urinary Apparatus in the other Animals . 579 

Comparison of the Urinary Apparatus of Man with that of Animals . 581 

BOOK V. 
CIRCULATORY APPARATUS. 

rlRST SECTION.— THE HEART . .... 583 

1. The Heart as a Whole ...... 583 

2. External Conformation of the Heart ..... 584 

3. Internal Conformation of the Heart ..... 587 



TABLE OF CONTENTS. 



4. Structure of the Heart .... 

5. The Pericardium ..•••• 

6. The Action of the Heart 
Differential Characters in the Heart of the other Animals 

Comparison of the Heart of Man with that of Animals . 
SECOND SECTION.— THE ARTERIES 
Chapter I.— General Considerations . 
Chapter II.— Pulmonary Artery . 
Chapter III.— Aorta ..... 
Article I.— Common Aorta, or Aortic Trunk 

Cardiac, or Coronary Arteries, 
Article II. — Posterior Aorta .... 

Parietal Branches of the Posterior Aorta 

1. Intercostal Arteries .... 

2. Lumbar Arteries .... 

3. Diphragmatic Arteries .... 
Middle Sacral Artery .... 

Visceral Branches of the Posterior Aorta . 

1. Broncho-CEsophageal Trunk 

2. Cceliac Artery ..... 

3. Anterior or Great Mesenteric Artery 

4. Posterior or Small Mesenteric Artery 

5. Renal or Emulgent Arteries 

6. Spermatic Arteries . . . ' • 

7. Small Testicular Arteries (Male), Uterine Arteries (Female) 
Differential CLaracters in the Posterior Aorta and its Collateral Branches in 

the other Animals . . . . • 

1. Posterior Aorta in Ruminants 

2. Pesterior Aorta in the Pig .... 

3. Posterior Aorta in Carnivora 
Comparison of the Aorta of Man with that of Animals 

Article III.— Internal Iliac Arteries, or Pelvic Trunks 

1. Umbilical Artery . . • • • 

2. Internal Pudic Artery, or Artery of the Bulb 

3. Lateral Sacral or Subsacral Artery 

4. Ilio-lumbar Artery, or Iliaco-muscular 

5. Gluteal Artery . . . • • 

6. Obturator Aitery . . • • • 

7. Uiaco-femoral Artery . . • • • •. 
Differential Characters in the Internal Iliac Arteries of the other Animals 

1. Internal Iliac Arteries of Ruminants 

2. Internal Iliac Arteries of the Pig 

3. Internal Iliac Arteries of Carnivora .... 
Comparison of the Internal Iliac Arteries of Man with those of Animals 

iiETicLE IV.— External Iliac Arteries, or Crural Trunks 
Femoral Artery ...••• 

1. Prepubic Artery . • • * . " ^ x," 

2. Profunda Femoris, Great Posterior Muscular Artery of the 

Deep Muscular Artery . . • • • 

3. Superficialis Femoris, Superficial Muscular, or Great Anterior 

Artery ..-•••• 

4. Innominate or Small Muscular Arteries . 

5. Saphena Artery ..•••• 
Popliteal Artery ..•••• 
Terminal Branches of the Popliteal Artery 

1. Posterior Tibial Artery . . • • • 

2. Anterior Tibial Artery . . . • • 

3. Pedal Artery . • • • ',/»., 
Differential Characters in the External Iliac Arteries of the other Animals 

1. External Iliac Arteries of Ruminants 

2. External Iliac Arteries of the Pig .... 



Thigh 



Muscular 



TABLE OF CONTENTS. 



3. External Iliac Arteries of Carnivora. 
Comparison of the External Iliac Arteries of Man with those of Animals 
Article V. — Anterior Aorta ..... 

Article VI.— Brachial Trunks, or Axh.lary Arteries 
Collateral Branches of the Axillary Arteries 

1. Dorsal, Dorso-muscular. or Transverse Cervical Aiteiy . 

2. Superior Cervical, Cervico-muscuiar, or Deep Cervical Artery 

3. Vertebral Artery ...... 

4. Internal Tiioiacic Pectoral, or Internal Mammary Artery 

5. External, Infi-rior Thoracic, or External Mammary Artery 

6. Inferior Cervical Artery . ^ . . . 

7. Supra-scapular Artery ...... 

8. Infra-scapular or Subscapular Artery 
Humeral Artery, or Terminal Artery of the Brachial Trunk . 

1. Anterior Radial (or Spiral) Artery .... 

2. Posterior Radial Artery ...... 

(1) First Terminal Branch of the Posterior Radial (Radio-Palmar) Artery, 
ur Common Trunk of the Interosseous Metacarpals 

(2) Second Terminal Branch of the Posterior Radial Artery, or Collateral 

Artery of the Cannon .... 

Dififerential Characters in the Axillary Arteries of tht other Animals 

1. Axillary Arteries of Ruminants .... 

2. Axillary Arteries of the Pi^ .... 

3. Axillary Arteries of Carnivora .... 
Comparison of the Axillary Arteries of Man with those of Animals 

Article VII.— Common Carotid Arteries .... 

Occipital Artery ...... 

Internal Carotid Artery ...... 

External Carotid Artery ...... 

Collateral Branches of the External Carotid Artery 

1. Submaxillary, Facial, or Glosso-facial Artery 

2. Maxillo-muscular Artery ..... 

3. Posterior Auricular Artery . . . '. 
Terminal Branches of the External Carotid Artery 

1. Superficial Temporal Artery, or Temporal Trunk 

2. Internal Maxillary, or Gutturo-maxillary Artery 
Differential Chaiaftt-rs in the Carotid Arteries of the other Animals 

1. Carotid Arteries of Carnivora .... 

2. Carotid Arteries of the Pig .... 

3. Carotid Arteries of Ruminants .... 
Comparison of the Carotid Arteries of Man with those of Animals 

THIRD SECTION. -THE VKINS ..... 

Chapter I.— General Considerations . 
Chapter II.— Veins of the Lesser Circulation, or Pulmonary Veins 
Chapter III.— Veins of the General Circulation 
Article I.— Cardiac or Coronary Veins 
Abticle II. — Anterior Vena Cava 

Jugular Veins ..... 
Roots of the Jugular .... 

1. Superficial Temporal Vein 

2. Internal Maxillary Vein . 

3. The Sinuses of the Dura Mater 
Axillary Veins .... 

1. Brachial or Subscapular Vein 

2. Humeral Vein .... 

3. Subcutaneous Thoracic or Spur Vein 

4. Deep Veins of the Forearm 

5. Superficial Veins of the Forearm 

6. Metacarpal Veins 

7. Digital Veins .... 

8. Veins of the Ungual Region, or Foot 



TABLE OF CONTENTS. 



a External Venous Apparatus 
b. Internal or lutra-osseous Venous Apparatus 
Article III. — Posterior Vena Cava 
Plirenic or Diaphragmatic Veins 
Vena Portse 

1. Roots of the Vena Portse 

2. Collateral AflBnents of the Vena Portse 
Renal Veins . 
Spermatic Veins . 
Lumbar Veins 
Common Iliac Veins 

1. Internal Iliac Vein 

2. External Iliac Vein . 

3. Femoral Vein 

4. Popliteal Vein 

5. Deep Veins of the Leg 

6. Superficial Veins of the Leg 

7. Metatarsal Veins 

8. Veins of the Digital Region 
Diiferential Characters in the Veius of the other Animals 

Comparison of the Veins of Man with those of Animals 
FOURTH SECTION.— THE LYMPHATICS 
Chapter I. — General Considerations 

Lymphatic Vessels ..... 
Lymphatic Glands, or Ganglia 
Chapter II.— The Lymphatics in Particular 
Article I. — The Thoracic Duct . • • 

Article II.— The Lymphatics which constitute the Affluents of the Thoracic 
Duct . 



Lymphatics of the Abdominal Limb, Pelvis, 
inguinal Organs 



Abdominal Parietes, and Pelvi 



1. Sublumbar Glands 

2. Deep Inguinal Glands 

3. Superficial Inguinal Glands 

4 Popliteal Glands 

5. Iliac Glands 

6. Precrural Glands 
Lymphatics of the Abdominal Viscera 

1. Glands and Lymphatic Vessels of the Rectum and Floating Colon 

2. Glands and Lymphatic Vessels of the Double Colon 

3. Glands and Lymphatic Vessels of the Csecum 

4. Glitnds and Lymphatic Vessels of the Small Intestine 

5 Glands and Lymphatic Vessels of the Stomach 
6. Glands and Lymphatic Vessels of the Spleen and Liver . 

Glands and Lymphatic Vessels of the Organs contained in the Thoracic Cavity 
Glands and Lymphatic Vessels of the Thoracic Parietes 
Lyijiphatic Vessels of the Head, Neck, and Anterior Limb 

1. Prepectoral Glands ..... 

2. Pharyngeal Glands ..... 

3. Submaxillary, or Subglossal Glands 

4. Prescapular Glands ..... 

5. Brachial Glands ...... 

Article III. — Great Lymphatic Vein 

Diflerential Characters in the Lymphatics of the other Animals 
Chapter III.— The Circulatory Apparatus in Birds . 
Article I.— The Heart ...... 

Article II. — The Arteries ..... 

Article III.— The Veins • . , , , 

Article IV. — The Lymphatics 



xm TABLE OF CONTENTS. 

BOOK VI. 
APPARATUS OF INNERVATION. 

FIRST SECTION.— THE NERVOUS SYSTEM IN GENERAL 

General Conformation of the Nervous System 
Structure of the Nervous System .... 

Properties and Functions of the Nervous Systems .... 
SECOND SECTION.— THE CENTRAL AXIS OF THE NERVOUS SYSTEM 
Chapter I.— Protective and Enveloping Parts of the Cerebro-spinal Axis 
The Bony Case containing the Central Cerebro-spinal Axis 

1. The Spinal Canal 

2. The Cranial Cavity . 
The Envelopes of the Cerebro-spinal Axis 

1. The Dura Mater 

2. The Arachnoid .... 

3. The Pia Mater ....... 

Differential Characters in the Protecting and Enveloping Parts of the Cerebro- 
spinal Axis in the other Animals . 

Comparison of the Protective and Enveloping Parts of the Cerebro-spinal Axis 
of Man with those of Animals ...... 

Chapter II.— The Spinal Cord ...... 

External Conformation of the Spinal Cord 
Internal Conformation and Structure of the Spinal Cord 
Differential Characters in the Spinal Cord of the other Animals . 
Comparison of the Spinal Cord of Man with that of Animals 
Chapter III.— The Brain, or Eneephalon .... 

Article I.— The Brain as a Whole ..... 

Article II. — The Isthmus ...... 

External Conformation of the Isthmus .... 

1. The Medulla Oblongata ..... 

2. The Pons Varolii ...... 

3. The Crura Cerebri ...... 

4. The Crura Cerebelli ...... 

5. The Valve of Vieusseus ..... 

6. The Corpora Quadrigemina, or Bigemina 

7. The Optic Tiialami ...... 

8. The Pineal Gland ...... 

9. The Pituitary Gland ..... 
Internal Conformation of the Isthmus ..... 

1. The third or Middle Ventricle, or Ventricle of the Thalami Optici 

2. The Aqueduct of Sylvius ..... 

3. The Posterior, or Cerebellar Ventricle 
Structure of the Isthmus ...... 

Differential Characters in the Isthmus of the other Animals 

Comparison of the Isthmus of Man with that of Animals 
Article III. — The Cerebellum ..... 

1. External Conformation of the Cerebellum .... 

2. Internal Conformation of the Cerebellum 
Differential Characters of the Cerebellum in the other Animals 

Comparison of the Cerebellum of Man with that of Animals 
Article IV. — The Cerebrum ...... 

External Conformation of the Cerebrum . 

1. The Longitudinal Fissure 

2. The Cerebral Hemispheres . 
Internal Conformation of the Brain 

1. The Corpus Callosum 

2. The Lateral or Cerebral Ventricles 
8. The Septum Lucidum 

4. The Trigonum, or Fornix 

5. The Hippocampi 



TABLE OF CONTENTS. 



xxiii 



6. The Corpora Striata .... 

7. The Choroid Plexus and Velum Interpositum 
Structure of the Brain .... 
DifFereutial Characters in the Brain of the other Animals 

Comparison of the Cerebrum of Man with that of Animals 
THIKD SECTION.— THE NERVES* . 
Chapter I.— The Cranial or Encephalic Nerves 

1. First Pair, or Olfactory Nerves 

2. Second Pair, or Optic Nerve* 

3. Third Pair, or Common Oculo-:JIotor Nerves 

4. Fourth Pair, or Pathetici Nerves . 

5. Fifth Pair, or Trigeminal Nerves 

6. Sixth Pair, or External Motor Ocular Nerves 

7. Seventh Pair, or Facial Nerves 

8. Eighth Pair, Auditory, or Acoustic Nerves 

9. Ninth Pair, or Glosso-Pharyngeal Nerves 

10. Tenth Pair, Vagus, or Pneumogastric Nerves 

11. Eleventh Pair, Spinal, or Accessory Nerves of the Pneumogastrics 

12. Twelfth Pair, or Great Hypoglossal Nerves 
Differential Characters in the Cranial Nerves of the other Animals 

Comparison of the Cranial Nerves of Man with those of Animals 
Chapter II.— Spinal Nerves ... 

Article I.— Cervical Nerves (Eight Pairs) 
Article II.— Dorsal Nerves (Seventeen Pairs) 
Article III. — Lumbar Nerves (Six Pairs) 

Article IV.— Sacral Nerves (Five Pairs) .... 
Article V. — Coccygeal Nerves (Six to Seven Pairs) 
Article VI. — Composite Nerves formed by the Inferior Branches of 

Spinal Branches ...... 

Diaphragmatic (or Phrenic) Nerve .... 

Brachial Plexus ....... 

1. Diaphragmatie Branches ..... 

2. Levator Anguli Scapulae and Rhomboideal Branch 

3. Serratus Magnus, or Superior Thoracic Branch . 

4. Pectoral or Inferior Thoracic Branches 

5. Subcutaneous Thoracic Branch .... 

6. Latissimus Dorsi Branch .... 

7. Axillary or Circumflex Nerve .... 

8. Nerve of the Teres Major .... 

9. Subscapular Branches .... 

10. Supra-scapular Nerve 

11. Anterior Brachial or Musculo-Cutaneous Nerve . 

12. Radial (or Mu^culo-spiral) Nerve 

13. Ulnar or Culdto-cutaneous Nerve 

14. Median or Cubito-plantar Nerve 
Differential Characters in the Brachial Plexus of the other Animals 

Compa4son of the Brachial Plexus of Man with that of Animals 
Lumbo-Sacral Plexus ...... 

A. Anterior Portion ..... 

1. Iliaco-muscular Nerves .... 

2. Crural or Anterior Femoral Nerve 

3. Obturator Nerve ..... 

B. Posterior Portion ..... 

4. Small Sciatic or Anterior and Posterior Gluteal Nerves 

5. Great Sciatic or Great Femoro-popliteal Nerve 
Collateral Branches ...... 

Terminal Branches ...... 

Differential Characters in the Lumbo-sacral Plexus of the other Animals 

Comparison of the Lumbo-sacral Plexus in Man with that of Animals 
Chapter III.— The Great Sympathetic .... 

1. Cranial Portion of the Sympathetic .... 



887 



TABLE OF CONTENTS. 



2. Cervical Portion of the Sympathetic .... 

3. Dorsal Portion of the Sympathetic .... 

4. Lumbar Portion of the Sympathetic .... 

5. Sacral Portion of the Sympathetic ... 
Differential Characters in the Great Sympathetic of the other Animals 

Ciimparison of the Great Sympathetic of Man with that of Animals . 
Chapter IV.— The Nervous System of Birds .... 



PAGE 

887 
891 
892 
893 
894 
894 



BOOK VII. 



APPARATUSES OF SENSE. 

Chapter I.— Apparatus of Touch . . . . - 

Article I. — The Skin ...... 

Article II. — The Appendages of the Skin . . . 

Hairs ........ 

Horny Productions ...... 

1. The Hoof of Solipeds ..... 

a. The Parts container! in the Huof .... 

b. Description of the Hoof .... 

2. The Claws of Kuminants and Pachyderms 

3. The Claws of Carnivora ..... 

4. The Frontal Horns ...... 

5. The Chestnuts ...... 

(6. The Ergots). ...... 

Chapter II.— Apparatus of Taste .... 

Differential Characters in the Apparatus of Taste in the other Animals 
Comparison of the Apparatus of Taste in Man with that of Animals 
Chapter III.— Apparatus of Smell ..... 
Chapter IV.— Apparatus of Vision .... 
Article I.— Essential Organ of Vision, or Ocdlar Globe 

Membranes of the Eye ..... 

A. Fibrous Membranes ...... 

1 The Sclerotica ...... 

2. The Cornea ...... 

B. Musculo-vascular . . c . . 

1. The Choroid Membrane . , , . . 

2. The Iris ...... 

C. Nerve Membrane ...... 

3. The Betina ...... 

The Media of the Eye ...... 

1. Crystalline Lens ...... 

2. Vitreous Humour . . ... 

3. Aqueous Humour ..... 
Article II.— Accessory Organs of the Visual Apparatus 

Orbital Cavity ...... 

Muscles of the Globe of the Eye ..... 

Protective Organs of the Eye ..... 

1. Eyelids ....... 

2. Membrana Nictitans ..... 

Lachrymal Apparatus ...... 

Differential Characters in the Visual Apparatus of the other Animals 

Comparison of the Visual Apparatus of Man with that of Animals . 
Chapter V.— Auditory Apparatus .... 
Article I. — Internal Ear, or Labyrinth .... 
The Osseous Labyrinth ..... 

1. The Vestibule ...... 

2. The Semicircular Canals .... 



899 
904 
904 
907 
908 
908 
914 
921 
921 
922 
922 
922 
922 
924 
924 
924 
925 
926 
927 
927 
927 



929 



933 
936 
936 
937 
938 
938 
938 
939 
941 
941 
943 
944 
946 
947 
947 
947 
947 
948 



TABLE OF CONTENTS. 



3. The Cochlea 
The Membranous Labyrinth 

1. The Membranous Vestibule 

2. The Membranous Semicircular Canals 

3. The Membranous Cochlea 
Fluids of the Labyrinth . . . . , 
Distribution and Termination of the Auditory Nerve in the Membranous 

Labyrinth ••■•.. 

Article II.— Middle Ear, ob Case of the Tympanum 

1. Membrane of the Tympanum .... 

2. The Promontory, Fenestra Ovalis, and Fenestra, Rotunda 

3. The Mastoid Cells .... 

4. The Bones of the Middle Ear 

5. The Mucous Membrane of the Tympanum 

6. The Eustachian Tube 

7. Tlie Guttural Pouches . 
Article III.— The External Ear . 

The External Auditory Canal. 
The Concha, or Pavilion . 

1. Cartilages of the Concha. 

2. Muscles of the External Ear . 

3. Adipose Cushion of the External Ear 

4. Integuments of the External Ear 
Differential Characters in the Auditory Apparatus of the other Animals 

Comparison of the Auditory Apparatus of Man with that of Animals 



PAGE 

948 
949 
949 
950 
950 
951 

951 
951 
951 
952 
953 
953 
955 
955 
956 
957 
957 
957 
958 
958 
958 
958 
958 
958 



BOOK VIII. 

GENERATIVE APPARATUS. 

Chapter I.— Genital Organs of the Male 

Tiie Testicles, or Secretory Organs of the Semen . 

1. The Tunica Vaginalis . . 

2. The Testicles . . .'.*.*." 
Excretory Apparatus of the Semen . 

1. The Epididymis and Deferent Canal. ..'.*. 

2. The Vesiculse Seminales and Ejaculatory Ducts 

3. The Urethra . . . •.".*." 

4. The Glands annexed to the Urethra .'.'.'.* 

5. The Corpus Cavernosum . . 

6. The Penis 

Diiferential Characters in the Male Genital Organs of the otlier Animals . 
Comparison of the Genital Organs of Man with those of Animals 
Chapter II.— Genital Organs of the Female 
1 The Ovaries .... 

2. The Fallopian or Uterine Tubes, or Oviducts 

3. The Uterus .... ... 

4. The Vagina . • . . 

5. The Vulva . . .'.'.*.' 

6. The Mammae 

Differential Characters in tlie Female Genital Organs of the othpr Animals . 
Comparison of the Genital Organs of Woman with those of Domesticated Female 
Animals 
Chapter III.— Generative Apparatus of Birds ... * 

1. Male Generative Organs ...... 

2. Female Generative Organs ..... 



960 
960 
963 
967 
967 
968 
970 
973 
973 
975 
976 



984 



993 
995 
997 
999 

1002 
1003 
1003 
1004 



UTi 



TABLE OF CONTENTS. 



BOOK IX. 



EMBRYOLOGY. 

Chapter I. -The Ovum and its Sarly Embryonic Developments 

Article I.— The Ovum ...... 

Article II. — First Embryonic Developments .... 

Article III. — General Direction of Development.— Vertebral Type 
Chapter II.— The Foetal Envelopes of Solipeds 

1. The Chorion ...... 

2. The Amniou ..... 

3. The Allantois ....... 

4. The Umbilical Vesicle . . ... 

5. The Placenta ....... 

6. The ITmbilical Cord ... . . 
Differential Cliaracters in the Annexes of the Foetus of the other Animals 

Comparison of the Annexes of the Human Foetus with those of Animals 
Chapter III.— Development of the Foetus 
Article I.— Formation of the Embryo ..... 

Development of the Chorda Dorsalis and Vertebral Laminae 
Article II. — Development of the Various Organs in the Animal Economy 

Development of the Nervous System. 

Development of the Organs of Sense 

Development of the Locomotory Apparatus . 

Development of the Circulatory Apparatus 

Development of the Respiratory Apparatus . 

Development of the Digestive Apparatus 

Development ot the Genito-urinary Apparatus 



PAGR 

1005 
1005 
1005 
1011 
1016 
1018 
1019 
1019 
1023 
1023 
1025 
1027 



1032 
1032 
1033 
1033 
1035 
1038 
1040 
1045 
1046 
1049 



TABLE OF ILLUSTRATIONS. 



FIG. 
1. 

2. 
3. 
4. 
5. 



Skeleton of the Dog . 

Skeleton of the Cat . . 

Skeleton of the Pig . 

Skeleton of the Rabbit . 

Skeleton of the Horse 

Skeleton of the Cow 

Skeleton of the Slieep 

Skeleton of the Camel . 

Vertical section of bone 

Minute structure of bone 

Lacunae, or osteoplasts of osseous substance 

Cartilage at the seat of ossification 

Elements of a vertebra 

A cervical vertebra 

Atlas (inferior surface) 

The axis or dentata (lateral view) 

Axis and sixth cervical of the Horse and Ass 

Type of a dorsal vertebra (the fourth) . 

Middle dorsal vertebra of the Horse, viewed from three typical lines 

Dorsal vertebra of the Horse and Ass (the eleventh) . 

Lumbar vertebra (front view) 

Upper surface of lumbar vertebrae . 

Lumbar vertebra of the Horse and Ass . , 

Lumbar vertebrae of the Cat and Rabbit . 

Lateral view of sacrum .... 

Horse's head (front view) .... 

Head of the Cat (posterior aspect) 

Head of the Pig (anterior face) . . , 

Head of tiie dog (anterior face) . 

Ox's head (anterior face) .... 

Head of a hornless Ox . . . , 

Ram's head (anterior face) .... 

Anterior bones of the head of a foetus at birth 

Posterior bones of the head of a foetus at birth 

Head of the Rabbit (posterior face) 

Head of the Rabbit (antero-lateral face) 

Ox's head (posterior lace) . . , , 

Posterior aspect of Horse's skull 

Head of the Pig (posterior face). 

Dog's head (posterior view) .... 

Longitudinal and transverse section of the Horse's head , 

Antero-posterior and vertical section of the Horse's head 

Median and vertical section of the Ox's head 

Inferior maxilla . . . , , 

Head of the Camel . , , 

Head of the Cat . 

Hyoid bone 

Wormian bones of the Ox 



Chauveau . 


PAGK 
8 


Chauveau . 


8 


Chauveau . 


9 


Chauveau . 


9 


Original 


10 


Original 


10 


Chauveau . 


11 


Chauveau . 


12 


Carpenter . 


16 


Carpenter . 


17 


Carpenter . 


17 


Carpenter . 


20 


After Owen . 


25 


Original 


27 


Original 


28 


(Jriginal 


28 


Chauveau . 


29 


Original 


32 


Chauveau . 


33 


Chauveau . 


34 


Original 


36 


Chauveau . 


37 


Chauveau . 


38 


( 'hauveau . 


39 


Original . 


40 


Original . 


46 


Chauveau . 


49 


Chauveau . 


50 


Chauveau . 


51 


Chauveau . 


52 


Chauveau . 


53 


Chauveau . 


53 


Chauveau . 


54 


Chauveau . 


57 


Chauveau . 


59 


Chauveau ■ 


62 


Chauveau . 


65 


Original 


66 


Chauveau . 


67 


Chauveau . 


68 


Chauveau . 


72 


Chauveau . 


72 


Chauveau . 


74 


Chauveau . 


76 


Chauveau . 


77 


Chauveau . 


78 


Cliauveau . 


78 


Cornevin . 


80 



TABLE OF ILLUSTRATIONS. 



pro. 
49. 

50. 
51. 
52. 
53. 
54. 
55. 
56. 
57. 
58. 
59. 
60. 
61. 
62. 
63. 
G4. 
65. 
66 
67. 
68. 
69. 
70. 
71. 
72. 
73. 
74. 
75. 
76. 
77. 
78. 
79. 
80. 
81. 
82. 
83. 
84. 
85. 
86. 
87. 



100. 
101. 
102. 
103. 
104. 
105. 
106. 
107. 
108. 
109. 



mb) 



Horse's head (anterior face) 

Horse's head (posterior face) 

Horse's head (lateral face 

Ass's head (lateral face) 

Crania of different breeds of Dogs 

Front view of the human cranium 

External or basilar surface of human skull . 

The sternum 

Typical ribs of the Horse 

Thorax of Man (anterior face) 

Scapula of the Horse (external face) 

Scapula of the Horse (internal face) 

Scapula of the Cat and Rabbit 

Antero-external view of right humerus 

Posterior view of right humerus . . 

Humerus of the Cat and Rabbit 

External face of the radius and ulna 

Forearm bones of the Ass 

Right fore foot of a Horse . 

Carpus of the Horse (anterior face) 

Carpus of the Horse (posterior face) 

Posterior view of right metacarpus 

Forearm and foot of the Ox (front view) 

Lateral view of the digital region (outside of right li 

Posterior view of anterior digital region 

Plantar surface of third phalanx 

Navicular bone .... 

Anterior limb of the Pig 

Forearm and foot of the Dog (anterior face) 

Human scapula (external aspect) 

Right human humerus (anterior surface) 

Human arm-bones (front view) . 

Palmar surface of left human hand . . 

Hand of Man and the domestic Mammalia, normal and 

The ossa innominata (seen from helow) . 

Pelvis (antero-lateral view) . 

Pelvis (lateral view) .... 

Pelvis of the Horse .... 

Pelvis of the Mare .... 

Pelvic bones of the Cat and Rabbit . 

Left femur (anterior view) 

Left femur (posterior view) . 

Section of left femur, showing its structure 

Femur of the cat and rabbit 

Posterior view of right tibia 

Leg-bone of the Mule 

Patella of the Horse (superior and posterior face) 

Patella of the Horse (anterior face) . 

Leg-bones of the Cat and Rabbit 

Left hind foot (external aspect) 

Tarsus of the Horse .... 

Left hock (front view) 

Left hock (internul aspect) 

Posterior aspect of left metatarsus . 

Human pelvis (female) .... 

Right human femur (anterior aspect) 

Human tibia and fibula of right leg (anterior aspect) 

Dorsal surface of left human foot 

Anterior limb of the Horse (antero-external view) 

Posterior limb of the Horse (antero-external view) 

Skeleton of a Fowl .... 



Original 


PAGE 

81 


. Original 


81 


Chauveau . 


84 


. . Chauveau . 


85 


. Chauveau . 


89 


Wilson 


90 


. Wilson 


91 


Chauveau . 


93 


, . Chauveau . 


94 


Wilmn 


97 


. Chauveau . 


99 


Chauveau . 


99 


. Chauveau . 


100 


, . Original 


101 


. . Original 


102 


Chauveau . 


103 


. Original 


104 


, Chauveau 


106 


. Original 


108 


Chauveau 


109 


, . Chauveau . 


109 


Original 


111 


e Chauveau 


113 


) . Original 


114 


. Original 


114 


. . Original 


116 


G . Original 


117 


Chauveau 


118 


Chauveau 


118 


Wilson 


119 


. Wilson 


120 


Wilson 


120 


Wilson 


121 


teratological Chauveau 


122 


Chauveau 


127 


. Original 


129 


Original 


129 


. Chauveau 


132 


. . Chauveau 


133 


. Chauveau 


136 


Original 


138 


Original 


138 


m . Original 


139 


Chauveau 


140 


Original 


141 


. Chauveau 


142 


Chauveau 


143 


Chauveau 


143 


Chauveau 


144 


. Original 


145 


Chauveau 


146 


. Original 


147 


Original 


147 


. . Original 


149 


Wilson 


151 


. Wilson 


152 


Wilson 


152 


. Wilson 


152 


Chauveau 


155 


Chauveau 


156 


Chauveau 


159 



TABLE OF ILLUSTRATIONS. 



FIG. 

110. Head of a Fowl (natural size : posterior view) 

111. Sternum and bones of the wing . 

112. Thoracic or pectoral vertebra of a Mammal • 

113. Caudal vertebra of the Turbot . 

114. Cephalic vertebrae of the Dog ..... 

115. Plans of the different classes of articulations . . Beaunis 

116. Section of branchial cartilage of Tadpole .... 

117. Fibro-cartilage ..... 

118. White or non-elastic fibrous tissue . 

119. Yellow or elastic fibrous tissue . 

120. Cervical ligament and deep muscles of the Horse's neck 

121. Intervertebral articulations 

122. Cervical ligament of the Ox ... 

123. Cervical ligament of the young Camel . 

124. Atlo-axoid and occipito-atloid articulations . 

125. Temporo-maxillary articulation . 

126. Articulations of the ribs with the vertebrae (upper plane) 

127. Articulations of the ribs with the vertebrae (inferior plane) 

128. Scapulo-liumeral and humeroradial articulations (external face) 

129. Carpal articulations (front view) .... 

130. Lateral view of the carpal articulations . . . . 

131. Details of the metacarpo-phalangeal articulation of the Horse . 

132. Carpal, metacarpal, and inter-phalangeal articulations of the Horse . 

133. Section of inferior row of carpal bones, and metacarpal and suspensory 

ligament ........ 

134. Posterior view of metacarpo-phalangeal and interphalangeal articu- 

lations ....... 

135. Metatarso-phalangeal and interphalangeal articulations of the Horse 

136. Articulation of the foot (inferior face) .... 

137. Longitudinal and vertical section of the digital region of the Horse 

138. Tendons and ligaments of the posterior face of the digital region of 

the Ox 

139. Sacro-iliac and coxo-femoral articulations .... 

140. Sacroiliac and coxo-femoral articulations 

141. Femoro-tibial articulation ...... 

142. Ligaments attaching the three bones of the leg . 

143. Tarsal articulations (front view) ..... 

144. Articulations of the tarsus (lateral view) 

145. Ultimate fibril of muscle ...... 

146. Striated muscular-tissue fibre ..... 

147. Primitive fibre of red muscle ..... 

148. Torn muscular fibre ...... 

149. Primitive muscular fibre ...... 

150. Relation of primitive muscular fibres with tendon 

151. Transverse section of frozen muscle . . . * . 

152. Arrangement of the fibres of a muscle . . . Beaunis 

1 53. Distribution of capillaries in muscle ..... 

154. Portion of elementary muscular fibre .... 

155. Striated fibre of muscle during contraction .... 

156. Horse fixed in first position ..... 

157. Horse fixed in second position ..... 

158. Lateral view of the neck (superficial muscles) . 

159. Superficial muscles of the neck and spinal region of the back and loins 

160. Lateral view of the neck (middle layer of muscles) . 

161. Cervical ligament and deep muscles of the neck . 

162. Muscles of the spinal region of the neck, back, and loins 

163. Deep ditto ....... 

164. Muscles of the back and cervix of Man .... 

165. Muscles of the sublumbar, patellar, and internal crural regions . 

166. Deep muscles of the sublumbar region .... 

167. Sacro-iliac and coxo-femoral muscles .... 



Chauveau . 


PAGh 

160 


Chauveau . 


164 


Chauveau . 


168 


Chauveau . 


168 


Lavocat 


168 


and Bouchard 


171 


Carpenter . 


172 


Wilson 


173 


Carpenter . 


174 


Carpenter . 


174 


Chauveau . 


181 


Chauveau . 


182 


Chauveau . 


184 


Chauveau . 


185 


Chauveau . 


187 


Chauveau . 


188 


Chauveau . 


191 


Chauveau . 


191 


Chauveau . 


196 


Chauveau . 


201 


Chauveau . 


202 


Chauveau . 


204 


Chauveau . 


205 


Chauveau . 


207 


Original . 


208 


Chauveau . 


210 


Chauveau . 


210 


Chauveau . 


211 


Chauveau . 


211 


Chauveau . 


213 


Chauveau . 


214 


Chauveau . 


217 


Chauveau . 


220 


Chauveau . 


222 


Chauveau . 


224 


Bowman 


232 


Bowman 


232 


Renaut 


233 


Renaut 


233 


Renaut 


234 


Renaut 


234 


Kiihne 


235 


and Bouchard 


236 


Berres 


236 


Beale 


237 


Bowman 


237 


Chaiiveau . 


240 


Chauveau . 


241 


Original . 


245 


Chauveau . 


247 


Original . 


248 


Chauveau . 


251 


Chauveau , 


261 


Chauveau . 


264 


Wilson 


267 


Chauveau . 


270 


Chauveau . 


271 


Chauveau . 


273 



TABLE OF ILLUSTRATIONS. 



168. Superficial muscles of the face and head .... 

169. Muscles of external ear of Mule . 

170. Muscles of the ear ....... 

171. Hyoideal and pharyngeal regions .... 

172. Superficial muscles of the Ox's head .... 

173. Muscles of the human head . . . . 

174. Muscles of the axillary and cervical regions .... 

175. Axillary und thoracic muscles ..... 

176. Muscles of the inferior abdominal region (Ass) 

177. Muscles of the anterior aspect of the body of Man 

178. Diaphragm (posterior face) ...... 

179. External muscles of the anterior limb .... 

180. Muscles of anterior aspect of Man's upper arm 

181. Internal aspect of left anterior limb .... 

182. Deep muscles on external aspect of right anterior limb , 

183. Tendons and burtse of anterior limb of Horse 

184. Flexor tendons of phalanges of Horse .... 

185. Muscles of the forearm of the Ox ... . 

186. Tendinous and ligamentous apparatus in the digital region of the Ox 

187. Anterior antibrachial region of the Pig 

188. Muscles of the forearm and paw of the Dog 

189. Superficial muscles of human forearm .... 

190. Deep layer of superficial muscles of human forearm 

191. Muscles of human hand = . . . . 

192. Dissecting- table ....... 

193. Superficial muscles of the croup and thigh . . 

194. Superficial muscles of the croup and thigh 

195. Muscles of the sublumbar, patellar, and internal crural regions 

196. Deep muscles of the coxo-femoral region 

197. Coccygeal and deep muscles surrounding the coxo-femoral articu- 

lation ...... 

198. Superficial muscles of the croup and thigh in the Cow 

199. Muscles of the anterior femoral region in Man 

200. Muscles of the posterior femoral and gluteal region in Man 

201. External deep muscles of right posterior limb 

202. Flexor muscle of metatarsus 

203. Muscles on inner aspect of left posterior limb 

204. Articular capsules and bursse in posterior limb . 

205. External muscles of the leg of the Ox 

206. Muscles of the human leg (anterior tibial region) 

207. Superficial posterior muscles of the human leg 

208. First layer of plantar muscles of human foot 

209. Third and part of second layer of plantar muscles of human foot 

210. Squamous epithelium from the mouth .... 

211. Columnar epithelium . . ... 

2 1 2. Columnar ciliated epithelium .... 

213. Conical villi on mucous membrane of small intestine 

214. Fusiform cells of smooth muscular fibre . . 

215. Hard and soft palate ..... 

216. Composite papilla from tongue of Dog . . . , 

217. Simple filiform papillae ..... 

218. Foramen of Morgagni ...... 

219. Vertical section of a foramen csecum 

220. Muscles of the tongue, soft palate, and pharynx . 

221. Lobe of racemose gland from the floor of the mouth 
222 Follicular gland ....... 

223. Section of an amysdaloid follicle .... 

224. Median longitudinal section of the head and upper part of neck 

225. Magnified section of a canine tooth ..... 

226. Section through the fang of a molar tooth . , 

227. Transverse section of enamel . . . . c 



Original 
Cliauveau 


275 

280 


Original 
Original 
Chauveau 


282 
287 
290 


Wilson 


291 


Chauveau 


294 


Original 
Chauveau 


295 
304 


Wilson 


306 


Chauveau 


309 


Chauveau 


311 


Wilson 


317 


Original 
Original 
Chauveau 


318 
321 
329 


Chauveau 


331 


Chauveau 


333 


Chauveau 


334 


Chauveau . 


335 


Chauveau 


337 


Wilson 


339 


Wilson 


339 


Wilson 


342 


Chauveau 


344 


Chauveau 


345 


Original 
Chauveau 


347 
354 


Chauveau 


356 


Chauveau 


358 


Chauveau 


359 


Wilson 


361 


Wilson 


361 


Original 
Chauveau 


363 
365 


Original 
Chauveau 


367 
370 


Chauveau 


372 


Wilson 


375 


Wilson 


375 


Wilson 


377 


Wilson 


377 


Wilson 


393 


Kolliker 


393 


Carpenter 
Wilson 


393 
394 


Bowman 


395 


Chauveau 


399 


Chauveau 


402 


Chauveau 


402 


Chauveau 


403 


Chauveau 


403 


Chauveau 


405 


KSlliker 


406 


KdlUker 


406 


Chauveau 


407 


Original 
Wilson 


4f)9 
412 


Carpenter 
Carpenter 


413 
414 



TABLE OF ILLUSTRATIONS. 



zxxi 



FIG. ''■*<5E 

228. Theoretical section of dental sac of permanent incisor . Chauveau . 415 

229. Section of dentine and pulp of an incisor tooth . . . Carpenter , 416 

230. Dentition of inferior jaw of Horse ..... Chauveau . 418 

231 . Section of incisor tooth of Horse .... Chauveau . 418 

232. Incisor teeth of Horse (details of structure) .... Chauveau . 419 

233. Profile of upper teeth of the Horse .... Chauveau . 421 

234. Transverse section of Horse's upper molar .... Chauveau . 422 

235. The teeth of the Ox . . . . . Chauveau . 425 

236. Ox's incisor tooth ....... Chauveau . 425 

237. Incisor teeth of a Sheep two years old . . . . Chauveau . 427 

238. Teeth of the Pig ... ... Chauveau . 428 

239. General and lateral view of the Dog's teeth . . . Chauveau . 429 

240. Anterior view of the incisors and canine teeth of Dog . . Chauveau . 429 

241. Lateral and general view of the Cat's teeth . . . Chauveau . 429 

242. Dentition of the Rabbit ..... Chauveau . 430 

243. Section of the human face ..... Quain . 432 

244. Lobule of parotid gland ... . . Wagner . 434 

245. Capillary network of follicles of pirotiil gland . . . Berres . 434 

246. Termination of the nerves in the salivary glands . . . Pfliiger . 435 

247. Inferior aspect of head and neck .... Origincd . 436 

248. Maxillary and sublingual glands ..... Chauveau . 437 

249. Pharyngeal and laryngeal region .... Original . 441 

250. Median lengitudinal section of head and upper part of neck . Original . 442 

251. Pharynx of the Horse (posterior view) .... Chauveau . 443 

252. Muscles of the pharyngeal and hyoideal regions . - . Original . 445 

253. Human pharynx ...... Wilson . 447 

254. Transverse vertical section of head and neck . . Original . 448 

255. Pectoral cavity and mediastinum .... Chauveau . 449 

256. Theoretical transverse section of abdominal cavity . . . Chauveau . 452 

257. Theoretical, longitudinal, and median section of abdominal cavity Chauveau . 453 

258. The abdominal cavity, with the stomach and other organs . . Origiiuil . 456 

259. Stomach of the Horse ...... Chauveau . 457 

260. Interior of the Horse's stomach ..... Chauveau . 458 

261. Muscular fibres of stomach (external and middle layers) . Chauveau . 460 

262. Deep and middle muscular fibres of stomach . . . Chauveau . 460 

263. Peptic gastric gland ...... KoUiker . 461 

264 Portion of a peptic caecum ...... Kolliher . 461 

265. Mucous gastric gland ... . . KoUiker . 462 

266. Capillaries of mucous membrane of stomach . . . Carpenter . 462 

267. Stomach of the Dog ... . . Chauveau . 463 

268. Stomach of the Ox . . . . . Chauveau . 464 

269. Interior of the stomacli of Ruminants . . , Chauveau . 465 

270. Section of the wall of the omasum of Sheep o . , , Chauveau . 467 

271. Stomach of the Sheep ...... Chauveau . 468 

272. Section of the omasum of the Sheep .... Chauveau . 469 

273. Section of a leaf of the omasum ..... Chauveau , 470 

274. Longitudinal section of a large papilla from the omasum . . Chauveau . 470 

275. Villi of human and Sheep's intestine .... Teichmann . 474 

276. Portion of Brunner's gland -...,. Thomson . 474 

277. Section through Peyer's patch of Sheep . . . Teichmann . 475 

278. Section through solitary follicle . . . . . Teichmann . 476 

279. Injected villi of intestine ..... KoUiker . 476 

280. Blood-vessels in Peyerian glandulse ..... KoUiker . 477 

281. Diagram of origin of lacteals in villi .... Funke . 477 

282. General view of the intestines of the Horse (right side) . . Chauveau . 479 

283. General view of the Horse's intestines (inferior aspect) » . Chauveau . 480 

284. The colon of the Horse ...... Original .. 481 

285. Plan of the colon ...... Chauveau . 482 

286. Intestines of the Rabbit (sreneral view) • c . . Cliauveau . 486 

287. Stomach and intestines of the Sheep .... Chauveau . 487 

288. General view of the intestines of the Ox . , . Chauveau . 488 



TABLE OF ILLUSTRATIONS. 



FIG. 

289. 
290. 
291. 
292. 
293. 
294. 
295. 
296. 
297. 
298. 
299. 
300. 
3(Jl. 
302. 
303. 
304. 
305. 
306. 
307. 
308. 
3ii9. 
310. 
311. 
312 
313. 
314. 
315. 
316. 
317. 
318. 
319. 
320. 
321. 
322. 
323. 
324. 
325. 
326. 
327. 



331. 
332. 



334. 
335. 



339. 
340. 
341. 
342. 
343. 
344. 
345. 
346. 
347. 
348. 
349. 



General view of the intestines of the Pig . . . Chauveau . 

Intestines of the Dog ...... Chauveau . 

Digestive apparatus of the Cat ..... Chauveau . 

Human intestines ....... Wilson 

Abdominal cavity, with the liver and other organs . . Original 

Portion of a hepatic column, with secreting cells . . . Leidy 
Biliary capillaries and ducts ..... Irminrjer and Frey 

Blood-vessels in lobules of liver ..... Kiernan 

Section of lobules of liver, witli intra-lobular veins . . Kiernan 

Excretory apparatus of the Horse's liver .... Chauveau . 

Structure of the spleen (diagrammatic) . . . Beaunis and Bouchard 

Malpighian corpuscles attached to splenic artery . . . KSlliker 

Splenic corpuscle from the spleen of Ox . . . . Kdlliker 

Liver of the Ox ...... . Cliauveau . 

Liver of the Dog, with its excretory apparatus . . . Chauveau . 

Under surface of the human liver .... Wilson 

General view of the digestive apparatus of a Fowl . . Chauveau . 

Cartilages of the nostrils ...... Chauveau . 

Transverse section of the head of a Horse . . . Chauveau . 

Longitudinal section of the head and upper part of neck . . Original 
Cells of the olfactory mucous membrane . . Clarke and Schultze 

Fibres of olfactory nerve ...... Ecker 

Cartilages of the larynx disarticulated .... Chauveau . 

Superior face of larynx ...... Chauveau . 

Inferior face of larynx ...... Chauveau . 

Muscles of tlie Horse's larynx ..... Chauveau . 

Postero-lateral view of larynx ..... Original 

Entrance to the larynx of the Horse .... Chauveau . 

The respiratory organs (inferior aspect) .... Original 

Trachea, bronchi, and lungs of the Horse .... Chauveau . 

Ciliated epithelium from the trachea .... Kdlliker 

Bronchial tube, with its bronchules ..... Heale 

Mucous membrane of a broncliial tube .... Heale 

Theoretical section of thoracic cavity, behind the heart . . Chauveau . 

Theoretical section of thoracic cavity, at root of lungs . . Chauveau . 

Theoretical section of thoracic cavity, in front of right ventricle . Chauveau . 

Lungs of the Horse ...... Chauveau . 

Lungs of the Horse ....... Chauveau . 

Cast of bronchiole ...... Chauveau . 

Cast of bronchial divisions ...... Chauveau . 

Plan of a pulmonary lobule . . , . Waters 

Infundibula of lung ....... Kdlliker 

Capillaries around the infundibula of lung . . . Carpenter . 

Lung of the Sheep (inferior view) ..... Chauveau . 

Human lungs and heart ...... Wilson 

Gland-vesicles of thyroid ..... Kdlliker 

Portion of thymus of Calf ..... Kdlliker 

Course and termination of ducts in thymus gland of Calf . . Wilson 

General view of the air-sacs in the Duck . . , Chauveau . 

General view of the genito-uriuary apparatus in the Horse . . Chauveau . 

Horizontal longitudinal section of the Horse's kidney . Chauveau . 

Section of the cortical substance of the kidney . . . Ecker 

Course of the uriniferous tubuli ..... Hertz 

Diagram of the circulation in the kidney 
Transverse horizontal section of kidney . 
The kidneys and bladder in the foetus of Solipeds 
Right kidney of Ox (upper and external face) . 
Left kidney of Ox (internal and inferior face) 
The calices in left kidney of Ox 
Theoretical plan of the circulatory system . 
The heart and principal vessels (left face) 



Original 

Chauveau 

Chauveau 

Chauveau 

Chauveau 

Colin 



PAGE 

489 
490 
491 
492 
496 
498 
498 
499 
499 
500 
504 
505 
505 
508 
509 
510 
513 
519 
520 
521 
523 
524 
.'i28 
531 
531 
532 
533 
535 
537 
538 
539 
540 
541 
545 
545 
545 
546 
548 
549 
550 
551 
551 
551 
553 
.')53 
554 
556 
556 
564 
569 
371 
572 
573 
573 
574 
577 
580 
580 
680 
582 
585 



TABLE OF ILLUSTRATIONS. 



FIG. 

350. 
351. 
352. 
353. 
354. 
855. 
356. 
357. 
358. 
359. 
360. 
361. 
362. 
363. 
364. 
365. 
366. 
367. 



370. 
371. 
372. 
373. 
374. 
375. 
376. 
377. 
378. 
379. 
380. 
381. 



385. 



387. 



391. 
392. 



395. 
396. 
397. 



400. 
401. 
402. 
403. 
404. 
405. 
406. 
407. 
408. 



The heart and principal vessels (right face) . . . Chauveau 

Right side of the heart laid open ..... Wilson 

Section of the heart at the level of the valves . . . Sibson 

Left cavities of the heart laid open ..... Wilson 

Auriculo-ventricular fibro-cartilaginous rings . . . Parchappe 

Anastomosing muscular fibres of heart .... KoUiker 

Muscular whorl at point of heart .... Bourgery 

Posterior unitive fibres of auricles ..... Bourgery 

Epithelium of the endocardium ..... KoUiker 

Human lungs and heart (front view) .... WiUon 

Web of Frog's foot, showing blood-vessels and their anastomoses Wagner 

Epithelial cells of blood-vessels ..... KoUiker 

Fenestrated membrane from the carotid artery of the Horse . KoUiker 

Coarse elastic tissue from pulmonary artery of the Horse . KoUiker 

Transition of a minute artery of the brain into capillary vessels . KoUiker 

Abdominal or posterior aorta and cceliac axis in the Horse . Chauveau 

Distribution of the small mesenteric artery .... Chauveau 

Arteries of the stomach of Ruminants .... Chauveau 

Lateral view of ttie genito-urinary organs in the male . . Chauveau 

Abdominal aorta, with its branches, in Man . . . Wilson 

The external and internal iliac arteries in the Mare . . Chauveau 

Principal arteries of posterior foot of Horse . . . Cliauveau 

Anterior aspect of human leg and foot .... Wilson 

Posterior aspect of human leg . . . . . Wilson 

Arteries of sole of human foot ..... WiUmi 

Distributiou of the anterior aorta .... Chauveau 

Terminations of the axillary artery in the Horse , . . Chauveau 

Arteries of the anterior foot (seen from behind) . . Chauveau 

Arteries of the anterior foot of the Horse .... Chauveau 

Arteries of the human forearm and hand . . . Wilson 

Arteries of the brain ...... Chauveau 

Arteries of the head ...... Chauveau 

Rete mirabile of the Sheep (seen in profile) .... Chauveau 

Rete mirabile of the Ox (posterior face) .... Cliauveau 

Arteries of the face and head of Man .... Heath 

Radicles and collateral branches of the jugular vein in the Horse Chauveau 
Sinuses of the dura mater and radicles of the jugular vein of tiie 

Horse ........ Chauveau 

Subsphenoidal confluents in the Horse .... Cliauveau 

Veins of the foot ....... Bouley 

General view of the veins in the Horse .... Chauveau 

Vena portae and its roots ...... Chauveau 

A lymphatic vessel with its valves .... Chauveau 

Section of a lymphatic rete mirabile .... Teichmann 

Section of lymphatic gland ..... KoUiker 

Section of simple lymphatic gland ..... Teichmann 

Section of the medullary substance of lymphatic glaud of Ox . KoUiker 

Ordinary disposition of the thoracic duct .... Colin 

Double variety of the thoracic duct .... Colin 

Triple variety of the thoracic duct ..... Colin 

Lymphatic system of the Horse ..... Colin 

Great lymphatic vein and entrance of the thoracic duct . . Colin 

Great lymphatic duct (another variety) .... Colin 

Thoracic duct in the Ox . . . . . . Colin 

A variety of the thoracic duct in the Ox . . . Colin 

Another variety of the thoracic duct . . . . Colin 

A fourth variety of the thoracic duct .... Colin 

Thoracic duct of small Ruminants ..... Colin 

Diagram of structure of nerve-fibre .... Carpenter 

Nerve-tube ....... Ranvier 

Multipolar or stellate nerve-cell .... Ecker 



PAGE 

586 
587 
589 
591 
592 
594 
594 
595 
597 
599 
603 
604 
604 
604 
605 
614 
619 
622 
627 
628 
630 
637 
642 
642 
643 
647 
651 
653 
655 



678 
680 
681 



695 
700 
704 
707 
714 
717 
718 
718 
719 
723 
723 
723 
725 
731 
731 
732 
733 
733 
733 
7:-<4 
740 
740 
741 



TABLE OF ILLVSTBATIONS. 



410. Several multipolar nerve-cells 

411. Pyriimidal cell of the grey substance 

412. Ganglion from heart of Frog 

413. Bipolar ganglionic cells and nerve' 

414. Stellate nerve-cell . « . . 

415. Structure of ganglionic cells .... 

416. General view of tlie spinal cord ... 

417. Spinal cord at the cervical bulb or brachial plexus 

418. Section of the spinal cord of the Horse at the lumbar region 

419. Transverse section of spinal cord in the lumbar region . 

420. Transverse section of spinal cord of Man in the middle of the lumbar 

region ...... 

421. Ganglionic cell from the inferior cornu of spinal cord 

422. Longitudinal secti>m through cervical bulb of spinal cord of the Cat 

423. Brain of tlie Horse (upper surface) . 

424. General view of the brain (lower surface) 

425. Superior view of the encephalic isthmus 

426. Lateral view of the isthmus .... 

427. Transverse section of the brain . . • 

428. Dissection of the medulla oblongata . . 

429. Median and vertical section of the brain 

430. Layers and cells of grey matter of cerebellum . . 

431. Section of the cortical substance of the cerebellum . 

432. Antero-posterior and vertical section of the brain . 

433. Brain of the Horse (lateral face) 

434. Corpus callosum . . . . , 

435. Anterior portion of the lateral ventricles 
436; Transverse section of human brain 

437. Course of association nerve-fibres . . . 

438. Course of association fibres in corpus callosum . • 

439. Course of radiating fibres in the corona radlata 

440. Layers and cells of a frontal convolution , . 

441. Corticle substance; of the cerebral hemispheres 

442. Brain of the Ox . 

443. Brain of the Slieep ..... 

444. Brain of the Pig ..... 

445. Lateral face of the Dog's brain 

446. Brain of the Dog (upper face) ... 

447. Brain of the Cat ... . 

448. Base of the human brain .... 

449. Muscular fibres, with termination of motor nerve . 

450. Nerves of the eye ..... 

451. Section of the pons Varolii .... 

452. Lateral view of the medulla oblongata . 

453. General view of the superior and inferior maxillary nerves 

454. Section of medulla oblongata and pons Varolii . 

455. Section of middle portion of medulla oblongata 

456. Origin of the nerves arising from the medulla oblongata 

457. Origin and distribution of the eighth pair of nerves in Man 

458. Distribution of the nerves in the larynx of the Horse 

459. Deep nerves of the head .... 

460. Nerves of the guttural region in the Ox. 

461. Innervation of submaxillary and sublingual glands . 

462. Nerves of the face and scalp of Man 

463. Distribution of eighth pair of nerves on left side 

464. Ganglion of a spinal nerve from the lumbar region 

465. Nerves of the brachial plexus 

466. External nerves of anterior limb . . . 

467. Nerves of the digit of Horse 

468. Nerves of tlie digital region of Ruminants 

469. Nerves of the palmar face of Dog's foot 





PAOB 


, . Chauveau . 


741 


Chauveau . 


741 


. Ecker 


742 


Ecker 


742 


. Beale 


742 


. Beale and Arnold 


742 


. Colin 


755 


Colin 


755 


. Chauveau . 


757 


Deiters 


758 


e lumbar 




. I. L. Clarke 


759 


Kraus^e 


760 


the Cat I. L. Clarke 


761 


. CJiauveau . 


764 


Chauveau . 


766 


Chauveau . 


770 


Chauveau . 


773 


Cliauveau . 


775 


Solly and Carpenter 


776 


. Cliauveau . 


780 


Duval 


781 


. Kolliher . 


782 


Chauveau . 


783 


. Cliauveau . 


787 


Cliauveau . 


789 


. Chauveau . 


789 


Edinger 


793 


. Edinger 


794 


. Edinger 


795 


. Edinger 


795 


. Cliauveau . 


796 


. Kolliher . 


796 


, Chauveau . 


797 


, . Cliauveau . 


798 


. Chauveau . 


799 


Chauveau . 


800 


Chauveau . 


801 


. Chauveau . 


801 


Emchfeld and LeveilU 


802 


, . Cohnheim . 


806 


Chauveau . 


812 


. Duval 


814 


Erb 


815 


Chauveau . 


818 


Duval 


825 


. Duval 


833 


Toussaint . 


836 


. Wihon 


837 


Toussaint , 


838 


Chauveau . 


843 


Toussaint . 


845 


Bernard 


848 


Eirschfeld and LeveilU 


850 


Hirschfeld and LeveilU 


851 


KolUker . 


854 


. Chauveau . 


863 


Chauveau . 


863 


. Bouley 


866 


, Cliauveau . 


868 


. Chauveau . 


870 



TABLE OF ILLUSTRATIONS. 



FIG. 

470. Nerves of the palmar face of Cat's foot . , , . Chauveau . 

471. Nerves of the axilla of Man .... Hirschfeld ami LeveilU 

472. Nerves of the front of forearm and hand of Man . Hirschfeld and Leveill€ 

473. Lumbo-sacral plexus and internal nerves of posterior limb . . Cliauveau . 

474. Posterior portion of the lumbo-sacral plexus . . . Chauveau . 

475. External nerves of posterior limb ..... Chauveau . 

476. Lumbar plexus of Man ..... Hirschfeld and Leveill^ 
'ill. Nerves at the posterior aspect of human leg . . Hirschfeld and Leveill^ 
478 Nerves at the front aspect of human leg . . Hirschfeld and Leveill€ 

479. Sympathetic ganglion from a Puppy .... Kolliker 

480. Sympathetic system of the Horse .... Cliauveau . 

481. Brain of a Bird ....... Chauveau . 

482. Section of Horse's skin ...... Chauveau . 

483. Capillary loops in cutaneous papillae .... Berres 

484. Tactile papillae from the skin ..... Ecker 

485. Interungulate sinus of Sheep ..... Owen 

486. Branches of cutaneous nerves in skin .... Ecker 

487. Sudoriparous gland ....... Wagner 

488 Oblique section of epidermis ..... Carpenter . 

489. Hair-follicle ...... Morel and Villemin 

490 Longitudinal median section of Horse's foot . . « Original 

49L Horizontal section of Horse's foot ..... Original 

492. Lower surface of the Horse's foot .... Original 

493. Lateral view of the Horse's foot ..... Original 

494. Horizontal section of hoof ..... Chauveau . 

495. Horizontal section of the junction of the wall with the sole of hoof . Leisering . 

496. Horizontal section of wall, and horny and vascular lamiuse . Leisering . 

497. Hoof removed from the foot ...... Leisering . 

498. Hoof with outer portion of wall removed . . . Leisering 

499. Plantar surface of hoof ...... Leisering . 

600. Horn-cells from the sole of hoof ..... Leisering . 

501. Constituent elements of the wall ..... Leisering . 

502. Theoretical section of the Horse's eye .... Chauveau . 

503. Anterior segment of a transverse section of the globe of the eye 

(human) ........ Wilson 

504. Cells from pigmentum nigrum ..... Carpenter . 

505. The eye (human) with the sclerotic coat removed . . . Holden 

506. Muscular structure of the iris ..... Kolliker 

507. Vertical section of retina ...... MUller 

508. Diagram of the structure of the retina .... Krause 

509. Capillaries in the vascular layer of the retina . . . Berres 

510. Muscles of the eyeball (viewed from above) , . . Original 

511. Labyrinth in Fishes, Birds, and Mammals .... Gegenbaur . 

512. Section of lamina spiralis of the cochlea . , , Carpenter 

513. Section of the cochlea parallel to its axis .... Breschet 

514. Cochlea opened ....... Chauveau . 

515. Eight tympanic cavity of Horse's ear .... Chauveau 

516. Bones of the middle ear of the Horse .... Lavocat 

517. Diagram of the testicle ••.... Holden 

518. Human testis, injected with mercury .... Lauth 

519. Vertical section of the Horse's testis .... Chauveau 

520. Internal genito-urinary organs of the foetus of a Mare , . Chauveau . 

521. Spermatozoa of various animals ..... Carpenter 

522. Superior view of the genito-uriuary organs . . . Chauveau 

523. Transverse section of penis ...... Chauveau 

524. Longitudinal section of the free extremity of the Horse's penis . Chauveau 

525. Internal genital organs of a young Bull .... Chauveau 

526. Sections of the urethra of the Ox at different points . . Chauveau 

527. Penis and muscles of the sheath of the Bull .... Chauveau 

528. Section of human pelvis ...... Gray 

629. Section of the ovary ....... Schroen 



PAGE 

870 

871 
872 
876 
877 
879 



884 



895 
900 
900 
901 
901 
902 
902 
903 
905 
908 
909 
910 
912 
912 
914 
914 
915 
916 
916 
919 
919 
927 

931 
931 
932 
933 
935 
936 
936 
940 
948 
949 
949 
950 
953 
954 
963 
963 
964 
965 
967 
969 
974 
976 
977 
978 
979 
982 



TABLE OF ILLUSTRATIONS. 



FIG. 

530. Ovaries, oviducts, and uterus of a foetus (equine) 

531. Ovarium of the Rabbit .... 

532. Constituent parts of Mammalian ovum, entire . 

533. Constituent parts of Mammalian ovum, ruptured . 

534. Formation of the corpus luteum 

535. Generative organs of the Mare, isolated 

536. Generative organs of the Mare, in situ . 

537. Termination of milk-duct in cluster of follicles 

538. Ultimate follicles of mammary gland, with secreting cells 

539. Microscopic appearance of milk 

540. Human uterus, witii its appendages 

541. Ovary of the Bird ..... 

542. Graafian vesicle ..... 

543. Optical section of ovum of Eabbit . 

544. Ovum of Rabbit ..... 

545. Blastodermic vesicle of Rabbit 

546. Section of a Fowl's unhatched egg 

547. Area pellucida in early blastoderm 

548. Transverse section of blastoderm 

549. Area pellucida of blastoderm 

550. Area pellucida in blastoderm .... 

551. Transverse section of blastoderm 

552. Transverse section of dorsal region 

553. Manner in which embryo and envelopes are formed 

554. Diagram of foetal membranes .... 

555. Exterior of the chorial sac (Mare) . 

556. Different parts of foetal Horse .... 

557. Foetus of the Mare, with its envelopes 

558. Portion of ultimate ramifications of umbilical vessels . 

559. Vertical section of injected placenta 

560. Portion of one of the foetal villi 

561. Equine foetus, opened on left side to show umbilical vessels 

562. Blood-vessels in liver of an equine foetus at mid-term . 

563. Liver of a Lamb at birth .... 

564. Foetus of the Slieep .... 

565. Vertical section of a maternal cotyledon 

566. Embryo of the Chick .... 

567. Section of embryo Duck .... 

568. Embryo of the Chick .... 

569. Transverse section of embryo of Chick on third day 

570. Plan of development of eye .... 

571. Origin of encephalic centres in human embryo of fourth week 

572. Plan of chorda dorsalis at period of formation of embryo 

573. Plan of vertebra at an early period of development 

574. Head of a foetal Lamb, showing Meckel's cartilage 

575. Plan of first system of vessels (embryo) 

576. Embryonic heart at an early period (anterior view) 

577. Ditto, seen from behind 

578. Heart of an equine foetus 

579. Plan of the aorta and its arches at an early period 

580. Plan of the circulation in the human embryo (side view) 

581. Section of embryo of Rabbit 

582. First appearance of the lungs . 

583. Embryo of Dog at twenty-five days 

584. Origin of liver from intestinal wall of embryo Chick 

585. Urinary and genital apparatus in embryo Chick 



Chauveau . 


PAGE 

986 


Pouchet 


987 


Coste 


988 


Coste 


988 


Pouchet 


989 


Chauveau . 


991 


Chauveau . 


994 


Sir A. Cooper 


998 


Lehert 


998 


Funke 


999 


Wilson 


1002 


Chauveau 


1004 


BalUani 


1006 


VanBeneden 1006 


Van Beneden 1007 


Kdlliker 


1008 


Thomson 


1010 


Balfour 


1010 


Balfour 


1011 


Balfour 


1012 


Balfour 


1012 


Balfour 


1013 


Balfour 


1014 


Balfour 


1015 


Turner 


1017 


Chauveau 


1018 


Chauveau 


1020 


Chauveau 


1022 


Carpenter 


1023 


Turner 


1024 


Eclcer 


1025 


Cliauveau 


1026 


Colin 


1026 


Colin 


1027 


Cliauveau 


1028 


Turner 


1029 


Balfour 


1032 


Balfour 


10.33 


Balfour 


1034 


Kolliker 


1035 


Kdlliker 


1035 


Wagner 


1037 


Kdlliker 


1039 


Kolliker 


1039 


Huxley 


. 1039 


Kolliker 


1041 


Kolliker 


. 1042 


Kdlliker 


1042 


Chauveau 


. 1043 


Kolliker 


. 1043 


Coste 


. 1044 


Balfour 


. 1045 


Wagner 


. 1046 


Bischoff 


. 1046 


Muller 


. 1049 


Muller 


. 1050 



THE COMPARATIVE ANATOMY 

OF THE 

DOMESTICATED ANIMALS. 



GENERAL CONSIDERATIONS. 

DEFINITION AND DIVISIONS OP ANATOMY. 

Anatomy is the science of organization ; it studies the structure of animals 
when these are dead. It comprises two grand divisions — physiological anatomy ^ 
which describes healthy organs, and pathological anatomy, the object of which is 
the description of diseased organs. 

Physiological anatomy, which alone is treated of in this book, in its turn 
embraces — 

1. General anatomy, which is occupied with similar substances or tissues of 
the animal body, with regard to their texture, and their physical, chemical, and 
physiological properties, irrespective of the organs in which these tissues are 
found. The particular study of the anatomical elements entering into the 
composition of the tissues, is named histology. Histology necessarily requires 
the aid of the microscope. 

2. Descriptive anatomy, which studies the situation, form, and relations of 
organs, as well as the relative arrangement of the various tissues composing 
them, with the exception of the structure and properties of these tissues. 

If this study be devoted to a single species, it is designated special anatomy. 
Example : human anatomy, or anthropotomy ; the anatomy of the Horse, or 
hippotomy. 

"When descriptive anatomy embraces the study of the organization of the 
entire animal kingdom, and examines the differences which characterize the same 
organ or the same series of organs in each class, family, genus, or species, it is 
named comparative anatomy. Restricted to the domesticated animals, this study 
constitutes veterinary anatomy. 

Philosophical or transcendental anatomy differs from comparative anatomy, 
in that it indicates the analogies of organs or apparatus, rather than their 
differences, in order to exhibit as clearly as possible the general laws of 
organization. 

Finally, if descriptive anatomy be limited to denoting the relations existing 
between the various organs of a region, particularly with a view to the perform- 
ance of operations and the diagnosis of external diseases, it takes the names of 
topographical, regional, or surgical anatomy. 



GENERAL CONSIDERATIONS. 



Enumeration and Classification of the Species of 
Domesticated Animals. 

The object of this book is the study of veterinary anatomy. The animals of 
which it treats belong to the Mammiferous class and to that of Birds. 

The domesticated Mammals of om- clunates have their representatives in a 
large number of orders. Thus, we find among them — 

1. Of the Carnivora, the Dog and Cat; 

2. A Rodent, the Rahhit ; 

3. A Pachyderm, the Pig ; 

4. Of Solipeds, the Horse and Ass ; the produce of the Male Ass with the 

mare, i.e. the 3fule, and that of the Horse with the Female Ass, known 
by the name of Hinny ; 

5. Of Ruminants, the Ox, Sheep, and Goat. 
With regard to Poultry, they range themselves — 

1. In the Gallinaceous or Columba order, the genera to which the Common 
Fowl, Guinea Foivl, Turkey, and Pigeon belong ; 

In the order of Palmipeds, the Goose and Duclc. 

Girard has proposed a special classification for the domesticated Mammals, 
based upon the number of digits terminating each of their limbs, and has defined 
four categories : the first comprises the Horse, Ass, Mule, and Hinny, which take 
the name of monodactyles, because their digital region is composed of a single 
digit ; in the second, under the denomination of didactyles or bisulcate animals, 
those with two digits, such as the Ox, Sheep, and Goat ; in the third, or regular 
tetradactyles, is found the Pig, each of whose limbs has four digits ; lastly, the 
Dog and Cat, which most frequently have four digits on the posterior members 
and five on the anterior ones, and form the class of irregular tetradactyles. 

This nomenclature will not be followed here, as it is opposed to the general 
laws of organization. Philosophical anatomy has, in fact, demonstrated that there 
are really no true monodactyles, didactyles, etc. ; all are materially or virtually 
pentadactyles. It is therefore considered better to keep to the classification 
established by zoologists, because it prevents confusion in scientific language. 

The regimen and habits of the domesticated animals bring about diiferences 
in their organization ; these appear very great at first sight, though in reality they 
are not so marked as they seem. 

In order to study the descriptive anatomy of all these annuals, we will not 
pass them in review, one after another, giving for each the description of every 
organ ; but shall take a type, which will most frequently be the Horse, implicitly 
compared with man, and briefly compare all the others with it. In this com- 
parison, the animals will be generally classed according to their domestic value ; 
though exceptions will be made to the rule which has been instituted by our 
predecessors, whenever any advantage m point of concision or perspicuity is likely 
to be obtained. 

General Ideas of the Organization of Animals. 

Order followed in studying the Various Apparatuses. 

The bodies of animals contain fluid and solid organic matters, as well as gases 
and some mineral substances. 

Organic Fluids. — The fluids are very abundant in the animal economy ; 



GENERAL CONSIDERATIONS. 3 

not only do they fill certain vessels constructed for them, but they also 
impregnate all the solid parts of the body. Their importance is very great, for 
without them the organic solids would perish ; an element deprived of humidity 
is ipso facto deprived of life. 

These fluids vary in their nature and composition. Apart from those that 
the solids imbibe, there is not one which is completely amorphous. In the 
midst of a liquid holding organized matter in solution, there are always formed 
elements which will be referred to hereafter. Examples : the blood and lymph. 

Organic Solids. — In studying the organic solids, we will proceed from the 
simple to the complex. 

Solid organized matter is amorphous — as in the hyaline substance of cartilage 
and the fundamental substance of bone tissue, or it assumes the form of more 
or less voluminous particles in every instance invisible to the naked eye, and to 
which the name of anatomical elements has been given. They may be reduced to 
three principal : the granule, the cell, and the fibre. 

Granules. — These are the smallest known elements. They may be held in 
suspension in animal fluids, remain free among the other elements, or be enclosed 
in the interior of cells. Their nature is not always the same : they are proteic, 
fatty, or pigmentary. The pigmentary granules are of a brown colour. 

Cells. — The cell is pre-eminently the anatomical element. 

Theoretically, the cell is a microscopic mass of a nitrogenous substance, viscid 
{protoplasm or sarcode), uniformly transparent, or slightly granular. Frequently 
in the midst of this protoplasm there is perceived a nucleus provided with a 
nucleolus, and at its periphery an enveloping membrane. 

The cell lives like an entire organism : it feeds, grows, multiplies, absorbs, 
secretes, moves, etc. It behaves like a complete animal, though it be a micro- 
scopic one. 

The form of the cell, as well as its volume and nature, vary. It has therefore 
received various names. 

There are round, polyhedral, fusiform, conical, stellate, and other shaped 
cells. Some have a diameter of 1-1 2000th part of an inch, while others are 
l-2000th part. Cells multiply in various ways : 1st, by the division of the 
nucleus and segmentation of the protoplasm in the interior of the enveloping 
membrane {endogenous multiplication) ; 2nd, by constriction, then division of the 
nucleus, protoplasm, and enveloping membrane {flssiparous multiplication) ; 3rd, 
by a kind of bulging or swelling of the enveloping membrane, and constriction 
and separation of the enlargement thus formed {gemmation). 

A large number of cells only temporarily remain in this condition. In con- 
sequence of modifications that cannot be referred to here, they are converted 
into fibrillse or other elements, in which it is difiicult to recognize the primordial 
element. 

Others maintain the cellular form : then they develop, live, and die in several 
ways. Sometimes they are worn by the contact of foreign bodies, as on the sur- 
face of the skin ; sometimes they become liquefied, as in some glands ; and at 
other times they undergo fatty degeneration, which gradually brings about their 
complete destruction. 

The permanent cells are — 

1. Hcematies or red corpuscles, which are found in a state of suspension in the 
blood ; they are round and discoid in Mammalia, with the exception of the 
Camel and Llama, in which they are elliptical, as well as in Birds, Reptiles, and 



4 GENERAL CONSIDERATIONS. 

the majority of Fishes. These cells have an envelope, but they do not have 
a nucleus in JVIammalia ; 

2. Leucocytes, white corpuscles, or lymph cells, which float in the blood, lymph, 
chyle, and the connective tissue interspaces. These cells are susceptible of amae- 
boid movements, and their fundamental form is spherical ; though they are often 
Irregular in shape, owing to the contractile prolongations they throw out, called 
pseupodes. They may have one or more irregular nuclei ; 

3. Connective cells, which are flat, nucleated, and irregular ; they are applied 
to the fasciculi of connective fibres ; 

4. Adipose cells, lying in the connective tissue and filled with fat, which has 
pushed the protoplasm and nucleus towards the envelope ; 

5. Medullary cells, with a budding nucleus or multiple nuclei (myeloplaxes 
and medullo-cells), forming the principal elements of the marrow of bones ; 

6. Cartilage cells, which have no envelope, and which, single or associated 
with a variable intermediate substance, form cartilages ; 

7. Bone cells, lodged in a space remarkable for its elliptical shape and the 
numerous prolongations on its margin. The cells are nucleated, have no envelope, 
and secrete the fundamental solid substance of the bony tissue ; 

8. Contractile cells, which constitute the basis of muscular tissue. They are 
fusiform and nucleated ; 

9. Nerve cells, met with in the cerebro-spinal centres and the ganglia of the 
cerebro-spinal and sympathetic systems. They are provided with one, two, or 
more prolongations called poles ; hence they are uni-, bi-, or multipolar. 

10. Epithelial cells, found on the surface of tegumentary membranes, or laid 
over the interior of more or less diverticulated cavities (glandular cavities or glands). 
The epithelial element is lamellar or polyhedric, cylindrical, calcif orm, vibratile, etc. 

11. Endothelial cells, always lamellar, and hning serous cavities and vascular 
canals. 

Fibres. — A fibre is an elongated element of variable dimensions and com- 
position. Thus, it may be very fine {connective fibre), or thick and limited by 
two borders more or less apart (muscidar fibre) ; it is homogeneous throughout 
{elastic fibre), or has a contents and a distinct envelope {nerve fibre). The vitality 
of fibres is not comparable with that of cells. Once formed, they are only 
nourished, for it is not yet definitely ascertained whether they can multiply. 

In the animal economy there are four kinds of fibres — 

1. Connective fibre, an extremely fine element, but in which, nevertheless, 
two borders can be distinguished if it be examined by a power of from 800 to 
1000 diameters. The fibres form fasciculi in the connective tissue, or are distri- 
buted in the midst of a fundamental substance — as in the fibro-cartilages. The 
connective fibre constitutes the most solid organs of the animal economy — the 
ligaments, tendons, etc. 

2. Elastic fibre, found closely packed in certain organs, such as the cervical 
ligament and abdominal tunic, or forming a network in the midst of connective 
tissue ; it is even found in the framework of bones. 

3. Muscular fibre, smooth or striped (striated), which has the property of 
contracting under the influence of stimuli. Smooth (or unstriped), is found 
in a large number of viscera ; striped is more especially in the domain of the 
locomotory apparatus. 

4. Nerve fibre, very remarkable for its continuous axis-cylinder. It is found 
in the nerve centres, cerebro-spinal nerves, and great sympathetic system. 



GENEBAL CONSIDERATIONS. 5 

I 

Inorganic Substances. — These substances (gases and mineral matters) are 
usually found in solution in the animal fluids. Their presence is indispensable 
in the constitution of the living body. 

Sometimes the mineral matters are solid, amorphous, or crystallized. In this 
condition they are rarely met with in healthy organs (iriternal ear) ; but they are 
frequently found in diseased ones. 

Tissues. — The anatomical elements, by being grouped in different manners, 
form tissues. Some tissues are constituted by one kind of element ; these are 
simple tissues — for example, epithelial tissue. But the larger number are formed 
by a combination of several different elements ; these are composite tissues — for 
example, nerve tissue. 

The anatomical, physico-chemical, and physiological characters of the tissues, 
are repeated, it need scarcely be remarked, in the anatomical, physico-chemical, 
and physiological properties of the elements which enter into their composition. 

Only four simple types of fundamental tissue are described, and which are 
based on the morphological, chemical, and physiological characters of the 
constituent elements — 

1. In the first place, there are to be noted the tissues of connective substance 
or framework, comprising the varieties of connective tissue, fibrous tissue, elastic 
tissue, cartilaginous tissue, and bone tissue. 

2. Then there are the cellular tissues, formed entirely of persistent cells ; 
they are the epithelial tissue proper, and the glandular tissue. 

The cells of the epithehal tissue are differently arranged. If they are 
disposed in a single layer, they constitute a simple epithelium ; but if superposed 
so as to form two or more layers, then it is a stratified epithelium. According to 
the form of the superficial layer of cells, the epithelium is polyhedric, pavement., 
cylindrical, spherical, or calciform. In certain parts the superficial cells are 
furnished with vibratile cilia, and the epithehum is then called vibratile (or ciliated). 

3. The third type is represented by the muscular tissue, the agent of move- 
ment, which is divided into striated and non-striated muscle. 

4. Lastly, there is the nerve tissue, which is present under two aspects — 
white substance and grey substance. The first is formed entirely of nerve fibres 
and a supporting tissue or neuroglia ; the second by fibres and nerve cells united 
by neurogha. The grey substance belongs to the most important portions of the 
nervous system — the brain, spinal cord, and gangha, where it co-exists with the 
white substance. The latter entirely constitutes the peripheral ramifications of 
the nervous system. 

Organs. — The term " organ " is given to any portion of the body having a 
determinate form and a function to fulfil. A bone, a muscle, the stomach, the 
liver, and the brain, are organs. 

General Arrangement of the Organs and Apparatus. — All animal 
organs are enclosed between two membranes named limitary or tegumentary 
membranes, which are continuous with one another at the margin of the natural 
openings. These are the skin and the mucous membranes, in the composition of 
which are included a layer of connective tissue and an epithelium 

Organs protected by these membranes are solid or hollow. 

Among the first, a certain number act as supports : such are the organs formed 
by the connective tissue, and particularly the cartilages and bones. 

Others are destmed to produce movements : these are the muscles. The 
action of the muscles is communicated directly to the organs that are to be 



e GENERAL CONSIDERATIONS 

moved, or it is transmitted through the medimn of oth%r organs, such as the 
tendons and the aponeuroses. 

The central nervous organs — the nerves properly so called — belong to this group 
of solid organs. The activity of muscles and the sensibility of limitary membranes 
are due to them. 

With regard to the hollow organs, they are everywhere formed by an envelope 
of smooth (or unstriped) muscular tissue, lined by an internal tegumentary or 
mucous membrane. Examples : the bladder and stomach. There must also be 
included the vessels formed by elastic and contractile membranes arranged as 
canals, in which the blood and lymph circulate ; the glands, and, lastly, the serous 
membranes which line the interior of the splanchnic cavities, cover the surface of 
the organs contained in them, and the inner face of the articulations and synovial 
sheaths. 

It is remarkable that, in the trunk, the bones form two superposed cylinders, 
one of which lodges the organs of circulation, digestion, and respiration, and the 
other the central nervous system (neural and luemal ajUnder). 

Apparatus. — Organs are very numerous in the animal economy, and in order 
to study them profitably it is necessary to classify them in a methodical manner, 
according to their physiological affinities. Consequently, there have been col- 
lected into a single category all those organs which are destined to achieve the 
same physiological finality, and to such a group has been given the name of 
apparatus. 

Bichat has grouped the apparatuses according to the ultimate object of their 
functions, and has thus formed two great categories : one, comprising the 
apparatuses which maintain the individual {apparatuses of nutrition and relation) ; 
the other, the apparatus destined for the preservation of the species {apparatus of 
generation). 

We will describe these apparatuses in the following order : — 

1. Locomotory Apparatus ; 

2. Digestive Apparatus ; 

3. Respiratory Apparatus ; 

4. Urinary Depurative Apparatus ; 

5. Circulatory Apparatus ; 

6. Inner vatory Apparatus ; 

7. Sensory Apparatus ; 

8. Generative Apparatus. 

This description will be terminated by a brief notice of the evolution of ths 
/(Btus^ and its appendages. 



BOOK I. 

LocoMOTORY Apparatus. 

The locomotory apparatus is composed of all those organs which minister to the 
movements an animal may execute. It is certainly one of the most important in 
the economy, from the nmnber and size of the pieces which enter into its 
formation, and by the necessary co-operation it affords the majority of the other 
apparatuses in the performance of the physiological acts allotted to them. 

It is constituted of two kinds of organs— the bones and muscles. The hones, 
hard and resisting, stony in appearance, are really inert levers, joined by firm 
and movable articulatmis, which permit their playing upon each other with the 
greatest facility, at the same time maintaining them in their relative positions. 
The muscles, grouped around the bones and attached to them, are soft organs 
which possess the property of contraction, under certain determinate conditions, 
and of involving in that movement the bones to which they are fixed by their 
extremities. The bones are altogether passive in their motion, while the muscles 
are really the active organs of locomotion — the power intended to move the bony 
levers. 

We will study, successively — 

1. The bones, a particular branch of descriptive anatomy which has received 

the name of Osteology ; 

2. The articulations, or Arthrology ; 

3. The muscles, or Myology. 



FIRST SECTION. 
The Bones. 

CHAPTER I. 
THE BONES IN GENERAL. 



Bones, properly speaking, are only to be found in vertebrate animals, and 
constitute their principal zoological character. In the animal body they form 
an internal framework which consolidates the entire edifice, and gives it its 
general form and dimensions. It is advantageous, before commencing a particular 
description of each bone, to survey them in a general manner. This study 
comprises: 1. The description of the skeleton; 2. A summary indication of 



8 TEE BONES. 

ihQ general principles which should be known, in order to comprehend the details 
of the special descriptions. 

Aeticle I. — The Skeleton. 
The whole of the bones, considered in their natural relations to each other, 
constitute the skeleton. In order to prepare the skeleton of any animal, it is 




SKELETON OF THE DOG. 



sufficient to free it from the soft parts surrounding it. The skeleton should be 
designated natural, if in this operation the ligaments that naturally join the 

Fig. 2. 




SKELETON OF THE CAT. 



various pieces together are allowed to remain ; and artificial if, after these liga- 
ments have been destroyed, it is necessary to replace them by materials foreign 
to the organization, such as iron or brass wire. 



THE SKELETON. 9 

The skeleton is divided into trunk and limbs. 

1. The trunk offers for consideration, in the middle line, the spine or 
vertebral column — a flexible stalk measuring the entire length of the animal, and 
composed of a series of distinct pieces articulated one behind the other. An- 
teriorly, this stalk supports the head — a pyramidal mass which results from the 
assemblage of a large number of bones. On each side of the middle portion of 

Fig. 3. 




SKELETON OF THE PIG. 

I 

the spine, there are detached bony arches which have received the name of ribs, 
and which rest, directly or indirectly, by their inferior extremities, on a single 
bone called the sternum. These bony arches in this way circumscribe the thorax — 
a spacious cavity destined for the reception of the principal organs of respiration 
and circulation. 

2. The limbs, four in number — two anterior and two posterior — are the ap- 

Fig. 4. 




SKELETON OF THE RABBIT. 



pendages which support the trunk of the domestic Mammals. They are usually 
distinguished as anterior and posterior (or fore and hind), but it will be more 
convenient to name them according to their relations, as thoracic (or pectoral) and 
abdominal limbs. Each represents a column divided into several rays resting upon 
one another, and generally forming more or less open angles. The anterior limbs 



10 



THE BONES. 



are each divisible into four principal regions : the shoulder, applied against the 
front part of the thorax ; the arm, which succeeds the shoulder ; and the fore- 




SKELETON OP THE HORSE. 



arm, and foot. The posterior limbs also comprise four regions : the haunch or 
pelvis, which articulates with the posterior part of the spine ; and the thigh, leg^ 
and posterior foot. 

Fig. 6. 




SKELETON OF THE COW. 



In Birds, the posterior limbs alone assume the function of columns of support. 
The thoracic limbs, formed for flight, constitute the wings. 



GENERAL PRINCIPLES APPLICABLE TO THE STUDY OF ALL THE BONES. 11 



The number of bones entering into the composition of the skeleton of the 
principal domesticated animals, arrived at the adult period of life, varies accord- 



Fig. 7. 




SKELETON OF THE SHEEP. 



ing to the species. They are apportioned to the regions of the trunk and limbs 
just mentioned, in the manner indicated in the following table : — 



Designation. 


SOLIPEDS.' 


Ruminants. 


Pig. 


Dog.' 


Vertebral Column' 

Head^ 


48 

28 

37 

1- 2 

1— 2 

2— 2 
16-32 

1— 2 
1- 2 

3— 6 
15-30 


45 

28 

27 

1— 2 

1- 2 

2- 4 
20-40 

1- 2 
1— 2 

3- 6 
19—38 


50 

29 

29 

1— 2 

1— 2 

2— 4 
36—72 

1— 2 
I— 2 

3— 6 
36-72 


46 

28 

27 

1— 2 

1— 2 

2— 4 
36—72 

1- 2 
1— 2 

3— 6 
32—64 


Thorax 
Shoulder 
Arm . 
Forearm 
Fore foot 
Pelvis 
Thigh 
Leg . 
Hind fool 




^ Double regions - 


Tc 


tals 


191 


196 


270 


255 



AeTICLE II. — GElfEEAL PkINCIPLES APPLICABLE TO THE StUDY OF ALL 

THE Bones, 

The description of a bone comprises its name, situation, shape, internal cori' 
formation, structure, and mode of development. 

' One lumbar vertebra less is found in the Ass, and sometimes also in the Mule. 

* The 08 penis has not been included. 

' The sacrum is reckoned as a single bone, and the number of coccygeal vertebrae at aa 
average of 16 for the Horse, 18 for the Ox, 22 for the Pig, and 18 for the Dog. 

* The OS hyoides is reckoned as a single bone. 



12 



THE BONES. 

Name. 



The nomenclature of osteology does not rest on any basis capable of confer- 
ring upon it a methodic form. Consequently, we find bones which derive their 
name from their shape (example : the fibula) ; others from their resemblance 




to known objects (the tibia and vomer). Some owe it to their position (the 
frontal bone), or their uses (the axis and parietal bones). Several attempts 
have been made to submit the nomenclature of the bones to more precise 



GENERAL PRINCIPLES APPLICABLE TO TEE STUDY OF ALL THE BONES. 13 

and uniform rules, but the new designations proposed have not been sanctioned 
by custom. 

Situation. 
The situation of a bone should be viewed in two ways : 1st, Relative to the 
median plane of the body ; 2nd, Relative to the other portions of the skeleton. 

A. Situation relative to the median plane of the body. — The designation of 
median plane, improperly median line, is given to an imaginary vertical plane 
passing through the middle of the skeleton, which it divides from before to 
behind, into two equal portions. The bones may be situat|^ on the median 
plane, in which case there is only one of each kind, and they are called single ; 
they are also named symmetrical bones, because the median plane divides them 
into equal lateral halves exactly alike.^ The bones disposed in a double and 
regular manner on the sides of the median plane bear, for this reason, the name 
of pair bones ; they are also called asymmetrical bones, because their form does 
not admit of their being divided, in any sense, into two similar portions. On the 
contrary, a bone of this kind always offers the most perfect symmetry with its 
fellow on the opposite side.^ 

B. Relative situation to the other parts of the skeleton. — To indicate the 
situation of a bone, considered from this point of view, is to make known the 
place it occupies in the region to which it belongs, and the connections it may 
have with adjoining regions. Thus, the radius is situated in front of the ulna, 
between the arm-bone and the carpus. 

Direction. 

This is absolute or relative. 

A. The absolute direction is related to the axes of the bones themselves. Thus 
it is that a bone may be rectilinear, curvilinear, or twisted. 

B. The relative direction is determined by the relation to the fictitious planes 
established around or in the interior of the skeleton, or with regard to the 
neighbouring bones. For example, a bone is vertical, horizontal, or oblique. In 
the latter case it may be downwards and backwards, or in the reverse direction. 
Example : the scapula is placed obliquely downwards and forwards. 

Shape of the Bones. 

Form. — This is also absolute or relative. 

A. Absolute Form. — The absolute form of a bone is that which it owes to 
the relations existing between its three dimensions — length, width, and thickness. 
a. A bone in which one of its dimensions much exceeds those of the other two is 
a long bojie (example : the femur), provided it be hollowed out internally by an 
elongated space— the medullary canal. Long bones belong exclusively to the 
limbs. In the animal economy there are found bones which resemble them in 
their dimensions, but they have no medullary canal (example : the ribs). 
These differ essentially from the true long bones, and are also distinguished from 
them by the appellation of elongated bones, b. A bone that offers two dimensions 
much more developed than the third, is a flat or tvide bone (example : the 
parietal bone). The bones of this category, destitute of a medullary cavity, are 

• Instances have been recorded of asymmetry in single bones. Lesbre has seen the sixth 
cervical vertebra of the Horse tricuspid on one side and bicuspid on the other, and a last dorsal 
vertebra with one of its transverse processes having the characters of the lumbar vertebraj. 

* But there might be slight differences in weight, torsion, etc. In Man there is nearly 
always a difference between the right and the left side. 

4 



14 TEE BONES. 

met with in the head and the upper regions of the Umbs. c. A bone which 
offers nearly the same development in all its dimensions, is called a short bone 
(example : the astragalus). Destitute, like the preceding, of a medullary canal, 
the short bones are found in the spine and some regions of the limbs. 

B. Relative Form. — To make known the relative form of a bone, is to indicate 
the greater or less exact resemblance it may bear to geometrical figures, or to 
familiar objects. Thus, the scapula is a bone of a triangular shape. 

Regions of the Bones. — When describing the eminences and external 
cavities of bone^ it is essential not to allude to them casually by passing 
indifferently from one to another. To avoid the diificulties resulting from the 
application of such an irrational system, it is necessary to divide the bone to be 
studied into several regions, in which external peculiarities can be examined 
successively, as they present themselves. The general course to be followed in 
order to learn the regions of a long, a flat, and a short bone, is as follows : — 

a. A long bone is always divided into three parts — a body and two extremities. 
The bod// or middle portion, or diaphysis, is the narrowest part of the bone. In 
shape it is a geometrical solid, inclining somewhat to that of a very long prism. 
On the body of a bone, therefore, there are studied as many faces and planes, 
angles or borders, as on the prism it represents. 

The extremities, or epiphyses, are more or less considerable enlargements, 
formed primarily by a special bony nucleus, and offering articular surfaces, as 
well as surfaces for muscular or ligamentous insertion. 

b. A flat bone must necessarily have two faces, and borders and angles. 

c. A short bone has more or less faces, and plane or salient angles which are 
often ignored, because of their trifling ijnportance. 

External Peculiarities of Bones. — These markedly attract the attention, 
because they modify the general shape of bones, and singularly assist in 
distinguishing one bone from another. These peculiarities, which are real 
distinctive features that permit their description to be precisely established, are 
always either eminences or cavities, according to their different uses. 

A. Eminences. — The eminences that stand out in relief from the surfaces 
of bones, are divided into two different categories. One class concurs in the 
formation of the articulations which join the bones to each other ; they are 
named articular eminences, in which, again, are distinguished diarthrodial and 
synarthrodial eminences, according as they belong to movable or immovable 
articulations. The others, usually destined for the insertion of ligaments and 
muscles, are called non-art icidar eminences or eminences of insertion. 

(The term imp-int is also used in anatomy, and signifies a collection of small 
rugged eminences which make the surface of the bone uneven and rough. There 
are muscular, tendinous, ligamentous, and aponeurotic imprints, according as 
they give attachment to muscles, tendons, ligaments, or aponeuroses.) 

a. The synarthrodial eminences are always indentations more or less deep and 
finely cut, which stud the border of large bones. 

b. The diarthrodial eminences are volimiinous, smooth, and in a fresh state 
covered with cartilage. They are named heads and condyles : heads, when they 
describe the segment of a sphere (head of the femur, head of the humerus) ; 
condyles, when they represent an ovoid segment cut parallel to its larger axis 
(condyles of the femur). 

c. The non-articular eminences receive various names. If they are volumi- 
nous and much detached from the bone, they are called processes or apophyses. 



GENERAL PBINOIPLES APPLICABLE TO THE STUDY OF ALL THE BONES. 15 

Apophyses receive qualificatives derived from the analogies perceived between 
them and known objects (examples : the styloid, clinoid, coronoid, and coracoid 
processes). The appellations of protuberances and hiherosities are given to non- 
articular eminences when they are large and round, and slightly detached. 
Lastly, they are named lines, crests, and ridges, when they are narrow and 
very long. 

The processes are sometimes epiphysary in early life, and formed by a special 
nucleus. 

B. Cavities. — The cavities of bones have also been divided into articular, 
diarthrodial or synarthrodia! , and non-articular cavities. 

a. The diarthrodial cavities correspond to the eminences of the same name in 
the bony joints. They take the designation of glenoid cavities when they are 
oval and shallow, and cotyloid cavities when they are deeply excavated, like a 
basin or the cup of an acorn (examples : the glenoid cavity of the scapula, and the 
cotyloid cavity of the coxa). The synarthrodial cavities fit into the dentations 
opposed to them. 

b. The non-articular cavities serve either for hgamentous or muscular 
insertion, or for the passage of vessels, nerves, tendons, etc. 

They are termed channels or furrows, when they are wide, deep, and smooth ; 
grooves, when they are long, narrow, and smooth at the bottom ; and fissures, 
when they are narrow and rugged. Digitcd impi'essions is the name given to 
those excavations in bones which look as if produced by the pressure of the 
finger. The fossce, sinuses, cells, and notches are also non-articular cavities of 
bones. The sinuses and cells are formed by open spaces in the interior of 
bones ; notches, by cavities excavated on their margins. 

When a cavity passes quite through a bone, it is termed a foramen. If this 
foramen has a certain length, it is designated a conduit or canal. Fissures are 
long, narrow openings ; hiatus is the term applied to a wide opening with an 
irregular outline. 

In order to aid the memory, the external peculiarities of bones are grouped 
in the following synoptical table : — 



i Non-Articulars 



( Synarthrodials . Dentations. 
JDiarthrodials . ( gf^^^^s. 

I Styloids. 
Coracoids. 
Mastoids. 
1 1 uoerosiiies. 

Lines. 
^Crests. 



i 


Articulars. . .. 


aynarmroaiaiB -J Dentation 
^Diarthrodials .{^^^^ 




Channels. 


^, 




Furrows. 


•< ' 




Grooves. 


o 




Digital impressions. 


pa 




Fossae. 
Sinuses. 




Non-Articulars .< 


Cells. 




Notches. 




Foraminse. 




Canals. 




Ducts. 




Slits. 






, Hiatuses. 



Internal Conformation of Bones. 

Sections made in various directions through the substance of bones, show 
that their internal conformation varies, according as they belong to the category 
of long, flat, or short bones The diaphysis of long bones is hollowed out into a 
large fusiform cavity — the medullary canal. This' canal is absent in the flat and 
short bones, and is replaced by irregular cavities which communicate with each 
other, called medullary spaces. Its walls are formed by a very dense bony tissue, 



16 



TEE BONES. 



the pores of which are scarcely visible to the naked eye, and which is called the 
compact substance. The extremities of long bones are surrounded by a thin 
layer of compact substance, while the remainder of their mass is constituted by 
the spongy substance — bony tissue channeled into medullary spaces. { Reticulated 
bony tissue is but another form of spongy substance, the only difference between 
the two consisting in the cells or meshes of the first being formed of intercrossed 
osseous fibres, while those of the second are formed of lameUce.) The medullary 
canal, and areolae of the spongy tissue, are filled by the marrow (or medulla). 

The flat bones are constituted by a layer of spongy tissue placed between two 
plates of compact substance. (In the flat bones of the cranium, the two layers 
of compact tissue are termed the vitreous tables, while the cells of the spongy 
tissue are designated diploe.) In certain points of their extent, the spongy 
substance disappears, and then the bone is composed of a single lamina of 
compact tissue. 

The short bones have a nucleus of spongy substance, enveloped in a layer^ 
more or less thick, of compact tissue. 

The compact substance of the bones, being very resisting, is found in all 
those situations which have to sustain violent efforts. The spongy substance is 
very hght when compared with its volume, and is met with in the wider portions of 
the bones, to which it affords increased size without adding sensibly to their weight. 

Structure of Bones. 

Bones are formed of a proper tissue, covered externally by a particular 
membrane — the periosteum, and occupied internally by the medulla, vessels, and 
nerves. 

A. Proper tissue. — The elements of the proper tissue of bone are always and 
everywhere the same ; the texture alone is modified in 
the compact and spongy substance. 

Everywhere the bone tissue is composed of a funda- 
mental substance, which is amorphous or slightlj 
granular, white, and more or less opaque, according to 
the thickness it offers. This fundamental substance is 
penetrated by an infinite number of vascular canaliculi 
[bone cavities), with prolongations {hone canaliculi), 
which contain cells {bone cells). The cavities and their 
contents are named osseous corpuscles or osteoplasts. In 
a dried plate of bone, the corpuscles appear dark when 
viewed by reflected light, white and shining by direct 
light. 

In the spongy tissue, the bone corpuscles, anasto- 
mosing by the ends of their canahcuh, are distributed 
throughout the lamellte of fundamental substance, which 
is intercrossed in such a way as to circumscribe the 
numerous medullary spaces. 

In the compact tissue, the corpuscles are regularly distributed in the 
substance of the bony lamellae, which are arranged in concentric layers. 

In a transverse section of the diaphysis of a long bone, it is noticed that the 
fundamental substance is excavated by an infinite number of vascular canaliculi, 
named Haversian canals (Figs. 9, 10). These canals measure from l-2500th to 
l-200th of an inch in diameter, and are parallel to each other and to the larger 



Fig. 9. 




VERTICAL SECTION OF BONE, 

showing the network of 
Haversian canals. 



GENERAL PRINCIPLES APPLICABLE TO THE STUDY OF ALL THE BONES. 17 



axis of the bone ; they communicate frequently by transverse branches. "While 
the most superficial open on the surface of the bone, beneath the periosteum, 
and the deepest into the medullary canal, a certain number terminate in the 
areolae of the spongy substance at the 
ends of the bones. '^" * 

The wails of these canals are con- 
stituted by several concentric lamellae 
of fundamental substance, in which are 
lodged the essential elements of the 
bony tissue. Each canal, with its 
vessels, its system of concentric lamellae, 
its osteoplasts, and its osseous canaliculi, 
forms a whole (the Haversian system) 
which represents the complete bone in 
miniature. All the Haversian systems 
preserve a certain independence ; the 
canalicuh of each, after reaching the minute structure of bone, as shown iu a thia 

. , 1 11 n , 1 , section cut transversely to the direction of the 

periphery, are nearly all reflected to- Haversian canals. 

wards the centre (the recurrent canaliculi l, A Haversian canal surrounded by its concentric 




lamellse ; the lacunae are seen between the 
lamella', but the radiating tubuli are omitted; 
2, ibid., with its concentric laminae, lacunae, and 
radiating tuhuli; 3, the area of one of the 
canals ; 4, 4, intervening lamelljE, and between 
them, at the upper part, several very long 
lacunae with their tubuli. 



Fig. 11. 




of Ranvier) and rejoin the canaliculi of 
the same system, instead of anasto- 
mosing with those of the neighbouring 
system. 

Between the Haversian systems, 
there are the intermediate systems of 
lamellae which fill the spaces left through 
the imperfect contact of the former. 
In all the long bones there is a system 
of periphercd lamellae, enveloping, ex- 
ternally, all the Haversian systems ; 
while a system of perimediiUary lamellce, 
more or less perfect, also exists at the 
inner surface of the medullary canal. ^*«^^^^' ^^ '^'''^*?rf ™ °!- ''''f''' substance, 

,,, , ^ , 1-11 magnified 500 diameters. 

Sharpey observed that the peripheral ^^ ^^^^,^1 ^^^-^^ . j^ j^s ramifications, 

bony lamellte were traversed by fibres 

{Sharpey's ov perforating fibres), and J. Renaut has remarked in the same lamellae 
the presence of elastic fibres. 

The proper tissue of bones is a framework of organic matter which has 
gelatine for its base, and in which are deposited the calcareous phosphates 
and carbonates which give to this tissue its characteristic hardness. This 
is easily rendered evident by immersing any bone in dilute nitric or hydro- 
chloric acid ; acid dissolve the calcareous salts, but do not act upon the organic 
framework. So it is, that after some days' maceration the bone becomes 
flexible, like cartilage, and loses part of its weight, although it preserves its 
volume and shape. The counterpart of this experiment may be made by 
submitting it to the action of fire. It is then rendered quite friable, because its 
organic skeleton has been destroyed, without the earthy salts it contained being 
affected. 

B. Periosteum. — This is a very vascular and nervous fibrous membrane which 
covers the entire bone, with the exception of the articular surfaces and the 



18 THE BONES. 

insertions of tendons and ligaments. Its thickness and adherence are not the 
same everywhere ; it adheres most closely near the ends of bones. By its inner 
face it corresponds to the surface of the bone, into which it sends prolongations 
{arciform fibres) which ultimately become Sharpey's fibres ; by its external face, 
it is continuous with the surrounding connective tissue and that of the muscular 
aponeuroses. 

The periosteum may be resolved into two layers, though these are not always 
very distinct. The superficial layer is essentially fibrous, and is formed by a 
network of elastic fibres containing bundles of longitudinal fibres and cells. 
The deep layer is a closer elastic network, with finer connective tissue fibres, and 
a larger quantity of cells and vessels. This is called the osteogenous layer , 
because of its functions. 

C. Medulla. — The medulla, or marrow, is a pulpy, fatty substance, which fills 
the medullary canal and the areola of the spongy tissue of the bones, and 
partly the Haversian canals. Somewhat consistent, and of a rosy tint in the 
bones of young animals, the marrow becomes diffluent and yellow in the bones 
of those advanced in age, except in the vertebrae of the Horse, Ox, Dog, etc., 
and in the limbs of the Rabbit. In the first state, it is also mucous or fibrous in 
the cranial and facial bones undergoing development, and, rosy in colour, it 
only contains traces of fat ; while in the second, it has 96 per cent, of this 
substance. The medulla of bones is composed of : 1st, some trabecul^e of 
delicate connective tissue and a network of stellate cells, to support the vessels 
and nerves ; 2nd, fat cells ; 3rd, particular cells, named by M. Robin medullo- 
cells and myeloplaxes. 

The medullo-cells, abundant in the red or foetal marrow, are small cells with a 
spherical or budding nucleus {Bizzozero's cells), analogous to the lymph cells ; 
some are impregnated with hgemoglobine. With regard to the myeloplaxes, these 
are enormous flat cells, irregular in outline, and containing a large number of 
nuclei. Rare in the yellow marrow, they are more particularly found adhering 
to the walls of the medullary canal, or the alveoli of the spongy tissue. 

D. Blood-vessels. — The arteries of bones belong to three orders — a distinction 
based on their volume and the extent of their distribution. 

The arteries of the first order penetrate to the interior of the medullary 
canal of long bones, by a particular orifice — the nutrient foramen. They soon 
divide into two branches, which break up into a network that lines the walls 
of the canal and enters the tissue of the medulla. This network communicates 
with the arteries of the second order, which go to the spongy tissue of the 
extremities of the long bones, penetrating them by the numerous nutritive 
foramina that surround the epiphyses. Lastly, the arteries of the third order 
are branches of the periostic network that enters the superficial Haversian 
canals. These canals may be considered, strictly speaking, as a third category 
of nutrient conduits. In the flat and short bones there are no arteries of the 
first order. 

Veins accompany the arteries, and are always more voluminous than these ; 
they frequently make their exit by special and very large openings at those 
points where the spongy tissue is abundant. The veins of bones sometimes 
exhibit saccular dilatations on their course. Certain veins in the cranial bones 
have their walls partly or entirely channeled in the bony tissue ; they are lined 
by a simple endothelium. 

E. Lymphatic vessels. — The existence of these cannot be affirmed. 



GENERAL PRINCIPLES APPLICABLE TO THE STUDY OF ALL THE BONES. 19 

Nerves. — These belong to the eerebro-spinal and ganglionic system of nerves ; 
the latter are always vaso-motor nerves. 

Almost constantly, a somewhat volmninous nerve enters the medullary canal, 
by passing through the nutrient foramen, and is distributed to the medulla. 
The compact tissue receives few nerve filaments ; while, on the contrary, the 
spongy tissue at the extremities of the long bones, as well as the short bones, 
contains many. Certain short bones, such as the vertebrse, are 
remarkable for the numerous nerves they receive. 

DEVELOPMENT OP BONES. 

The bones, before arriving at the condition in which we see them in the 
adult animal, pass through several successive phases, the study of which consti- 
tutes Osteogemj. 

Nearly all the bones were originally cartilaginous, those of the roof of the 
cranium and the face being only represented by fibrous tissue. We will examine 
the development of these cartilaginous and fibrous bones. 

A. Development of the Cartilaginous Bones. — In the embryo at an early period, 
the bones are composed of a mucous material analogous to that which enters into 
the composition of all the other organs ; this matter is constituted by a mass of 
embryonic cells. Later, they become harder, white, and elastic — that is, cartila- 
ginous. Certain portions of the skeleton persist in this condition during the life 
of the animal. These permanent cartilages are found where the bony skeleton 
must have a certain amount of flexibility, and on the articular surfaces. 

The temporary cartilages, like the permanent, have a fundamental amorphous : 
01 hyahne substance, in which are embedded round cells containing one or several 
nuclei. But they soon undergo modifications, which result in giving to the 
pieces they form the hardness and structure of perfect osseous tissue. 

These modifications gradually cause the cartilage to disappear, and to be 
replaced by bony tissue, without the skeleton ceasing for an instant to preserve 
its form and functions. The process commences by calcification of the peri- 
chondrium and of the middle part of the diaphysis, which ensures the stability 
of the organ. Then the blood-vessels, which are constantly present in temporary 
cartilages, pass through the diaphysary nucleus, ramify, and are directed in a 
parallel manner towards the extremities. Simultaneously, the chondroplasts are 
arranged in parallel series in front of the vessels (rivulation of the cartilage), and 
finish by merging into large, irregular, elongated cavities, incompletely separated 
by bands of fundamental substance of the calcified cartilage, designated the 
directing lines of ossification. 

The blood-vessels enter these cavities, carrying to their surface cells which 
proliferate, and are differentiated into osteoblasts or productive cells of bone. 
The osteoblasts are deposited, layer upon layer, against the walls of the spaces 
limited by the lines of ossification, and form, by a kind of secretion, concentric 
strata of the osseous fundamental system which surrounds them ; then the 
osteoblasts become osteoplasts. The cavities made in the cartilage finish by 
becoming filled up, except at the centre, where a central cylindrical space 
remains (Haversian canal), and a blood-vessel. 

In the extremities of the bones, where there are no Haversian canals, the 
preparatory modifications are the same as in the diaphysis, only the cartilaginous 
cells collect in small irregular masses, and not in parallel piles. Each of these 



20 



THE BONES. 



masses forms layers of bone substance, that finish by constituting the lamellaB of 
spongy tissue at the periphery and medullary tissue at the centre, to fill the 
areola of the latter. 

In this way is accomplished the transformation of cartilage into bone. As 
will have been observed, it is not a mere calcification of the cartilaginous tissue, 
«^A, but a real substitution of bone tissue, presentmg the following phases : 1. Peri- 
tijfe*^- , ( chondrial and endochondral calcification in places (nuclei or centres of ossifica- 
tion). 2. Invasion of the centres of ossification by vessels, rivulation of the 
cartilage. 3. MedulHzation of the cartilage, and 
formation of^ osteoblasts. 4. Development of the 
'Jt^ <^^ .^^^ ■'• '■ " bone tissue, appearance of the osteoplasts. 

J"^ ^§ e^^ /^:r^ B. Development of the Fibrous Bones. — The bones 

originally fibrous are not merely charged with lime 
salts in order to acquire a bony appearance. They 
do not pass through a transitory cartilaginous state, 
but the phenomena of ossification take place in the 
fibrous tissue in the following manner : — 

The fasciculi of connective tissue become calcified, 
separate here and there from one another to form 
spaces, into which blood-vessels enter or osteoblasts 
appear. To this phase of medullization succeeds the 
phase of ossification, which is accomplished in the 
same manner as in the cartilaginous bones. Only 
the directing lines are represented by connective 
fasciculi, which later become Sharpey's fibres. 

0. Progress of Ossification. — Ossification com- 
mences simultaneously in several parts of the skeleton, 
and in each of the bones in particular— though not 
throughout their entire extent at the same time. On 
CARTILAGE AT THE SEAT OF thc coutrary, lu certain determinate points of the carti- 
ossiFicATioN, showing at its lagiuous or fibrous mass, osseous tissue is developed 
ir^'lsCi:;...'": c:lr™: ^Wch, gradually extendmg, ends by completely in- 
each of which is enclosed in a vadiug it. These points are named nuclei (or centres) 
sheath of calcified intercellular ^f ossificatiou. The nuclei are primitive or comple- 
mentary. The latter, termed epiphyses, are in a 
fashion added to the bone, and wholly or partly form certain' apophyses, rtjlj* , '^' 
Although these centres of ossification increase from day to day, they never- 
theless remain for a long time independent of each other, and are united only by 
cartilage. When the skeleton is completely developed, the various centres of 
ossification become joined to each other, and the entire bone forms one piece ; 
there are no longer any apophyses. 

Up to the present time, attempts to discover the laws which govern the 
appearance of the centres of ossification have been futile ; the size of the bone 
counts for nothing ; and the influence of proximity to the centres of circulation, 
which has been sometimes brought forward (for the sternum, for example, 
which is never completely ossified), cannot be accepted. The law which 
presides over the union of the centres of ossification has also been sought 
for. A. Berard imagined he could formulate it in the following proposition .- 
Of the two extremities of along bone, it is always that towards ivhich the nutrient 
foramen is directed that is first united to the body of the bone. But to Berard's 




GENERAL PRINCIPLES APPLICABLE TO THE STUDY OF ALL THE BONES. 21 

law there are nmnerous exceptions ; and in order to demonstrate that it is not 
absolute, it is sufficient to indicate that the direction of the nutrient foramen 
varies much, not only in similar bones of different species of animals, but also in 
similar bones of the same species^ ; and yet the progress of ossilication is alwajs 
the same. 

The period when fusion of the epiphyses terminates in the domestic animals 
is still little known ; fusion is evidently complete when growth is achieved, but 
this period is markedly modified by hygiene and the :'ood animals receive. Renault 
and some breeders have observed, that in the proocious breeds of cattle the 
evolution of the teeth is more rapid than in the common breeds. More recently, 
Sanson has affirmed that precocity, characterized by this prompt dental evolution, 
is marked by a more rapid fusion of the epiphyses, and he believes there is a 
direct relation between the evolution of the teeth and that of the bones. 
According to this principle, in the Horse the fusion of the epiphyses should 
commence and terminate between three and five years of age. 

Toussaint, however, did not share this opinion. In the Ox, Sheep, and 
Horse, he remarked that the first centres of ossification appeared in the body 
of the flat and the longbone^and in the centrum and arches of the vertebrae. 
When the first half of ^esrajtionnad not been passed, no other points of ossifica- 
tion were seen. It is necessary to add, however, those of the second and third 
phalanges and the calcis, which comport themselves as long bones. 

In the last half of gestation, ossification invades the complementary nuclei, as 
well as the short bones ; the exceptions are the pisiform bone and the inner condyle 
of the humerus in the Calf and Foal, and the large and small sesamoid bones in 
the Calf only. Ossification of these bones of the skeleton is slow. It must also 
be mentioned that at birth the complementary nuclei of the coxas^ are not yet 
visible, and they are net seen until ten months or a year afterwards. ^^ ^ ""' ^^^J 

With regard to fusion of the epiphyses, it occurs at the following periods in 
the principal bones of the Horse ; at the twelfth to the fifteenth month in the 
second phalanx at first, then in the first phalanx ; at the fifteenth to the 
eighteenth month in the middle metacarpal, afterwards in the metatarsal. At 
this age fusion also occurs at the upper end of the radius and inferior ex- 
tremity of the humerus : from twenty months to two years, at the lower end of 
the tibia ; from three to three and a half years, at the upper extremity of the 
humerus, at the two ends of the femur, and at the upper end of the tibia ; 
lastly, about five years, in the bodies of the vertebrae and in the coxae. 

In the Ox, ossification progresses at about the same rate as in the Horse, 
except that there is a little greater precocity in the fusion of the epiphyses of the 
humerus and radius, which are fused at the same time as those of the phalanges, 
and matacarpal and metatarsal bones. In this animal, the two lateral halves of 
the latter bones are united before union of the inferior epiphysis to the body of 
the bone. The Sheep offers an interesting peculiarity, in that the humero- 
radial epiphyses are consolidated before those of the phalanges, and towards the 
tenth month. 

If the results of these observations, made on our principal domestic animals, 
are compared with the evolution of the dental system, we are compelled to con- 
clude, with Toussaint, that fusion of the epiphyses does not commence at the 
same time as the eruption of the first permanent teeth. If a relationship exists 
between the evolution of the teeth and that of the bones, it has yet to be 
demonstrated in an exact manner. 



22 THE BONES. 

Toussaint has also studied the course of ossification in the Bog, Pig, and 
Rabbit. In the Dog at birth, none of the complementary nuclei have been 
invaded by ossification. Consequently, bone tissue is only found in the dia- 
physis of the long and flat bones. In the thrge months after birth, the great 
majority of the epiphyses commence to ossify ; and after this period there only 
remain the pyramidal bone and the complementary nuclei of the coxffi, in the 
cartilaginous condition ; the ossification of these latter commence at from five to 
six months. 

The skeleton of the Rabbit is, at birth, in a condition almost identical with 
that of the Dog ; nearly all the epiphysary nuclei of the humerus and that of 
the lower end of the femur, however, show osseous points. 

In the Fig, at birth ossification is much more advanced than in the Dog ; 
but it is less so than in the larger Herbivora. 

The fusion of the epiphyses has been studied in the Dog. It commences at 
five months, in the phalanges and metacarpals, and continues in the humerus 
and radius, the corresponding epiphyses of which are consolidated at nine 
months ; at eighteen months there can be distinguished the nuclei at the upper 
border of the scapula, the upper end of the humerus, inferior extremity of the 
radius and uhia, the epiphyses of the femur, and the bodies of the vertebrae. 
The latter facts support the preceding ones, and likewise demonstrate that the 
conclusions of Sanson are probably too absolute. 

Growth of the Bones. 

Bones increase by the superposition of new elements, while the soft parts of 
the organism grow by the interposition of new elements in the mass of pre- 
existing elements. The manner in which this apposition of new elements is 
accomplished is not the same in the long, the flat, or the short bones. 

1. Long Bones. As a general rule, the long bones elongate by the growth 
and ossification of the temporary cartilage situated between the diaphysis and 
the osseous nuclei at the extremities. Consequently, elongation ceases when the 
primitive or complementary nuclei are fused with one another. The increase in 
length in the bones of the Ihnbs does not take place everywhere in the same 
proportion. Duhamel, Flourens, and particularly Oilier and Humphry, have 
remarked that, in the thoracic limb, the extremity furthest removed from the 
humero-radial articulation grows fastest ; while in the abdominal limb, the 
extremity most distant from the femoro-tibial articulation grows the least. 

With regard to the increase in thickness of the bone, this occurs by ossifica- 
tion of the deeper layer of the periosteum — the osteogenous lager. The experiments 
of the authors just mentioned irrefutably demonstrate this, and those of Oilier 
have even proved that the periosteum may produce bone at a point where it has 
been transplanted. 

The periostic bone is developed according to the process of ossification in the 
fibrous tissue. In a transverse section of the diaphysis of a growing long bone, 
there is seen, as Laulaine has indicated, concentric circumferences united by 
radii of osseous substance. The diaphysary portion of the periostic bone is 
fused with the extremities, through the medium of the ossification notch of 
Ranvier — a prolongation of the periosteum into the articular enlargement around 
the cartilage of conjugation. The formation of bone tissue in the deeper layer 
of the periosteum is very active during the youth of animals, but it soon 
diminishes, and ceases completely in advanced age. 



GENERA L PRINCIPLES A PPLICABLE TO THE STUD Y OF ALL TEE BONES. 23 

If the phenomena of growth were not counterbalanced by those of absorption, 
long bones would acquire an enormous thickness and weight. But in the first 
period of life, in proportion as new layers are applied to the surface of bones, the 
deeper parts — those occupying the axis of the diaphysis — disappear by absorption. 
In this way the medullary canal is formed, and a just proportion established 
between the volume and weight of the skeleton. 

When the bones are completely formed, during the entire adult period the 
process of destruction is equal to that of growth, so that their weight and com- 
position does not vary. At a later period, absorption is greater than the forma- 
tive force, which in old age is altogether in abeyance ; so that the organic 
matter of the bones is rarefied, and these lose their elasticity and gain in 
fragility. 

It has been remarked that the development of the bones is subordinate, in 
a certain measure, to the activity and resistance of the organs in their vicinity. 
Lesshoft and Popoff beheve that the development of a bone is in proportion to 
the activity of the neighbouring muscles, that the pressure of external organs- 
such as an aponeurosis — may produce torsion in a bone and retard its growth, 
so that its greatest thickness will correspond to the point where the surrounding 
Ijf^ resistances are at a minimum. Oilier, however, has noted that the long bones 
i^*^"^ become more elongated when they do not sustain pressure on their extremities. 

2. Flat Bones. — These bones have sometimes only one primary nucleus of 
ossification, placed in the centre. They grow by the increase of this nucleus, 
which gradually invades the mass of the bone in radiating from the centre towards 
the periphery. When they have several nuclei, some of these are at the margin, 
and in such a case the bones increase by ossification of the marginal efpiphyses 
and growth of the central nucleus. 

Flat bones increase in thickness by the formation of sub-periosteal layers, 
and by the development of the spongy tissue between the two compact plates. 

3. Short Bones. — These grow in thickness by the progressive ossification of 
the osteogenic layer of the periosteum ; and in length by ossification of the 

• epiphysary cartilages, when they possess complementary nuclei. 

Nutrition of Bones. 

The experiments which consisted in feeding young animals with madder, and 
afterwards examining their osseous system, have for a long period demonstrated 
the nutrition of bones. When bones cease to grow, nutrition becomes less active ; 
but it is evident that it does go on, in order to maintain the organic matter of 
the osseous tissue in a proper condition. 

The abundance of vessels carrying blood to all parts of the bone tissue, alone 
suffices to prove the existence of a nutritive movement in these apparently stony 
organs. 



THE BONES. 



CHAPTER 11. 
THE BONES OF MAMMALIA IN PARTICULAR. 

Article I. — Vertebral Column. 

The vertebral column, or spine, is a solid and flexible stalk situated in the middle 
and upper part of the trunk, of which it forms the essential portion. It protects 
the spinal cord and sustains the thorax, as well as the principal or2:ans of circu- 
lation, respiration, and digestion. Articulated anteriorly with the head, and 
terminating in a point at its posterior extremity, this stalk is formed by a some- 
what considerable assemblage of short, single, tuberous bones, to which has been 
given the name of vertehne. These bones, though all constructed on a uniform 
type, yet do not offer the same configuration throughout the whole spine. The 
differences they present in this respect have permitted their being divided into 
five principal groups ; whence the division of the vertebral column in five regions, 
which are, enumerating them from before to behind : 1. Cervical region. 2, 
Dorsal region. 3. Lumbar region. 4. Sacral region. 5. Coccygeal region. The 
first comprises seven vertebrse, which serve as a base for the animal's neck ; the 
second has eighteen, against which the ribs are placed ; the third has only six, 
which correspond to the loins ; in the fourth there are five, constantly fused into 
one mass in the adult, to constitute a single bone — the sacrum ; while the fifth 
possesses a variable number of small degenerate vertebrte, gradually decreasing 
in size to form the tail. The pieces constituting the first three regions are called 
true veiieircB ; those of the last two are designated /(v/se vertehrce. 

The subjoined table indicates the number of vertebrae in each of the regions 
of the spine, in the horse and other domestic Mammalia. 



Animals. 


Vertebra. 


Cervical. 


Dorsal. 


Lumbar. 


Sacral. 


COCCTGEAL. 


Horse 

Ox 

Sheep 

Goat 

Camel 

Pig 

Dog 

Cat 

Rabbit 


7 
7 
7 
7 
7 
7 
7 
7 
7 


18 
13 
13 
13 
12 
14 
13 
13 
12 


6 or 5 

6 
6—7 

6 

7 

6—7 

7 

7 

7 


5 
5 
4 
4 
4 
4 
3 
3 
4 


15-18 
16—20 
16—24 
11-12 
15—18 
21-23 
16—21 

21 
16-18 



The characters belonging to all these vertebrae will be first studied ; then a 
particular description of those of each region will be given ; and, finally, an 
examination will be made of the spine as a whole. 

Characters common to all the Vertebrae. 

Each of these small bones is pierced from before to behind by a wide opening — 

the spinal foramen., or vertebral canal ; whence results, for the entire spine, a long 

canal traversing its whole length, and which lodges a very important portion of 

the nervous centres— the spinal cord. This canal, which traverses the vertebrae 



VEBTEBB^. 25 

from one end to the other, transforms it into a ring in which we recognize, for 
facility of description, two parts — the one inferior, the other superior. The first, 
or hotly, is very thick, and forms the base of the vertebras ; the second, which 
is thin, has been designated spinous or spinal — from one of the pecuUarities it 
presents, or annular — because it circumscribes the major portion of the spinal 
foramen. This division is not altogether an arbitrary one, for the body and the 
annular portion constitute, in the foetus, two distinct pieces, which do not become 
united for a long time after birth. 

Body {centrum). — The shape of the body of a vertebra is that of a prism 





Fig. 13. 




k 




B A. 


A 






i 




w. 


•{{ 





ELEMENTS OF A VERTEBRA. (AFTER OWEN.) 

A, Ideal typical vertebra ; B, Actual thoracic vertebra of a bird ; c, Centrum (or 
body), giving off, d, d, the diapophyses, and p,p, the parapophyses (transverse and 
articular processes) ; the neural arch, enclosing the spinal cord, is formed by 
n, n, the neurapophyses (lamince), saxd n, s, the neural spine {spinous process); 
the hamal arch, enclosing the great centres of the circulation, is formed by h, h, 
the haemapophyses (costal cartilages) ; and h, s, the haemal spine (sternum). 
From both the neurapophyses and haemapophyses may be given off the zygapo- 
physes, z, z. The lateral arches, which may enclose the vei'tebral arteries, o, o, 
are completed by the pleurapophyses (ribs), pi. ; these in B are bent downwai-ds, 
so as to form part of the hasmal arch, and give off the diverging appendages, a, a. 

with four faces, of which two only — the superior and inferior — are free, and can 
be studied in the adult ; the two lateral faces are united and confounded with 
the annular portion. This prism also presents two extremities — an anterior and 
posterior. 

Faces. — The superior face, limited in extent, forms part of the spinal foramen, 
constituting its floor. It exhibits : 1. On the middle line, two roughened, 
prominent surfaces, representing two triangles, whose summits are opposed. 
2. On the sides, two depressed smooth surfaces, perforated by one or more 
openings that lead to the interior of the bone. The inferior face is divided into 
two lateral portions by a median crest (the htemal spine). 

Extremities. — The anterior has a prominent convex head, more or less 
detached. The posterior offers a cavity for the reception of the head of the 
next vertebra. These two planes — the one convex, the other concave — do not 
come into immediate contact ; an elastic, flexible fibro-cartila^e, firmly attached 
to each, is interposed between them. 



26 THE BONES. 

Annulae Portion {neurcd arch or neuropophyses). — This is formed by an 
osseous plate that curves suddenly downwards, in the shape of an arch, the two 
extremities of which approach each other, enclose the body, and become united 
to it. It offers for study : 1. An internal and an external surface. 2. An 
anterior and &, posterior border. 

Surfaces. — The internal surface, concave and smooth, forms, with the superior 
face of the body, the spinal foramen. The external, convex and irregular, pre- 
sents : 1 . A single prominence, raised in the middle of the superior portion, and 
named the spinous process {neural spine). 2. The transverse processes (diapo- 
physes) are a double pair of eminences, one on each side, and projected trans- 
versely outwards. 

Borders. — The anterior border has two articular facets looking upwards : 
these are the anterior articular processes {prezygopophyses), right and left. In 
each is a notch which, when placed in opposition to a similar excavation in the 
preceding vertebra, forms the inter vertehrcd foramen. The posterior border pre- 
sents the same pecuUarities, with this difference, that the articular faces of the 
posterior articular processes {postzygopophyses) are inclined downwards, to corre- 
spond with the anterior facets of the succeeding vertebra.^ 

Structure of the vertebrce. —The compact substance, which is abundant in the 
spinous portion, forms in the body an extremely thin layer, inclosing a volumi- 
nous nucleus of spongy tissue. The latter is traversed by numerous venous 
canals, which open on the surface of the bone. 

Development. — It has been already shown that the body and spinous 
portion of a vertebra constitute, in yoimg animals, two distinct pieces. Each 
was primarily formed from two lateral centres, which met on the median line. 
In the body, the fusion of these centres is so prompt, that it is generally believed, 
perhaps justly, that the development of this part of the vertebra proceeds from 
a single centre of ossification. The union of the two centres in the annular 
portion, usually designated the vertebral lamince {parapophyses), is slower. It 
commences in the most anterior vertebrae, and is latest in the sacral and coccy- 
geal regions. To the three principal pieces of the vertebra in process of 
ossification, are added, at a subsequent period, complementary centres of ossifi- 
cation, variable in number according to the regions and species of animal ; 
there is always one for each of the anterior and posterior surfaces of the 
vertebral bodies ; while others, much less constant, concur to form the spinous 
and transverse processes. 

Characters proper to the Vertebrae of each Region. 

A casual inspection of a vertebra might suffice, strictly speaking, to dis- 
tinguish the region of the spine to which it belonged. For instance, a cervical 
vertebra is recognized by its volume, the absence of a spinous process, and the 
foramen which traverses the base of its transverse processes. The dorsal 
vertebra is conspicuous by its tubercular transverse processes, and by being 
furnished, outwardly, with an articular surface, as well as by the depressions on 
its body destined to receive the heads of the ribs. The lumbar vertebra has its 
long flattened transverse processes ; while the coccygeal vertebra offers rudi- 

(' Vertebrae which have centra concave at both ends, are designated amphicselous. Those 
distinguished by a concavity in front and a convexity behind, are known as procxlous ; but if 
the cavity is behind and tlie convexity before, they are then named opisthocxlous. A vertebra 
of the above description belongs therefore, to the opisthocaslous class.) 




VEBTEBRM 27 

mentary laminae and processes. There is no necessity for noticing the sacrum, 
the five pieces of which form one bone— a feature that markedly distinguishes 
it from the other regions of the vertebral column. But these few distinctive 
characteristics do not satisfy the requirements of descriptive anatomy ; so that 
it is necessary to undertake a more extensive study of each of these regions. 

1. Cekvical Vertebe^. 
General Characters. — These vertebrae, the longest and thickest in the 
spine, present generally a cubical form. They are usually distinguished from the 
vertebrae of the other regions by the following characters : The inferior spine of 
the body is strongly marked, especially behind, where it terminates in a small 
tubercle. The head is well detached from the remainder of the bone, and 
describes a very short curve. The posterior cavity, 
wide and deep, represents a veritable cotyloid de- 
pression, which is too large to fit the head exactly; 
the intermediate fibro-cartilage on these two sur- 
faces is also of a great thickness. The spinous 
process forms a simple roughened, and but slightly 
prominent, ridge. The transverse processes, very 
developed, are elongated in an antero-posterior 
direction, and inclined downwards. In this region 

they are designated the trachelian processes, be- ^ cervical vertebra. 

cause of their relations with the trachea ; a j^ Superior spinous process ; 2, an- 
f oramen that traverses them from before to terior articuiaj processes ; 3, pos- 
behind at their base has been, for the same f^tr ^^n^et fac^'^o^Tod^ f 'e!?; 
reason, named the trachelian foramen {^vertebral transverse processes, with their 
foramen). The articular processes, large and tubercles or rudimentary ribs ; 8, 

' . , -TIT 1 J • J inferior crest, or spine : 9, concave 

promment, are mchned downwards and mwards. posterior face. 
The notches are wide and deep. 

Specific Characters. — The seven cervical vertebrae are reckoned from 
before to behind, and receive numerical names indicating their place in the 
region. 

First. — The first vertebra of the neck, which has been named the atlas,^ 
deserves a very careful description. At first sight there is recognized the great 
development of its transversal diameter, the considerable dimensions of the 
spinal foramen, and the thinness of its body. The intra-spinal face of the latter 
is divided into two portions by a transverse ridge : one anterior, furnished with 
hgamentous imprints, exhibits, laterally, two deep excavations, which lodge the 
venous sinuses ; the other, posterior, is smooth and concave from side to side, 
and forms an articular surface into which is received the odontoid process of the 
axis ; this surface takes the place of the cotyloid cavity. The inferior spine of 
the body appears as a large tubercle (Fig, 15, 6), The head is absent, and is 
replaced by two concave facets. The anterior articular processes have their 
gliding surfaces looking downwards ; they are joined to the two preceding facets 
to constitute two large diarthrodial cavities, which articulate with the occipital 
condyles (Fig, 15, 1), There is no spinous process, but a roughened surface 
instead. The transverse processes are large, flattened above and below, inclining 
forwards and downwards, and are provided with a thick rugged lip. Posteriorly, 

* Rudimentary ribs are sometimes attached by ligaments to the ends of the transverse 
processes (.Leshre). 



28 



THE BONES. 



Fig. 15. 




atlas; inferior sitrface. 
1, Articular cavities for condyles of 
the occipital bone ; 2, articulai facet ; 
3, vertebral or antero-internal fora- 
men ; 4, posterior, or cervical fora- 
men ; 5, transverse process or wing 



quite at their base, and on each side of the spinal foramen, they show two large 
vertical facets which represent the posterior articular processes ; these facets are 
uneven, are confounded with the articular cavity 
of the upper face of the body, and correspond to 
the two analogous facets of the axis. Each trans- 
verse process is pierced at its base by two foramina, 
which traverse it from below upwards. The 
posterior represents the vertebral foramen of the 
other vertebrae ; while the anterior is continued 
to the external surface of the process by a wide, 
deep, but very short channel, running from with- 
out to within, and joins a third foramen, which 
enters the spinal canal. These last two openings, 
with the demi-canal which unites them, replace 
the anterior notch ; the posterior is altogether 
absent. Lastly, an inflected venous canal, the 
position of which varies, and it is also sometimes 
tubercle representing the inferior absent, crosscs the lamiuffi of the atlas, and opens, 
spinous process; 7, superior arch, qjj Qjjg ^[^q^ j^to the Spinal caual, and on the 

forming the roof of the spinal fora- , , ^t ^^ ^ mi- ^i 

^gn ^ other, beneath the transverse process, ihe atlas 

contains much compact tissue, and is generally 
developed from six centres of ossification : two for the body, which at an early 
period becomes a solid piece, and two for the annular part ; the other two are 
complementary centres, each of which forms one of the two posterior undulated 
facets and lip of the corresponding transverse process. 

Second. — This is named the axis, or dentata (Fig. 16). It is the longest of 

all the cervical vertebrae ; those which 
succeed it gradually diminish in length 
and in thickness. The body of the axis 
has no increase anteriorly, but a conical 
process termed the odontoid, which is 
flattened above and below, concave and 
rough from one side to the other on its 
superior face ; convex in the same direc- 
tion and perfectly smooth on its inferior 
face. The latter represents an articular 
half-hinge, around which glides the con- 
cave articular surface on the superior 
face of the body of the atlas. The 
anterior articular processes are carried 
to the base and to each side of the 
odontoidian pivot, in the shape of two 
undulated facets, which are confounded with the gliding surface of the latter, 
the destination of which has been already noted. The spinous process, very 
large and elongated antero-posteriorly, is divided behind into two roughened lips. 
The transverse processes are slightly developed, and terminate posteriorly in a 
single tubercle, directed backwards. The anterior notches are very deep, and 
are most frequently converted into foramina. This vertebra, although voluminous, 
is light, in consequence of its containing much spongy substance. In the young 
animal, the odontoid process and the articular surfaces on each side, constitute 



Fig. 16. 




THE AXIS, OR dentata; LATERAL VIEW. 

1, Superior spinous process ; 2, odontoid pro- 
cess; 3, intervertebral foramen, or hole of 
conjugation; 4, body; 5, inferior spinous 
process ; 6, 7, inferior and superior articu- 
lating processes. 



VERTEBRM 29 

two centres, distinct from each other and from the body of the vertebra. After 
the axis, the cervical vertebrae diminish in length and increase in thickness ; 
while the obliquity of their articular processes becomes more pronounced the 
more distant they are from that vertebra. 

Third, fourth, and fifth.— Each, of these has, at its transverse processes, two 
prolongations — one anterior, the other posterior. The inferior face of their bodies 





AXIS AND SIXTH CKRVICAL OF THE HORSE AND ASS. 

A. Axis of the Horse. 1, spinous process ; 2, transverse process ; 3, odontoid process ; 
4, lateral articular facet. 

B. Axis of the Ass. Same numbers and same signification. 

a', Sixth cervical vertebra of the Horse. 1, Articular head ; 2, posterior articular process ; 
3. articular cavitv ; 4, posterior prolongation of the transverse process : 5, anterior ditto. 
b', Sixth cervical vertebra of the Ass. Same numbers and same signification. 

exhibits a median spine terminated posteriorly by a tubercle, which gradually 
increases in volimie from the third to the fifth vertebra. 

The third presents, between its anterior and posterior articular processes, an 
almost complete gap ; if its anterior extremity be placed on a horizontal plane, 
it will touch that plane by its articular and transverse processes and its head. 



30 TEE BONES. 

In the fourth, the articular processes are united by a thin, sharp osseous plate, 
notched only in front. Laid on a horizontal plane, the head remains some 
distance from that plane. The fifth is recognized by the continuous, thick, and 
rugged lamina which unites the articular processes, and by the tubercle of the 
inferior spine on the body, which is in shape like the heart on a playing-card. 

Sixth.— T\n& is distinguished by the slight prominence of the spinous process, 
but particularly by the almost total disappearance of the inferior spine, and the 
presence of a third prolongation, very strong and inchning downwards at its 
transverse process — a circumstance to which this vertebra owes its designation of 
tricuspid. 

Seventh. — This has received the name of prominens, because its spinous pro- 
cess, terminating in a point, is more distinct than in the preceding vertebrae, the 
axis excepted. It exhibits, besides : deep imprints, which replace the inferior 
spine ; a concave demi-facet on each side of the posterior cavity of the articulation, 
of the head of the first rib ; a particular disposition of its transverse processes, 
which are unituberculous ; the complete absence of the vertebral foramen ; and, 
lastly, the depth and width of its notches. The spinal foramen, which has 
already assumed a somewhat considerable diameter in the sixth cervical vertebra, 
is still larger in the seventh. 

Ass. — The cervical vertebra3 in this animal much resemble those in the 
Horse. Studying them more closely, however, it is possible to discover certain 
differences which distinguish them from those of the other Equidfe. Thus, the 
rugosities on the arch of the atlas are much less marked than in the Horse, and 
form a kind of thick depressed tubercle. The vertebral foramen is very large 
in proportion to the size of the vertebra, and the canal uniting the two portions 
of the anterior foramen of the transverse process is deep and protected by a 
well-defined rim. The axis has a less elevated spinous process than that of the 
Horse ; its upper border, nearly parallel with the transverse process, is more 
deeply divided into two lips, and the summit of its transverse process extends, 
backwards to the articular process, while in the Horse it does not go beyond the 
origin of the latter. In the third, the lamina uniting the two prolongations or 
points of the transverse processes, is notched behind the anterior prolongation, 
instead of being notchless as in the Horse. In the fourth Siud fifth this notch is 
still more marke4. In every instance the anterior prolongation of the transverse 
process is always more detached and better circumscribed in the Ass than in the 
Horse. The same remark applies to the tricuspid ; the posterior prolongation is 
also better detached, and the middle prolongation extends nearly to the articular 
cavity of the vertebra — a prolongation which, in the Horse, does not exceed one- 
half the length of the posterior one. The seventh differs little from that of the 
Horse ; nevertheless, the uni-tubercular transverse process has, in front, a small 
sharp projection which resembles somewhat the anterior prolongation of the 
bicuspid processes. 

In the Mule and Hinny, the cervical vertebrae hold the middle place between 
those of the Ass and the Horse. 

Differential Characters of the Cervical Vertebra in the other Domesticated 

Animals. 

A. Ox, Sheep, and Goat. — The cervical vertebrae of these animals differ from those of 
Solipeds by their shortness, and the greater development of their insertion eminences. In the 
Sheep and Goat they are relatively longer than in the Ox. The transverse processes of the 



VERTEBRA. 31 

atlas are less inclined than in the Horse, and have no vertebral foramina ; the posterior facets 
for articulation with the axis, are nearly flat and join each other. The axis has a semi-cylindri- 
cal, not a conical, odontoid process, which is so concave on its upper t^urface that it looks like 
a groove. Its spinous process is not so thick as in the Horse, and is not bitid posteriorly. 

In the Jive succeeding vertebras, a rugged continuous lamina unites the anterior articular 
processes to the posterior. The spinous process inclines forward, and is flattened transversely 
at its summit, which is sometimes bifid ; it progressively increases in height from the third to 
the fifth vertebra. 

In the sixth, the transverse processes have only two prolongations — a superior and inferior; 
the latter, large and flattened on both sides, is bent abruptly downwards. The spinous process 
has already attained the height of 1| to 2 inches in this vertebra, and is flattened laterally. 

The seventh well deserves the name of prominens, its spinous process being no less than 
from 4 to 4f inches (see Figs. 6 and 7). 

B. Camel.— In the Camel, the cervical vertebrae are longer and thinner than in the other 
large domestic animals. Altogether, they form oue-third of the total length of the spine. 
Their vertebral lamiiise are deeply notched before and behind, which allows them to easily 
enter tlie spinal canal. Their articular processes are convex, and from the second to the sixth 
inclusively, the vertebral foramen is small and deeply placed in the laminae. 

The atlas is distinguished from that of the Horse and Ox by the absence of the tubercle on 
the inferior face of the body, and the shortness of the transverse processes, of which the border 
is thin and sharp. The vertebral foramen makes a somewhat long course in the transverse 
process of this vertebra, and opens at the bottom of the excavation in which the anterior inter- 
vertebral foramina meet — the latter being double. 

The axis is very long and constricted in its middle ; the inferior crest is only slightly 
salient ; there are ilouble invertebral foramina, the largest of which is divided by a bony 
septum ; the odontoid process is as in the Ox. The other cervical vertebrae gradually diminish 
in size and increase in thickness from before to behind. 

In the third, fourth, and fifth, the transverse processes are bi-tuberculated. 

In the sixth, the transverse process is a wide and thick plate, inclining downwards. 

The seventh is recognized by its long spinous process and the smallness of its transverse 
process, which has a larger and more obvious vertebral foramen than the other vertebras 
(see Fig. 8). 

C. Pig. — Of all the domesticated animals, this has the shortest, the widest, the most 
tuberous, and consequently tlie strongett cervical vertebrae. The body of these bones has no 
crest on the inferior face ; the head, but little detached, is scarcely round, and looks as if driven 
back on itself; consequently, tiie posterior cavity is not deep. The vertebral laminae are very 
narrow, and scarcely extend from one part of the vertebra to the other in the superior portion, 
so that the spinal canal appears at this point to be incomplete. 

In the atlas, the transverse processes are less inclined than in Ruminants ; the vertebral 
foramen is not constant, and when it exists, opens on one side, under the transverse process, 
and on the other, on its posterior margin, after pursuing a certain tiack in the substance of 
the bone. 

The odontoid process of the axis is constricted at its base. This verte*bra is distinguished 
by its high and thin spinous process inclining slightly back, by its transverse processes being 
but slightly prominent, and perforated by an enormous vertebral foramen. 

In the four succeeding vertebrae, the spinous process terminates in a blunt point, and inclines 
forward ; slightly salient in the first, it gradually rises in the others. The transverse processes 
form two prolongations : one, the superior, is tuberous, and is joined to the anterior articular 
process by a plate of bone, which is pierced by a foramen ; the other, the inferior, flattened on 
both sides, bent downwards, and large, as it belongs to a posterior vertebra, transforms the 
inferior face of these vertebral bodies into a large groove. The seventh has a spinous process 
as long as those of the dorsal region. A peiforated bony plate, as in the preceding vertebrae, 
unites the anterior articular process to the single tubercle composing the transverse process; 
the latter is continued back nearly to the posterior notch by a second plate, also perforated 
with a foramen (see Fig. 3). 

D. Dog and Cat. — In these animals, the cervical vertebrae are long and thick, and much 
resemble those of Solipeils. Nevertheless, besides their smaller volume, they are distinguished : 
1. By the disposition of their corresponding articular surfaces ; the anteiior, or head, is nearly 
flat, and is even slightly excavated in its centre ; the posterior, or cavity, is l.ut little hollowed 
to receive the head of the next vertebra; 2. By the width of the vertebral laminae, which 
overlap one another; 3. By the height of their spinous processes, which increases as the 
vertebrae extend back ; 4. By the great extent of the anterior and posterior articular processes, 



32 THE BONES. 

which are united by means of a continuous and very salient bony plate, that considerably 
augments the transversal diameter of each vertebra. 

In the atlas, the articular surface for the odontoid pivot is confounded in front with the 
cavities which correspond to the occipital condyles. The two facets which are annexed 
posteriorly to this articular surface, instead of being plane or gently undulated, as in the 
other domesticated animals, are transformed into real glenoid cavities. The triinsverse pro- 
cesses are carried directly outwards and a little backvvanl ; the lip wljicli borders eacli is 
slightly raised ; of the two foramina wiiich replace the anterior notch, one only exists, and 
this penetrates to the interior of the spinal canal ; the other is merely a simple notch. 

In the axis, the odontoid process is cylindrical, narrow at its base, and bent a little upwards ; 
the lateral facets of this eminence represents true condyles. The spinous process is very thin 
and undivided, and is curved forward above the laminae of the atlas. The anterior notches are 
never converted into foramina. 

The third cervical vertebra is the largest : and the succeeding ones gradually diminish in 
thickness to the last, contrary to what occurs in the other species. The seventh does not show 
the spinous process so developed as in Ruminants and Pachyderms (see Figs. 3, 4, 7). 

E. Rabbit. — The cervical vertebrae in this animal somewhat resemble those in the Cat, 
though they differ in certain general and particular characters. Thus, in the Rabbit they 
become larger as they proceed backward ; the atlas has its transverse processes horizontal, and 
they are narrow at their oriain ; the axis has a bifid tubercle at the posterior extremity of its 
spinous process, and a notch below it ; the succeeding vertebrae are thin ; the fourth, fifth, and 
sixth are trifid in their transverse processes ; and the seventh has a short spinous process. 



2. DoESAL Vertebe^ (Fig. 18). 

Geneeal Chaeacters. — In the dorsal vertebrae the body is very short, and 
in front has a large slightly projecting head ; behind, it has a shallow cavity. 
Laterally, these vertebrae present, at the base of 
the transverse processes, four concave articular 
Jacets, the two anterior of which are situated near 
the head, while the posterior two are hollowed out 
of the border of the articular cavity of the body. 
Each of these facets is joined to an analogous 
facet on the neighbouring vertebra to form a 
small excavation, into which is received the head 
(or capitulum) of the corresponding rib. The 
spijious process is very high, is compressed on 
both sides, inclines backwards, and its summit 
is terminated by a tubercle. The transverse 
processes are unitubercular, and directed obliquely 
outwards and upwards ; on their external aspect 
they have a diarthrodial plane facet which corre- 
sponds to the tuberosity (or tuberculum) of the 
rib (and may therefore be named the tubercular 
transverse process). The articular processes are 
narrow, and constitute simple unrelieved facets 
cut on the base of the spinous process. The 
posterior notches are deep, and sometimes con- 
verted into foramina. 

Specific Charactees. — None of the eigh- 
teen dorsal vertebrae differ much from the type 
just described ; and it is difficult to establish 
special characters for each. It is, nevertheless 
possible to assign to a dorsal vertebra, approximately, the rank it should occupy, 
in accepting the following facts as a guide : 1. The vertical diameter of the 




ttpe op a dorsal vertebra (the 
fourth). 

1, Body, 2, 2, articular facets for the 
head of the rib; 3, articular facet for 
tuberosity of the rib; 4, articular 
processes ; 5, spinal foramen ; 6, 
tuberous base of spinous process; 

7, posterior articular face of body ; 

8, 8, transverse processes ; 9, 
superior spinous process ; 10, an- 
terior articulation of body. 



TEE VERTEBRA. 



vertebral bodies augments progressively from before to behind. Their lateral 
diameter, which determines that of the spinal canal, becomes, on the contrary, 
less from the first to the tenth vertebra ; after which it assumes increasing 
proportions to the last one. The articular surfaces, which serve for the mutual 
contact of head and cavity, become 
larger and shallower in proportion 
as the vertebrae are more posterior. 
The inferior spine on the body is 
very salient and tuberculated in the 
two first vertebrae, very acute in the 
third and fourth ; it disappears in 
the sixth and ninth, to reappear and 
become more marked from the tenth 
to the last. 2. The intervertehral 
cavities, intended for the reception 
"of the heads of the ribs, diminish 
in depth and extent from the first to 
the last. 3. The longest spi^ious pro- 
cess belongs to the third, fourth, 
and fifth vertebra ; those which 
follow gradually decrease to the 
eighteenth. Their width diminishes 
from the second to the eighth : it 
afterwards increases in a progressive 
manner in the succeeding vertebrfe ; 
from the second to the tenth vertebra, 
the summit of the spinous process is 
large and tuberculated ; in the last 
seven it is flattened laterally. Their 
obliquity is less marked as they pro- 
ceed backwards ; in the sixteenth and 
seventeenth vertebrae, the spinous 
process is nearly vertical ; it inclines 
slightly forward in the eighteenth. 
Those of the tenth, eleventh, and 
twelfth vertebrae are slightly curved 
like an S. 4. The articular processes, 
from the first to the tenth vertebra, 
gradually contract and approach the 
median line ; in the succeeding 
vertebrae they, on the contrary, 
increase, and become concave and 
wider apart from those of the oppo- 
site side. 5. The volume of the transverse processes and the size of their diarthrodial 
facets, diminish from before to behind. In the three first vertebrte this facet is 
concave ; in the first nine the articular facet looks outwards and backwards, 
while the facet on the body looks forwards ; in the last the two facets are 
directed forwards. These two facets are generally confounded in the seventeenth 
and eighteenth vertebrae. The first dorsal vertebra much resembles the 
prominens ; it is distinguished from it, however, by the presence of four 




MIDDLE DORSAL VERTEBRA OF THE HORSE, 
VIEWED FROM THREE TYPICAL LINES. 

The first line, A B, passes from before to behind by 
the most salient point of the transverse process, 
intersecting the middle of the lateral facet in- 
tended for the tuberosity of the rib, and of the 
cavity on the border of the posterior articular 
surface of the body. Below is the intervertebral 
foramen, the spinous process, and the articular 
facets on the base of the latter. The line c D 
is tangent to the summit of the transverse pro- 
cess and head of the vertebra ; it intersects the 
anterior articular processes. The line M N is 
horizontal, and tangent to the inferior face of 
the body. 



9i 



TEE BONES. 



diarthrodial facets on its extremities. It also differs from the other vertebrae by 
the shortness of its spinous process, which terminates in a point ; by the size and 
prominence ,of its articular processes ; and by the depth of its notches. The 
last vertebra never has facets on the contour of its posterior cavity. 

Ass. — Besides the smaller volume of the vertebrse, the following differential 
characters will serve to distinguish these bones in this animal : 1. The spinous 
processes, as far as the tenth vertebra, are a little more inclined backwards than 



Fig. 20. 




A DORSAL VERTEBRA OF THE HORSE AND ASS (THE ELEVENTH). 

A, Vertebra of the Horse {anterior face). 1, Head ; 2, spinous process ; 
3, 3, transverse processes. 

B, Vertebra of the Ass (anterior face). Same description as for the horse. 
a', Vertebra of the Horse (lateral face). 1, Head ; 2, spinous process ; 

3, transverse process. 
b', Vertebra of the Ass (lateral face). Same description as for the horse. 



in the Horse, while the inclination forward of the latter is equally marked ; the 
anterior part of the summit of the spinous process is in contact with a horizontal 
plane, when the three last vertebrae of the Ass are laid on their anterior portion. 
2. From the first to the tenth, the summit of the transverse processes lies behind 
the margin of the anterior articular facets in the Ass, while it is beyond them 
from the fourth in the Horse. From the eleventh to the thirteenth, the projection 
of the transverse processes is equal to that of the anterior articular facets in the 



THE VERTEBRA. 35 

two species ; then the processes become predominant in the Ass (Fig. 20, 
A', B', 3, 3), and they preserve this character to the eighteenth. 3. All the 
transverse processes are" less oblique than those in the Horse ; also the line which 
intersects, in the middle, the summit of these processes and their lateral articular 
facet, passes always in front of the posterior facet on the body ; in the Horse, 
this line traverses the latter facet, except in the first and fifth vertebra (Fig. 20, 
A. B). 4. There are not seen on the nine last dorsal vertebrse of the Ass, the 
anterior articular facets ascending to the base of the spinous process, as usually 
occurs in the Horse. 5. Lastly, the notches of the intervertebral foramina are 
nearly always closed by a bony bridge in the Ass, and only rarely so in the Horse. 
The dorsal vertebrae in the Mule and Hinny off"er the same mixture of 
particular characters which are found in their parents ; though it is not doubtful 
that the vertebr^ of the Mule (Hinny) produced by the union of the female Ass 
-with the Stallion Horse, more resemble the former than the latter, especially 
in the transverse processes. 

Differential Characters in the Dorsal Vertebrae of other Animals. 

A. Ox.— In the Ox, these thirteen bones are longer and thicker than in the Horse. Their 
flpinous processes are larger and incline more backward ; their transverse processes are very- 
voluminous, and are provided with a convex facet from above to below ; while their posterior 
notclies are nearly always converted into foramina. 

Considered individually, they are more slender in the middle than at the extremities. Their 
spinous processes diminish in width, especially at their summits, from the first to the eleventh 
vertebra, and widen again in the two last ; they progressively increase in slope to the tenth, 
after which they become more and more upright; tlie first four are the longest, and are nearly 
the same in height ; the others gradually decrease. 

In the first four or five vertebrae, the articular facet of the transverse processes, while 
retaining its vertical convexity, is concave in an antero-posterior direction. This facet is 
always absent in the last vertebra, and sometimes even in the preceding one. The two bones 
terminating the dorsal region show, in addition, the articular processes disposed like those of 
"the lumbar vertebrae. 

B. Sheep and Goat.— The thirteen dorsal vertebrae of the Sheep and Goat are relatively 
less strong than those of the Ox; their spinous processes are not so wide, and their posterior 
notches are never converted into foramina. 

C. Camel.— The dorsal vertebrae of the Camel, twelve in number, are remarkable for the 
length of their bodies, and the height and width of their spinous processes. The transverse 
processes are a little less detached than in the Ox, but they are very tuberous. The posterior 
notclies are narrow, deep, and close to the base of the spinous processes; they do not form 
foramina. The convexity or concavity of the articular surfaces of the body diminishes from the 
first to the last bone; while the spinous processes increase in length and width from the first 
to the sixth, and diminish in the last six. These processes are much inclined from the third 
to the ninth ; then they gradually become erect in the last three. 

D. Pig.— The Pig has fourteen dorsal vertebrae, which, in their general disposition, are 
not unlike those of the Ox. As with that animal, the intervertebral foramina are double, each 
-vertebral lamina being perforated laterally by an opening situated in front of the posterior 
notch. In addition, the vertebrae of the Pig present this peculiarity, that their transverse 
processes are generally traversed at the base by a single or multiple foramen, which communicates 
with the preceding. 

With regard to the special characters proper to some of the vertebrae, these are, as with the 
other animals, very few, and may be described as follows: I. The transverse processes of the 
four vertebrae preceding the last project but slightly. 2. In the fourteenth this process 
resembles those of the lumbar vertebrae. 3. The articular facet of the transverse process in the 
four last vertebrae is confounded with the anterior lateral facet corresponding to the head 
of the rib. 4. The articular processes of the last five vertebrae are arranged like those of the 
lumbar vertebrae ; and the prominence formed by the tubercle on the outside of the anterior 
articular process replaces, to a certain degree, the transverse process of these vertebrae. 

E. Dog and Cat.— These animals have thirteen dorsal vertebrae formed on the same model 



36 TEE BONES. 

as those of the Horse ; but their spinous processes are in general narrower and thicker. The 
tenth always has its spiuouss process vertical, triangular, and terminated in a sharp point. The 
last three liave no posterior facets tor tJie articulation of tlie heads of the ribs, and exhibit, in 
the conformation of their articular processes, the same disposition as the lumbar vertebrae. In 
the Cat, the transverse processes of the three last dorsal vertebrae are thin, sharp, and turned 
backwards ; they never possess facets for the tuberosity of the ribs. 

F. Rabbit. — The twelve dorsal vertebrae of this animal are similar to those of the Cat. 
But the spinous process of the first nine is thinner and more oblique, while that of the three 
last is higher and thinner than in the Cat. Besides, the transverse process is continued, in 
the Rabbit, by a triangular portion which increases the width of the vertebral lamina. The 
inferior face of the body is more hollowed in its middle portion, and the inferior crest is more 
salient than in the Cat. 

3. Lumbar Vertebra (Figs. 21, 22). 

General Characters. — A little longer and wider than the dorsal vertebrae, 
which they resemble in the arrangement of their bodies, these vertebrae are 
characterized : 1. By their short, thin, and wide spinous processes, which are slightly 
inclined forwards, and are provided at their summits with a scabrous tubercle. 

2. By their largely developed trans- 
^'S- 21- verse processes, flattened above and 

below, and directed horizontally 
outwards.^ 3. By the salient an- 
terior articular pit'ocesses, hollowed 
out on each side, and provided ex- 
ternally with a tubercle for inser- 
tion. 4. By their equally prominent 
posterior articular processes, rounded 
in the form of a half -hinge. 

Specific Characters. — The 
LUMBAR VERTEBRA (FRONT VIEW). charactcristics which may serve to 

1. Body ; 2, its articular face ; 3, superior spinous distinguish these Vertebrae from 
process ; 4, spinal foramen ; 5, anterior articular Qjjg another, are derived from the 
processes ; 6, 6, tran>verse, or costiform processes ; , t , , . -, , 

7, posterior articular process. oody, and the spmous and trans- 

verse processes. 1. From the first 
to the last there is a progressive diminution in the vertical diameter of the bodies, 
and an increase in their transverse diameter. The inferior spine on the body 
becomes shorter and wider from the first to the last vertebra ; in the six vertebrae 
it resembles an elongated triangle, the summit of which is directed forwards. 

2. The spinous processes decrease in width from before to behind, and their 
anterior border becomes more and more concave ; their summits are thickened 
and tuberculated in the three first, and thin and sloping forward in the three last. 

3. The transverse processes are longer in the middle vertebrae than in those placed 
before and behind. The processes in the first and second vertebrae incline slightly 
backward ; in the third they are more upright ; and in the succeeding ones they 
are directed a little forward. In the last two they are remarkable for their thick- 
ness ; in the fifth an oval-shaped articular facet is observed on their posterior 
])order ; in the sixth, two are present — one in front, corresponding to the pre- 
ceding, and one behind, slightly concave, meeting a similar facet on the sacrmn. 
The fourth and fifth vertebrae very often correspond, at their transverse processes, 
by means of analogous facets. 

' Rudimentary ribs are sometimes found attached by ligaments to the extremities of the 
transverse processes (Lesbre). 




THE VERTEBR^\ 



37 



Fig. 22. 



According to Sanson, five is the natural number of lumbar vertebrae in the 
specific type of African Horses (see remarks on the Spine in General). The 
transverse processes in these animals also offer some peculiarities. Thus the 
increase in their length ceases at the second, and from this an almost insensible 
diminution occurs to the fifth. The transverse processes of the first lumbar ver- 
tebra are alone less inclined backward ; they are perpendicular to the direction 
of the body in the second and third, and inclined forward in the fourth and fifth. 

The thoroughbred English Horse has sometimes five, sometimes six lumbar 
vertebrae, but in every instance the 
lumbar region is comparatively short 
(Cornevin). 

Ass. — The lumbar vertebrae in the 
Ass, five in number, are easily distin- 
guished from those of the Horse by the 
characters special to their spinous and 
transverse processes, and articular 
tubercles. 

1. The spinous processes are propor- 
tionately longer that those of the Horse, 
and they are also more inclined forward. 
If their bodies rest on a horizontal plane, 
and if a line be drawn tangent to the 
posterior border of the spinous process, 
an acute angle is always obtained at the 
point of junction of the line and plane ; 
but if this be done with the vertebras of 
the Horse, there is at least a right angle. 

2. The transverse processes increase 
in length from the first to the second ; 
they are nearly equal in the second and 
third, and decrease suddenly in the ffth. 
They are usually inclined downwards ; their posterior border and superior face, 
near the body, are marked by a vasculo-nervous furrow, which is scarcely visible 
in the Horse. Finally, it is not rare to find no inter-transverse articulation 
between the two last. 

3. The most important differential character is observed in the articular 
tubercules. The diarthrodial facets are surmounted by a flat tongue of bone, 
which is projected outwards in the direction of the summit (see Fig. 23, A, B, 4, 
4). This piece gradually becomes lower from theirs;* to the fifth vertebra ; in the 
first, it projects beyond the articulation by more than one-fourth of an inch, and, 
up to a certain point, resembles the condition observed in the Rabbit or Dog. 

In the Mule there are sometimes six, sometimes only five, lumbar vertebras. 
These have the spinous and transverse processes somewhat as in the Horse ; their 
articular tubercles resemble those of the Ass. 

In the Hinny, of which opportunity has rarely been had for study, Goubaux 
and ourselves have found five lumbar vertebrae, which, in their shape, much 
resembled those of the Ass. 




UPPER SURFACE OF LUMBAR VERTEBRAE. 

, SuQimit of spinous process ; 2, 2, anterior 
articular jirocesses ; 3, 3, posterior articu- 
lar processes ; 4, 4, transverse processes. 



Differential Characters in the Lumbar VERTEBRiE of other Animals. 
A. Ox, Sheep, and Goat. — The six lumbar vertebrae of the Ox are longer and thicker 
than those of the Horse. The transverse processes are also generally more developed, are 



38 THE BONES. 

coDcave on the anterior border, convex on the posterior, and incline slightly downward, with 
the exception of the two first, which remain nearly horizontal. They increase in length from 
the/r«< to the fourth vertebra ; in the latter and the fifth, they are nearly of the same dimensions ; 
in the last they suddenly become shorter. Their width gradually decreases from before to beliind. 
In the fifth and sixth vertebrae, these processes have no articular facets between them and the 
sacrum, these being only met with in Solipedd. The articular processes are prominent, and 
further removed from the median line as they belong to posterior vertebrae. 
« 

Fig. 23. 




A LUMBAR VERTEBRA OF THE HORSE AND ASS. 

A, Lumbar vertebra of the Horse {anterior face). 1, Head ; 2, 2, transverse processes ; 
3. spinous process ; 4, 4, articular tubercles. 

B, Lumbar vertebra of the Ass {anterior face). Same description as for the horse. 



In the Goat the transverse processes are more inclined downwards. 

In the Sheep, on the contrary, the processes of the six or seven vertebrae ascend towards 
their extremities. 

B. Camel. — Apart from number, which is seven, the lumbar vertebrae of this animal offer 
nearly the same features as those of the Ox. 

C. Pig.— The lumbar vertebrae of the Pig greatly resemble those of ruminant animals. It 
commonly happ( ns that seven are met with ; but in this case the supplementary vertebra is 
generally a sacral one. It is not denied, however, that seven lumbar vertebrae may exist in the 
Pig, along with the normal number of sacral vertebrae. 

D. Dog and Cat.— In the Dog and Cat, the lumbar vertebrae, seven in number, are 
remarkable for their strength, due to their length, thickness, and the development of the 
eminences for insertion. The spinous process is low, and becomes acute in the last vertebra. 



TEE VERTEBRA. 39 

The transverse processes incline very much forward and downward ; they become longer from 
the first to the second-last bone ; in the latter they become contracted, and in the seventh 
vertebra they are still more diminislied, and terminate in au obtuse point. The tubercle of the 
anterior articular process is extremely prominent, and the posterior notches are surmounted bv 
a small, very acute prolongation, directed backwards, which becomes more developed towards 
the anterior vertebrae. This small prolongation exactly represents the transverse process of the 
dorsal vertebrae. 

E. Rabbit.— They are stronger than those of the Cat, and the first three have on the lower 
surface of their bodies a very salient crest, which simulates a real inferior spine ; the others 
have a median crest which gradually decreases towards the last bone. The tubercle surmount- 



Fig. 24. 




LUMBAR VERTEBRA OF THE CAT AND RABBIT. 

A, Second, third, and fourth lumbar vertebrcB of the Cat (inferior face}. 1, 1, 1, 
TraDsverse processes ; 2, 2, 2, crest on the inferior face of the body; 3, articular 
tubercles of the first vertebra. 

B, Second, third, and fourth lumbar vertebra of the Babbit (inferior face}. 1, 2, 
Same signification as in preceding. 

C, Third lumbar vertebra of the Cat (lateral face}. 
prolongation; 2, ditto posterior prolongation; 3, 
4, 4, posterior ditto; 5, spinous process. 

D, Third hcmbar vertebra of the Babbit (lateral face}. 
prolongation ; 2, ditto posterior prolongation ; 



1, Transverse process, anterior 
I, anterior articular tubercles; 

1, Transverse process, anterior 
, anterior articular tubercle : 



4, 4, posterior articular tubercles : 5, spinous process. 

ing the posterior notches is more developed than in the Cat. The spinous process is prolonged 
backward by a translucent bony plate, wliich disappears in the last two. The anterior articular 
tubercles are more developed, more erect, and nearer the median line, than in the Caruivora. 
Lastly, the transverse processes are relatively longer, and those of the first are remarkable for 
the notched enlargement they offer at their free extremities. 



4. Sacrum (Fig. 25). 

The sacrum results, as already stated, from the consolidation of five vertebrse. 
This single bone articulates, in front, with the last lumbar vertebra ; behind, 
with the first coccygeal bone, and on the sides with the ossa innominata. It is 
triangular, flattened above and below, and from before to behind describes a 
slight curve upwards. It offers for study a superior and an inferior face, two 
borders, a base, a summit, and a central canal — the extension of the spinal canal. 

Faces. — The superior face presents, on its middle, the spinous processes of the 



THE BONES. 




sacral vertebrae, which together constitute what is called the sacral or supersacral 
spine. These processes are united at their base only, and remain isolated for the 
remainder of their extent ; they all incline backwards and terminate, with the 
exception of the first, by a tuberous summit, which is often bifid ; their length 
diminishes from the second to the fifth bone. On each side of the sacral spine 
exists a groove, at the bottom of which are four openings — the super-sacral Jara- 
raina. These orifices open into the spinal canal, and communicate with four 
analogous, but wider apertures, pierced at the inferior face of the bone, and for 

this reason named the sub-sacral 
Fig- 25. foramina. The inferior face is 

smooth, and shows traces of the 
N^L ,m^''''. J^S&^fi^ ^^^ '''•■' primitive separation of the vertebral 

^^■-^'"^^^P^^^^^^^i^m S^ V bodies ; the sub-sacral foramina, 

~ ' ' ^ which represent, with the corre- 

sponding super-sacral openings, the 
intervertebral foramina of the other 
regions of the spine, are observed 
on this surface. 

Borders. — The hvo borders, thick 
and concave, form, posteriorly, a 
rugged lip ; in front, they present 
an irregular surface inclining ob- 
liquely from above to below, from 
within outwards, and from before 
to behind. This surface, which is 
intended for the articulation of the 
sacrum with the ossa innominata, is divided into two parts : one, the inferior — 
named in Man the auricular facet — is slightly undulated and diarthrodial ; the 
other, the superior, serves for ligamentous insertions. 

Base. — This offers : 1. On the median line, the anterior orifice of the sacral 
canal, and the anterior articular surface of the body of the first sacral vertebra, 
which is oval and slightly convex. 2. On the borders, the articular processes and 
anterior notches of this vertebra, as well as the elliptical and somewhat convex 
facets which bring it into contact with the transverse processes of the last lumbar 
vertebra. 

Siimmit. — The summit, thrown back, presents : 1. The posterior orifice of the 
sacral canal. 2. The posterior articular surface of the body of the last sacral 
vertebra. 3. The vestiges of the articular processes and posterior notches of that 
vertebra. 

Sacral canal. — This is the portion of the spinal canal which is channeled out 
of the sacrum ; it is triangular, and diminishes in width from before to behind. 

The sacrum of the Ass much resembles that of the Horse ; nevertheless, it is 
possible to distinguish it by the shape of the articular tubercles of the first sacral 
vertebrae, which resemble those of the articular tubercles of the lumbar region, 
and the traces those tubercles have left between the sacral vertebra3, especially 
between the first. 



LATERAL VIEW OF SACRUM. 

1, Articular surface of body ; 2, 3, articular surfaces 
corresponding to those on the transverse processes 
of the last lumbar vertebra; 4, spinal foramen; 5, 
auricular facet; 6, anterior articular processes; 
7, inferior or sub-sacral foramina ; 8, superior 
spinous processes ; 9, summit or coccygeal ex- 
tremity. 



Differential Characters in the Sacral Vertebra op other Animals. 

A. Ox. — The sacrum of the Ox is more voluminous and curved than that of the Horse 
The spinous processes are entirely consolidated, and are surmounted by a thick rugged lip ; 



THE VERTEBRAE. 41 

they are bordered at their base and on each side by a ridge that represents the rudiments of the 
articular processes. The lateral borders are sharp and bent downwards. The surfaces that 
serve to unite the sacrum to the ossa innominata have a somewhat vertical direction. There 
are no lateral facets on the base of the bone, for the union of the sacrum with the transverse 
processes of the last lumbar vertebra. 

B. Sheep and Goat. — In the Sheep and Goat, the sacrum is shorter ; sometimes the con- 
solidation of the spinous processes is late, or never occurs. 

C. Camel. — Sacrum short ancl composed of four vertebrae; broad and curved on its inferior 
face. The spinous processes, rather low, are strong and free throughout their extent. The 
auricular facets are cut very obliquely. 

D. Pig. — This is formed by four vertebrae, which are a long time in becoming fused 
together ; and it is often difficult to discover where the sacrum ends and the coccyx begins.' 
The spinous processes are entirely absent. The vertebral laminae are not consolidated ; so that 
the spinal canal is half cut through in its upper portion, as in the cervical region ; this canal is 
also much compressed above and below. 

E. Dog and Cat. — The three vertebrae which form the sacrum of Carnivora are early con- 
solidated. The sacral spine constitutes a thin sharp ridge, while the lateral surfaces for 
articulation with the ossa innominata are turned quite outwards, and are nearly vertical. 

F. Rabbit. — Relatively longer than tliat of Carnivora, the sacrum of this animal is remark- 
able for the presence of four vertebrae, the spinous processes of which are isolated from each 
other. 

5. Coccygeal Vertebe^. 

The coccygeal region, or coccyx, comprises from fifteen to eighteen degenerate 
vertebrae, which gradually diminish in thickness from the first to the last. In the 
first three or four, nearly all the characteristics of true vertebrae are found ; they 
show a vertebral foramen, a body, a spinous process, and transverse processes, 
directed backwards ; the articular processes only are altogether absent. In the 
succeeding vertebrae, these characters become effaced ; the vertebral laminte do not 
join completely, and the vertebral canal is only a simple groove, which, gradually 
decreasing in depth, at last entirely disappears. The insertion eminences also 
become less salient, and the coccygeal vertebrae are soon reduced to small bony 
cylinders, narrow in the middle and wider at both extremities, with a convex 
articular surface at each end (except the last, which has only one articular surface). 
These small cylinders — the last traces of the vertebral bodies — are each developed 
from three centres of ossification ; they are very spongy and light. The first 
coccygeal vertebra is frequently consolidated with the sacrum in aged animals. 

Differential Characters of the Coccygeal Bones in other Animals. 

A. Ox, Sheep, and Goat. — In proportion, the coccygeal vertebrae of ruminants are stronger 
and more tuberous than those of the Horse. The anterior articular processes exist in a rudi- 
mentary condition. 

B. Camel. — Fifteen to eighteen in number, they are not so strong and are less tuberous 
than in the Ox. The first six are channeled by a triangular canal. 

C. Pig. — These vertebrae in tlie Pig are more particularly distinguished by the presence of 
articular processes, by means of which the foremost bones correspond with each other. 

D. Dog and Cat. — In these animals, the vertebrae of the coccyx are very strong and 
tuberous. The first five or six are as perfect as the true vertebrae, and comport themselves in 
every respect like them. The last are small V-shaped bones, which M. Goubaux has described 
by the name of hypMoid bones. 

E. Rabbit. — The coccyx of the Rabbit is analogous to that of the Cat. 



' This can always be made out, however, by consulting the disposition of the articular pro- 
cesses. Thus, in the sacral vertebrae these eminences — if we except the anterior ones of the 
first and the posterior of the last — never exist except in a rudimentary state ; while in the other 
five coccygeal vertebrae they reappear with all their characters. 



12 THE BONES. 

The Spine in General. 

The vertebral column has now to be considered in its entirety, and examined 
successively in its superior face, its inferior face, its lateral faces, and its spinal 
canal. Afterwards its direction and mobility will be noticed. 

Superior surface. — This presents, on its median line, the series of spinous pro- 
cesses. But little salient in the cervical region, these eminences are much 
developed in the dorsal and lumbar, where they constitute a long crest — the 
dorso-Iumbar spine, as well as in the sacrum, where they form the sacral spine. 
They soon disappear in the coccygeal vertebrae. Outwards, and on each side of 
these processes, is seen a succession of tubercles for insertion, represented iu the 
cervical and lumbar vertebrae by articular processes, and in the dorsal vertebrae 
by the superior or rugose portion of the transverse processes. These tubercles 
are disposed in line, and separated from the spinous processes by a channel 
designated the vertebral groove, which is more or less deep and wide. It is on 
these, and on the spinous processes, that the extensor muscular fascicuU of the 
spine receive the greater portion of their fixed or movable insertions. 

Inferior surface. — Wide at the neck, this surface becomes narrow in the dorsal 
region, to be again widened at the lumbo-sacral region, and once more contracted 
at the coccyx. Crests more or less developed, which divide the vertebral bodies 
into two lateral portions, right and left, are remarked. 

Lateral surfaces. — These offer for study the thirty-six intervertebral foramina, 
through which the spinal nerves pass. They exhibit besides, in the neck, the 
transverse processes ; in the back, the external facets of these processes, and the 
intervertebral facets, all destined to sustain the heads of the ribs ; on the loins, 
the transverse or costiform processes. It may be remarked that the ribs and the 
transverse processes of the neck and loins furnish points of insertion to the 
powerful muscles which produce the lateral movements of the spine. In the sacrum, 
the lateral faces are formed for the articulation of the spine with the ossa 
innominata. 

Spinal canal. — This canal communicates, in front, with the cranial cavity. 
Very wide in the atlas, for the reception of the odontoid process and to permit 
the rotatory movements of the head without injury to the spinal cord, this canal 
suddenly diminishes in the axis. It again dilates at the termination of the 
cervical region and the commencement of the dorsal ; there the spinal cord 
presents a greater volume, and the movements of the spine are very extensive. 
Towards the middle of the back, the spinal canal offers its smallest diameter ; it 
widens from this part to the lumbo-sacral articulation ; after which it contracts 
rapidly, and disappears altogether near the fourth or fifth coccygeal vertebra. 
The lumbo-sacral dilatation coincides with the enlargement of the cord in this 
region, and with the enormous quantity of nerves lying beside it. 

Direction of the Spine.— The spine does not extend in a straight line from the 
head to the posterior extremity of the body. If it is followed from the caudal 
extremity — which is free and looks downwards — to the anterior extremity, it will 
be observed that it passes upwards and forwards, forming a convex inflexion 
corresponding to the roof of the pelvis. In the lumbar and posterior half of the 
dorsal region, it is nearly horizontal and rectilinear ; thence it descends to the 
cervical region, where it again rises and forms two curves — one, posterior, bend- 
ing upwards, the other anterior, passing downwards. This direction "of the spine 
gives it the form of a console. 



THE VERTEBRA. 43 

MoMity of the Spine. — In the cervical region, the almost total absence of 
spinous processes, the great development of the articular processes, and the very 
short curve described by the surfaces of contact of the vertebral bodies, allow 
the spine very extensive and varied movements. In the dorsal region, however, 
these movements are very limited, the spinous processes and the costal arches 
preventing the play of the vertebrae on each other. In the lumbar region, the 
spine can be flexed and extended more than in the dorsal ; but its lateral move- 
ments are quite as restricted, owing to the presence of the transverse processes and 
the reciprocal union or dovetailing of the articular processes. Lateral motion is 
even rendered impossible in the posterior half of this region, from the manner 
in which the transverse processes are adapted to each other. It may be remarked, 
however, that this disposition singularly favours the integral transmission of the 
propulsive efforts communicated to the trunk by the posterior extremities. 

The sacral vertebrae, having to afford the ossa innominata a solid fixed point, 
could not preserve their independence and mobility if they were like the other 
vertebrae ; they are consequently consolidated into a single piece, which fulfils all 
that is required of it in this respect. In the coccyx the spine again recovers its 
mobility, and to an extent more marked than elsewhere ; the bones, articulating 
with each other by means of convex surfaces, and having no long processes at 
their extremities, are placed in the best possible conditions for effecting varied 
and extensive movements. 

Varieties in the Vertebral Column. 

To anatomists, the bones of the spine have frequently offered curious varieties 
in their shape and number. 

1. Shape. — Goubaux has observed varieties of this kind in the last two cervical 
vertebrae of the Horse. In one instance, the sixth had the transverse process 
biscuspid on the left and tricuspid on the right. This anatomist has collected 
several similar examples. Husson has found the sixth cervical vertebra with a 
prolongation deficient in the transverse processes ; and the seventh, on the con- 
trary, with an additional prolongation. 

The dorsal vertebra have also exhibited varieties in shape. Daubenton has 
referred to the skeleton of an Ass, in which the last vertebra had on one side 
only a transverse process like that of the lumbar vertebrae. We have seen this 
variation in the Horse. 

In the lumbar region, Goubaux has noticed — as we have done — the fourth and 
fifth vertebrae sometimes articulating by their transverse processes ; the articula- 
tions may even be fused. Sometimes the transverse processes of the first lumbar 
vertebra articulate at their base with the body of the bone, and become floating 
ribs. 

Thomas has remarked an interesting variation in the sacrum. He found in 
the Sheep a long, costiform, transverse process on one of the sides of the first 
sacral vertebra. The last vertebra in this region sometimes shows, in the Dog — • 
either to the right or left, or on both sides at the same time— one or more articular 
facets on the transverse processes, uniting with similar facets on the first coccygeal 
bone (Goubaux). 

2. Number. — For a long time, instances have been accumulating of variations 
in the number of bones in the spine ; but they do not form a very imposing 
array, probably because it is difficult to observe them without making a special 
and attentive study of the subject. 



41 THE BONES. 

These variations have been noted in all the regions of the vertebral column, 
though they are rare in the cervical region. Sometimes they consist in a dimi- 
nution, sometimes in an increase, in the number of the vertebrse. 

a. So far as it is known, a decrease in the nimiber of the cervical vertebrae 
in the domestic animals has not been observed. Goubaux has sometimes met 
with eight cervical vertebrae, though, as the eighth offered relations with the first 
rib, he was disposed to place it in the dorsal region. In this case the anomaly was 
in the number of bones in the spine. 

b. The dorsal region is more frequently abnormal. Bourgelat and Rigot 
have dissected Horses which had only seventeen dorsal vertebra. Groubaux and 
ourselves have seen similar instances, though the length of the animals afforded 
no suspicion of modification in their spines. It is certainly more common to see 
the nimiber of dorsal vertebrae increased to nineteen, as is proved by the observa- 
tions of Bourgelat, Higot, Husson, Goubaux, and our own. 

This increase is observed also in the asinine species. We have the skeleton 
of an Ass in which there are twenty ribs on each side, and therefore twenty 
dorsal vertebrae. In the Ox, fourteen dorsal vertebrae have been found. 

c. The lumbar region is still more frequently modified. The Horse at 
times has only five lumbar vertebrae (Daubenton, Chauveau, Goubaux, Sanson, 
and several German anatomists) ; the Ass only four (Goubaux). In the other 
animals — the Dog, for example — an increase in nunlber has been remarked ; 
Girard has seen eight lumbar vertebrae, instead of seven. Goubaux and ourselves 
have on several occasions seen seven lumbar vertebrse in the Sheep. 

d. The sacrum has often one or two pieces more in old subjects, due to 
the fusion of the first or second of the coccygeal vertebrae with its posterior 
extremity. At other times, the supernumerary piece is situated at the base. 
Earely is the number of sacral vertebrae diminished ; Goubaux has only met with 
one instance in which there were four sacral vertebrae in the Horse. 

e. The number of coccygeal bones is extremely variable ; and in order to 
be convinced of this, one has only to look at the tables drawn up by anatomists. 
Nevertheless, it is certain that the normal number is never less than seven or 
eight, as Bourgelat stated in the first edition of his Anatomie. 

To resume, it is seen that all the regions of the spine may offer variations in 
the number of vertebrte, and that these variations — rare between the neck and 
the back — are, on the contrary, frequent at the two extremities of the lumbar 
region. When the bones are deficient, the diminution is only apparent — that is, 
the vertebra which is absent in one region is carried to the adjoining region. It 
frequently happens, for instance, when a lumbar vertebra is missing, that the 
sixth is united to the sacrum ; or when there are nineteen dorsal vertebrae, there 
is one less in the lumbar region. It is not always sufficient to examine the 
regions contiguous to the one which is modified, to gain an exact notion as to the 
modification. In fact, a change in the number of vertebrae in a region may be 
compensated for by an alteration in a distant region. In the museum of the 
Lyons school, there is the skeleton of an Ox in which there are fourteen dorsal 
vertebrae, with the normal number of cervical, but only four sacral. We also 
possess the skeleton of a Horse which has seven lumbar vertebra, with the normal 
number in the other regions, though the seventh bone is certainly the first sacral, 
as it has all its characteristics ; and with regard to the fifth sacral bone, this 
evidently comes from the coccygeal region. In the first skeleton, the increase 
in the dorsal region has therefore been com^imsated for by a decrease in the sacral 



THE VERTEBRA. 45 

region ; and in the second, the augmentation in the lumbar region has been com- 
pensated for by a diminution in the coccygeal region. 

These transpositions occur more especially on the confines of the dorso-lumbar 
and lumbo-sacral regions. 

But the increase or decrease in the normal number of vertebrae is sometimes 
absolute. Goubaux and Husson have found, in the Horse, nineteen dorsal 
vertebrae with the normal number of the other vertebrae. The Ass with twenty 
ribs already mentioned, had the usual number of vertebras in the other regions. 
The first-named anatomist has counted, under the same conditions, seven lumbar 
vertebrae in the Sheep. Hering, Rueff, Leyh, Sanson, etc., have found five lumbar 
vertebrae in the Horse, without any modifications in any other parts of the 
vertebral column. Sanson has even remarked, that in several oriental Horses 
there are generally only five lumbar vertebrae. The presence of this anomaly is 
always allied to a particular shape of the cranium and face. In the estimation 
of Sanson, these characters are so important that they serve to distinguish specific 
types. The specific type with five lumbar vertebrae is pecuHar to north-east 
Africa, probably Nubia, 

It is not intended in this place to discuss the opinions of Sanson and the 
value of his specific types, but merely to remark that the number of vertebrae is very 
liable to variation in each region of the spine, and that these variations are even so 
frequent in animals of the same origin, that it would be perhaps premature to 
attribute to the number of vertebra in a given region the value of an absolutely 
specific character. 

It has been attempted to explain these variations by an ancestral influence, 
or by the influence of surroundings and exercise. But why might they not be 
the consequence of irregularities in the fusion of the nuclei which constitute the 
vertebral column of the foetus ? Fol has observed that at the fifth week the 
human embryo has thirty such pieces, and that at the sixth week the thirty- 
eighth, thirty-seventh, and thirty-sixth vertebrae have become one, while the 
thirty-fifth has no longer perfect limits — so that an embryo measuring nineteen 
millimetres has only thirty-four vertebrae. The spine of the embryo is com- 
posed, therefore, of a larger number of pieces than that of the adult. The 
reduction in number is due to fusions ; consequently, it is reasonable to admit 
the possibility of variations in the extent of these fusions and the places where 
they may occur. (For further details, see the Memoirs of Goubaux and Sanson, 
in Robin's Journal de VAnatomie de la Physiologie, 1867 and 1868.) 

Comparison of the Vertebral Column of Man with that of the Domesticated 

Animals. 
The vertebral column of Man is composed of twenty-nine bones : twenty -four vertebrae, 
the sacrum, and four pieces constituting the coccyx. The twenty-four vertebrae are thus 
distributed : 

Cervical vertebrae 7 

Dorsal „ 12 

Lumbar „ 5 

In all these vertebrae, the bodies are slightly excavated at the two extremities, while in the 
domesticated animals, the superior or anterior is convex, and the inferior or posterior concave. 

1. Cervical vertebrae. — These are wide and short. The spinous processes are moderately 
developed and bifid at their summits ; the transverse processes are also divided into two 
branches — a posterior and an anterior. 

2. Dorsal vertebrx.—ln these vertebrae, the bodies increase in thickness from the first to 
the last. In the first as well as in the last dorsal vertebrae, the spinous process is almost 



46 



THE BONES. 



immediately directed backwards ; in the middle portion of this region these processes are very 

obliquely directed downwards and backwards. 

3. Lumbar vertebras. — The lumbar vertebrae are the strongest bones in the spine, and their 
bodies are nearly as thick as those of the larger domesti- 
cated animals. This enormous development of the lumbar 
vertebrae in Man is related to his position as a biped. In 
the fifth, the lower face of the body is cut very obliquely 
backwards and upwards, and the transverse processes are 
more voluminous than those of the other lumbar vertebrae. 

4. Sacrum. — The sacrum is formed by the union oi 
five pieces. It is very concave from above to below and 
before to behind. In becoming united to the lumbar 
region, it forms a salient angle in front, to which has 
been given the name of promontory or sacro-vertebral angle. 
The sacral spine is continuous or interrupted, according 
to the subject ; it is always bifid inferiorly. 

5. Coccygeal vertebras. — These are little bones or flat- 
tened tubercles, four in number, rarely five, and usually 
consolidated. Tbe coccyx is conical in shape. Its base 
shows two processes directed upwards, which are called 
the cornua of the coccyx. Its summit is often deviated 
to the right or left. 



Article IL— The Head (Fig. 26). 

The head is a large, bony, quadrangular 
pyramid, elongated from above to below, sus- 
pended by its base to the anterior extremity of 
the spine. Its direction varies with the atti- 
tudes of the animal, but we will suppose it, 
for convenience of description, to be nearly verti- 
cal. It is formed of a great number of particular 
bones, which are only distinct from one another 
in very young animals ; for well before the adult 
period is reached, the majority of the bones are 
united and cannot be separated. 

The head is divided into two parts : the 
cranium and the face. 




horse's head (front view) 

I, Occipital tuberosity; 2, origin 
of the mastoid crest ; 3, parietal 
bone ; 4, saggital suture ; 5, junc- 
tion of the parietal and temporal 
bones ; 6, zygomatic arch ; 7, 
frontal bone ; 8, frontal suture ; 
9, temporal fossa; 10, supra-orbital 
foramen ; 11, 12, lachrymal bone ; 
13, malar bone ; 14, nasal border of 
frontal bone ; 15, nasal bone ; 16, 
suture of nasal bones; 17, super- 
maxillary bone ; 18, infra-orbital 
foramen ; 19, anterior, or pre- 
maxillary bone; 20, foramen in- 
cisivum ; 21, incisor teeth (young 
mouth). 



Bones of the Craniam. 

The cranium, or upper part of the head, is 
composed of seven flat bones, five of which are 
single : the occipital, parietal, frontal, sphenoid, 
and ethmoid; one only, the temporal, is double. 
These bones circumscribe a central cavity, the 
cranial, which communicates behind with the 
spinal canal, and lodges the principal portion of 
the nervous centres — the brain. 



1. Occipital Bone (Fig. 26, 1). 

The occipital bone occupies the superior extremity of the head, which it 
supports from the anterior extremity of the spine. This bone is very irregular 
m its form, aud is bent at a right angle in front and behind. It has an external 



TEE HEAD. 47 

and an internal face, and a circumference which brings it into contact with the 
adjoining cranial bones ; the latter is subdivided into two anterior lateral borders, 
two posterior lateral borders, an anterior and posterior salient angle, and two 
lateral re-entering angles. 

Faces. — The external face is divided into three portions by the double flexure 
of the bone : one looks forward, another upward, and the third backward. It 
exhibits : — 1. On the median line, and from before to behind : a, an antero- 
posterior ridge which constitutes the origin of the parietal ridges, to be mentioned 
hereafter ; b, a transverse, voluminous, and very prominent eminence, marked 
posteriorly by deep imprints, with a medium projection named the cervical 
tuberosity ; this is the external occipital tuberosity which, in the Horse, corre- 
sponds at the same time to the superior curved lines of the occipital bone of Man. 
This protuberance forms the culminating point of the head, and divides the 
anterior and superior parts of the external face of the bone ; c, the occipital 
foramen {foramen magnum), a large orifice that passes through the bone at the 
posterior flexure, and establishes a communication between the cranial cavity and 
spinal canal ; d, the external surface of the basilar process — a narrow and thick 
prolongation formed by the bone as it passes to meet the sphenoid : this surface 
is convex laterally. 2. On the sides : a, A sharp crest which prolongs, laterally, 
the superior curved lines, and descends on the middle of the lateral anterior 
border, to be continued with the superior root of the zygomatic process and the 
mastoid crest of the temporal bone ; b, Linear imprints, parallel to the latter, 
and prolonged on the base of the styloid process : they are destined for the 
insertion of the small oblique muscle of the head, and represent the inferior 
curved lines of the occipital bone of Man ; c, Within these imprints is a slightly 
roughened cavity for the insertion of the posterior recti muscles ; d, The two 
condyles — articular eminences with a double convexity, one superior, the other 
inferior : these eminences are situated on each side of the occipital foramen 
{foramen magnum), and correspond to the anterior cavities of the atlas ; e, More 
outwards are the two styloid {paroccipital) processes, or jugular eminences — long 
projections flattened on each side, terminated in blunt points, directed backwards, 
and separated from the condyles by a deep space, the stylo-condyloid notch ; f. 
Under the condyles is the condyloid fossa — a smooth depression, pierced at the 
bottom by the condyloid foramen, which penetrates the cranium. 

The internal face of the occipital bone is concave, and shows : behind, the 
foramen magnum ; above, an uneven surface, which forms the roof of the 
cerebral cavity ; below, the superior face of the basilar process, slightly hollowed 
into a groove ; on the sides, the internal orifice of the condyloid foramen. 

Circumference. — The anterior lateral borders are thick, and are united by 
suture with the parietal bone, and with the tuberous portion of the temporal 
bone by the harmonia suture. The posterior lateral borders are sharp, and 
constitute the sides of the basilar process ; each concurs in the formation of the 
occipito-spheno-temporal hiatus, also termed the foramen lacerum basis cranii — a vast 
irregular opening, extending from above downwards, penetrating the cranium, and 
divided by a ligament, in the fresh state, into two portions, one inferior, the 
anterior foramen lacerum, the other superior, the posterior foramen lacerum. The 
anterior angle, which is dentated, is dovetailed into the parietal bone. Theposterior 
angle is very thick, and forms the summit of the basilar process ; it is united by 
suture with the body of the sphenoid. The lateral re-entering angles, or jugular 
notches, correspond to the point where the bone is bent posteriorly ; they separate 



48 THE BONES. 

the anterior lateral from the corresponding posterior lateral border, and are occupied 
by the petrous portion of the temporal bone. 

Structure. — The occipital bone contains much spongy substance. 

Development.— li is developed from four centres of ossification ; one, the 
anterior, is single, and forms the occipital tuberosity ; another, the posterior, 
also single, forms the basilar process ; the other two are pairs, and comprise each 
a condyle, with a styloid process and the corresponding condyloid foramen. 

The occipital bone in the Ass is distinguished by the prominence of the 
external occipital tuberosity (see the Head in General), by the depth of the 
groove (mastoid) which com^ses over the outer face of the styloid process, and 
by the articular surface prolonged to the origin of the basilar process, which 
constricts it in a circular manner. 

Differential Characters in the Occipital Bone op other Animals. 

A. Ox. — The occipital bone of this animal does not show any anterior elbow, neither does 
it form a portion of the iinierior part of the head. The external occipital tuberosity is obtuse, 
and givts rise on each side to the superior curved lines. 

The styloid processes are short and much bent inwards. Tlie basilar process, wide, short, 
and thick, has a groove in the middle of its external face ; this groove is sometimes absent in 
the Sheep and Goat. 

The condyloid foramina are double, sometimes triple ; the superior foramen does not pass 
directly into the cranium, but goes to a vast conduit that opens behind on the lateral margin 
of the occipital foramen, and wliich terminates in front by two orifices, one entering the parieto- 
temporal canal, the other opening on the external surface of the bone. The foramen lacerum 
is divided into an anterior aud posterior foramen, by the mastoid portion of the temporal 
bone. 

B. Sheep and Goat. — The inner tuberosity is only marked by a slight prominence of the 
internal plate of the bone. In the occipital bone of these animals are found the peculiarities 
noted in that of the Ox ; the groove on the basilar process is sometimes absent, and in the 
Sheep the superior curved lines are very salient and occupy the summit of the head. This 
feature is still more marked in the Goat, and also more in the Cervine species, in wliich this 
bone somewhat resembles that of the Horse. 

C. Camel. — The bone shows a double angle as in Solipeds. In its anterior and superior 
portions it resembles that of the Horse, and in its posterior portion that of the Ox. The crest, 
which constitutes the origin of the parietal crests, as well as the superior curved lines, are 
thin, sharp, and very high. The styloid processes are short, wide, thick, and articulated by 
harmonic suture with the tuberosity of the temporal bone. The superior curved lines are 
scarcely marked in young animals. 

D. Pig. — The occipital bone in this animal is not bent anteriorly; but the transverse 
protuberance representing the curved lines forms, nevertheless, as in the Horse, the summit of 
the Head. This eminence, which is excavated on both sides on the posterior face, unites in 
front with the parietal bone, which abuts on the occipital at an acute angle. There is no 
externa] occipital protuberance, properly speaking, and the styloid processes are very long and 
directed downwards. 

E. Camivora.— The external occipital tuberosity is very strong and high. The external 
occipital crest is absent or little marked ; the styloid processes are short. The foramen lacerum 
is divided into two portions by the mastoid process, and the basilar process is wide, long, and 
thick, and hollowed on the side by a channel that joins a similar one in the temporal bone to 
form a large venous canal. Tliis last communicates, behind, with the posterior foramen 
lacerum, and opens, in front, in the cranium, where it is continuous with the cavernous groove 
of the sphenoid. The anterior angle forms a very marked prominence, which is deeply fixed 
into the parietal bone, and partly constitutes the internal occipitnl process of that bone. The 
latter does not show the lateral excavations at its base; they are found lower, towards the 
summit of the petrous bone, on the sides of the occipital. The parieto-temporal canals are, 
nevertheless, continued to the base of the process, which they traverse to open into its interior. 
In the most intelligent breeds, the occipital foramen is deeply notched above (Faure). 



THE HEAD. 



2. The Parietal Bone (Fig. 26). 

The parietal is a wide and thin bone, very much arched to form the roof of 
the cranial cavity. It is bounded above by the occipital bone, below by the 
frontal, and laterally by the two temporal bones. It offers for study an external 
and internal face, and a circumference divided into four regions or borders. 

Faces. — The external face is convex. It exhibits two curved ridges with 
concavity directed outwards ; these two crests, which are termed the parietal 
ridges, approach each other and unite superiorly, to be continued with the antero- 
posterior ridge of the occipital bone ; below they diverge and proceed, one on 
each side, to join ike supra-orbital process. They divide the surface of the bone 
into three portions : two lateral, which are rough and traversed by vascular 
channels, forming part of the temporal f ossa3 ; the 
third, or middle, is plane, smooth, and of a triangu- 
lar form, and covered by the skin. The interjial 
face is concave, covered by digital impressions, 
and grooved by small vascular canals ; it offers, 
on the middle line, and altogether above, the 
parietcd protuberance. This trifacial and very 
salient projection presents at its base, on each side, 
an excavation elongated transversely, into which 
opens the parieto-temporal canal, and which 
lodges a venous sinus. It is continued, in front, 
by a median crest, which is often replaced by a 
slight groove — ^the saggital furrow, bordered by 
linear imprints. Two other ridges, resulting from 
the abutment of the lateral border of the bone 
against the anterior face of the petrous bone, rise 
from the sides of this eminence and descend to 
the sphenoid bone ; they separate the cerebral 
from the cerebellar cavity. 

Borders. — The superior border is notched, 
thick, and slightly dentated ; it articulates with 
the occipital bone. The inferior border, slightly 
concave, and deeply dentated, offers an external 
bevel in its middle portion, and an internal bevel 
on its sides ; it corresponds with the frontal bone. 
The lettered borders are very thin, and are cut, at 
the expense of the external plate, into a wide, sloping edge, which shows a groove 
destined to form the parieto-temporal canal. A very prominent angle separates 
each into two portions — an inferior, that articulates by suture with the squamous 
portion of the temporal bone ; and a superior, curved inwards towards the centre 
of the cranial cavity. The latter portion of the lateral border is in contact with 
the anterior face of the petrous portion of the temporal bone, with which it 
concurs to form the lateral crest that descends to the parietal protuberance. 

Structure. — This bone contains much compact tissue, the spongy substance 
existing only in its middle. 

Development. — It is developed from two large lateral centres of ossification, to 
which is added a single centre to form the parietal protuberance. In early life 
the parietal ridges are absent. 




head of the cat (posterior 
aspect). 
1, Occipital bone; 2, zygomatic 
process of the temporal bone; 
3, tympanic bulb ; 4, condyle of 
the temporal bone ; 5, malar 
bone ; 6, orbital process of the 
malar ; 7, ditto of frontal bone ; 
8, 8, palatine bones ; 9, 9, maxil- 
lary bone; 10, premaxillary bone; 
11, pterygoid bone; 12, sphenoid 
bone ; 13, vomer. 



50 



THE BONES. 



Differential Characters of the Parietal Bone in other Animals. 

A. Ox. — The parietal bone in the Ox does not occupy the anterior aspect of the head, but 
concurs with the occipital to form the base of the neck. It represents a very narrow osseous 
plate, elongated transversely, and curved at its two extremities, which descends into the 
temporal fossae to rest upon the sphenoid bone. There are no parietal ridges. The internal 
protuberance is only marked by a slight elevation of the internal plate ; for the most part it 
belongs to the occipital bone. The parietal bone of the Ox is developed from three centres 
of ossification, and the middle nucleus is even primarily divided into lateral halves ; but these 
centres «re consolidated with each other at an early period, as well as with the anterior 
portion of the occipital. It does not aid in the formation of the 
parieto-teniporal canal, and is excavated internally by cavities 
which communicate with the frontal sinuses. 

B. Sheep, Goat.— The parietal bone of the Sheep and Goat 
is relatively much larger than that of the Ox. It participates in 
the formation of the parieto-temporal canal, and has no sinuses. 

C. Camel.— This bone occupies the anterior face of the 
cranium ; but it is long, narrow, and deeply lodged between the 
squamous portion of the temporal bone and the frontal bone, to 
rest on the sphenoid. The parietal crests, thin and elevated, lie 
against each other for nearly their entire lengtli, and are not pro- 
longed to the frontal bone (Fig. 45). These crests do not exist at 
an early age. 

D. Pig. — The parietal bone is very thick ; it has two very 
marked crests, which do not meet at their upper part (Fig. 28). 

E. Dog, Cat. — In the Dog, the parietal bone is distinguished 
by the great development of the temporal crests (Fig. 2li). 

In the Cat there are scarcely any parietal crests, and the in- 
ternal protuberance is replaced by two great transverse bony plates, 
which separate the cavity of the cerebrum from that of the 
cerebellum. 

F. Rabbit.— Almost quadrilateral, the parietal bone of the 
Rabbit has its temporal crests carried to near its lateral borders. 

3. Frontal Bone (Fig. 26). 

The frontal is a flat quadrilateral bone, the sides of 
which are bent in the middle at an acute angle, and are 
carried back, and a little inwards, to meet the wings of 
the sphenoid bone. It assists in forming the cranial roof 
and part of the face. It is bordered : above, by the 
parietal bone ; below, by the nasal and lachrymal bones ; 
and on each side, by the temporal bones. It offers for 
study an external and an internal face, and four borders. 

Faces. — The external face is divided, by the double 
flexure of the bone, into three regions : a middle and 
two lateral. The first, nearly plane, is lozenge-shaped, 
is covered by the skin, and constitutes the base of the 
forehead. It gives rise on each side, at the point where 
it is inflected, to a long process, flattened above and 
below, which curves backward, forming the orbital arch. 
The superior or external face of this process is convex and slightly roughened ; 
the internal face is smooth and concave, and forms part of the orbital fossa. Its 
posterior border, thick and concave, is continued, inwardly, with the correspond- 
ing parietal ridge, and outwardly with the superior border of the zygomatic 
process. It limits, in front, the temporal fossa. The anterior border, also 
concave, but thin, concurs in the formation of the orbital margin ; the summit, 




head of the pig 
(anterior face). 
1, Summit of occipital 
tuberosity. 2, parietal 
bone. 3, frontal bone : 
A, Supra-orbital fora- 
men ; a', channel de- 
scending from it. 4, 
zgomatic process. 5, 
malar bone. 6, lachry- 
mal bone : b, Lachrymal 
canals. 7, supermax- 
illary bone : C, Inferior 
orifice of the super- 
maxillo-dental canal. 
8, nasal bone. 9, pre- 
maxillary bone. 



THE HEAD. 



thickened and denticulated, rests upon, and is united to, the zygomatic process 
of the temporal bone ; the base is wide, and is traversed by an opening termed 
the supra-orUtal, or superciUarij foramen. The two lateral regions of the external 
face of the frontal bone are slightly excavated, and assist, for the greater portion 
of their extent, to form the orbits. They often show, near the base of the 
orbital arch, a small depression corresponding to the flexure described by the 
great oblique muscle of the eye in passing through its pulley. 

The interned face of the frontal bone is concave, and divided into two unequal 
parts by a transverse ridge, corresponding to the 
anterior border of the cribriform plate of the ethmoid 
bone. The superior, the most extensive, is covered 
with digital impressions, and belongs to the cranial 
cavity. It exhibits : 1. On the median line, a slight 
furrow, or a crest which is continuous, above, with the 
median ridge of the parietal bone, and below, with 
the crista-gaJU process. 2. On the sides, and in the 
re-entering angle formed by the flexure of the bone, 
there is a narrow slit, or mortise, which receives the 
wing of the sphenoid bone. The inferior part is united, 
on the median line, to the perpendicular plate of the 
ethmoid. It assists in forming the bottom of the 
nasal cavities, and presents laterally two large openings 
which lead to the frontal sinuses — vast anfractuous 
spaces excavated between the two plates of the bone. 

Borders. — The superior border is denticulated and 
cut obliquely in its middle portion, at the expense of 
the internal plate, and on the lateral parts at the 
expense of the external table ; it is in contact with 
the parietal and squamous portion of the temporal 
bone. The inferior, prolonged to a point in the middle, 
is in apposition with the nasal bones through the 
medium of a wide external bevel ; laterally, it is very 
thin, faintly serrated, and articulates with the lachrymal 
bone. The lateral borders, thin and irregular, present 
two notches : one, the superior {incisura spJmioidaUs), 
is wide and deep, and occupied by the wing of the sphe- 
noid bone ; the other, inferior, is very narrow, and, 
uniting with a similar notch in the sphenoid bone, forms 
the orbital foramen, which opens into the cranium, 
very near, but external to, the ethmoid fossa. Each of these borders, also, is 
adapted, for a limited extent, to the corresponding palatine bone. 

Structure. — The two compact plates of the frontal bone are separated by 
spongy texture towards the middle and in the upper part ; they separate below 
to form the frontal sinuses. Laterally, they are very thin and consolidated with 
each other. 

Development. — The frontal bone is developed from two lateral centres of 
ossification, which only coalesce at a late period. In youth the cranial portion 
of the bone forms, in front of the head, a large rounded protuberance standing 
beyond the facial portion. This prominence disappears when the frontal sinuses 
begin to be developed. These cavities do not exist at an early period of foetal 




head of dog (anterior 
face). 

1, Occipital tuberosity; 2, 
median spur of the occi- 
pital bone ; 3, parietal 
bone ; 4, origin of the pa- 
rietal crests; 5, zygomatic 
process ot the temporal 
bone ; 6, frontal bone ; 6', 
orbital process ; 7, malar 
bone ; 8, lachrymal bone ; 
9, nasal bone ; 10, super- 
maxilla ; 11, inferior ori- 
fice of the supermaxillo- 
dental canal; 12, pre- 
maxillary bone. 



52 THE BONES. 

life ; but commence to form about the fourth month of conception, by a process 
of resorption, which removes the spongy substance interposed between the two 
compact tables of bone, and may even cause the destruction of the internal table. 
The sinuses enlarge with age, and remain during life separated from one another 
by a vertical septum. 

Differential Characters in the Frontal Bone of other Animals. 

A. Ox, Sheep, Goat. — In Eumiaants, the frontal bone does not come in contact with 
the temporal or palatine bones (Figs. 30, 31, 32). 

In the Ox, this bone is extremely developed, occupying alone nearly one-half of the anterior 
surface of the head. It is particularly distinguished by: 1. Its great thickness. 2, The 

Fig. 30. 




ox's head (anterior face). 

1, Mastoid process ; 2, superciliary, or supra-orbital foramen ; 3, malar bone ; 4, lachrymal 

bone ; 5, maxillary spine ; 6, inferior orifice of the supermaxillo-dental canal. 



osseous conical cores which support the horns. These eminences, more or less long and curved, 
very rugged, perforated by foramina, and grooved by small vascular channels, are detached 
outwards from each side of the bone, near the summit of the head. The proce.-^ses which form 
the orbital arches rest by their summits on the zygomatic bone. The supra-orbital foramen is 
transforraeil into a veritable and frequently multiple canal ; its anterior orifice opens into a 
vasculo-nervous groove, which ascends towards the base of the horns, and descends to near the 
lower border of the bone. Between this groove and the base of the orbital arch is the frontal 
boss. Thp orbital foramen entirely belongs to this bone. The inferior border is deeply notched 
in its middle to receive the nasal bones; the frontal sinuses are prolonged into the horn-cores, 
the parietal bone, and even into the occipital bone. , 

The frontal bones of the Angus breed of cattle (^polled cattle) have no horn-cores. The 
ablation in the calf of the periosteum, followed by cauterization, at the point where appear 
the osseous prolongations which serve as bases for the horns, prevents the development of 
these appendages. Cornevin mentions that a farmer of Haute Marne has in this way muti- 
lated the cattle bred on his farm for twenty-three years, and yet the mutilation has not become 
hereditary. Fig. 31, representing the head of an Ox so mutilated, shows that the removal of the 



THE BEAD. 



53 



periosteum in such animals has the effect of producing a considerable elongation and narrowing 
of the upper part of the frontal bone. 

In the Sheep and Goat, tlie frontal bone is relatively less extensive and strong than in the 
Ox; it does not ascend to the summit of the head, and the frontal sinuses are not prolonged 
beyond its superior border (Fig. 32). 

B. Camel. — The frontal bone of this animal much resembles that of Solipeds. The 
middle portion of its external face is triangular in shape, the base being wide, and the apex 
fixed in the deep notch formed on the inferior border of the parietal bone; it is slightly 
hollowed in the middle line, and convex on the lateral parts. The orbital arch rests on the 



Fig. 32. 




HEAD OF A HORNLESS OX. 



ram's head (anterior face). 
1, Occipital bone ; 2, parietal bone ; 3, core of right 
frontal bone ; 4, the left core covered by its horn ; 
5, supra-orbital foramen ; 5', channel descending 
from it ; 6, lachrymal bone ; 7, malar bone ; 8, nasal 
bone ; 9, supermaxillary bone ; 10, premaxillary 
bone; 10', its internal process; 11, incisive open- 
ing. 

zygomatic bone, as in the Ox (Fig. 37). The supra-orbital foramina are transformed into 
inflected canals, which open on the anterior face of the bone, near its middle. 

On the circumference of the bone are several notches, some of which concur with the 
other bones, to form foramina (orbital, nasal) ; two are seen to the right and left of the line of 
union of the bone with the supra-nasal, and two others are in the orbital cavity. These open- 
ings are partially closed by the Wormian bones ; they open into the upper compartments of the 
turbinated bones. 

In the young Camel, the middle portion is deeply excavated ; this excavation diminishes 
as the animal advances in age, and as the frontal sinuses enlarge. 

C. Pig.— The frontal bone of the Pig is very thick and short, and does not join the 
temporal or zygomatic bones ; the orbital arch is completed by a ligament. The supra-orbital 
foramen, disposed as in the Ox, abuts in a channel that descends on the nasal bones. The 



* In the Museum of the Lyons Veterinary School. 



54 



THE BONES. 



orbital foramen is formed by the frontal bone only. There is no mortise for the union of the 
frontal with the sphenoid bone ; and the frontal sinuses are prolonged into the parietal. The 
frontal bone articulates with the superior maxillarie.s (Fig. 28). 

D. Carnivora. — In the Carnivora, the external face of the frontal bone presents in its 
middle a more or less deep depression. The ori)ital arch is incomplete, and there is no supra- 
orbital foramen or mortise on the inner face. 




superior maxilLiry bones 



anterior bones of the head op a fcetus 
(horse) at birth, disarticulated, and 
viewed from behind. 



It unites with tht 
(Fi-. 29). 

E. Rabbit. — In this animal the frontal 
bone is long and narrow, and the orbital 
process is thin, elevated, and directed upwards 
and backwards, but it does not reach the 
zygomatic bone, and is deeply notched at its 



4. Ethmoid Bone (Fig. 33). 

The ethmoid bone, deeply situated 
m the limit between the cranium and 
the face, is enclosed between the frontal, 
the sphenoid, the vomer, the palatine, 
and the supermaxillary bones. It is 
composed of three portions — a jjer- 
pendicular plate, and two lateral masses. 

The Perpendicular Lamina of 
THE Ethmoid Bone. — Situated in the 
mesian plane, and flattened on both 
sides, this bone presents tu'o faces, a 
left and right, and four borders. 

Faces. — The faces, covered by the 



., Occipital bone : 1, condyle ; 2, condyloid 
foramen ; 3, styloid process ; 4, summit of 
basilar process. B, Parietal bone : 8, j)arie- 
tal protuberance; 9, channel which concurs 
to form the parieto-temporal canal. C, Fron- 
tal bone: 10, transverse crests separating 
the cranial from the facial portion of the 
bone; 11, frontal sinuses; 12, notch on the 
lateral border occupied by the wing of the 
sphenoid bone ; 13, notch for the formation 
of the orbital foramen ; 14, summit of the 
orbital process ; 15, supra-orbital foramen. 

D, Perpendicular lamina of the ethmoid bone. 

E, E, Lateral masses of the ethmoid bone : 
16, the great ethmoid cell. F, Squamous 
portion of the temporal bone : 17, Supra- 
condyloid process ; 18, channel for the forma- 
tion of the parieto-temporal canal. G, Pet- 
rous portion of the temporal bone : 5, 
mastoid process ; 6, internal auditory hiatus ; 
7, opening for the Eustachian tube into the 
tympanum, h, Lachrymal bone. I, Nasal 
bone. J, Superior turbinated bone. 



pituitary membrane, present, posteriorly, small sinuous crests ; elsewhere they are 
smooth. A very narrow interval, constituting the bottom of the nasal cavities, 
separates them from the lateral masses. 

Borders. — The superior border looks towards the centre of the cranial cavity, 
and constitutes what is called the ethmoidal ridge, or crista-galli ^wocess. It is 



THE HEAD. 55 

free, concave, and sharp, prolonged in front and above by the median crest of 
the frontal bone, and confounded behind with the middle portion of the inferior 
sphenoid. The inferior border is continuous with the cartilaginous plate which 
separates the nasal cavities. When this plate becomes ossified, which is not 
unfrequent, it is impossible to discover the point where it begins or the ethmoid 
bone terminates. The middle Septum of the nose has been considered, and 
justly, as a prolongation of the perpendicular plate (or lamina) of this bone. 
The anterior border is consolidated with the vertical septum which separates the 
frontal sinuses. The posterior border is joined above to the median plate which 
divides the sphenoidal sinuses into two compartments. Below, it is fixed in the 
groove of the vomer, and soon becomes confounded with that bone, which is 
itself consolidated with the inferior sphenoid. 

Lateral Masses of the Ethmoid Bone. — These are two large pyriform 
tuberosities placed on each side of the perpendicular lamina, and offering for 
study a middle portion, a base, and a summit. Each of these is formed by an 
assemblage of numerous, extremely thin, osseous plates, curved into small and 
very fragile convolutions. These, elongated from above to below, become 
longer as they are more anterior ; they are attached by their superior extremities 
to the transverse plate which separates the cranium from the nasal cavities, and 
by one of their borders to a thin leaf of bone which envelops the lateral masses 
outwardly. They have received the name of the ethmoidal volutes (or cells). 

Middle portion. — This should be studied externally and internally 

The external surface of each ethmoidal mass is divided into two sections : 
an internal, making part of the nasal cavities ; the other, external, concurs in 
forming the walls of the frontal and maxillary sinuses. The first, the least 
extensive, is almost plane ; parallel to the perpendicular lamina, it is isolated 
from it by the narrow space which forms the bottom of the nasal cavities ; it 
presents several openings which separate the most superficial cells, and join the 
internal canals to be hereafter noticed. The second, very extensive and convex, 
looks outwards in front and behind, and is covered by an osseous plate traced 
with shallow furrows, which correspond internally with the small crests to which 
the cells are attached. This lamella is prolonged, inferiorly, a little beneath the 
inferior extremity of these latter, and turns outwards to articulate with the 
palate and superior maxillary bones ; superiorly, it coalesces with the sphenoid 
and the orbital portion of the frontal bone. 

Internally, the lateral masses are hollowed from above to below by extremely 
diverging canals, which open inferiorly into the nasal cavities, and separate the 
cells from one another. The latter are so incurvated that the internal cells 
communicate with each other. There are some, however, which are completely 
closed ; the anterior, or great cell, is frequently so.^ 

Base. — The base of each lateral mass looks upwards, and is formed by the 
transverse septum between the cranium and the nasal cavities. This septum is 
perforated by openings which give passage to the ethmoidal nerves ; it is named 
the cribriform plate of the ethmoid bone. It is concave on the superior surface, 
which constitutes the ethmoidal fossa, and convex on the opposite face, where 
attachment is given to the superior extremities of the cells. It is consolidated 
internally with the perpendicular plate ; the other points of its circumference 
are attached to the sphenoid bone, and to the transverse ridge on the internal 
face of the frontal bone. 

' It is not rare to find it opening into the superior maxillary sinus. 



96 THE BONES. 

Summit. — The summit of each lateral mass is formed by the inferioi 
extremity of the ethmoidal cells, which is directed downwards, towards the nasal 
cavities. One, more volmninous than the others, is carried much lower, and 
terminates by a rounded protuberance. It corresponds to the middle cornu 
{concha media) of Man. 

Structure of the ethmoid hone. — Very little* spongy tissue enters into the 
composition of this bone, and this is only found near the anterior border of 
the perpendicular plate. 

Development. — The ethmoid bone is late in attaining its development, and 
the adjoining bones are nearly completely ossified when it is yet entirely 
cartilaginous. The bony transformation commences in it at the inferior ex- 
tremity of the cells, and advances progressively from below upwards. The per- 
pendicular plate is only ossified in part when the cells have passed through the 
first half of the process ; at the same time it coalesces with the inferior 
sphenoid. The cribriform plate is the last to become ossified, this transforma- 
tion having scarcely been achieved when the animal is six or eight months old. 

Differential Characters in the Ethmoid Bone of other Animals. 

A. Ox, Sheep, Goat. — In Ruminants, the great ethmoidal cell is enormously developed, 
and looks like a third turbinated bone prolonged beyond tlie usual two ; it has been named 
the olfactory antrum. The bone is closely imprisoned between the adjacent bones, in con- 
sequence of the slight development of the sinuses around it. This character otherwise belongs 
to all the domesticated animals, except Solipeds (Fig. 36). 

B. Camel.— The crista-galli process is very thick, and the ethmoidal fossae are narrow 
and deep. 

C. Pig.— The superior turbinated bone is very long, and the papyraceous plate appears in 
the orbital cavity. 

D. Dog, Cat. — The ethmoidal fossa is very deep, and the cells very developed and 
diverticulated. The perpendicular lamina is at a late period consolidated with the sphenoid 
bone. 

5. Sphenoid Bone (Fig. 34). 

The sphenoid bone is situated behind the cranium, between the occipital, 
ethmoidal, palatine, vomer, pterygoid, frontal, and temporal bones. It is formed 
by the union of two pieces, which have been sometimes described as distinct 
bones — the anterior or inferior sphenoid, and the posterior or superior sphenoid. 
It is now supposed, in the description, that this union has been completed. 

It is a bone flattened before and behind, curved from one side to the 
other, thick in its middle part, named the bodi/, and thin on the sides, which, in 
their inferior half, are prolonged in the form of aJce, or U'ings. It has two 
surfaces a,nd four borders. 

Surfaces. — The exfermd surface is convex, and presents : 1. On the median 
line, the external surface of the body, rounded from one side to the other, is 
continued with that of the basilar process, and has marked muscular imprints 
superiorly. 2. On the sides and from within outwards : (a) the Vidian (or 
pterygoid) fissure, directed from above downwards, and continued by the Vidian 
canal, a very smaU foramen which opens into the orbital hiatus ; (b) the sub- 
sphenoidal, or pterygoid process, a long eminence, flattened on both sides, inclining 
downwards, articulating with the palatine and pterygoid bones, and traversed at 
its base by the Vidian canal ; (f) a little behind and above this eminence, the 
superior orifice of the sub-sphenoidal (or pterygoid) foramen — a large canal which 
bifurcates inferiorly ; (d) more in front, the orbital hiatus, a kind of vestibule into 



THE HEAD. 



F 



Fig. 34. 



which open, in common, the principal branch of the subsphenoidal canal, the three 
supra-sphenoidal canals, the Vidian and optic canals, and the orbital opening : 
this hiatus is surmounted by a thin and sharp bony plate, above which opens 
the smallest branch of the subsphenoidal foramen ; (e) altogether without the 
hiatus is remarked a smooth surface belonging to the wing of the sphenoid, and 
which concurs to form the orbital cavity. 

The internal face is concave from side to side. It shows : 1. On the median 
line, and from before to behind, a small 
projection united to the crista-galli ; the 
optic fossa, elongated transversely in the 
form of a shuttle, and presenting at the 
bottom, and on each side, the superior 
orifice of the optic foramen, a cylindrical 
canal directed obliquely downwards, for- 
wards, and outwards, to reach the orbital 
hiatus ; the supra-sphenoidal or pituitary 
fossa, also named the sella Turcica, a slight 
depression, limited behind by a scarcely 
noticeable transverse projection separating 
it from the superior channel of the basilar 
process. 2. On the sides, and in front, the 
internal surface of the wings, depressed by 
very superficial digital impressions ; more 
behind and outwards, a fossa, elongated 
from before to behind, which lodges the 
mastoid lobule of the brain ; between this 
fossa and the sella Turcica, two vertical 
fissures — an internal, named the cavernous 
sinus, and an external, wider and deeper, 
for the passage of a large nervous branch. 
These two fissures open below, near the 
junction of the three supra-sphenoidal canals. 
Two of these, which are very wide, are placed 
one before the other, and separated only by 
a slight partition. The superior of these con- 
stitutes the great sphenoidal fissure {foramen 
lacerum orhitale) ; the other, the lower, is the 
foramen rotundum, and opens into the orbital 
hiatus. The third, very small {foramen pathe- 
ticiim), is situated outside the great anterior 
canal, opens above the optic foramen, within 
the bony mass surmounting the hiatus, and 
sometimes on the free margin of this lamina. 

Borders. — The superior is a little con- 
cave, and shows, in its middle, the superior 

extremity of the body, mammillated and articulated with the summit of 
the basilar process ; on each side, two notches which circumscribe below the 
occipito-spheno-temporal hiatus {foramen lacerum basis cranii). The internal 
notch is the narrowest, and from its affording a passage for the internal carotid 
artery, is called the carotid notch ; it is continued on the external face of the 




POSTERIOR BONES OF THE HEAD OF A 
FOETUS (horse) AT BIRTH, DISARTICU- 
LATED AND viewed in FRONT. 

A, Sphenoid bone : 1, ma.xillary notch ; 2, 
carotid notch ; 3, groove for the passage 
of the maxillary nerve ; 4, cavernous 
sinus ; 5, optic fossa ; 6, great wing ; 
6', unossified portion of the great wing; 
7, notch for the formation of the orbital 
foramen. B, Vomer. C, Palatine bone. 
D, Malar bone. E, Supermaxilla : 8, 
inferior orifice of the raaxillo-dental 
canal. F, Premaxillary bone. 



5^ THE BONES. 

bone by a smooth excavation to which Rigot has given the name of carotid fossa. 
The external is also prolonged on the exterior surface of the sphenoid, by a short 
and wide fissure ; it lodges the inferior maxillary nerve. Outside this is another 
very narrow notch, intended for the passage of the middle meningeal artery. 
The fibro-cartilaginous substance that partly fills the occipito-spheno-temporal 
hiatus, transforms these notches into foramina, the first of which is named the 
carotid canal ; the second, the foramen ovale ; and the third, the foramen spinosum. 
The inferior' border, also concave, is likewise divided into three portions, a middle 
and two lateral. The first is thick, and formed by the inferior extremity of the 
body ; it is excavated by two large cavities belonging to the sphenoidal sinus. 
These cavities are separated from one another by a vertical osseous plate, often 
perforated, which, at an early period, is fused with the perpendicular lamina of 
the ethmoid bone. The very thin lateral portions form part of the circum- 
ference of the wings ; they are notched near their union with the middle piece 
to assist in the formation of the orbital foramen. The ttvo lateral borders are 
thin and convex in their anterior half, as is also the contour of the wings, which 
are mortised in the frontal bone. For the remainder of their extent they are 
thick, denticulated, and bevelled at the expense of the external plate, to articulate 
with the squamous portion of the temporal bone. 

Structure. — This bone is compact on its sides, and spongy in its middle part ; 
inferiorly, it is excavated by the sphenoidal sinuses. 

Development. — It is developed from two principal nuclei of ossification ; a 
superior forms the subsphenoidal process and the canal of the same name, the 
Vidian fissure, pituitary fossa, fissures of the internal face, and the most posterior 
of the great supra-sphenoidal canals ; the other, the inferior, forms that portion 
of the body hollowed by the sinuses, the lateral alas,^ and the optic fossa and 
canals. In meeting each other, these centres form the Vidian canal and the two 
anterior supra-sphenoidal canals. They are not consolidated with each other 
until a very late period ; for which reason they are sometimes described as two 
distinct bones. M. Tabourin has even proposed to attach the description of the 
inferior sphenoid to that of the ethmoid, because it is united with this bone a 
long time before it is joined to the superior portion.^ 

Differential Characters in the Sphenoid Bone op other Animals. 

A. Ox. — In the Ox, the subsphenoidal or pterygoid processes are large and thin The 
subsphenoidal canal is absent. The sella Turcica is deep, and the bony projection separating 
it from the basilar process is very high. The three supra-sphenoidal canals are converted into 
a single, but wide one. There are no notches in tlie superior border, for the passage of the 
internal carotid and spheno-spinous arteries. The oval foramen is entirely confined to this 
bone. 

B. Sheep. — In the Sheep, the osseous prominence that limits the pituitary fossa posteriorly 
forms a lamina curving forwards, and prolonged at its extremities into two points, which 
constitute' the posterior clinoid processes. 

C. Camel.— The sphenoid is longer and tliicker than in the Ox. The subsphenoidal 
or pterygoid processes are narrow and very thick. The oval foramen is relatively small. The 
optic canals are covered at their internal ojiening by a bony plate. The optic fossa is nearly 
on a level with the pituitary fossa. 

D. Pig. — The sphenoid of the Pig is very short, but the subsphenoidal processes are 
extraordinarily developed, and flattened before and behind. There is no subsphenoidal canal, 
and the sella Turcica is deep, and limited behind by a very salient crest. A single canal 



These wings are not analogous to those portions of the sphenoid bone in Man bearing the 
( name. They are the processes of Ingrassias enormously developed. 
Tabourin, Journal de Med. Ve'tifrinaire, p. 229. Published at Lyons, 1845. 



THE READ. 



replaces the tbiameu rotimdum and the great sphenoidul fissure, as in the Ox. The wings, 
shghtly salient, are articulated by suture witli the frontal bone. 

E. Dog, Cat. — The superior sphenoid of the Dog is very short, and bears, laterally, two 
wide wings which ascend to the temporal fossa ; they correspond to those of the sphenoid bone 
in Man. The inferior sphenoid is, on the contrary, very narrow, and its lateral prolongations, 
or processes of Ingrassias, are reduced to very small proportions. The subsphenoidal or 
pterygoid process is very short, and the canal is single, and communicates witli the foramen 
rotundum. The pituitary fossa is shallow, limited behind and before by the posterior clinoid 
and anterior clinoid processes, so named because of their being 

compared to the four posts of an ancient bed. The supra- 
sphenoidal canals are only two in number: one represents 
the great sphenoidal fissure, the other the round foramen. 
The carotid notch, joining a similar one in the temporal 
bone, forms an opening which may be designated the carotid 
foramen, because it gives passage to an extremely remark- 
able loop the internal carotid artery describes after passing 
through the carotid canal. The oval foramen is the same as 
in the Ox. 

In the Cat there is the same disposition, with the excep- 
tion of no sphenoidal canal or carotid notch being present. 

F. Rabbit.— The body of the sphenoid is short, tri- 
angular, thick at its upper border, pierced in the middle by 
an orifice which opens into the pituitary fossa. Tlie wings 
are very developed ; the subsphenoidal processes, bifid, are 
closely embraced by the pterygoids and palatine bones ; and 
the optic fossa is replaced by a large foramen, which com- 
municates at the same time with the two orbital fossae. 



6. Tempokal Bone (Figs. 26, 33). 



HEAD OF THE RABBIT (POS- 
TERIOR face). 
Occipital tuberosity; 2, sty- 
loid process of the occipital 
bone ; 3, condyle of ditto ; 4, 
tympanic bulb ; 5, basilar pro- 
cess of the occipital bone ; 6, 
body i)f the sphenoid ; 7, ptery- 
goid bone; 8, zygomatic bone ; 
9, 9, condyles of the temporal 
bone; 10, palatine bone; 11, 11, 
superior maxillary bone; 12, 12, 
premaxilla; 13, orbital pro- 
cess of the fi-ontal bone ; 14, 14, 
superior double incisors. 




The temporal ■ bones enclose the cranial cavity 
laterally, and articulate with the occipital, parietal, 
frontal, sphenoidal, and malar bones ; also with 
the inferior maxilla and the hyoid bone. Each 
is divided into two pieces, which are never consoli- 
dated in the horse ; one forms the squamous portion 
of the temporal bone ; the other, the petrous portion. 
They will be described separately. 

Squamous -portion. — This is flattened on both 
sides, oval, and slightly incurvated like a shell, a 
shape to which it owes its name. It offers for 
study an external and an internal face., and a circum- 
ference. 

Faces. — The external face is convex, and marked 
by some muscular imprints, vascular fissures, and 
openings which penetrate the parieto-temporal canal. 
It forms part of the temporal fossa, and gives origin near its middle to the zygomatic 
process — a long eminence which at first runs outwards, and soon curves forwards 
and downwards to terminate in a thin summit. The base of this eminence forms, 
in front, a concave surface belonging to the temporal fossa ; behind, it offers the 
articular surface which corresponds with the maxillary bone. The latter is com- 
posed of : 1. A condyle transversely elongated, convex above and below, and slightly 
concave from side to side. 2. A glenoid cavity, limited below by the condyle, above 
by a mammilif orm eminence, the supra-condyloid (or anterior mastoid) process^ 

' In Man this is represented by the inferior or vertical ramus of the upper root of the 
zygomatic process. 



60 THE BONES. 

against %yhich rests the maxillary condyle when this bone is drawn backwards ; it 
is immediately above this eminence that the inferior orifice of the parieto-temporal 
canal (mastoid foramen) opens. The external face of the zygomatic process is 
smooth and convex ; the internal, concave, is also smooth, and bordered outwards 
by the temporal fossa. Its anterior border is sharp and convex ; the posterior, very 
short, is thick and roughened. Its summit is ilattened from before to behind, and 
marked by notches on its two faces ; it somewhat resembles a wedge, fixed as it is 
between the orbital process of the frontal bone and the zygoma ; it comes in contact 
with the maxillary bone, and by a small portion of its anterior face, which is 
deprived of notches, it concurs in circumscribing the orbital cavity. In the 
domesticated animals, as in Man, the zygomatic process appears to arise from the 
surface of the bone by two roots — one, the inferior or transverse, is represented by 
the condyle ; the other, the siqjerior, forms a sharp crest which is continuous with 
the anterior border of the process, and above, joins the lateral crest of the occipital 
protuberance. 

The internal or cerebral face of the squamous portion is divided into two parts 
by an almost vertical channel, which terminates above the supra-condyloid 
process, and which, meeting a similar furrow on the parietal bone, forms the 
parieto-temporcd canal. The superior portion is of small extent, and of a 
triangular form ; it articulates by a simple harmonia suture with the external 
face of the petrous portion. The inferior part, the widest, present in its middle 
some cerebral impressions. For the remainder of its extent or circumference, it 
is cut into a wide, dentated, and lamellar bevel, which brings it in contact with 
the surrounding bones. 

Circumference. — This may be divided into tivo borders .- one, anterior, is 
convex and united with the parietal and frontal bones ; the other, posterior, articu- 
lates with the sphenoid in its inferior moiety, and is provided, above the level of 
the supra-condyloid process, with a deep notch which receives the external 
auditory canal. Superiorly, the two borders unite at the summit in a thin point, 
which rests on the occipital bone. 

Structure. — The squamous portion of the temporal bone is formed of two 
very thin compact plates, which have but little spongy tissue between them ; the 
latter, however, is very abundant in the body of the zygomatic process. 

Development. — It is developed from a single nucleus of ossification. 

Petrous Portion. — This is one of the most interesting parts of the 
skeleton for study, in consequence of its containing two systems of cavities which 
enclose the essential organs of hearing. One of these systems is named the cavity 
of the tympanun or middle ear ; the other forms the interned ear. These cavities 
will be studied when we come to speak of the auditory apparatus. In the mean 
time, only the external surface, and the structure and development of this portion 
of the temporal bone, will be noticed. 

It is wedged between the antero-lateral border of the occipital bone, the 
lateral border of the parietal, and the superior part of the internal face of the 
temporal shell. It represents a quadrangular pyramid, the base of which is turned 
downwards and a little backwards. It will be studied successively in four faces, 
a summit, and base. 

Faces. — The anterior face is united by harmonia suture to the parietal bone. 
The posterior face articulates in the same manner with the occipital bone. The 
external face lies against the squamous portion of the bone. The internal face, 
slightly concave and marked by very superficial digital impressions, forms a part 



THE HEAD. 61 

of the lateral wall of the cerebellar cavity. It presents the canal or internal audi- 
tory hiatus {rneatus auditorius internus), a small fossa, the bottom of which is 
pierced by several foramina for the transmission of nerves ; the largest of these 
is the internal orifice of the aqimdudus Fallopii — a flexuous canal which passes 
through the bone and opens at the external surface of its base ; the other 
foramina penetrate the cavities of the internal ear. 

These faces are separated from each other by so many borders or plane angles, 
two of which more particularly merit attention ; one of these isolates the external 
from the posterior face, and the other separates the anterior from the internal 
face. The first is thick and rugged, and constitutes the mastoid crest ; it is con- 
tinuous above with the lateral ridge of the occipital bone, after being united to 
the superior root of the zygomatic process, and terminates, near the base of the 
bone, by a tuberosity for muscular insertion, to which has been given the name 
of (poster io7-) mastoid process. This border is traversed by a slit, the mastoid fissure^ 
which passes under the squamous portion and enters the parieto-temporal canal. 
The second is thin, and, with the superior part of the lateral border of the parietal 
bone, forms the crest which establishes the line of demarcation between the 
cerebral and cerebellar cavities of the cranium ; it gives attachment to the 
tentorium cerebelli. 

Summit. — This is slightly denticulated, and articulates with the occipital bone. 

Base. — This is very irregular, and offers : outwardly, the external auditory 
canal which penetrates the middle ear, and the external orifice of which has been 
named in veterinary anatomy the external auditory hiatus ; inwardly, a sharp 
crest which circumscribes the external contour of the foramen lacerum basis cranii ; 
above, and under the mastoid process, the stylo-mastoid or pre-mastoid forammi, the 
external orifice of the aqueduct of Fallopius ; below, the subuliform (or styloid) 
process for the attachment of the tensor palati muscle and the Eustachian tube : 
this is a long, thin, and pointed process presenting, at its base and within, a canal 
(styloid foramen) which enters the cavity of the tympanum, and which is incom- 
pletely partitioned by a small bony plate into two parallel portions ; in the centre, 
the hyoid prolongation or vaginal process ^ — a little cylindrical eminence surrounded 
by a bony sheath, and the mastoid protuberance or auditory bulla — a slightly sahent, 
smooth, and round eminence hollowed internally by numerous cells, which form 
part of the middle ear. 

The several small and very remarkable canals which pass through the petrous 
portion of the temporal bone, will be noticed when the nervous and arterial 
branches they lodge are described. 

Development. — The petrous portion of the temporal bone is developed from 
two principal centres of ossification which are consolidated at birth, and which 
are often described as two distinct portions — the one as the petrous or stony 
portion, the other as the mastoid portion. 

The faces, borders, summit, and inner side of the base of the bone are formed 
by the petrous part, which contains the cavities of the internal ear and furnishes 
the inner wall of the middle ear. 

The mastoid portion constitutes almost entirely the base of the temporal 
pyramid ; to it belong the external auditory canal, the mastoid process, the 
sheath of the hyoid prolongation, and the styloid process ; it forms the external 
wall and circumference of the case of the tympanum. 
' This is the analogue of the mastoid canal in Man. 

* This process is prolonged by a cartilage that unites it to the styloid hone. 
7 



62 TEE BONES. 

For the petrous portion of the temporal bone there are also two small com- 
plementary nuclei : one for the vaginal process — the base of which is united to 
the petrous portion, and another forming the ring of the tympanum. 

Structure. — The petrous portion is the hardest mass of bone in the skeleton, 
and scarcely contains any spongy tissue, except at the centre of the mastoid 
process ; in the mastoid portion it may be said not to exist. 



Differential Characters in the Temporal Bone of other Animals. 

In the other domestic animals, the petrous portion of the temporal bone becomes 
consolidated with the squamous portion, and the summit of the zygomatic process only 
articulates with the malar bone. 

A. Ox, Sheep, Goat.— The condyle of the zygomatic process is very wide and convex in 
every sense. The parieto-temporal canal is very large, and entirely excavated in the temporal 
bone; its superior or internal extremity opens above the petrous portion in an excavation which 
represents the lateral cavity of the parietal protuberance in the Horse ; at its inferior extremity 
it always shows several orifices. 

Tiie mastoid process is very salient, and belon<^s to the squamous portion. The mastoid 
cre.st is confounded with the upper root of the zygomatic process ; iiiferiorly, it surpasses the 
mastoid process, and is prolonged to the mastoid protuberance. Tlie latter is very voluminous. 

The subuliform process is larger and stronger than 
in the Horse ; there is no mastoid fissure. 

In the Sheep and Goat, the mastoid process is 
scarcely distinct from the crest ; and the mastoid 
portion of the bone is only at a late period consoli- 
dated with the petrous portion. 

B. Camel. — The squamous portion of the 
temporal is wider than that of the Horse ; it is 
excavated in tlie upper part of its external surface. 
The zygomatic process has a large and thin base; 
its articular surface is nearly level from before to 
behind, and is concave from one side to the other ; 
the supra-condyloid process is very developed (Fig. 
45). The petrous portion is thin, and closely con- 
fined between the occipital and squamous bones. 
The mastoid crest and process are not markedly 
developed. The hyoid prolongation is placed at the 
bottom of a great bony sheath. 

C. Pig.— The articular surface of this bone 
resembles that of Rodents; it is not limited pos- 
teriorly by a subcondyloid eminence, and, in addition, 
offers a wider transverse surface. The zygomatic 
process articulates with the jugal bone by the wliole 
extent of its posterior border. A crest leading from 
the external auditory hiatus to the mastoid pro- 
The mastoid crest is, as in the Ox, confounded with 




head of the rabbit (antero-lateral 
face). 

1, Occipital bone ; 2, parietal ; 3, tym- 
panic bulb ; 4, auditory canal ; 8, 8, 
nasal bones; 9, supermaxilla; 10, pre- 
maxilla; 11, inferior maxilla. 



tuberance replaces the mastoid process, 
the superior root of the zygomatic process. 

D. Carnivora. — In tlie Carnivora, the articular surface of the zygomatic process merely 
forms a glenoid cavity, into which the condyle of the msixillary bone exactly fits. Tlie 
temporal bone in these animals is alsodistinguisliedby the width of the externul auditorv canal, 
the absence of a liyoid prolongation, the small development of the mastoid and styloid pro- 
cesses, the enormous volume of the mastoid protuberance, and the presence of two particnlar 
canals which cannot be traced in the other animals. One of them— the carotid mmni-tra verses 
the mastoid portion, and joins, superiorly, the venous canal which passes between the basilar 
process and the temporal bone ; by its inferior extremity it joins the carotid foramen, which 
itself pern tiates the cranium, a little beyond the venous canal just mentioned. The other 
conduit is pierced in the petrous portion immediately above the carotid canal ; it affords a 
passage to tlie fifth pair of cranial nerves. 

E. Rabbit. --Tlie squamous portion is circular, and has a shoit process flattened from 
before to behind at its base, and from side to side at its extremity. The articular surface is 



TBI, HEAD. 63 

concave transversely, and elongated from before tobeliind. The petrous portion has a consider- 
able tympanic bulb applied closely to the auditory canal, which is large and obliquo behind. 
The mastoid process is a simple crest situated above the auditory canal ; the hyoid prolongation 
is absent. 

Bones of the Pace. 

The face is much more extensive than the cranimn in the majority of the 
domesticated animals, and is composed of two jmvs — a bony apparatus that serves 
as a support to the passive organs of mastication — the teeth. The superior or 
anterior jaiv, traversed in its entire length by the nasal cavities, is formed by 
nineteen flat bones, only one of which, the vomer, is a single bone. The pairs 
are : the superior and intermaxilJaries (or premaxillaries), the palate, piterijgoid, 
malar, lachrymal, nasal, and superior and inferior turbinated hones. Of these 
only four — the maxillaries — are intended for the implantation of the teeth ; the 
others form the union between the cranium and the superior maxilla, or concur 
in the formation of the nasal cavities. The loiver jaw has for its base a single 
bone — the inferior maxilla, or maxillary hone. « 

1. SuPEEioR Maxillary Bone (Fig. 26). 

This bone, also named the supermaxillary hone, the most extensive in the 
upper jaw, is situated on the side of the face, and is bordered above by the 
frontal, palate, zygomatic, and lachrymal bones ; below, by the premaxillary 
bones ; in front, 'by the nasal bone ; behind and within, by that of the opposite 
side. It is elongated vertically, is irregularly triangular, and exhibits two faces, 
two borders, and two extremities. 

Faces. — The external face, which is more convex in the young than the old 
animal, presents : 1. On the level of the fourth and fifth molar teeth, a vertically 
elongated ridge which is continued above with the inferior border of the 
zygomatic bone ; this is the maxillary spine. 2. The inferior orifice of the 
maxillo-dental canal, or infra-orbited foramen. 

The internal face concurs in forming the external parietes of the nasal cavities. 
We observe, above and in front, a deep, wide, and diverticulated excavation, 
forming part of the maxillary sinus ; above and behind, a surface roughened by 
fine lamellffi and denticulations to correspond with the palate bone, and traversed 
from above to below by a fissure which forms, in uniting with a similar fissure in 
the latter bone, the pcdatine canal. For the remainder of its extent it is unequally 
smooth, covered by the membrane of the nose, and divided into two surfaces by 
a slightly vertical and sinuous crest that affords attachment to the maxillary 
turbinated bone : the anterior surface, which responds to the middle meatus of 
the nasal fossa, shows the lower orifice of the osseous lachrymal canal continued 
by a fissure to the lower extremity of the bone ; the posterior surface belongs to 
the inferior meatus. From this face is detached, near its inferior border, a wide 
and long vertical plate, which forms, in Man and short-faced animals, a simple 
process — t\iQ palatine process. This plate, uniting in the middle line with that on 
the opposite side, concurs in forming the greater portion of the palatine arch. It 
shows : an anterior slightly concave face, forming the floor of the nasal fossae ; a 
posterior face, buccal, furrowed by small fissures, perforated by fine openings, and 
traversed along its length by a somewhat wide groove — the pcdatine fisstfre, which 
commences above at the lower orifice, of the palatine canal ; a denticulated border 



61 THE BONES. 

which articulates with a similar border on the palatine process of the opposite 
side. 

Borders. — The anterior, thin and convex, is divided into two parts : an 
inferior, which is mortised to receive the external border of the nasal bone and 
the external process of the premaxilla ; and a superior, cut in a wide bevel, at 
the expense of the external plate, to respond to the lachrymal and zygomatic 
bones. The external border is very thick, and hollowed into six large quadrilateral 
cavities, named alveoli, in which are implanted the molar teeth. Above the last 
alveolus it forms a rugged eminence designated the alveolar tuberosity ; below the 
first alveolus it becomes thin and sharp, and constitutes part of the interdental 
space {diastema) which separates the molar from the incisor teeth. 

Extremities. — The superior is the thickest, and represents a smooth rounded 
protuberance, into the interior of which the maxillary sinus is prolonged. Above 
and within this eminence is a wide and deep excavation, in the formation of 
which the palate bones participate. This is the maxillary hiatus, situated directly 
opposite the orbital hiatus. At the bottom of this cavity is seen the nasal 
foramen, as well as the upper orifice of the infra-orbital and the palatine 
canals. The nasal foramen belongs to the palate bone, and enters the nasal cavity. 
The infra-orhital cayial traverses the maxillary sinus in passing above the 
roots of the molar teeth, and terminates by two branches — one, short and 
wide, which opens on the external surface of the bone, on a level with the 
third molar ; the other, very narrow, continues the course of the canal in the 
substance of the bone, and is prolonged by several small, very fine branches 
into the premaxillary bone. The palatine canal, channeled between the super- 
maxillary and the palate bone, extends from the maxillary hiatus to the palatine 
fissure. 

The inferior extremity presents a cavity which forms the alveolus of the tusk, 
by uniting with a similar space in the premaxillary bone. 

Structure and develojyment. — This bone is developed from a single nucleus, and 
is the more spongy- — particularly towards the alveolar border and the superior 
extremity — as the animal is young. 

Differential Characters in the Superior Maxillary Bone of the other Animals. 

A. Ox, Sheep, Goat. — In the Ox, Sheep, and Goat, the maxillary spine does not directly 
join the zygomatic crest ; a curved line, with concavity posterior, effects the union between 
these two parts. The inferior oriiice of the infra-orbital foramen is pierced above the first 
molar tooth. There is no fissure for the formation of the palatine canal. Tlie cavity of the 
sinus is more spacious than in the Horse, and is prolonged (in the Ox only) between the two 
laminae of the palatine roof. There is no alveolus for the tusk. 

B. Camel. — Not so long or wide as in the Horse and Ox, the supermaxilla of the 
Camel is deeply excavated iibove the forehead and the orbit. The maxillary spine is replaced 
by a round and i?mooth prominence, which disappears at the inferior opening of the superior 
dental canal, pierced above the interval separating the second from the third molar. The 
posterior face of the palatine process is narrow, has no palatine fissure, but shows the orifice 
of the palatine canal. 

C. Pig. — In the Pig, the external surface of this bone is hollowed in its middle, and 
presents in front a voluminous relief formed by the alveolus of the canine tooth. The cavity 
is entirely formed in the supermaxilla. There is no alveolar tuberosity, and the interdental 
spaoe is very short, while the cavity for the sinus is little developed. The lower orifice of the 
palatine canal is even pierced in the substance of the supermaxilla. 

D. — Dog, Cat. — In Carnivora, this bone is very short; its anterior border offers a long 
process analogous to the nasal spiiie of Man. It alone furnishes the alveolus of the tusk. 
The palatine canal, pierced entirely in the bone of that name, nevertheless opens, by its 



TBE HEAD. 



65 



inferior extremity, at tlie junction of the supermaxilla with the palatine bone. The maxillary 
sinus is not very spacious, and there is no maxillary spine (Fig. 29). 

E. Rabbit. — The superior maxilla in this animal is less extensive, proportionately, than 
that of the other animals. The external table is thin, and even cribriform. The malar tubercle 
is narrow and directed outwards. The palatine process is very narrow, and therefore only 
very slightly concurs in the formation of the arch of the palate ; it does not extend to the 
summit of the internal process of the incisive bone (Fig. 36). 

Fig. 37. 




ox's HEAD (POSTERIOR FACE), 

A, Parietal bone: 1. occiintal foramen; 2, occipital condyle; 3, styloid process of that bone; 
4, condyloid foramina; 5, mastoid process; 6, mastoid protuberance; 7, subuliform (temporal) 
process; 8, hyoideal sheath ; 9, stylo-mastoid foramen ; 10, external auditory hiatus ; 11, inferior 
orifice of the" parieto-temporal canal; 12, temporal condyle; 13, posterior foramen lacerum ; 
14, oval foramen ; 17, subsphenoidal process ; 18, orbital hiatus ; 19, optic foramen. B, Frontal 
bone : 20, supra-orbital foramen ; 21, orbital foramen ; 22, lachrymal protuberance. C, Malar bone : 
23, pterygoid bone, d. Palatine bone : 24, nasal foramen ; 25, inferior orifice of the palatine 
canal. E, Supermaxillary bone : 26, maxillary spine. G, Premaxillary bone : 27, its internal 
process ; 28, external process ; 29, incisive openings. 

2. Premaxillaey, Inteemaxillary, or Incisive Bone (Figs. 26, 38). 

This bone occupies the inferior extremity of the head, and is composed of a 
thick prismatic jwrtion, lengthened superiorly by two long processes. 

Thick portion or base. — This presents a solid mass with three faces : an 
external or labial, smooth and convex : an internal, denticulated for union with the 
opposite bone, and traversed from before to behind by an inflexed fissure, which 
forms, with an analogous one in the other premaxilla, the incisive canal or fora- 
men incisivum ; the third or posterior, also called the buccal, is slightly concave, and 



66 



THE BONES. 



shows the continuation of the 
foramen. These three faces 

Fig. 38. 




POSTERIOR ASPECT OF HORSE'S 
SKULL. 

, Occipital tuberosity ; 2, fora- 
men magnum ; 3, 3, occipital 
condyles ; 4, 4, styloid pro- 
cesses ; 5, 5, petrous bone ; 6, 
basilar process ; 7, pterygoid 
fissure of the sphenoid bone ; 8, 
foramen lacerum ; 9, 9, supra- 
condyloid, or anterior mastoid 
process ; 10, 10, articular emi- 
nence, or temporal condyle ; 11, 
body of sphenoid bone ; 12, ptery- 
goid process ; 13, ethmoid bone ; 
14, temporal bone and sphenoidal 
sutuie; 15, lachrymal bone; 16, 
vomer; 17, malar bone; 18, 
maxillary tuberosity ; 19, pos- 
terior nares, or guttural opening 
of the nose ; 20, palatine bone ; 
21, palatine styloid process ; 22, 
palato-maxillary foramen; 23, 
palatine process of superior 
maxillary bone, with suture ; 24, 
ditto of premaxillary bone; 25, 
premaxillary bone ; 26, upper 
incisor teeth ; 27, point of junc- 
tion of the premaxillary with 
the supermaxillary bone ; 28, up- 
per molar teeth (young mouth). 



palatine groove, which terminates in the incisive 
are separated by as many borders : two internah 
hmitiug the corresponding face before and be- 
hind ; and an external, separating the labial from 
the buccal face. The latter only merits notice. 
It is very thick, and is divided into two parts : 
an inferior, which describes a curved line, con- 
cavity upwards, and is excavated by three alveoli 
for the reception of the incisor teeth ; another, the 
superior, is straight, vertical, and somewhat sharp, 
and forms part of the dental interspace. It is 
limited above, near the base of the external process, 
by a cavity for the formation of the alveolus of 
the canine tooth. 

Processes. — These are distinguished as external 
and intei'iial. The first, the longest and strongest, 
is flattened on both sides ; its external face is 
smooth, and continued with that of the thick por- 
tion of the bone ; its internal face is covered by 
the mucous membrane of the nose ; the anterior 
border is smooth and rounded ; the posterior, 
denticulated to respond to the supermaxillary bone, 
is in contact with the external border of the base ; 
its summit is thin, and is insinuated between the 
latter and the nasal bone. The internal {ox palatine) 
process, the smallest, is flattened from before to 
behind, and forms a very thin tongue of bone, sepa- 
rated from the other portions by a narrow and very 
deep notch, named the incisive opening or cleft. Its 
inferior face constitutes a small portion of the floor 
of the nasal fossae ; the posterior, continuous with 
the same face of the principal mass of the bone, 
forms part of the palatine roof ; its external border 
circumscribes, inwardly, the incisive opening ; the 
internal is united by dentated suture with the 
opposite bone. 

Structure and development. — It is a spongy 
bone, developed from a single nucleus. 

Differential Characters in the Premaxillary Bone 
OF OTHER Animals. 

A. Ox, Sheep, Goat (Fig. 37).— Tlie iuferior or prin- 
cipal portion of this bone is flattened befure and behind, 
and deprived of alveoli in its external border; neither is there 
any incdsive foramen. It is rarely consolidated with the 
adjacent bones, and is never, in the smaller Ruminants 
(Sheep and Goat), articulated with the nasal bone by the 
summit of the external process. 

B. Camel. — By its form, tlie premaxillary bone much 
resembles that of the smaller Ruminants. Its base is 
not so wide, but it is thicker than in the Ox. This base is 
rugged in its lower surface, and excavated by an alveolar 



THE HEAD. 



67 



cavity. The incisive opening is very small, and the external process does not reacli the 
nasal bone. 

C. Pig. — In the Pig, the external process of tlie premaxillary bone is very long and wide 
at its base, and consolidated with the nasal bone fur about the upper two-thirds of its length. 
There is no incisive foramen or cavity for the tusk. The incisive openings are oval. 

D. Dog, Cat. — Of small size, the premaxilla of Carnivora has no incisive foramen or 
alveolar cavity for the canine tooth. The incisive open- 
ings are the same as in the Pig. Fig. 39. 

E. Rabbit.— Proportionately voluminous, the pre- r ^ 
maxilla of the Rabbit is remarkable for the great de- '^ ^ 
velopnient of its ascending processes, which reach the _ ^ {^mWI^^S^^ f 
frontal bone, and the width of the incisive slits, which 
are conlounded above the internal processes. It carries 
two incisors, placed one before the other. 



3. Palatine Bones (Fig. 38). 

The folate or palatine hones are situated be- 
tween the supermaxillaries, at the margin of the 
guttural opening of the nasal cavities, and are 
articulated with the sphenoid, ethmoid, vomer, 
frontal, and pterygoid bones. Elongated from 
above to below, flattened laterally, and curved 
towards each other at their inferior extremity, 
which is flattened from before to behind, these 
bones, though irregular in shape, offer for study 
two faces, tivo herders, and two extremities. 

Faces. — The external face of the palate bone 
is divided into three fractions — a superior, or 
orbital, an inferior, or palatine, and a middle, or 
articular. The first is smooth and slightly ex- 
cavated, and participates in the formation of the 
maxillary hiatus ; it shows a small groove, the 
staphyloid, which reaches the palatine fraction 
in passing between the posterior border of the 
bone and the alveolar tuberosity. The second is 
not extensive, and looks backwards in conse- 
quence of the antero-posterior flattening which 
the bone presents at its inferior extremity ; it 
forms part of the roof of the palate. The third 
presents a lamellar and denticulated surface 
which corresponds to a similar face on the 
superm axillary bone, and is channeled from 
above to below by the internal groove of the 
palatine canal. 

The interned face, smooth and concave, forms 
part of the external wall and the floor of the 
nasal fossa. 

Borders. — The anterior is indented, near its superior third, by a deep notch, 
which is often converted into a foramen, the nasal. Below this notch the bone 
is thin and denticulated for union with the supermaxillary bone ; above, its two 
plates separate widely from one another, giving rise to a very spacious cavity 




HEAD OF THE PIG (POSTERIOR FACE). 

1, Occipital tuberosity ; 2, occipi- 
tal foramen; 3, occipital con- 
dyle; 4, condyloiil foramen; 5, 
basilar process ; 6, 6, mastoid crest; 
7, styloid process of the occipital 
bone ; 8, articular surface of the 
temporal bone ; 9, mastoid protu- 
berance ; 10. foramen lacerum ; 1 1, 
subsphenoidal process — external 
wing of pterygoid process ; 12, 
palatine crest ; 13, pterygoid bone 
(internal wing of the ])terygoid 
process) ; 14, inferior orifice of the 
palatine canal ; 15, 15, incisive 
openings. 



TEE BONES. 



which forms part of the sphenoid sinus. The posterior border presents, above, 
a rugged crest called the palatine, flattened from side to side, bent outwards, and 
bordered at its base and inwards by a very narrow synarthrodia! surface, which 
responds to the pterygoid bone. It is smooth and concave in its inferior half, 
and forms, with that of the opposite side, a parabohc arch (palatine arch) which 
circumscribes, below and at the side, the double guttural orifice of the nasal 
cavities. 

Extremities. — The superior, flattened on both sides, is bevelled on the external 
side to articulate with the subsphenoidal process. The 
inferior, flattened from before to behind, is curved 
inwards and united by simple suture with that of the 
opposite bone. 

Structure and deveJopment. — This is a very com- 
pact bone, developed from a single centre of ossifi- 
cation. 

Differential Characteks in the Palatine Bone in 
OTHER Animals. 

The principal distinctive feature of this bone in the different 
domestic animals is due to the part it takes in forming the 
arch of the palate. In this respect there are very great differ- 
ences in various species, but in none of them is tliis part so 
reduced as in Solipeds, in which the bone is scarcely equal to 
one-fifth of tlie palatine surface. 

A. Ox, Sheep, G-oat. — Tlie palatine bone in these animals 
is very developed, and noticeable for the considerable extent of 
the palatine portion of its external surface. The palatine canal 
is entirely channeled out in its substauce. The palatine crest, 
very thin and elevated, is formed altogether by the posterior 
border of the palate bone, the pterygoid, and the subsphenoidal 
process. There is no excavation for the sphenoidal sinuses ; 
but, instead, all that part of the bone which enters into the roof 
of the palate is hollowed, but in the Ox only, by irregular 
cavities which communicate with the maxillary sinus of the 
same side. The nasal foramen is very wide. 

B. Camel. — The staphyline fissure is wide and deep ; the 
palatine crest is very developed, and has two rugged depressions 
at its base. The palatine canal is not included in the palate 
bone ; it opens at the second molar. 

C. Pig. — The palatine portion is leas developed than in 
Ruminants, for it forms less tlian one-fourth of the palatine 
arch ; on the other hand, the orbital portion is very limited. 
The palatine crest is rt-placed by a tuberosity, against which 
rests, outwardly, the subsphenoidal process, and inwardly the 
pterygoid bone. The union of these three parts constitutes, on 
tlie posterior surface of the head, a thick and very remarkable 
trifid projection or mamelon. 

D. Dog, Cat.— It is in the Carnivora that the palatine bones 
are of greatest extent in their proper palatine portion, as they 
constitute nearly one-half of the palatine arch. They have no 
share in t)ie formation of the sphenoidal sinuses, but furnish a 
small excavation to the maxillary sinuses. 

E. Rabbit. — The palatine bones resemble those of the Horse, 
with regard to the part they play in forming the palatine arch. 
The palatine canal opens also between the palatine and superior 
maxillary bones, but the palatine crests are proportionately 

more developed than in Solipeds (Fig. 35). 




dog's head (posterior face). 

1, Occipital tuberosity ; 2, 
occipital foramen ; 3, occi- 
pital condyle ; 4, condyloid 
foramen ; 5, styloid process 
of the occipital ; 6, mastoid 
protuberance ; 7, concave 
temporo-maxillary articular 
surface ; 8, supra-condy- 
loid eminence ; 9, inferior 
orifice of the parieto-tem- 
poral canal ; 10, posterior 
foramen lacerum ; 11, 
ditto, anterior. On the op- 
posite side at a is shown 
the orifice communicating 
with the Eustachian tube 
and the tympanum ; at h 
the passage for the carotid 
loop. 12, Body of the 
sphenoid ; 13, oval fora- 
men ; 14, inferior orifice of 
the subsphenoidal canal ; 
15, pterygoid bone; 16, 
nasal surface of the palate 
bone; 17, palatine surface 
of the same; 18, vomer; 
19, supermaxillary bone ; 



20. 



incisive opening. 



THE HEAD. 69 

4. Pteeygoid Bone (Figs. 34, 38).* 

A small and very short bone, elongated from above to below, flattened on 
both sides, and situated on the inner aspect of the subsphenoidal process, but 
external to the vomer. 

Its external face is in contact with the palate and sphenoid bones ; the 
internal is smooth, and covered by the pharyngeal mucous membrane. Its 
superior extremity is tapering, and concurs in forming the Vidian canal ; the 
inferior is thickened into a small pointed process (the hamular process), the 
apex of which, directed backwards, offers outwardly a groove which serves as a 
pulley to the tendon of the tensor palati muscle. 

This bone is composed entirely of compact tissue, and is developed from a 
single centre of ossification. 

Differential Characters in the Pterygoid Bone of other Animals. 

A. Ox, Sheep, Goat. — The pterygoid of the Ox, Sheep, and Goat is very wide, and closes 
an aperture left between the s|ihenoid and palatine bones. 

B. Camel. — In the Camel the pterygoid is short, broad, and applied to the internal face 
of the subsphenoidal process and palatine crest. It does not concur in the formation of the 
Vidian canal. Its inferior extremity has a narrow and deep fissure. 

C. Pig. — (See the description of the palatine bone.) 

D. Camivora. — This bone is very strong in Carnivora, and quadrilateral in shape. 

5. Malar or Zygomatic Bone (Figs. 26, 34). 

This bone, also -designated the juf/al bone, is elongated from above 
to below, flattened on both sides, and irregularly triangular in shape ; it is 
situated on the side of the face, and articulates with the supermaxillary, 
lachrymal, and temporal bones. It is described as having tivo faces, two borders^ 
a base, and a summit. 

Faces. — The external face comprises two portions separated from each other 
by a semicircular ridge that extends from the summit to the middle of the 
anterior border of the bone, and concurs to form the outer margin of the orbit. 
The anterior portion, smooth and concave, belongs to the orbital cavity. The 
posterior, more extensive, is also smooth and slightly convex. The internal face 
is excavated in its central part, which corresponds to the maxillary sinus. On 
its margin it shows denticulations and lamellae for articulation with the super- 
maxillary bone. 

Borders. — The cmterior, thin and denticulated, is joined to the lachrymal 
bone. The posterior, or masseteric border, is thicker, and constitutes a roughened 
crest, the zygomatic ridge, which is continued above with the posterior border of 
the process of the same name, and below with the maxillary spine. 

Base and summit. — The base, very thin, is united to the supermaxillary bone. 
The summit, flattened from before to behind and bevelled on its anterior face, 
joins the zygomatic process, and forms with it the j'l/gal bridge, or zygomatic arch. 

SU-ucture and development. — This bone is rather spongy in its upper part, and 
is developed from a single nucleus of ossification. 

Differential Characters in the Malar Bone op other Animals. 
A. Ox, Sheep, Goat. — The malar bone of Kuminants is very developed. The zygomatic 
crest is no longer formed by the posterior border of the bone, but is carried to the posterior 
part of the external face, and runs parallel with the eyebrow. The summit is bifurcated, the 

' This bone is the representative of the internal wing of the pterygoid process in Man. 



70 THE BONES. 

anterior branch forming a buttress against tlie summit of tbe orbital process of the frontal 
bone, while the posterior articulates with the temporal. In these animals, the bone offers 
several centres of ossification. 

B. Camel. — This bone is very little developed, aud is compressed from before to behind^ 
Its anterior face is very concave, and circumscribes the orbit posteriorly. Its posterior face 
considerably overhangs the maxillary bone, and forms a very salient zygomatic crest. The 
summit is bifurcated, as in the Ox. 

C. Pig. — The summit of this bone in the Pig is flattened on each side, and divided inta 
two brandies, between which is wedged the summit of the zygomatic process ; the anterior 
branch is very sliort, and does not join the frontal bone. 

D. Camivora.— The malar of the Dog and Cat only articulates with the supermaxillary 
bone, and by its base alone. The crest describes a curve, the concavity backwards, and the 
summit comports itself as in the Pig. 

F. Rabbit. — The bone is flattened on both sides ; the summit, united with the zygomatic 
process of the temporal bune, is single ; while the base is confounded entirely with the malar 
tuberosity (Fig. 36). 

6. Lachrymal Bone (Figs. 26, 51). 

A small, thin, and very light bone, bent on itself at a right angle, it is 
situated beneath the orbit, which it aids in forming, and is wedged between the 
frontal, nasal, snpermaxillary, and malar bones. It is studied on its external 
and internal faces and circumference. 

Faces. — The external is divided into two regions, superior and inferior, by 
a curved crest which forms part of the orbital margin, and is provided with 
notches, which are variable in their form and number. The superior region, 
named the orbital, because of its situation in the orbit, is slightly concave and 
smooth. It presents, near the orbital margin, the orifice of the laclirynud diict, 
which traverses the maxillary sinus and opens on the internal face of the super- 
maxillary bone, where it is continued by a fissure ; behind this is the lachrymal 
fossa. The inferior ov facial region is slightly bulging, and provided sometimes 
with a tubercle for insertion, — the lackrymal tubercle. The internal face is 
employed, for the whole of its extent, in the formation of the walls of the 
maxillary and frontal sinuses ; it exhibits a cylindrical prominence produced by 
the bony tube of the lachrymal duct. 

Circumference. — This is very irregular, and denticulated for articulation with 
the neighbouring bones. 

Structure and development. — This bone is entirely compact, and is developed 
from a single nucleus of ossification. 

In the Ass, the lachrymal tubercle is placed towards the anterior border of 
the bone ; usually, it partly belongs to the nasal bone, and is consequently found 
on the suture uniting the lachrymal bone to the proper bones of the nose. 

Differential Chakactebs in the Lachrymal Bone of other Animals. 

A. Ox, Sheep, Goat.— The lachrymal bone, much more extensive than that of tlie 
Horse, forms in tlie bottom of the orbit an enormous protuberance, hollowed internally by the 
maxillary sinus, and the walls of whicii are so thin and fragile that the slightest jar is sufficient 
to cause their fracture (in the skeleton). It would be convenient to designate it the lachrymal 
protuberance.^ In the smaller Kuminants, the inferior region of the internal face shows a 
depression — the lachrymal fossa. 

B. Camel.— This bone is much smaller than in the Horse ; its facial portion especially Is 
almost rndimi ntary. There is no lachrymal protuberance nor tubercle, the latter being carried 
to the superior maxilla. 

C. Pig.— In the Pig there are observed a lachrymal fossa and two lachrymal canals, which 

' Girard, who named this eminence the orbital protuberance, wrongly described it as; 
belonging to the supermaxillary bone. 



THE HEAD. 71 

are pierced outside the orbital cavity, and soon coalesce in the substance of the bone to 
constitute a single canal. The fossa is very deep. 

D. Camivora. — This bone in Carnivora is extremely small. Its external face entirely 
belongs to the orbit, and does not descend beneath the margin of tliat cavity; it has no 
lachrymal fossa. The reduced dimensions it presents in these animals well justifies the name, 
OS unguis, given to it in anthropotomy. 

7. Nasal Bones (Fig. 26). 

Situated on the anterior aspect of the head, these bones articulate with each 
other in the median hne, and are fixed between the frontal, lachrymal, and super- 
maxillary bones ; they are triangular in shape, elongated from above to below, 
flattened from before to behind, and offer for study two faces, two borders, a base, 
and a summit. 

Faces. — The external or anterior face, wider above than below, is convex from 
side to side, and almost smooth. The posterior, internal, or nasal face exhibits a 
vertical crest passing along the external border of the bone, which gives attach- 
ment to the turbinated portion of the ethmoid ; at its superior extremity this 
crest bifurcates, and between its two branches shows a concave surface which 
forms part of the frontal sinus. For the remainder of its extent the internal 
face is smooth, and' covered by the mucous membrane of the nasal fossa ; it 
is also excavated into a channel to form the superior meatus of this cavity. 

Borders. — The extermd border is very thin in its upper two-thirds, and articu- 
lates with the lachrymal bone, the anterior border of the supermaxillary, and the 
extremity of the external process of the premaxilla. In its lower third it becomes 
isolated from the latter bone, in forming with the anterior border of its large pro- 
cess a very acute re-entering angle, the opening of which looks downwards. The 
interned border is denticulated for contact with the opposite bone. 

Base and Summit. — The base occupies the superior extremity of the bone ; 
it describes a curved line with the convexity above, and, in uniting on the median 
line with that of the opposite bone, forms a notch similar to that of the heart 
figured on playing-cards ; it is bevelled, at the expense of the internal plate, to 
articulate with the frontal bone. The summit of the two nasal bones, which is 
pointed, constitutes the nasal prolongation — the name given to a single triangular 
process which comprises all that portion of the nasal bones separated from the 
premaxillaries by the re-entering angle before mentioned. 

Structure and development. — Almost entirely compact in structure, it is 
developed from a single centre. 

Differential Characters in the Nasal Bones of other Animals. 

A. Ox, Sheep, Goat. — The nasal bones of the Ox are never consolidated with each other, 
nor yet with the neighbouring bones. The external border only comes in contact to a small 
extent with the supermaxillary bone ; the superior extremity is fixed in the notch of the inferior 
border of the frontal bone. At their inferior extremity, they each present a notch which divides 
them into two points. 

In the Sheep and Goat the nasal spine is unifid, as in the Horse (see Figs. 30, 32). 

B. Camel. — In the Camel, the proper bones of the nose are short and narrow; their 
external border is in contact only with the superior maxilla; the upper extremity is rounded. 
At the inferior extremity, they show a well-marked notch, which divides them into two points, 
but the inner point is very small. 

C. Pig. — Tliese bnnes are long and narrow, and traversed on their external face by the 
fissure that descends from the supra-orbital foramen. The nasal prolongation is short. 

D Carnivora.— The two bones of the nose are little developed, and are wider below than 
above ; they have no nasal prolongation, but offer, instead, a semicircular notch. 



THE BONES. 



E Rabbit.— Proportionately long and wide, the nasal bone of the Rabbit articulates, by 
the whole of its external border, with the ascending process of the preuiaxillary bone. The 
anterior extremity of the nasal bone is very slightly salient. 



Fig. 41. 



Fig. 42. 




LONGITUDINAL AND TRANSVERSE SECTION OP 
THE horse's head, SHOWING THE FLOOR OF 
THE CRANIAL AND NASAL CAVITIES, WITH 
THE MAXILLARY SINUSES. 

1, Condvloid foramen. 2, Section of the parieto 
tem[ioval canal. 3, Foramen lacerum basis 
cranii. 4, Carotid notch. 4', Maxillary 
notch: o,supermaxillary fissure ; 6, cavern- 
ous fissure. 5, Origin of the supra-sphe- 
noidal canals : c, sella Turcica. 6, Optic 
fossa. 7, Portion of the crista-galli process. 

8, Cribriform plate of the ethmoid bone. 

9, Perpendicular plate of the s^ame bone. 

10, 10, Its lateral masses. 11, Interior of 
the great ethmoidal cell. 12, 12, Bottom of 
the maxillary sinuses communicating with 
the sphenoidal sinuses. 13, Superior 
maxillary sinus. 14, Inferior maxillary sinus. 
14', Superior compartment of the maxillary 
turbinated bone, forming part of the latter 
sinus. 15, Section of ttie supermaxillo- 
dental cannl. 16, Channel of the vomer. 
17, Internal proc.'ss, or point of the pre- 
maxillary bone. 




ANTERO-POSTERIOR AND VERTICAL 
SECTION OF THE HORSE'S HEAD. 

1, Condyloid foramen ; 2, parietal 
protuberance ; 3, internal audi- 
tory hiatus ; 4, cerebral cavity ; 
5, cerebellar cavity; 6, supe- 
rior border of the perpendicular 
plate of theethmoidbone(crista- 
galli process) ; 7, ethmoidal 
volutes — nasal face; 8, vestiges 
of the right frontal sinus; 9, 
ditto of the sphenoidal sinus ; 
10, pterygoid process; 11, eth- 
moidal turbinated bone; 12, 
maxillary turbinated bone ; 13, 
crest of the supermaxillary 
bone to which the latter is 
fixed ; 14, vomer. A, Orifice of 
communication between the 
nasal cavity and the sinus. 



THE BEAD. 73 



TUEBINATED BONES (Fig. 42). 



The turlinated (or turUnal) hones, two on each side, represent two irregular 
bony columns, wider above than below, compressed laterally, hollowed internally, 
and lying vertically side by side on the external wall of the nasal fossa, which 
they divide into three meatuses or passages. 

They are distinguished into anterior and posterior turbinated hones. 

The anterior or superior, also named the ethmoidal, is formed by a very thin 
plate of compact tissue— fragile and like papyrus, fixed by its anterior border to 
the internal crest of the nasal bone, and rolled on itself, from before to behind, 
in the same manner as the cells of the ethmoid bone. Above, it is confounded 
with the last-named bone, of which it is only, properly speaking, the most anterior 
volute. At its inferior extremity, it is prolonged by a fibro-cartilaginous frame- 
work to the external orifice of the nose. 

Its internal cavity is partitioned by a transverse plate into two portions : the 
superior compartment forms part of the frontal sinus ; the inferior is subdivided 
by other small lamellEe into a variable number of cells which communicate with 
the nasal cavity. This bone, developed from a single nucleus, is ossified at the 
same time, and in the same manner, as the ethmoidal cells. Before birth, it is 
already intimately consolidated with the nasal bone. 

The posterior, inferior, or maxiUary turbinated hone resembles the first, except 
in some particulars. Thus, its bony or proper portion is not so long or volu- 
minous, while its cartilaginous part is, on the contrary, more developed. It is 
attached, by its posterior border, to the vertical and sinuous crest of the super- 
maxillary bone, and is rolled from behind to before, or in an inverse direction to 
the other. It has no connection with the ethmoid, and its superior cavity forms 
part of the inferior maxillary sinus. It is late in becoming ossified, and is 
scarcely united in a definite manner to the maxillary bone until the horse is 
about a year old. 

The meatuses are distinguished into anterior or superior, middle, and posterior 
or inferior. The first passes along the front of the ethmoidal turbinated bone ; 
the second separates the two turbinated bones, and presents, near its superior 
extremity, the opening communicating between the sinuses and the nasal cavities.^ 
The third is situated behind the maxillary turbinated bone, and is confounded 
with the floor of the nasal fossa. 

The turbinated bones are essentially disposed to furnish the membrane of the 
nose with a vast surface of development. This membrane, indeed, covers their 
entire superficies, and even penetrates the anfractuous cells of their lower 
compartment. 

Differential Characters in the Turbinated Bones of other Animals. 

A. Ox, Sheep, Goat. — In the Ox (Fig. 43), the ethmoitlal turbinated bone is very small, 
and is united to the nasal bone bv the two borders of its osseous plate ; its internal cavity entirely 
belongs to the frontal sinus. The maxillary turbinated bone is very developed, and is joined 
to the bone which sustains it at a later period than in the Horse. The bony lamina of which 
it is composed, is curved on itself in two different directions — from before to behind by its 
posterior border, and behind to before by its anterior border. It is fixed to the supermaxillary 
bone by its middle part, through the medium of a particular bony lamina, and it very incom- 

' The two turbinated bones, in being applied against the excavation on the inner face of the 
supermaxillary, almost entirely close it, only leaving between them a vertical slit which con- 
stitutes the opening mentioned above. 



74 



THE BONES. 



pletely closes the excavatioh which coucurs to form the maxillary sinus. In the skeleton there 
is also found behind, and at the base of this turbinated bone, a vast opening which is totally 

closed in the fresh condition by the pituitary membrane. 
The maxillary sinus is not prolonged in its interior. 
In the smaller Euminants, tlie cavity of the sinus is 
closed by the maxillary turbinated bone in a more 
complete manner than in the Ox. 

B. Camel. — The ethmoidal turbinated bone is 
very small. Otherwise it is as in the other Ruminants. 

C. Pig. — The same arrangement as in tlie Sheep 
and Goat, except that the bones are mucli longer and 
less fragile. 

D. Carnivora.— These bones in tlie Dog and Cat 
are particularly distinguished for their numerous cou- 
volutions. Neither participate in the formation of 
the frontal or maxillary sinuses; the latter is not in 
any way closed by the maxillary turbinated bone, but 
opens into the nasal cavity by a large gaping aperture. 

E. Rabbit. — The bones are arranged as in the 
Dog, but the folds are less numerous. 



9. VoMEE (Figs. 34, 38). 

This, a single bone, elongated from above 
to below, flattened on both sides, and extending 
on the median line from the body of the 
sphenoid to the premaxillary bone, offers for 
study two lateral faces, two borders, and two 
extremities. 

The faces are smooth, plane, and covered 
by the nasal membrane. The anterior border 
is channeled for the whole of its length by a 
deep groove, which receives the posterior border 
of the cartilaginous septum of the nose. The 
posterior border is sharp and smooth in its 
upper half, which separates the two guttural 
openings of the nasal cavities : it is thick and 
slightly denticulated for the remainder of its 
extent, and rests on the median suture resulting 
from the union of the two supermaxillary 
bones. The superior extremity is provided, in 
its middle, with a notch which divides it into 
two lateral prolongations shaped like a cat's 
ears {wings of the vomer) ; it articulates with 
the inferior sphenoid, ethmoid, palatine, and 
pterygoid bones. The inferior extremity rests 
on the prolongations of the premaxillae. 

This bone is entirely compact, and is 
developed from one centre of ossification. 




MEDIAN AND VERTICAL SECTION OF 
THE ox's HEAD. 

X, Condyloid foramen; 1', posterior ori- 
fice of the occipital lateral canal 
joining the parieto-temporal canal 
in front ; 2, internal auditory hiatus ; 
3, anterior foramen lacerum ; 4, pos- 
terior ditto ; 5, iutra-cranial orifice 
of the parieto-temporal canal ; 6, 6, 
median bony plate separating the 
frontal sinuses ; 7, lamina which iso- 
lates the sphenoidal sinus; 8, lamina 
partitioning the palatine portion of 
the maxilliary sinuses ; 9, oval fora- 
men ; 10, optic fossa; 11, vomer; 
12, pterygoid bone ; 1.3, large open- 
ing leading into the maxillary sinus, 
and which, in the fresh state, is closed 
by the pituitary membrane ; 14, max- 
illary turbinated bone; 15, ethmoidal 
turbinated bone; 16, great ethmoidal 
cell. 



Differential Characteks in the Vomer of 

OTHER Animals. 
A. Ox, Sheep, Goat. — This is a very wide and 
thin bone, resting only on the lower half of the median 
suture of the premaxillaries (Fig. 43). 
B. Camel.— Wider in its upper part than in the Ox, the vomer reaches, outwardly, the 



THE HEAD. 75 

orbital cavity. By its inferior border, it rests on the entire length of the median suture of the 
palatine and superraaxillary bones. 

C. Pig. — The vomer in this animal adheres to the bones of the palatine arch for a great 
extent. The free portion of the inferior border is short and but little prominent. 

D. Camivora.— In the Dog and Cat, the vomer is short, but its wings are very large. 

10. Inferior Maxillary Bone (Fig. 44). 

The inferior maxillary hone is not consolidated with any of the preceding bones, 
and is only united to two of them — the temporals — by diarthrodial articulation. 
It is a considerable bone, situated behind the upper jaw, and composed of two 
symmetrical branches, which are flattened on both sides, wider above than below, 
curved forwards in their upper third, joined at their lower extremities, and 
separated superiorly so as to leave a wide gap between them, like the letter V in 
shape, called the intra-maxillary space. Each offers for study tivo faces, two 
borders, and two extremities. 

Faces. — The external face of the maxillary branches is smooth and rounded in 
its inferior two-thirds, and transformed superiorly into a rugged surface, in which 
is implanted the fibres of the masseter muscle. The internal face presents, in the 
corresponding point, an excavated surface on which is remarked the superior 
orifice of the maxillo-dental caned, a long channel which descends between the 
two plates of the branch, passing under the roots of the molar teeth, and insensibly 
disappearing in the body of the bone after being widely opened externally by the 
mental {ov anterior maxillary) foramen. In its inferior two-thirds, the internal 
face is smooth, nearly plane, and shows nothing very remarkable. Near the 
alveolar border there is a slightly projecting line — the myloid ridge ; and quite 
below, or rather at the very summit of the re-entering angle formed by the 
separation of the branches, there is a slight rugged excavation confounded with 
that of the opposite branch, and named the ye)iicd surface. 

Borders. — The anterior, also named the alveolar border, exhibits for study a 
straight or inferior, and a curved or superior portion. The first is hollowed by 
six alveoU to receive the inferior molar teeth. 

The second, thinner, concave, and rugged, serves for muscular insertion. 
The posterior border is also divided into straight and curved portions. The latter 
is convex, thick, rugged, and margined on each side by an uneven lip ; the first 
is regularly rectilinear, so that all its points rest at the same time on a horizontal 
plane ; it is thick and rounded in the young animal, but becomes sharp with 
age ; an oblique and transverse fissure — the maxillary — separates it from the 
curved part. The union of these two portions forms the angle of the jaw. 

Extremities. — The superior e.vtremity has two eminences : a condyle, and a 
long non-articular process named the coronoid process. The condyle is elongated 
transversely, and convex in its two diameters ; it responds, through the medium 
of a fibro-cartilaginous disc, to the articular surface of the zygomatic process. 
■ The coronoid process is situated in front of the condyle, from which it is sepa- 
rated by a division called the sigmoid or corono-condyloid notch ; it is flattened on 
both sides, and curved backwards and slightly inwards. 

From the union of the branches of the maxillary bone at their inferior 
extremity, results a single piece, flattened before and behind, and widened like a 
spatula, which has been designated the body of the bone. This merits a special 
description. 

Its form allows us to divide it into an anterior or buccal face, a posterior or 



76 



THE BONES. 



labial face, and a circumference. The anterior face is smooth and concave, is lined 
by the buccal mucous membrane, and supports the free extremity of the tongue. 
The posterior face is convex, more extensive than the preceding, and continuous 
with the external face of the branches. It presents : 1. On the median line, a 
slight crest or small groove— traces of its being originally separated into two 
pieces. 2. On the sides and above, the mental foramen — the inferior orifice of the 
maxillo-dental canal. On a level with this foramen, the bone very markedly 
contracts to form the neck. The circumference describes a parabolic curve, the 
concavity being uppermost, and joins, by its extremities, the anterior border 
of each branch. It is excavated in its middle part by the six alveoli for the 
lodgment of the inferior incisors, and behind these— in male animals only— there 
is an additional alveolus for the tusk. The portion included on each side 



Fig. 44. 




INFERIOR MAXILLA. 

1, Mental foramen; 1', superior orifice of the maxillo-dental canal ; 2, surface of implantation for 
the masseter muscle ; 3, myloid ridge ; 4, coronoid process ; 5, condyle. 

between the last incisor and first molar, forms a more or less sharp ridge, which 
constitutes the inferior interdental space or bar {diastema). 

Structure and development. — Formed, like all the flat bones, by two compact 
plates separated by spongy tissue, the inferior maxilla is developed from two 
centres of ossification, which correspond to each branch, and which coalesce some 
time after birth. 

But in the human foetus, there can oe seen five pieces developed around the 
dental canal — the coronary, articular, angular, opercular, and premaxillary — 
which proves that the maxilla of Mammalia is formed on the same type as that 
of oviparous Vertebrata (Lavocat). 



DiFFEKENTIAL CHARACTERS IN THE INFERIOR MaXILLA OP OTHER ANIMALS. 

A. Ox, Sheep, Goat.— In these animals, the part of the posterior border of the inferior 
maxilla below the molars is convex, and cannot rest on a horizontal plane by all its points at 
the same time. The condyle is convex in its small diameter, and slightly concave laterally The 
coronoid process is bent backwards and outwards. The body does not show any alveolus for 
the tusk, because this tooth is not present in these animals ; but it is hollowed by eight alveoli 
for the incisor teeth. The two branches of the bone are never consolidated, but remain 
movable on each other during life. 



THE HEAD. 



77 



B. Camel. — The branches are short and thick, the body very long, and the interdental 
space considerable. The straight border of tlie branches has a posterior rectilinear border, aa 
in the Horse ; the anterior margin of the curved portion is tliin and sharp. Oa its internal 
face is seen a plate in front of the superior opening of the inferior dental foramen, and a mylo- 
hyoid fissure. 

The condyle is convex in front, flat and oblique behind. The coronoid process is very 
strong. Below the condyle is a process separated from the latter by a deep notch. 

The circumference of the body is excavated by eight alveoli — six for the incisors, and two 
for the canines. 

C. Pig. — A straight line leading from the greater axis of the alveoli of the molar would 

Fig. 45. 




HEAD OF THE CAMEL. 

1, Occipital bone ; 2', parietal crest ; 3, .squamous temporal ; 4, frontal bone ; 4', supra-orbital 
foramen; 5, malar bone; 6, nasal bones; 7, supermaxillary bone; 7', infra-orbital foramen; 
8, premaxillary bone; 9, inferior maxilla; 10, 11, openings of the inferior dental foramen. 



not traverse the posterior border of the maxillary branches , the bottom of these alveoli corre- 
sponds to the relief on the iimer face. The condyle is compressed on both sides, and elongated 
from before to behind; while the coronoid process is short and wide. TIjere is no neck; the 
interdental spaces are very short ; and the maxillo-dental canal opens inferiorly by multiple 
orifices. 

D. Carnivora.— In Carnivore, this is hollowed at the point corresponding to the insertion 
of the masseter muscle into a somewhat deep fossa. The posterior border is disposed as in 
Ruminants, and below the condyle lias a very marked tuberosity. The condyle represents an 
ovoid segment, and fits exactly into the temporal cavity. The coronoid process is very strong, 
elevated, and wide. The mental foramina are double or treble. There are no interdental 
spaces, nor excavated surface on the inner face of tlie branches ; and the latter are never 
consolidated. 

E. Rabbit. — In the maxilla of the Rabbit, the coronoid process is very short, and the 
condyle narrow and elongated from before to behind. The posterior border is deeply notched 

8 



78 



THE BONES. 




HEAD OF THE CAT. 

Parieto-occipital suture; 2, parietal bone; 
3, frontal bone ; 4, orbital piocess of the 
frontal bone; 5, malar bone; 6, supermaxil- 
lary bone ; 7, 7, premaxilla ; 8, nasal bone ; 
9, tympanic bulb ; 10, inferior maxilla. 



in its curved portion ; the interdental space is very long ; and the body has only two alveoli 
for the incisors. 

11.— The Hyoid Bone (Fig. 47). 

The hi/oid bone constitutes a small and special bony apparatus which serves 

to support the tongue, as well as the 
Fig- -iS. larynx and pharynx ; its description is 

placed immediately after that of the 
bones of the head because of its con- 
nection with that region, it being situ- 
ated between the two branches of the 
supermaxillarybone, and suspended from 
the base of the cranium in an oblique 
direction from above to below, and from 
before to behind. 

This apparatus is composed of seven 
distinct pieces, arranged in three series : 
a middle, constituted by a single bone, 
and named the body ; two lateral, form- 
ing two quasi-parallel branches, to the 
extremities of which the body is articu- 
lated. 

Body or basihijal. — The body of the 
hyoid resembles a fork with two prongs. It presents : 1. A middle part flattened 
above and below, and consequently provided with a superior and an inferior face. 

2. A single and long pro- 
p's- '*^' longation flattened on 
both sides, which is de- 
tached from the middle 
part, and directed forward 
and downward to plunge 
into the muscular tissue 
of the tongue : this is the 
anterior appendix of the 
hijoideaJ body, or Ungual 
prolongation. 3. Two late- 
ral cornua, thyroid cornua, 
great cornua, or urohyals, 
projecting backwards and 
upwards, articulating by 
their extremities with the 
thyroid cartilage of the 
larynx, and offering, at 
their point of union with 
the middle part, two con- 
vex diarthrodial facets 
looking upwards, and 
corresponding with the styloid cormia. The body of the hyoid bone is developed 
by three centres of ossification — a middle, and two lateral for the cornua. 

Branches. — The three pieces composing these are articulated end to end, by 




HYOID BONE OF THE HORSE. 

Body or ba^ihyal ; 2, lingual prolongation ; 3. 3, thyi'oid 
cornua, great cornua, or urohyals ; 4, 4, styloid cornua. 
small cornua. or apohyals ; 5, 5, styloid nuclei or ceratohyals ; 
6, 6, styloids, great hyoideal branches, or stylohyais ; 7, 7, 
arthrohyals. or cartilaginous nuclei attaching the hyoid to 
the temporal bone. 



THE HEAD. 79 

means of a cartilaginous substance that joins them together ; they are of very 
unequal dimensions. The first, which is in relation with the body, is of medium 
size, and is named the styloid cormi, small conm, or small branch. The second, 
termed the styloid nucleus, is the smallest. The third, the largest, constitutes 
the styloid process or bo7ie, or great branch. 

1. The styloid cornua {cfpohyaV) is a small cylindrical piece bearing a concave 
diarthrodial surface on its inferior extremity to unite it to the body ; it is very 
spongy, and is developed from two ossifying centres, one of which, the epiphysary, 
is for the inferior extremity. 

2. The styloid nucleus {ceratohyal), which is often absent, is embedded in the 
uniting cartilaginous substance. 

3. The styloid bone, or great hyoideal branch {stylohyal), is long, thin, flattened 
on both sides, and directed obliquely from above to below, and before to behind ; 
it presents two faces, two borders, and two extremities. The faces — an external 
and internal — are marked by some few imprints. The anterior border is sharp 
and slightly concave in its upper third. The posterior border is thicker, and is 
divided into two portions — a superior or horizontal, which is very short, and an 
inferior or vertical, much more extensive. The angle they form at their point 
of junction presents a salient, and more or less roughened, tuberosity. The 
superior extremity is united to the hyoideal prolongation of the temporal bone 
by means of a cylindrical fibro-cartilage. By its inferior extremity, the styloid 
bone is united either to the styloid nucleus or the styloid cornu, forming a sharp 
elbow directed forwards. The styloid bone, developed from a single centre of 
ossification, is almost entirely formed of compact tissue. 

Differential Characters of the Htoid Bone in other Animals. 

A. Ox, Sheep, Goat. — The hyoid bone of Ruminants is always composed of seven piecea. 
the styloid nucleus, the presence of which is not constant in Solipeds, is never absent in these,' 
and has the proportions of the second small branch. The anterior appendix is very short, and 
only represents a large mamelon. 

B. Camel. — The liyoid is in this animal as in the Ox. 

C. Pig.— The body is voluminous and deprived of an appendix; the small branches are 
short and consolidated with the body ; while the large branches, curved like an S, are very 
thin, and are not united to the small branches and the temporal bone by libro-cartilage, but by 
veritable yellow elastic ligaments. 

D. Carnivora. — The three pieces composing the body of the hyoid in early life are never 
consolidated in the adult animal, but always remain isolated, as in Man. The middle piece 
has no anterior appendix; the fibro-cartilages uniting the styloid portions to each other and to 
the temporal bone are very long and flexible. 

12. WoEMiAN Bones (Fig. 48). 

This name has been given to small irregular bones which Worms observed 
between some of the sutures of the cranial bones. They are developed after 
birth, in the cranial, cranio-facial, and facial sutures. Their number and position 
varies with the species of animals, and even the breeds of the same species. 

Vaguely described by Rigot, they have been recently studied by Cornevin, 
who observes that the cranial Wormian bones are rare. In more than sixty 
crania, they were found only once or twice in the Ox and Horse at the junction 
of the petrous with the occipital bone. The Wormian bones of the cranio-facial 
and the facial suture are more frequent ; nevertheless, they have been met with 
almost exclusively in the heads of common-bred animals, particularly in the 
bovine species. Cornevin has described a fontanelle lachrymo-nasal bone (Fig. 



80 THE BONES. 

48, 2), and Wormian fronto-nasal (Fig. 48, 1), as well as an interaasal, orbital, 
zygomato-maxillary, maxillo-nasal-incisive bone. (Sometimes two Wormian 
bones are found in the same head.) 

OP THE HEAD IN GENERAL. 



1. Geneeal Configueation. 

From the union of all the bones which constitute the cranium and faoe, 
there results a quadrangular pyramid, with summit inverted, which it is necessary 

to study as a whole. We will pass in 
^'S- *^" review, successively, its four faces, its 

base, and its summit. 

A. Anterior Face.— This is 
subdivided into four regions (Fig. 
49) : 

1. Parietal region. — This has for 
base the anterior portion of the 
occipital bone and the parietal bones. 
Limited, above, by the external occi- 
pital tuberosity, it presents on the 
middle line a spur which soon bifur- 
cates to form the parietal or temporal 
crests ; the latter join the posterior 
border of the zygomatic process. i 

2. Frontal region. — Larger than^ 
the preceding, it is usually plane and 
lozenge-shaped. Boimded iuferiorly 
by the fronto-nasal suture, this region 
projects, laterally, the orbital pro- 
cesses, the base of which is pierced 
by the supra-orbital foramen, and the 
anterior border — somewhat sharp— 
is frequently made irregular by small 

notches, one of which is often converted into a foramen. 

3. Nasal region. — This region has for its base the proper bones of the nose. 
It is narrow, convex on each side, and plane, concave, or convex in its length, 
according to the animals. It advances above the entrance to the nasal cavities, 
where it forms the nasal prolofigation, the summit of which, in the Horse, ceases 
at nearly two fingers' breadth from the intermaxillary symphysis. 

4. Incisive region. — Principally formed by the incisive bones, this region 
presents : the inferior opening of the nasal cavities, divided in the fresh state by 
the median cartilaginous septum of the nose ; the incisive slits on the floor of 
the nasal fossfe ; the intermaxillary symphysis, channeled above by a more or 
less deep groove in nearly all Horses, but raised, on the contrary, into a conical 
tubercle in the Ass and Hinny, and perforated in the middle by the incisive canal. 
Right and left of the intermaxillary symphysis this region is convex, and elevated 
by the prominence which the roots of the incisor teeth form. 

B. Posterior Pace. — In this are recognized four distinct regions (Fig. 50) : 
1. Sub-occipital region. — This presents : in the middle, the basilar process^ 




WORMIAN BONES OF THE OX. (AFTER CORNEVIN.) 

1, Fronto-nasal Wormian bones; 2, 2, lachrymo- 
nasal fontanellar bones. 



THE HEAD. 



81 



a strong piece more or less deeply channeled, according to the animals, and 
provided at its inferior extremity with rugosities for the attachment of the anterior 
straight muscles of the head ; on the sides, the lacerated foramina — large irregular 



Fig. 49. 




horse's head (anterior face). 
1, Occipital tuberosity ; 2, origin 
of the mastoid crest ; 3, parietal 
bone; 4, saggital suture ; 5, junc- 
tion of the parietal and temporal 
bones ; 6, zygomatic arch ; 7, 
frontal bone ; 8, frontal suture ; 
9, temporal fossa ; 10, supra-orbital 
foramen ; 11, 12, lachrymal bone ; 
13, malar bone ; 14, nasal border of 
frontal bone ; 15, nasal bone ; 16, 
suture of nasal bones; 17, super- 
maxillary bone ; 18, infra-orbital 
foramen; 19, anterior, or pre- 
maxillary bone ; 20, foramen in- 
cisivum ; 21, incisor teeth (young 
mouth). 




horse's head (posterior face). 
, Occipital tuberosity ; 2, foramen magnum ; 3, 
3, occipital condyles; 4, 4, styloid processes; 
5, 5, petrous bone ; 6, basilar process ; 7, ptery- 
goid fissure of the sphenoid bone ; 8, foramen 
lacerum ; 9, 9, supra-condyloid, or anterior mas- 
toid process; 10, lo, articular eminence, or 
temporal condyle; 11, body of sphenoid bone; 
12, pterygoid process; 13, ethmoid bone; 14, 
temporal bone and sphenoidal suture; 15, 
lachrymal bone; 16, vomer; 17, malar Ijone ; 
18, maxillary tuberosity; 19, posterior, or 
guttural opening of the nose ; 20, palate bone ; 
21, palatine styloid process; 22, palato-maxil- 
lary foramen ; 23, palatine process of superior 
maxillary bone, with suture ; 24, ditto of pre- 
maxillary bone; 25, premaxillary bone; 26, 
upper incisor teeth ; 27, point of junction of 
the premaxillary with the superior maxillary 
bone ; 28, upper molar teeth (young mouth). 



openings divided, in the fresh state, into two portions {anterior and posterior 
lacerated foramina). To the outside of these openings is the base of the tuberous 
portion of the temporal bones, especially the tympanic bulb ov petrous bone ; above 



82 THE BONES. 

are the condyloid fossae, with their condyloid foramen., and the styloid processes of 
the occipital hone or Jugular eminences. 

2. Suhsphenoidal region. — This region is notably constricted in its middle 
part, where it has for base the body of the posterior sphenoid bone ; it is enlarged 
above by the temporal articular surfaces. It is limited by the inferior border 
of the foramen lacerum, on which are three notches transformed into foramina 
by the tissue that partitions the foramen lacerum basis cranii in the fresh 
state. These openings are, passing from within to without, the carotid or cavernous 
foramen, the foramen ovcde or foramen rotundum ; they are all preceded by a 
groove on the surface of the bone. On each side of the body of the sphenoid is 
the narrow Vidian fissure, prolonged by the Vidian canal, and margined outwardly 
by the origin of the suhsphenoidcd process. Laterally, is the suhsphenoidal canal 
for the passage of the internal maxillary artery, which is continued forward 
by two branches, one of which opens into the orbital hiatus, the other into the 
temporal fossa. 

3. Spheno-pcdatine region. — This extends from the superior sphenoid to the 
palatine arch. In the median plane it shows a vast elliptical opening — the 
gutturcd opening of the nascd cavities, divided at the bottom into two portions by 
the vomer, and bordered laterally by two elevated crests (pterygo-pcdatines) 
resulting from the junction of the pterygoids with the palatine crests ; and 
limited in front by the posterior border of the palatine bones, which is raised in 
its middle by a blunt point directed backwards — the nasal spine. Beyond the 
pterygo-palatine orests is a slightly depressed surface, on which run the branches 
of the internal maxillary artery and the superior maxillary nerve. This surface 
extends, above, to the orhital or sphenoidctl hiatus, below to the maxillary hiatus. 
In the maxillary hiatus are : the upper opening of the superior dental canal, the 
palatine caned, and the nasal foramen. In passing from the maxillary hiatus on 
the margin of the guttural opening of the nasal cavities, we meet with the 
staphyline fissure, which is limited above by the alveolar tuberosity. 

4. Pcdatine region. — .This is a wide elongated surface, limited laterally by the 
molar teeth and interdental spaces, and in front by the incisors. It shows : in 
the middle, the pcdcdine and superior maxillary suture, which terminates at the 
incisive canal ; on the sides and above, the inferior opening of the pcdatine grooves^ 
prolonged by the pcdatine fissures ; in front, the incisive slits. 

C. Lateral Face. — This is a pair face, and comprises three regions (Fig. 51) : 

1. Maxillary region. — This is very extensive. Its shape is triangular, base 
superior — the supermaxilla being joined to the premaxilla. Proceeding backward, 
there are observed : a fossa, in which opens the infra^rhital foramen ; the lower 
orifice of the superior dental canal, pierced above the third molar tooth ; the 
malar or zygomatic spine — a long vertical crest for the insertion of the masseter 
muscle, commencing above the fourth molar teeth, and continuing upwards with 
the malar bone and zygomatic process. Lastly, the maxillary region is limited, 
above, by the orbit and the maxillary tuherosity. 

2. Orhital region. — This includes the orbit or orbital cavity, for the reception 
of the essential and some of the accessory organs of vision. In Man and the 
Quadrumana this cavity has complete bony walls, but in the domestic animals it 
always largely communicates with the temporal fossa, and it is not always 
even circumscribed at its opening by a soHd ring. A fibrous lining {ocular sheath) 
converts it into a distinct cavity. 

In the Horse, the outline of the orbit is constituted : below, by the lachrymal 



THE HEAD. 83 

bone ; above and in front, by the frontal bone and its process ; externally, by 
the malar bone. If its two largest diameters are measured, it is remarked that 
this opening is scarcely ever regularly circular, its width varying from above to 
below or from without to within. With nine Horses' heads of various ages and 
breeds, equal diameters were found in only one, the other eight being unequal ; 
of these, the vertical diameter of the orbit predominated in five, and was least in 
three. 

In the Ass, as a general rule the vertical diameter is smallest, the relation 
between the two diameters varying from ro9 to 1"15. Otherwise, the entrance 
to the orbit is irregularly square, and the orbital process which covers it is much 
wider and more salient than in the Horse — as Lecoq asserted, and as the 
observations of Goubaux and Sanson have confirmed. We have also noticed 
these differences, and they are not the only ones which permit the skeleton of 
the Ass to be recognized ; for there have been already cited those of the spine 
and bones of the head — such as the articular depression surrounding the basilar 
process, the vascular furrow on the styloid process, the position of the lachrymal 
tubercle, and the conical eminence surmounting the premaxillary symphysis, 
above the incisive foramen ; others will be noted hereafter (Figs. 51, 52). 

With regard to the cavity of the orbit, it is separated from the maxillary 
hiatus and the temporal fossa by two linear imprints, diverging forwards, to 
which the ocular sheath is attached. It presents, on its floor, the upper orifice 
of the lachrymal canal, the lachrymal fossa, where the small oblique muscle of the 
eye has its fixed insertion ; and within this, but higher, the little depression for 
the bend of the great oblique muscle of the eye. 

3. Temporal region. — This region is more extensive than the preceding, and 
is composed of three principal parts — the temporal fossa, zygomatic arch, and 
petrous portion of the temporal bone. 

The temporal fossa surmoimts the orbit, from which it is incompletely 
separated in Solipeds and Ruminants by the orbital arch ; in the other domestic 
animals, this arch is incomplete in such a way, that in the skull the temporal 
fossa is confounded for the greater part with the orbit. Situated obliquely down- 
wards and outwards on the sides of the cranium, the temporal fossa is oval in 
shape, and bounded inwardly by the occipital or temporal crest, outwardly by 
the anterior border and longitudinal root of the zygomatic process. It lodges 
the temporalis muscle ; consequently, its width in our animals is proportionate to 
the power of that muscle. It is studded with muscular imprints, and has several 
vascular foramina which enter the parieto-temporal canal. 

The zygomcitic arch is formed as if by a loop thrown from the cranium on to 
the face, outside the temporal fossa and the orbit. It is constituted by the 
zygomatic process of the temporal bone and the malar bone, which latter 
prolongs it to the maxillary region. 

The tuberosity of the temporal bone shows, outwardly, the external auditory 
canal, usually larger in the Ass than the Horse. Between this orifice and the 
supra-condyloid eminence is the opening of the parieto-temporal canal ; and 
behind the latter are several irregular ridges, one of them being the hyoid 
process. The external face of the tympanic case is also studded with some 
styloid prolotiyations, one of which, more developed than the others, serves for 
the insertion of the peristaphyline muscles. Above the hyoid process is the 
mastoid process, and between these two parts is the external orifice of the aqueduct 
of Fallopius. From the mastoid process extends the mastoid crest, the summit of 



84 



THE BONES. 



which meets the external occipital protuberance ; it is crossed by the mastoid 
groove, which gives the mastoid artery passage to the parieto-temporal canal. 
All of the petrous portion is surrounded by deep clefts, resulting from the 
simple union of this bone with its neighbouring pieces. 

D. Base. — The base or superior extremity of the head, formed by the 
occipital bone, represents a trapezoid surface, incurvated from before to behind. 
It is separated from the anterior face by the external occipital tiiherosity, the 
projection of which is always greater in the Ass and Mule than in the Horse, 
with the exception of the English Horse, in which it has been found very 
developed (Figs. 51, 52). It is separated from the lateral faces by two crests — 



Fig. 51. 




_ 19 IS 12 17 22 

horse's head (lateral face). 

1, Occipital condyle; 2, styloid process of the occipital bone; 3, external occipital tuberosity, 
4, parietal crest ; 5, external auditory hiatus ; 6, zygomatic process of the temporal bone ; 7, 
frontal bone; 8, orbit; 9, lachrymal bone and its tubercle; 10, zygomatic or malar bone ; 11, 
nasal bone; 12, supermaxillary bone; 13, zygomatic spine; 14, infia-orbital foramen; 15, pre- 
maxillary or intermaxillary bone; 16, incisor teeth; 17, molar teeth; 18, inferior maxilla; 19, 
maxillary fissure; 20, maxillary condyle; 21, coronoid process of the maxilla; 22, mental 
foramen; 23, supra-orbital foramen ; 24, basilar process of the occipital bone. 



the superior curved lines — which are prolonged backwards on the styloid processes 
of the occipital bone. 

In the middle plane is the occipital crest, behind the tuberosity ; it terminates, 
in becoming gradually effaced, at the orripital foramen, which is bordered 
on each side by the condyles of the occiput. The condyles are separated 
from the styloid processes by two deep notches — the stylo-condyloid notches. 
Between the middle line and the superior curved lines, are muscular imprints 
irregularly arranged in a half -circle — these are the inferior curved lines. 

The base of the skull joins the anterior and posterior faces in forming angles ; 
these possess some interest, as they may afford an important differential 
character between the Ass and Horse. 



THE HEAD. 85 

If one of the branches of a goniometer be placed tangentiallj to the surface 
of the basilar process, and the other to the summit of the external occipital 
tuberosity, the basilo-occipital angle will be obtained. In the measurements 
we have taken of eight heads of Horses of diverse ages and breeds, this angle 
has varied from 70° to 91°. We except the head of a young English Stallion, 
the basilo-occipital angle of which was from 92° to 100°. Measurement of the 
heads of Asses showed the angle to be 103°. The average basilo-occipital angle 
was 85*36° for the Horse, and 95° for the Ass. 

If, instead of taking the basilo-occipital angle, the goniometer be applied to 
the origin of the temporal crests and the superior outline of the occipital 



Fig. 52. 




ass's head (lateral face). 

, Occipital condyle ; 2, styloid process of the occipital bone, with a very marked furrow on its 
external face; 3, external occipital tuberosity, more developed than in the horse; 4, parietal 
crest ; 5, external auditory hiatus ; 6, zygomatic process of the temporal bone ; 7, frontal bone ; 
8, orbit, with its external outline more angular than in the horse; 9, lachrymal bone, with its 
tubercle partly implanted on the nasal bone; 10, zygomatic or malar bone; 11, nasal bone; 
12, supermaxilla ; 13, zygomatic spine; 14, infra-orbital foramen; 15, premaxillary bone, with 
its inner border raised by a salient tubercle above the incisive canal ; 16, incisor teeth ; 17, 
molar teeth; 18, inferior maxilla; 19, maxillary fissure; 20, maxillary condyle; 21, coronoid 
process ; 22, mental foramen ; 23, supra-orbital foramen, carried more to the middle of the orbital 
process than in the horse ; 24, basilar process of the occipital bone. 



In the Horse, this angle is 
and S7° — the average being 



foramen, the parieio-occipifal angle is obtained 
between 81° and 104° ; in the Ass between 7' 
91-12° for the Horse, and 84° for the Ass. 

It was foreseen that the value of these angles would be in inverse relation. 
In all cases when, on a head, the basilo-occipital angle was found very open and 
the parieto-occipital more closed, combined with a great development of the 
external occipital tuberosity and the differential characters already described, 
it was certain to be the head of an Ass. In the English Horse, the external 



Sa TEE BONES. 

occipital tuberosity of which is very developed, the two angles in question are 
nearly equal. In the JIule and Hinny, the value of the angles is intermediate 
between the Horse and Ass. In the Mule, the mean value has been 86-12° for 
the basilo-occipital angle, and 88° for the parieto-occipital angle. In the Hinny, 
it was 87° for the first, and 81° for the second. 

E. Summit. — This results from the union of the four faces ; but, instead of 
being acute, it is flattened from behind to before, curved from side to side, and 
furnished with the incisor teeth. ^ 

2. CONFOEMATION OF THE CrANIUM IN PARTICULAR. 

Retzius was the first to start the idea of considering the cranium of Man 
independently of the fafce. He distinguished the races of mankind as hrachtj- 
cephalic (short-headed), and dolichocephalic (long-headed) — that is, crania long 
from before to behind, and crania relatively short. Broca more recently compared 
the transverse diameter of the cranium with the antero-posterior diameter taken 
as a unit, and has expressed this relation in hundredths by the term cephalic 
index. For some years, Sanson has endeavoured to introduce into the classifica- 
tion of animals the calculations of Retzius and Broca. Taking the dimensions 
of the cranium as a basis, he has divided Horses into two groups — the brachy- 
cephalic and the dolichocephalic kinds. 

If the cerebral cranial cavity — the only important one for this purpose — be 
enclosed in a parallelogram, two sides of which shall be at a tangent to the most 
salient points of the parietal bones, and the other two pass in front of the 
external auditory canals and across the supra-orbital foramina, the dimensions of 
the base and height of this parallelogram, measured in a straight line., will 
correspond to the longitudmal and transverse diameters of the cranium. In 
proceeding thus, Sanson has found that in certain crania the transverse diameter 
is greater than the longitudinal {brachycephalic crania), while in certain others 
the transverse is shorter than the longitudinal diameter {dolichocq)halic crcmia).^ 

Toussaint took direct measurements of the interior of the cranium, and, no 
matter what the breeds of horses were which he examined, he always observed 
that the longitudinal diameter exceeded the transverse. We have made cranio- 
metrical investigations on a number of Horses, and are able to confirm Toussaint's 
statements. In eight skulls from different sources, the longitudinal diameter 
varied between 118 and 1S6 millimetres, the transverse between 88 and 104 
millimetres. Consequently, in none of these animals was the transverse diameter 
equal to the longitudinal. In the number examined were the skulls of a Syrian 
and an English stallion — types which Sanson would have selected as the most 
brachycephalic ; the relations between the length and width were 1'17 for the 
first, and VSl for the second. The average for the eight heads was 1*24. 

We are of opinion that there are no brachycephalic Horses, in the rigorous 
sense of the word, such as Sanson admits ; so that, if it is attempted to establish 
brachycephalic and dolichocephalic types, it will be necessary to previously fix 
what shall be the limit between these two types, and this has not yet been done. 

The crania of Asses from the south of France are longer than that of the 

' For the regions of the head, see Lavocat's Nouvelle Osteologie compar€e de la tete des 
Animaux Domestiques. 

^ Sanson, " Me'moire sur la Nouvelle determination d'un type specific de race Chevaline," 
Journal de VAnatomie et de la Physiologie, de Ch. Robin, 1867; also the later works of M, 
Sanson. 



THE READ. 87 

Horse ; for in eight the average relation between the length and width was 1-25, 
instead of 1'24 — a difference not very great, certainly. The difference becomes 
more marked, however, between the Ass and Horse, if the length of the cerebral 
be compared with that of the cerebellar cavity. This comparison has yielded an 
average of 1-962 in the Horse, and 1-927 in the Ass — which proves that the 
cerebellar cranium is longer in the Ass than the Horse. 

The cranium is, as it were, strangled behind the orbital processes of the 
frontal bones. In glancing at the cranium of the Horse and Ass, it would at first 
appear that that of the Ass is relatively narrower than the cranium of the Horse. 
We have measured six heads of each species for the width of the cranium at its 
greatest diameter, behind the orbital processes, and, in comparing these two 
diameters, have obtained the following results : in the H^orse, the relation varied 
between 1-18 and 1-27 ; in the Ass, between 1-20 and 1-47. The average has 
been, for the Horse, 1-226, and 1-335 for the Ass. From these figures, it might 
be concluded that the cranium of the Ass is relatively more constricted at its 
inferior extremity than that of the Horse. In the hybrids of the Horse and 
Ass, the cranial cavity is more elongated, and in this respect the Hinny more 
resembles the Ass than the Horse. With regard to narrowness of the crauium 
behind the orbital processes, the Mide holds the middle place between its parents, 
while the Hinny comes nearest to the Ass — the reverse of what is noticed 
in the development of the cerebellar cranium. 

In Ruminants, the shape of the cranium is more or less masked by the 
frontal or parietal sinuses ; consequently, it is difficult to study satisfactorily this 
part of the head, particularly in the bovine species. 

The cranium of the domestic Dog offers great varieties ; for the creation of 
numerous breeds has brought about important differences in the form and 
dimensions of this part, which it is impossible to deal with here. 

3. Relations between the Cranium and Face. 
Instead of studying the cranium alone, we may compare it with the face in 
regard to width, length, and the area that each of these two regions occupies in 
a vertical and median section. We may also, in measuring the facial angle, form 
an idea of the manner in which these two regions unite to form the head. 

1. The forehead, properly speaking, measured from the union of the parietal 
crests to the fronto-nasal suture, is always, in the Horse, longer than the cerebral 
cranium, the second to the first being as 1 : 1"425. The forehead of the Ass is 
proportionately less developed, for we have found that the cranium is to the 
forehead as 1 : 1-265. 

2. This shortness of the Ass's forehead, which renders the head heavy, is 
corrected by its narrowness ; the head enlarges at the orbital processes. In com- 
paring the distance between the supra-orbital foramina and the transverse 
diameter of the cerebral cavity, it has been noted that the width of the cranium 
is to the space between these foramina as 1 : 1-454 in the Horse, and 1 : 1-265 in 
the Ass. The forehead of the Ass is, therefore, in proportion to the cranium, 
shorter and narrower than in the horse. From this point of view, the heads of 
the 3I'uIe and Hinny are intermediate to those of their parents ; but the first of 
these hybrids is nearer the Horse, and the second approaches the Ass. 

3. Cuvier imagined that one of the means of judging of the intelligence ot 
animals, would be to compare the area of the cranium with that of the face, 
measured on a median section of the head, deprived of the lower jaw. This 



TEE BOXEd. 



great naturalist remarked that the area of the cranium diminishes as the animals 
are further removed from the hmuau type, while the area of the face increases 
in the same sense. Colin has studied the heads of the domesticated animals 
from this point of view. Putting to one side the surface occupied by the 
sinuses, he found that the area of the cranium to the face was as — 



1 : 2-69 in the Horse. 
1 : 2 09 in the Ass. 
1 : 3-43 in the Ox. 
1 : 2-20 in the Ram. 
1 : 1-95 in the Goat. 



1 : 3 24 in the Pig. 
1 : 117 in the Dog. 
1 : 0-68 in the Cat. 
1 : 1-47 in the Rabbit. 
1 : 054 in the Lamb. 



From this table it will be seen that, if the domesticated animals are classified 
according to the area of the cranium, they will stand in the following order : 
Cat, Dog, Rabbit, Goat, Ass, Ram, Horse, Pig, and Ox. 

4. Camper measured the facial aiigU by drawing two lines, starting from the 
entrance to the nasal cavities, and passing towards the middle of the external 
auditory canal and towards the most prominent part of the forehead. The facial 
angle gives an idea as to the relative volume of the face and cranium, and the 
dimensions of the latter ; but with animals it furnishes very imperfect information, 
because of the form of the face and the development of the sinuses around the 
cranial cavity. 

Colin has measured the facial angle of the domestic animals, by drawing two 
lines from the upper incisors towards the external auditory canal and the fore- 
head, in the point corresponding to the lower end of the brain ; and he obtained 
the following average values : from 12° to 15° for the Horse ; 16° for the Ass ; 
20° for the Bull ; from 20° to 25° for the Ram ; from 3-4° to 41° for Dogs ; and 
41° for the Cat. 

On the other hand, we have measured this angle in Equines, and find that it 
varies : in the Horse, between 11° and 13° ; in the Ass, between 12° and 16° ; 
and in the Mule, between 13° and 15°. In the Hinny, it measures 14°. It is 
somewhat remarkable that, in the Equidae, the Ass should have a greater facial 
angle than the Horse. 

4. Modifications due to Age. 

Age brings modifications bearing upon the form of some regions of the head, 
the development of external peculiarities of the bones, the shape of the cranium, 
and its relations with the surface. 

1. It has been remarked that the development of the occipital tuberosity, 
the temporal crests, and the lachrymal tubercle, increases with age in the Equine 
species ; the infra-orbital foramen, which is frequently only a notch in youth, 
becomes a true foramen when the animal is advanced in age. In the Foal, the 
forehead is convex ; that bone and the nasal bones become flat as the creature 
grows, and sometimes even the line of the nasal bones is concave in old age. The 
maxillary region, which is at first convex, becomes gradually hollow as the molar 
teeth are pushed out of the alveoli ; while the straight part of the posterior 
border of the inferior maxilla becomes thin and sharp in very old Horses. The 
entrance to the orbit is also notably modified, though its shape is not identical 
in all the animals. In every instance, it has been remarked that the direction of 
the larger axis of the orbital cavity, comprised at first in the plane which passes 
by the auditory canal and the implantation of the upper incisors, is depressed in 



THE HEAD. 



front, and at an advanced age is found in a plane passing by the inferior 
extremity of the zygomatic crest and the summit of the external occipital 
tuberosity. 

2. If the cranium be examined by itself, it will be noted that, in proportion, 
it is less narrowed behind the orbital processes in the young animal than in the 
adult. With regard to the cerebellar cranium, it is elongated when the animal 
is aged — a consequence of the natural development of the external occipital 
tuberosity. 

3. The relation of the areas of the cranium and face change with age. If 
the measurements obtained by Colin on the Lamb and Ram are compared, it 
will be perceived that the face grows as the creature ages. This change is very 
evident if the development of the young Hare is watched. At birth the face is 
very short — like that of a common dog, it is said ; but when development is 
completed, we know how much the face has become lengthened. 

4. Finally, in consulting the table of angles drawn up by Colin, we might 
believe that the facial angle widens as the animal advances in age. Thus, in the 
young Hinny, Colin estunated the facial angle at 15° ; this angle was 16° on an 



Fig. 53. 




A, B, C, D. 1, Fronto-parietal crests; 2, external occipital tuberosity; 3, 3, superior root of 
the zygomatic process of the temporal bone. 

old Hinny, and 17° on another very old one. In every instance, however, according 
to the same table, this angle will be equal in a four-years-old Horse and in an 
adult Horse ; and even in the Calf it diminishes one degree when it becomes an 
adult animal. 

The measurements we have taken in domestic Solipeds, have demonstrated 
that the facial angle diminishes in a constant manner as the animal grows old. 
Thus, this angle is 16° in an Ass three years old ; it is 15° in the adult, and 12° 
in the very old Ass. We have found it 13° in a Foal of two years, and 11° in 
an old Horse ; 15° in a Mule of eighteen months, and 12*30° in a very aged 
Mule. 

This question has, therefore, to be again examined ; and, however it may be 
decided, it will be seen, by what has been stated, that age induces very interesting 
changes in the form and proportions of various parts of the head. 

If the crania of different breeds of Dogs are compared, there will be found 
very marked diversities in the prominence of the parietal convexity, and the 
development and distance apart of the fronto-parietal crests. A mere glance 
at the ligures above (Fig. 53), will afford evidence of this. 



90 THE BONES. 

On the cranium of the Mastiff (a), the parietal bulgings are httle marked ; 
the parietal crests are very elevated, and join each other early, so that the 
temporal muscles are in contact throughout the greater part of their inner 
margin. In the little Lap-dog (d), the parietal crests are widely separated from 
one another, and the cranium is so very convex as to resemble that of a Monkey. 
Between these extremes are many intermediates (b, c) ; and it would appear 
that the development of inteUigence in the Dog results in rendering the parietal 
bones more convex, and the temporal fosssB narrower. 




Comparison of the Head of Man with that of the Domesticated Animals. 

1. Occipital hone. — The occipital of Man is large, flat, incurvated like a shell, and the ex- 
ternal tuberosity is slightly developed, and united by a ridge to the occipital foramen, which 
is relatively very wide. Two series of ridges arise from 
the external tuberosity and pass towards the circum- 
ference of tlie bone ; these are the superior and inferior 
curved or semicircular lines. There is an anterior and 
a posterior condyloid fossa pierced by a foramen at the 
bottom; and the jugular eminences, wide and slightly 
prominent, replace the styloid processes of the domesti- 
cated animals. 

The internal face of the occipital of Man corresponds 
with the cer( brum and cerebellum ; and for this purpose 
it shows four fossae, distinguished into superior or cerebral, 
and inferior or cerebellar. These fossse are separated by 
a crucial projection whose most developed portion forms 
the internal occipital protuberance. 

The union of the occipital with the parietal bones, con- 
stitutes the liimlidoidal suture. At the point where this 
bone meets the parietal and the squamous portion of the 
temporal, is found, in the infant, the lateral posterior 
fontanel. 

2. Parietal hones. — The parietals are always isolated 
in early life, and sometimes consolidated with each other 
at the adult age. They are very large, quadrilateral, 
and occupy the summit and sides of the cranium. 

The parietal crests are absent, but are replaced, in 
certain individuals, by two faintly marked curved lines 
situated a little above the inferior border of the bone. 
The middle portion of the external face is very convex. 

On the internal face there is no parietal protuberance, 
but in its stead the internal occipital tuberosity. It 
also exhibits ramous channels, which in disposition are 
analogous to the ribs of a tig-leaf ; as well as the parietal 
fossa, which corresponds to the parietal eminence. 

3. Frontal hone. — The frontal bone of Man forms the 
upper part of the face and the anterior portion of the 
cranium. Convex from behind forward, then vertical in 
its upper three-fourths, the bone suddenly bends at tlie 
orbits, so as to become horizontal in its lower fourth. 

The external face offers, above the forehead, two Literal 
frontal eminences, and above the nose, a middle frontal 
boss. To the right and left of the latter are two salient 
arches— the supra-orbital ridges. The internal face entirely belongs to the cranial cavity. It 
offers, on the median line, the saggital groove terminated by a frontal crest; and on each 
side of this line the frontal fosste, corresponding to the eminences of that name, and orbital 
bo.sses to match the orbital roofs. There is no mortise for the articulation of the sphenoid bone. 
On the middle poition of the superior frontal border, in young persons, is the anterior 
angle of the anterior fontanel. The anterior border exhibits three supra-orbital foramina 
and the orbital arches. 



front view of the human 
cranium. 

, Frontal bone ; 2, nasal tuberosity ; 
3, supra-orbital ridfijp ; 4. optic 
foramen ; 5, sphenoidal fissure ; 
6, spheno-maxillary fissure ; 7. 
lachrymal fossa ; 8, opening of 
the nose divided by the vomer; 9, 
infra-orbital foramen; 10, malar 
bone ; 11, symphysis of the lower 
jaw; 12, mental foramen; 13, 
ramus of the lower jaw ; 14, parie- 
tal bone ; 15, coronal suture ; 16, 
temporal bone ; 17, squamous 
suture ; 18, upper part of the great 
ala of the sphenoid bone; 19, com- 
mencement of the temporal ridge ; 
20, zygoma of the temporal bone 
concurring to form tlie temporal 
arch ; 21, mastoid process. 



THE HEAD. 



91 



Fig. 55. 




4. Ethmoid hone.— In Man, the external fa^e of the lateral masses— formed by a very 
thin lamina, termed the os planum or lamina pap2/r«e«— belongs to the internal wall of the orbit. 

5. Sphenoid bone.— TLiis is distinguished, in Man, into a body and four wings- two large 
and twfi small. 

Tlie inferior surface of the body oflfers nothing remarkable, except the presence of a conical 
prolongation named the beak (rostrum) of the .sphenoid. The external face of the greater 
wings forms part of the temporal fowsa, as also the external wall of the orbit. At the union 
of the wing.s with the body, are detached two bifid 
pterygoid proce.-^ses ; their internal branch represents 
the pterygoid bones of animals. There is no sub- 
sphenoidal canal. 

Tlie two lesser wings are very thin and triangular, 
and visible only on the superior surface of the bone ; 
they constitute the processes of Ingrassias. 

On the internal face of the bone are found : (1) 
a deep pituitary fossa, limited by four cUnoid pro- 
cesses; (2) an optic fossa, shallow, showing very 
short optic canals transformed into foramina ; (3) the 
sphenoidal fissure, which replaces the great super- 
spheiioidal canal in the Horse; (4) the great foramen 
rotundum; (5) the internal face of the wings, much 
excavated ; (6) the foramen ovale, which transmits 
the inferior maxillary nerve ; (7) the small foramen 
rotundum that lodges the spheno-spinous artery. 

6. Temporal hone. — In the squamous portion of 
the temporal bone of Man, the zygomatic process only 
rests on the malar bone, as in Ruminants. The glenoid 
cavity is concave in every sense, ami divided into two 
parts by an opening named t\\e fi'<sura Glaneri ; the 
anterior portion only is articular — the posterior, lying 
against the external auditory canal, does not belong 
to the articulation ; it corresponds to the supra-con- 
dyloid eminence of the Horse. The tuberous portion 
is consolidated with the squamous. It is divided into 
a mastoid and a pyramidal portion ; the latter com- 
prises, in its turn, the petrous an^l tympanic portions. 
The mastoid portions correspond to the mastoid pro- 
cess, mastoid protuberance, and superior border of the 
petrous bone in the Horse. It presents a rugged 
mast(;id process. Above this is the mastoid canal ; 
and aliove and behind it, tlie digastric groove — tlie 
pyramid forming a considerable projection in the 
interior of the cranium. The styloid process or bone 
is altogether separate from the other pieces of the 
hyoid, and in the adult is consolidated with the tem- 
poral bone. 

7. Supermaxilla. — In Man the premaxilla is no 
longer found independent, the centre which forms it 
coalescing with the supermaxillary bone. 

The supermaxilla of man concurs, for the greater 
part of its extent, to form the floor of the orbit ; it 

is also divided into three faces : an external or facial, a superior or orbital, and an internal 
or naso-palatine. The external face presents, from before to behind: (1) a small fossa, into 
which is inserted the niyrtiform muscle; (2) the infra-orbital, or canine fossa, showing the 
inferior orifice of the infra-orbital canal; (3) a crest corresponding to the maxillary spine of 
Solipeds : (4) the alveolar tuberosity. This face carries, in front, a prolongation that forms the 
ascending process, also named, because of its relation, the tronto-nasal process. The superior 
or orbital face oflfers a fissure which precedes the infra-orbital canal, and, outwards, the malar 
process. The internal face is divided by the palatine process. It shows, in front, the half of 
the anterior nasal spine and a groove which participates in the formation of the incisive canal. 

8. Palatine fcojie.- The palatine bone of Man isformedof two osseous laminae— one horizontal, 
the other vertical— which are joined at a right angle. The first part presents : one-half of the 



EXTERNAL OR BASILAR SURFACE OF 
THE BASE OF THE HUMAN SKULL. 

, ], The bony palate; 2, incisive, or 
anterior palatine foi-amea; 3, pala- 
tine process of p date bone, with the 
posterior palatine foramen ; 4, palate 
spine with transverse ridge ; 5, vomer ; 
6, internal pterygoid palate ; 7, sca- 
phoid fossa; 8, external pterygoid 
plate, with fossa ; 9, zygomatic fossa ; 

10, basilar process of occipital bone ; 

11, foramen magnum; 14, glenoid 
fossa; 15, meatus auditorius exter- 
nus ; 16, foramen lacerum anterius ; 
17, carotid foramen of left siile; 18, 
foramen lacerum posterius, or jugular 
foramen; 19, styloid process; 20, 
stylo-mastoid foramen, with jugular 
tubercle and digastric fossa ; 21, mas- 
toid process ; 22, occipital bone ; 23, 
posterior condyloid fossa. 



92 THE BONES. 

posterior nasal spine, whicli is altogether rudimentary, or even null in animals ; the orifice of 
the posterior palatine canal, which belongs entirely to the palate boue; the pterygo-palatine 
foramen ; lastly, the pterygoid process, which represents tiie pterygoid bone of animals. The 
vertical portion foims the external wall of the nasal cavities by its internal face, and by its 
external face concurs in the formation of the zygomatic or temporal fossa. 

9. Malar bone. — This oflfers three faces. The external, or cutaneous, serves as a base for the 
most salient part of the cheek. The superior, or orbital, forms part of the external wall and 
floor of the orbit ; it belongs to a long apophysis — the orbital process — which rests on the 
sphenoid and frontal bones. The posterior face is smooth and concave behind, where it aids to 
form the temporal fossa; in front it is uneven, and articulates with the supermaxilla. The 
posterior, or masseteric border, unites with the zygomatic process of the temporal bone. 

10. Lachrymal bone. — This bone is also called the os unguis in Man, because of its likeness 
to the nail in shape and tenuity. It is entirely lodged in the orbit, and its external face is 
divided into two portions by a vertical crest ; the portion situated in front of this crest forms 
part of the lachrymal groove. By its internal face, the lachrymal bone limits, outwardly, 
the bottom of the nasal cavities, and covers the anterior cells of the ethmoid ; by its posterior 
border, within the orbit, it articulates with the os planum of the ethmoid. 

11. Nasal bone. — The proper bones of the nose of Man exhibit a great analogy to those of 
the Dog. Tliey do not possess a nasal prolongation, and they articulate with the lateral 
cartilage of the nose. 

12. Vomer. — The same general form and relations as in Solipeds. 

13. Inferior maxillary bone. — This bone in Man is in shape somewhat like a horse-shoe. It 
is nearly of the same witlth throughout its whole extent. The symphysis is vertical — a 
character peculiar to Man. Below this symphysis is a triangular projection — the mental 
eminence. The genial surface of the Horse is replaced by four little tubercles, termed the 
genial processes. The alveoli of the molar teeth form a great projection on the inner face of 
the bi)ne. The mylo-hyoid ridge is very developed. The superior orifice of the dental canal 
is covered by a little sharp lamina. From this oritice begins the mylo-hyoidean groove. The 
coronoid process is short ; the condyle is bent towards the median line, and the sigmoid notch 
is wide and shallow. The superior border contains fourteen or sixteen alveoli. 

Aeticle III. — The Thorax. 

The thorax represents a coinoid cage, elongated from before to behind, 
suspended under the vertebrae of the dorsal region, and contains the principal 
organs of respiration and circulation. It is composed of bony arches named 
ribs, thirty-six in number — eighteen on each side — and a single piece — the 
sternum, which serves for the direct or indirect support of the inferior extremi- 
ties of the ribs. 

The Bones of the Thorax in particular. 
1. Sternum of the Horse (H^jial Spine) (Fig. 56). 

This is an osteo-cartilaginous body, elongated from before backwards, 
flattened on each side in two-thirds of its anterior extent, and above and below 
in its posterior third ; it is slightly curved on itself, and situated beneath the 
thorax in an oblique direction downwards and backwards. It offers for study, a 
superior face, two lateral faces, three borders, and two extremities. 

Faces. — The superior face, shghtly concave longitudinally, represents an 
isoscelated lengthened triangle, the summit of which is directed forwards ; it 
constitutes the floor of the thoracic cavity. The inferior face is shaped like the 
keel of a ship, having in its middle a longitudinal ridge, which decreases in 
height from before to behind. It has two inclined planes placed towards each 
other, each of which has two parts — a superior and an inferior. The first shows 
eight diarthrodial cavities, which receive the inferior extremity of the cartilages of 
the true ribs. These cavities are elongated vertically, and draw closer to each other 



THE THORAX. 93 

as they extend backwards. The inferior part, which is more extensive before 
than behind, offers to the powerful pectoral muscles a large surface for insertion.^ 

Borders. — The two inferior borders separate the superior from the inferior 
faces ; they are situated above the diai-throdial cavities, are united anteriorly, and 
each gives attachment to a fibrous band. 

Extremities. — The anterior, flattened on each side and curved upwards, exceeds 
to some extent the first articular cavity of the lateral faces, and in this way con- 
stitutes the cervical prolongation {prcesternum) of the sternum. The posterior 
extremity is flattened superiorly and inferiorly, and forms a large cartilaginous 
plate, very thin, concave above, convex below, which has received the name of 
the abdominal prolongation (ensiform cartilage), or xiphoid appendage. 

Structure and development, — The sternum is one of the parts of the skeleton 

Fig. 56. 




THE STERNUM. 

1, The cervical prolongation (prcesternum, or cariniform cartilage) ; 2, the xiphoid appendage (or 
ensiform cartilage); 3, 3, cavities for the articulation of the sternal cartilages ; 4, inferior burder. 

which do not undergo complete osseous transformation. It is developed, in 
Solipeds, from six single nuclei of spongy substance, ranged one behind the 
other, like beads on a string. These nuclei never coalesce to form a solid piece, 
but remain separated during the life of the animal, by the primary cartilaginous 
mass. The latter constitutes the entire anterior prolongation of the bone and its 
carina, as well as the xiphoid appendage. When these parts of the sternum 
become ossified — which is rare — they are only partially so. 

Differential Characters in the Sternum op other Animals. 

In all the domesticated animals except Solipeds, tlie sternum is flattened above and below 
instead of ou both sides. 

A. Ruminants. — In Ruminants, each piece is developed from two lateral centres of ossifi- 
cation. The bones wliich compose it are seven in number; they are much more compact than 
those in the sternum of the horse, and at an early period are united to each other, with the 
exception of tl:e first, which is joined to the secmid by a diarthrodial articulation tliat permits 
it to execute lateral movements. There is no cervical prolongation, and the xiphoid cartilage 
is feebly developed and well detached from the bodv of tiie bone. In the sternum of the Goat 
and Sheep, the two first pieces have no diarthrodial joint, but are simply united by a layer of 
cartilage, which, in old animals, becomes completely ossified. The sternum of the Camel has 
a very oblique direction downwards and backwards, and is formed by seven pieces ; the first is 
somewhat rudimentary, while the two are very strong, and serve as a base for the sternal 
callosity or pad. 

B. Pig. — Tlie sternum of this animal presents in its general conformation the essential 
features of that of large Ruminants. It is provided with a well-defined cervical prolongation, 
and is composed of six pieces, which, at least in the four or five last, are each divided into two 
lateral nuclei. 

C. Carnivora. — ^The sternum of the Dog and Cat is formed of eight pieces, elongated from 
before to beliiud, hollowed in their middle part, and thick at their ends— formed, indeed, like 
the last coccygeal vertebrae of the Horse. They are never ossified to each other. 

9 



94 



THE BONES. 



2. The Ribs (Pleuropophyses) (Fig. 57). 

As has been already remarked, on each side of the thorax there are eighteen 
ribs. These are nearly parallel to each other, and separated by the intervals 
termed the intercostal spaces. Attached by their superior extremity to the 
vertebrse of the dorsal region, these bones terminate at their inferior extremity 
by an elastic and flexible prolongation, named the costal cartilage, by means of 
which they are brought into direct or indirect relations with the sternum. The 

characters common to all the 
^'S- ^^- ribs will be first noticed, then 

the special features which serve 
to distinguish them from each 
other, and, lastly, the differences 
they exhibit in other than Soh- 
ped animals. 

A. Characters common to 
ALL THE Ribs. — These will be 
studied from a typical point of 
view, first in the rib itseK, and 
then in its cartilage. 

1. Description of a typical 
rib. — A rib is an elongated 
asymmetrical bone, oblique from 
above to below, and from before 
to behind, flattened on both 
sides, curved hke a bow, and 
twisted on itself in such a fashion 
that its two extremities cannot 
rest on the same horizontal 
plane. It is divided into a 
middle portion or bod//, and tivo 
extremities. 

3Iiddle portion. — This offers 
two faces and two borders. The 
external face is convex, and 
hollowed by a wide groove in 
its anterior half ; it shows 
superiorly, towards the point 
corresponding to the angle of 
the rib in Man, some tubercles 
and muscular imprints. The 
internal face is concave and 
smooth, and covered by the 
pleura, which separates it from 
the lungs. The anterior border 
is concave, thin, and sharp ; the posterior — convex, thick, and covered with rugged 
eminences — is channeled iuAvardly by a vasculo-nervous groove, which disappears 
near the middle of the rib. 

Extremities. — The superior has two eminences— a head {capitidum) and a 
tuberosity (tuberculum) — which serve for the support of the rib against the spine. 




TYPICAL RIBS OF THE HORSE. 

, Inner face of the fifth sternal rib. B, External face 
of the first asternal rib. 1, Head of the rib; 2, its 
fissure ; 3, neck ; 4, tuberosity ; 5, articular facet ; 
6, scabrous fossa for the insertion of the interosseous 
costo-transverse ligament ; 7, groove on the external 
face ; 8, vasculo-nervous groove on the posterior border ; 
9, prolonging cartilage ; 10, A, articular tuberosity 
for union with the sternum. 



THE THORAX. 9S 

The first is formed by two articular demi-facets, placed one before the other, and 
separated by a groove for ligamentous insertion ; it is isolated from the tuberosity 
by a narrow part, named the neck, which exhibits a rugged fossa for the implantation 
of a ligament. The second — situated behind the head, and smaller than it — is 
provided with imprints on its margin, and presents an almost flat diarthrodial facet 
at the summit. Each rib articulates by its head and tuberosity with two dorsal 
vertebrse ; the head is received into the intervertebral articular cavity ; the tube- 
rosity corresponds, by its facet, to the transverse process of the posterior vertebra. 

The inferior extremity is tuberous and excavated by a shallow cavity, 
irregular at the bottom, for the reception of the upper end of the costal cartilage. 

Structure and development. — The ribs are very spongy bones, especially in their 
inferior moiety, and are developed at a very early period from three centres of 
ossification — a principal for the middle portion and inferior extremity, and two 
complementary for the head and tuberosity. 

2. Description of a typiccd costal cartilage. — The costal cartilage QicBmapopliysis) 
very evidently represents the inferior rib in Birds ; it is a cylindrical piece, 
slightly compressed at the sides, and round and smooth on its faces and borders. 
By its superior extremity, it is united to the rib it serves to lengthen, and forms 
with it an angle more or less obtuse, opening in front. At its inferior extremity, 
it is terminated by an articular enlargement, or by a blunt point. In youth, the 
costal prolongations are entirely composed of cartilaginous matter, but they are 
soon invaded by ossification ; so that in the adult animal they are already trans- 
formed into a spongy, substance, with large areolae which remain during life 
surrounded by a thin layer of cartilage. 

B. Specific Characters of the Ribs. — The ribs, hke the vertebra of 
each region of the spine, have received numerical designations of first, second, 
third, etc., computing them from before to behind (Fig. 5). Owing to the 
presence of an altogether essential characteristic, they are naturally divided into 
two great categories — the sternal or true ribs, and the asternal or false ribs. The 
sternal ribs, numbering eight — the first eight — have their cartilages terminated 
inferiorly by an articular enlargement, which corresponds to one of the lateral 
cavities of the sternimi, and brings the true ribs into direct contact with this 
portion of the skeleton. The asternal ribs, ten in number, rest on each other — 
the last on the seventeenth, that on the sixteenth, and so on — by the inferior 
extremity of their cartilage, which ends in a blunt point. The cartilage of the 
first false rib is united somewhat closely to the last sternal rib, and it is through 
the medium of this that all the asternal ribs lie indirectly on the sternum. 

If, however, the ribs are considered altogether, with regard to the differential 
characters presented by them in their length, width, and degree of incurvation, 
it will be noted : 1. That their length increases from the first to the ninth, and 
from this diminishes progressively to the last, 2. That the same progressive 
increase and decrease exists in the cartilages. .3. That they become gradually 
wider from the first to the sixth inclusive, and then contract by degrees until the 
eighteenth is reached : 4. That the curve described by each is shorter and more 
marked as the rib is situated more behind. It may be added, that the channel 
on the external face is less conspicuous in proportion as the rib is narrow. 

The first rib, considered individually, is always distinguished by the absence 
of the groove on its outer surface, by the vasculo-nervous groove on its posterior 
border, and the groove or notch intermediate to the two facets of its articular 
head. It is also recognized by the deep muscular imprints on its external face, 



96 THE BONES. 

the shortness and thickness of its cartilage, and particularly by the articular facet 
which this cartilas^e exhibits inwardly, to correspond to that of the opposite rib. 
The last rib has no channel on its external surface, and the facet of its tuberosity 
is confounded with the posterior facet of the head. This last character is also 
nearly always remarked in the seventeenth rib, and sometimes even in the 
sixteenth. 

In the Ass, the ribs in general, but particularly those most posterior, are less 
curved than in the Horse. They differ more particularly in the curve of the neck 
being much shorter — a difference which is most obvious when the goniometer is 
applied to the angle of the rib, and the most salient part of the head and tube- 
rosity. By this means we have obtained an angle the value of which was greater 
in the Ass than in the Horse : from 7><° to 130° for the external ribs, and from 
100° to 132° for the asternal ribs, of the first ; from 60° to 125° for the sternal, 
and from 140° to 150° for the asternals, of the second. The upper extremity of 
the sternal ribs in the Ass is less twisted outwards than the same part in the 
Horse ; and in the latter, the plane which passes by the head of the rib is more 
distant than the plane which, in the Ass, passes across the tubercle. 

The ribs of the Mule are intermediate between those of the Ass and Horse, 
with regard to the value of the angle just indicated ; they approach those of the 
Ass by the twist in their superior extremity. 

Differential Characters in the Ribs of other Animals. 
The number of rib:^ varies like that of tlie dorsal vertebrae. The following table'* indicate 
the number uf these bones in the different domesticated animals : — 

Pig 14 

Ox l.S 

Sheep 13 

Goat 13 

Dog 13 

Camel ... 12 

Rabbit 12 

A. Ruminants. — These animals, with the exception of the Camel, have eight sternal and 
five asternal ribs. 

In the Ox, they are longer, wider, and less arched than in Solipeds. The articular 
eminences of the superior t-xtremity are voluminous and well <letafhed; the neck especially is 
very long. The sternal ribs are joined to their cartilage of prolnngment by a real diarthrodiai 
articulation. In the last rib, and sometimes in tlie one before it, the tuberosity is scarcely 
perceptible, and has no articuhir facet. In the Sheep and Goat, the sternal ribs are consolidated 
with the cartilages (Figs. 6. 7). 

The Camel has eight sternal and four asternal ribs. The rib.s increase in length to the 
tenth, and in width to the si.xth only. They are less curved and are shorter, proportionately, 
tiian those of the Ox, the shortness being very marked in the first three. The tubercle is less 
de'achefl than in the Ox, but the neck is longer and stronger (Fig. 8). 

B. Pig. — In this animal there are fourteen pairs of ribs, seven of which are sternal and 
seven asternal. The first are provided with cartilages of prolongment flattened on both sides, 
extremely wide and sharp, and convex on their superior border. In the four last asternal ribs, 
the fitcet of their tuberosity is confoundi'd with the posterior facet of the head (Fig. 3). 

C. Carnivora. — They possess thirteen ribs on each side — nine sternal an.l four asternal. 
These are very much arched, narrow, and thick, and their cartilages rarely ossify. In the Dog, 
the articular facet of tiie tuberosity remains isolated from the posterior facet of the head in all 
the ribs. It is absent in the three last ribs of the Cat (Fig. 2). 

The Thorax in General. 

The description of the interior of the thoracic cavity will be referred to when 
treating of the respiratory apparatus. It is only necessary here to examine the 



THE THORAX. 



97 



Fig. 58. 



external surface of this bony ca^e. For this purpose it is divided into six 
regions — a superior plane, an inferior plane, tivo lateral pla7ies, a base, and a 
summit. 

Planes. — The superior plane is separated into two portions bj the spinous 
processes of the dorsal vertebra ; each forms, with these spinous processes, the 
costo-vertebral furrow, intended to lodge the majority of the muscles belonging 
to the spinal region of the back and loins. The inferior plane, less extensive 
than the preceding, offers : 1. On the median line, the cariuiform and xiphoid 
cartilages of the sternum ; 2. On the sides, the chondro-sternal articulations, 
and the cartilages of prolongment of the true ribs. The lateral planes are con- 
vex and wider at their middle part than in front or behind, and exhibit the 
intercostal spaces. They serve to give support, anteriorly, to the superior 
segments of the two anterior limbs. 

Base. — This is circumscribed by the posterior border of the last rib, and by 
the cartilages of all the asternal ribs ; it is cut ouliquely downwards and for- 
wards, and gives attachment, by its internal 
circumference, to the diaphragm — a muscle 
which separates the thoracic from the ab- 
dominal cavity. 

Summit. — It occupies the anterior por- 
tion of the thorax, and presents an oval 
opening, elongated vertically, situated be- 
tween the two first ribs. This opening 
constitutes the entrance to the chest, and 
gives admission to the trachea, the oeso- 
phagus, and important vessels and nerves. 

Comparison of the Thorax of Man with 

THAT OF THE DOMESTICATKD AnIMALS. 

1. Sternum. 
The sternum of Man is flattened before and 
behind, and diminishes in widtii from above to be- 
low. The xiplioid ap[)endage is narrow, and single 
or bifid. Besides the articular surfaces for the ribs, 
there are found on the upper end two lateral 
notches for articulation with the clavicles. 




2. Ribs. 
Of the twelve ribs in Man, seven are eternals 
and five asternals. They are short, narrow, and 
much incurvated, especially the first ones. In each 
rib the curvature is more marked in the posterior 
fourth or fifth, than in the anterior three-fourths 
or four-fifths ; this sudden change of curvature is 
indicated in the external face by a kind of inflection 
and thickening, called tlie angle of the ribs. The 
prolonging cartilages of the eleventh and twelfth 
ribs are short, and are lost in the substance of the 
are termed ihe floating {or false) ribs (Fig. 58> 



thorax op man (anterior face). 
1, Superior piece of the sternum ; 2, 
middle piece, or body ; 3, inferior piece, 
or ensiform cartilage; 4, first dorsal 
vertebra ; 5, hist dor.^al vertebra ; 6, 
first rib ; 7, its head ; 8, its neck, rest- 
ing against the transverse process of the 
first dorsal vertebra ; 9, its tubercle ; 
10, seventh, or last true rib ; 11, costal 
cartilages of the true ribs ; 12, the last 
two false or floating ribs ; 13, the groove 
along the lower border of the rib. 

abdominal parietes ; for this reason they 



Article IV. — Anterior Limbs. 

The anterior ( pectoral or thoracic) limb is divided into four secondary regions — 
the shoulder, arm, forearm, and fore foot or hand. 



98 THE BONES. 

SHOULDER. 

In Solipeds, this region has for its base a single bone — the scapula or omoplat. 
^^ Scapula (Figs. 59, 60). 

This islW»^ triangular, and asymmetrical bone, prolonged at its superior 
border by a flexible cartilage, articulated interiorly with the humerus only, and 
applied against the lateral plane of the thorax in an oblique direction downwards 
and forwards. It has two faces, three borders, and three angles. 

Faces. — The external face (or dorsum) is divided by the scapidar or acroynian 
spine, into two cavities of unequal width — the supra- and infra-spinous (or antea 
and 2)ostea spinatus) fosscB. The spine is a very salient crest which runs the whole 
length of the external scapular surface ; very elevated in its middle part, which 
shows an irregular enlargement — the tuberosity of the spine — it insensibly decreases 
towards its two extremities. The supraspinous fossa — the narrowest — is situated 
above, or rather in front of the spine ; it is regularly concave from side to side, 
and perfectly smooth. The infra-spinous fossa is twice the width of the preceding, 
and occupies all the surface behind the spine. It exhibits : 1. Below, and near 
the posterior border, several rows of roughened lines for muscular insertion. 
2. Near the neck, the nutritient foramen of the bone, and some vascular grooves. 

The interned face is excavated in its centre to form a hollow, called the subsca- 
pular fossa, which is prolonged superiorly by three diverging points. The median 
point extends to the superior border of the bone, and separates two roughened 
triangular surfaces. 

Borders. — The superior is indented by an irregular groove, to receive the 
inferior margin of the cartilage of prolongation. The latter is convex on its 
superior border, extends beyond the posterior angle of the bone, and gradually 
diminishes in thickness as it leaves its point of attachment. In old horses it is 
nearly always found partially ossified. The anterior border, thin and sharp, is 
convex in its superior two-thirds, and slightly concave for the remainder of its 
extent. The posterior is thicker and a little concave. 

Angles. — The anterior, or cerviccd angle, is the thinnest of the three. The 
posterior or dorsal angle is thick and tuberous. The inferior, or humeral angle, is 
the most voluminous, and is separated from the remainder of the bone by a 
slight constriction, which constitutes the neck of the scapula. It exhibits : 1. The 
glenoid cavity — an oval diarthrodial surface, excavated to a slight extent to receive 
the head of the humerus, nbtched on the inner side, and bearing on the external 
margin of the ridge which surrounds it a small tubercle of insertion. 2. The 
coracoid process, situated in front, and at a certain distance from the glenoid 
cavity. This is a large eminence in which may be distinguished two parts : the 
base, a thick rugged process ; and the summit, a kind of beak curved inwards. 

Structure and development. — Like all the flat bones, the scapula is formed of 
two compact layers separated by spongy tissue. The latter is very scanty 
towards the middle of the supra- and infra-spinous fossfe, where it is often alto- 
gether wanting ; it is most abundant in the angles. In Solipeds and Ruminants, 
the scapula is developed from two principal centres of ossification, one of which 
forms the coracoid process. 

In the Carnivora, the cartilage of prolongation is replaced by an epiphysary 
lip. It may be added that in Mammaha, Meckel, Cuvier, and Strauss-Durckheim 
have noted a supplementary nucleus in the glenoid cavity ; and that Lavocat 
and Goubaux have observed it in Horses especially. Lavocat has described it as 



THE ANTERIOR LIMBS. 99 

a pyramidal nucleus, base inferior, and flattened before and behind. In the 
Horse, it appears at the centre of the cavity towards the seventh or eighth month ; 
it increases and pushes forward the coracoid process beyond the articular sur- 
face. In about nine or ten months it is fused with the principal part of the bone, 
and in about a year with the coracoid nucleus. In the Ass and Mule, the glenoid 



Fig. 59. 



Fig. 60. 




SCAPULA OF THE HORSE (EXTERNAL FACE). 1, Subscapular fossa ; 2, anterior triangular 

1, Tuberosity of the spine ; 2, supra-spinous f ^face ; 3 posterior triangular surface ; 

fossa ; 3, infra-spinous fossa ; 4, nutrient *' *' vascular furrow ; 5, glenoid cavity ; 

foramen; 5, 5, 5, linear imprints for the ^ base of the coracoid process (insertion 

insertion of the coraco-humeralis ; 6, of the coraco-humeralis). 

tubercle for the same ; 7, border of the 

glenoid cavity ; 8, coracoid process ; 9, 

cervical angle; 10, dorsal angle; 11, 

cartilage of prolongation. 

nucleus appears about the fourth month, and its evolution is completed at the 
seventh or eighth month. 

In the Ass, the scapula is usually more curved than in the Horse, while the 
greater development of its superior border, and the more considerable constric- 
tion of its neck, give it a peculiar appearance. It represents a wider and shorter 



]00 



TEE BOXES. 



triangle than in the Horse, and the spine gradually decreases from the tuberosity 
until it is nearly lost on the surface of the bone, towards the nutrient foramen. 
In the Horse, this subsidence of the spine occurs at the neck, where it takes, 
place quite suddenly ; so that it forms a more or less marked prominence. 

The scapula of the Hinny has the general form of that of the Ass ; in the 
Mule, on the contrary, it is elongated Kke that of the Horse. 

Differential Characters in the Scapula of other Animals. 

The shoulder is composed of one or two bones, according as the limb is intended exclu- 
sivelj' to support the body, or is required for other purposes. 

A. Ox, Sheep, Goat.— In these animals the shoulder comprises only one bone— the 
scapula— which is more regularly triangular than in the Horse. The spine does not diminish 
in passing to the neck, but, on the contrary, terminates at a certain distance above the glenoid 

Fig. 61. 




R A 

scapula of the cat and rabbit. 

A, Scapula of the Cat. B, Scapula of the Rabbit. 1, Inferior extremity of the acromian spine v 

2, supra-spinous fossa; 3, infra-spinous process; 4, superior border. 

cavity by an abrupt ridge prolonged to a point, which represents a rudimentary acromion pro- 
cess. It divides the external surfnce of the bone into two fossse, which in extent are as 1 :3. 
The neck is more constricted, and the humeral angle better detached, than in Solipeds. 

B. Camel. — The scapula of this animal resembles that of the Ox in its general form, but 
the spine divides the face into two equal fossae. The acromion process descends to the glenoid 
cavity. 

C. Pig. — The .spine, depressed at its two extremities, rises considerably at its middle por- 
tion, and bends over towards the infra-spinous process. 

D. Camivora.— Their shoulder has two bones — the scapula and clavicle. In the Dog , 
the latter is little more than a shell embedded in the muscles in front of the scapulo-humerul 
angle ; in the Cat, it constitutes a small styloid bone which is united to the acromion process 
and the sternum through the medium of two ligaments. The scapula has no cartilay;e of pro- 
longation ; its anterior border is very convex, as if it had been curved over on itself. The fos.'ife 
of the external face are equal, and the spine terminates in an acromion process that reaches the 
glenoid cavity. 

E Rabbit. — Two bones form the shoulder of this animal. The clavicle, although longer 
than that of the Cat. nevertheless does not rest directly on the sternum and scapula. The 
latter is in shape regularly triangular; the neck is slender; the fos^sse on the external face 
are very unequal ; the spine is prolonged by a thin acromion pedicle to the vicinity of the 
glenoid cavity ; and the superior border of the bone is [irovided with a cartilage of prolongation. 



TEE ANTERIOR LIMBS. 



101 



Arm. 



Fig. 62. 



This region has only one bone, the humerus. 

Humerus (Figs. 62, 63). 

The humerus is a long single bone, situated between the scapula and the bone 
of the forearm, in an oblique direction downwards and backwards. Like all the 
long bones, it offers for study a bodt/ and two extremities. 

Body. — The body of the humerus looks as if it had been twisted on itself from 
within to without in its superior extremity, and from 
without to within at the opposite end. It is irregularly 
prismatic, and is divided into four faces. The anterior 
face (Fig. 62), wider above than below, has in its middle 
and inferior portions some muscular imprints. The pos- 
terior, smooth and rounded from one side to the other, 
"becomes insensibly confounded with the neighbouring 
faces. The external is excavated by a wide furrow, which 
entirely occupies it, and turns round the bone obliquely 
from above to below and behind to before ; it is to the 
presence of this channel that the humerus owes its ap- 
parent twist, and it is in consequence designated the /?/rrow 
of torsion (or inusculo-spiral groove) of the body of the 
humerus. 

This furrow is separated from the anterior face by 
a salient border — the deltoid ridge, which ends inferiorly 
above the coronoid fossa, and superiorly, towards the 
upper third of the bone, by the imprint, or deltoid (or 
external) tuberosity. This is a roughened, very prominent 
eminence, flattened before and behind, and inclining to- 
wards the furrow of torsion ; by its superior extremity, 
it gives origin to a curved line which is carried backwards 
to join the base of the articular head. Near the inferior 
extremity, backwards and outwards, is seen the posterior 
deltoid ridge, which separates the latter from the posterior 
face of the bone. The internal face of the body of the 
humerus, rounded from side to side, is not separated from 
the anterior and posterior faces by any marked line of 
demarcation. It offers, near its middle, a depressed 
scabrous process (the internal tuberosity) for the insertion of 
the teres major and latissimus dorsi muscles. Towards its 
inferior third it shows the nutrient foramen of the bone. 

Extremities. — These are distinguished into superior and 
inferior. Both are slightly curved — the first backwards, 
the second forwards— a disposition which tends to give to the humerus the form 
of an S. 

The superior extremity is the most voluminous, and has three thick eminences — 
a posterior, external, and internal. The first constitutes the head of the humerus. 
It is a very slightly detached articular eminence, rounded like the segment of a 
sphere, and corresponding with the glenoid cavity of the scapula, which is too 
«mall to receive it entirely. The external eminence — named the trochiter, large 




ANTERO-EXTERNAL VIEW 
OF RIGHT HUMERUS. 

1, Trochlear or bicipital 
ridges ; 2, external or 
deltoid tuberosity ; 3, 
head or articular sur- 
face ; 4, external tuber- 
cle ; 5, shaft or body 
with its twisted fur- 
row; 6, 7, articular or 
trochlear condyles; 8, 
uluar fossa with a sul- 
cus; 9, fossa for the 
insertion of the exter- 
nal lateral ligament. 



102 



THE BONES. 



Fig. 63. 



(or external) trochanter, and great fuberositi/—corm[>Y[ses three portions, named 
the summit, convexitij, and crest of the great tuberosity. The internal eminence — 
the trochin, little (or interned) trochanter, or small tuherosity — also presents three 
distinct portions, which, by their position, correspond exactly with the three regions 
of the external trochanter ; these are so many muscular facets. 

The external and internal trochanters are separated from each other in front 
by a channel called the bicipital groove, because the superior 
tendon of the biceps muscle glides over it. It consists of 
two vertical grooves, with a median ridge between them. 

The inferior extremity of the humerus has an articular 
surface corresponding with the radius and ulna. This sur- 
face — elongated transversely, convex from before backwards, 
and of greater extent within than without — exhibits two- 
trochlea separated by an antero-posterior relief. 

The median or interned trochlea, the deepest, is limited 
internally by a kind of voluminous condyle, which corre- 
sponds to the inner lip of the humeral trochlea of Man. 
The external trochlea is bordered outwardly by a slightly 
salient lip, which corresponds to the condyle of the humerus 
of Man. Above and behind this articular surface is a wide 
deep fossa — the olecranian (or condyloid), so named because 
it lodges the rostrom of the olecranon in the extension move- 
ments of the forearm. It is bordered by two eminences, 
the external of which is less elevated than the internal. The 
first represents the epitrochlea, and the second the epicondyle, 
of the humerus of Man. In front, and above the inner 
trochlea, there is another, but less spacious fossa, which 
receives the coronoid process during extreme flexion of the 
forearm, and which, for this reason, it would be convenient 
to designate as the coronoid fossa. Always in front, but 
above the external trochlea, are imprints for the attach- 
ment of the capsular ligament of the elbow- joint and the- 
extensor metacarpi magnus. Lastly, at the extremities 
of the transverse axis of the inferior articular surface is 
remarked, outwardly, an excavation for ligamentous insertion; 
inwardly, a small tuberosity for the same purpose. 
Structure and development. — The humerus, like all the long bones, is only 
spongy at its extremities. It is developed from six points of ossification, one of 
which alone forms the body, one the head and the internal trochanter, another the- 
external trochanter, a fourth the inferior articular surface, a fifth the epicondyle, 
and the last for the epitrochlea. The latter is sometimes absent. In the young 
animal the humerus is less twisted, and the eminences for muscular insertion less 
developed, than in the adult. 

In the Ass, the humerus is more twisted and curved in S form than in that 
of the Horse, and these modifications replace the eminences on this bone in the 
latter. Consequently, the equilibrium of the humerus is altered when it lies on a 
horizontal plane by any one of its faces and its lower extremity. Thus, while the 
humerus of the Ass may rest in equilibrium on a plane — its trochlea and two other 
points of its anterior face touching it — the Horse's humerus can only do so when 
the condyle, trochlea, and one or two points of its superior extremity touch it.. 




POSTERIOR VIEW OF THE 
RIGHT HUMERUS. 

2, External trochanter; 
3, articular head of 
the bone; 4, external 
tubercle and ridge ; 
5, body or shaft of 
the bone ; 10, condy- 
loid fossa. 



THE ANTERIOR LIMBS. 



103 



Fig. 64. 



Laid on its posterior face, the humerus of the Ass is in unstable equiUbrium, if it 
has to touch the plane by the epicondyle and epitrochlea ; this is not so with the 
humerus of the Horse. If it is placed on its external side, the deltoid imprint 
remains above the horizontal plane with the Ass, and touches it with the Horse. 
Lastly, the epitrochlea descends nearly to the articular surface in the Ass, so that 
the bone is almost in equilibrium when it is placed on its inferior extremity. 

The humerus of the Mule and Hinny resembles that of their parents, but 
that of the Hinny is more like the Ass's, and that of the Mule the Horse's. 

Differential Characters in the Humerus of other Animals. 

Proportiot)ately, the Immeius is longer, ami more inflected like an S, as the number of 
apparent digits is increased. Therefore it is that, in the C.irnivora, the characters of length 
and inflection are most marked. 

A. Ox, Sheep, Goat.— In these animals, the furrow of torsion is less marked, and the 
deltoid imprint less salient than in the Horse, while 

the extremities are larger and more curved. The 
bicipital groove is divided into two depressions by 
a median ridge ; the external trochanter is enormous, 
and its very elevated summit is bent over the 
bicipital groove. Tlie head is better detitched and 
the trochlea deeper than in the Horse. The medul- 
lary eanal of the humerus of the Ox is sometimes 
crossed by an osseous band. 

B. Camel. — Humerus cylindrical and nearly 
straight. Torsion furrow shallow ; nutrient foramen 
on its anterior face. Bicipital groove double, the 
inner cavity being larger than the external. The 
inferior articular surface is relatively very narrow, 
and the external trochlea deep. 

C. Pig. — The humerus of this animal is com- 
pressed on both sides; the head is much bent back- 
wards, which increases its S inflection. A single 
bicipital groove placed within the superior extremity ; 
the external trochanter voluminous, and the summit 
turned over the bicipital groove. Deltoid imprint 
and internal tuberosity of the body replaced by 
simple muscular imprints. 

D. Dog and Cat. — The humerus is very elon- 
gated and more S-curved than in all the other 
animals, and the internal tuberosity is leplaced by 
some imprints ; while the bicipital groove is single, 
and the nutrient foramen, on the posterior face, is as 
in the Ox, Sheep, and Pig. The coronoid fossa com- 
municates with that of the olecranon by a foramen. 

E. Rabbit. — The humerus of this animal greatly 
resembles that of the Dog, except that it is much 
more flattened on each side, and the deltoid imprint 
is on the anterior face and nutrient foramen on the 
inner lace of the bone. 

Forearm. 

This region has for its base two bones — ^the radius and mtitus (or vino), 
united into a single piece {os aniihrachii) at an early period in most of the 
domesticated animals. 




HUMERUS OF THE CAT AND RABBIT. 

, Humerus of the Rabbit. B, Humerus of 
the Cat. 1, Condyle; 2, trochlea; 3, 
diaphysis ; 4, external trochanter ; 5, 
internal trochanter ; 6, bicipital groove. 



1. Radius (Figs. 65, 66). 

This is a long bone, placed in a vertical direction between the humerus and 
the first row of carpal bones, and divided into a body and two extremities. 



104 



THE BONES. 



Body. — Slightly arched and flattened before and behind, it presents for study 
two faces and two borders. The anterior face is convex and perfectly smooth. The 
posterior, a little concave from one extremity to the other, offers : 1. Near the 
external border, a triangular surface, covered with asperities, elongated vertically, 
very narrow, commencing near the upper fourth of the bone, and terminating in 
a fine point towards the lower fourth ; this surface is brought into contact with 
the anterior face of the ulna by an interosseous liga- 
^^S- 65. ment, which is completely ossilied before the animal 

-^''' reaches adult age. 2. Above, there is a wide, trans- 

verse, but shallow groove, which aids in forming the 
radio-ulnar arch, and shows, near the point where it 
touches the preceding surface, the nutrient foramen of 
the bone. 3. Near the internal border, and towards the 
inferior third, there is a vertically elongated and slightly 
salient eminence for insertion. The two borders — external 
and internal — are thick and rounded ; they establish an 
insensible transition between the faces. 

Extremities. — The superior is larger than the inferior. 
It has : 1. An articular surface elongated from one side 
to the other, concave from before to behind, wider 
within than without, and moulded to the articular sur- 
face of the inferior extremity of the humerus ; there 
is also seen, outwardly, a double depression (glenoid 
cavities), which receives the two lips of the external 
trochlea ; in the middle, an antero-posterior ridge, 
which is received into the internal trochlea ; within, 
an oval cavity corresponding to the internal border 
of the former. 2. The external tuberosity, placed at 
the extremity of the great diameter of the articular 
surface ; it is prominent and well detached. 3. The 
interned or bicipital tuberosity — a large, very rugged, and 
depressed process, situated within and in front of the 
glenoid cavity. 4. A little lower, and on the same side, 
there is a strong muscular and ligamentous imprint, 
separated from the preceding tuberosity by a transverse 
1, Ulna; 2, point of the groove intended for the passage of a tendon. .5. The 
coronoid process,^ a small conical eminence, at the 
summit of which terminates, anteriorly, the median 
ridge of the articular surface. (3. Two diathrodial 
facets elongated transversely, cut on the posterior outline 
of the large articular surface, with which they are con- 
founded by their superior border ; they correspond with 
similar facets on the ulna. 7. Below these, a roughened 
surface which extends to the radio-ulnar arch, and is in contact with an analogous 
surface of the same bone through the medium of an interosseous ligament. In 
the Horse, this hgament rarely becomes ossified. 

The inferior extremity, flattened before and behind, presents : 1. Inferiorly, an 
articular surface elongated transversely and somewhat irregular, responding to 
the four bones in the upper row of the carpus. 2. On the sides, two tuberosities 
* In Man this belongs to the ulna. 




EXTERNAL FACE OF THE 
RADIUS AND ULNA. 

Ulna; 2, point of the 
ulna; 3, beak of ulna or 
olecranon ; 4, radio-ulnar 
arch ; 5, supero-external 
tuberosity; 6, radio-ulnar 
articular surfaces for the 
humerus; 7, bicipital tu- 
b rosity ; 8, shaft or body 
of the radius ; 9, grooves 
for tendons. 



THE ANTERIOR LIMBS. 105 

for ligamentous insertion — the internal salient and well circumscribed, the other 
external, and excavated by a vertical fissure — in which passes a tendon. 3. In 
front, three grooves for the gliding of tendons ; the external is the largest, 
and vertical like the median ; the internal, the narrowest, is oblique downwards 
and inwards. 4. Posteriorly, a strong transverse ridge which surmounts the 
articular surface, and serves for the insertion of ligaments. 

Structure and development.— The radius is a very compact bone, and is 
developed from three centres of ossification — one for the body, and two for the 
extremities. 

2. Ulna (Figs. 65, 66). 

This is an elongated, asymmetrical bone, in the form of an inverted triangular 
pyramid, applied against the posterior face of the radius, to which it is united 
in adult Solipeds. It offers for description a middle portion and two extremities. 

Middle portion. — This has three faces wider above than below, and three 
borders which become joined at the inferior extremity of the bone. The external 
face is smooth and nearly plane. The internal is also smooth and shghtly 
hollowed. The anterior is formed to correspond with the radius, and presents 
pecuharities analogous to those of the posterior face of that bone. Thus, there 
is found, in proceeding from above to below : 1. Two small diarthrodial facets.^ 
2. A roughened surface. 3. A transverse groove for the formation of the radio- 
ulnar arch. 4. A triangular surface, studded with rugosities, which occupie^the 
remainder of the bone to its lower extremity. The lateral borders — externatand 
internal — are sharp, and, like the anterior face, are in contact with the radius. 
The posterior border is concave, rounded, and thicker than the other two. 

Extremities. — The superior extremity comprises all that portion which exceeds 
the articular surface of the radius. It constitutes an enormous process — the 
olecranon — flattened on both sides, and presenting : 1. An external face, slightly 
convex. 2. An internal excavated face. 3. An anterior border, thin and sharp 
superiorly, notched below to form the sigmoid cavity^ — an articular surface 
concave from above downwards, rounded from one side to the other, which 
corresponds with the humeral cavity, and is surmounted by a salient prolongation 
named the bectk of the olecranon. 4. A concave and smooth posterior border. 5. 
The summit — a kind of thick roughened tuberosity which terminates the uhia 
above, and into which are inserted the extensor muscles of the forearm. 

At its inferior extremity, the ulna ends, towards the lower fourth of the 
principal portion of the forearm, in an acute point, and sometimes by a small 
knob (capitulum ulnce). It is not rare to see it prolonged, especially in the Ass 
and Mule, to the inferior external tuberosity of the radius. This tuberosity then 
appears to belong to it, at least in part ; and all that portion which is situated 
behind its vertical groove might be justly considered as a dependency of the 
uhia. 

Structure and development. — The ulna contains much compact tissue, even in 
the region of the olecranon ; it is also very solid. It is an imperfect bone, 
developed from two centres of ossification only, one of these being for the apex 
of the olecranon. 

In the Ass (Fig. 66), the radius is more curved than in the Horse, and when 
its anterior face is placed on a horizontal plane, the bone only rests on its upper 

' Tlv smaller siqmmrl cavity of Man. 
* 'The qreater f^iijinoid en vity of Man. 



106 



THE BONES. 



end and the middle of the body. It is also distinguished from that of the Horse 
by the depth of a narrow groove, which passes through the rough lip above and 
behind the inferior surface, superior to the small fossa 
F'g- 66. that receives the third bone of the upper row of the 

carpus during flexion and extension movements. The 
ulna of this animal is more developed than that of the 
Horse, and its olecranon is proportionately shorter, 
broader, and more hollowed on its internal face. The 
inferior extremity (Fig. 66, 9) is nearly always formed 
by a particular nucleus, which is also sometimes the case 
in the Horse. 

In the Hinny, the bone of the forearm resembles 
that of the Ass, with the exception of the smallness of 
the lower end of the ulna. 

Differential Characters in the Forearm Bones of 
OTHER Animals. 

The principal ditferential characters that they present are con- 
nected with the relative dimensions of the two bones and their mode 
of union. Regarding these, and as generally applicable, tlie follow- 
ing principles may be laid down : — 

1 . The development of the ulna is in direct relation to the division 
of the foot. — Mouodactylous animals — such as the Horse, Ass, and 
Mule — have, in fact, only a rudimentary ulna. In the pentadacty- 
lous animals, on the contrary — as Man, the Cat, Elephant, etc., — 
this is a veritable long bone which equals, or even exceeds, the 
radius in volume. 

2. The closeness of union between the radius and ulna is in 
increased proportion as the animal exchmvely employs its inferior 
extremity for standing and walking. — Thus, in Solipeds and Rumi- 
nants, and Pachyderms in general, the two bones are consolidated, 
or at least united by an interosseous ligament, and in so firm a 
manner that they can only execute very obscure movements on 
each other. The anterior limb of these animals is, indeed, only 
used to support the body on the ground. In those, on the contrary, 
which may employ it to dig up the soil, climb on trees, etc., or as 
an organ of preliension, the radius and ulna are merely joined at 
their extremities by an articulation, which permits them to move 
upon one another with the greatest facility. Rodents, the 
majority of the Caniivora, and the Quadrumana, are so provided ; 
but it is in Man that the relative independence of the two bones 
is carried to the highest degree. No animal can so easily execute 
the movements of pronation and supination of tiie hand, which are 
determined by the play of tlie two bones of the forearm on each other. 

To the indication of these fundamental characters, may be added 
some details on a few particular and important points. 

A. Ox, Sheep, Goat. — The forearm of the Ox is short; 
that of the Sheep and Goat is longer ; but in the three species, the 
ulna— thicker than in the Horse— is a long bone developed from 
three primary nuclei. It extends the whole length of tlie radius, 
and concurs in forming the articular surface corresponding with 
the carpal liones. 

The inferior articular surface is cut obliquely downwards and 
inwards. There are two radio-ulnar arches — a superior and in- 
ferior — united externally by a deep fissure. The union of tlie two 
bones is more intimate than in the Horse; for ossification always 
ends by invading that portion uf the interosseous ligament placed 
above the superior vascular arcli (Fig. 71). 




forearm bones OF THE 



1, Diaphysis of the radius; 

2, bicipital tuberosity ; 

3, external and superior 
tuberosity of the radius ; 

4, groove for the passage 
ot the anterior extensor 
of the phalanges ; 5, 
surface for insertion of 
branch of the perforans 
tendon ; 6, body of the 
ulna interrupted at its 
lower third, but more 
complete than usual ; 7, 
summit of the olecranon ; 
8, beak of ditto ; 9, in- 
ferior extremity of ditto ; 
10, radio-ulnar arch ; 11, 
crest above the inferior 
articular surface of the 
radius, behind. 



THE ANTERIOR LIMBS. 107 

B. Camel. — The radius of this animal has a narrow, superior, articulating surface of two 
glenoid cavities, separated by a median salient crest terminating in front by a very marked 
coronoid process ; the bicipital tuberosity is large, and on the anterior face. The ulna is very 
-concave in its middle part, and tlie olecranon is broad and low. 

C. Pig. — The radius is short, its inferior surface cut rather obliquely as in Ruminants, and 
partly formed by the inferior extremity of the ulna, which is a voluminous bone provided with 
a medullary canal, and solidly united to the radius by an interosseous ligament, the complete 
ossification of wliich is rare. It is flattened before and behind, and is spread over the posterior 
face of the radius, so as nearly to completely cover it. The olecranon is very prominent (Fig. 7G). 

D. Dog, Cat. — The two bones of the forearm are nearly equal in volume, and are in 
contact only by their extremities, where they show for this purpose : 1. Above, on the ulna, 
a concave articular surface — the small sigmoid cavity ; and on the radius, a rounded hinge-like 
facet. 2. Below, two facets analogous to the preceding, but much smaller; that on the radius 
is concave, and that on the ulna convex. Tliese two bones slightly cross each other, so that the 
upper end of the ulna touches the radius behind and inwards, wliile the inferior terminates 
altogether outwards. In the Pig and Ruminants, the lower end is in contact with the upper 
row of carpal bones (Fig. 77). 

E. Kabblt. — The ulna is still more developed than in the Cat, and more curved length- 
ways. 

The posterior border of the olecranon is almost vertical, instead of being oblique from 
before to behind, and the sigmoid notch is deeper and shorter curved than in the 
Carnivora. 



ANTERIOR (OR FORE) FOOT, OR HAND. 

The anterior foot, or hand, is the region which presents the greatest 0flfe- 
rences when it is examined in the various individuals of the animal series. 
Nevertheless, notwithstanding these varieties, its constitution is fundamentally 
the same, and may be divided into three sections — ^the carpus, metacarpus, and 
phalangeal region. 

In vertebrate animals, the hand is composed of a certain number of parallel 
or quasi-parallel segments, which constitute the digits. Each complete digit is 
subdivided into three sections, placed one above the other ; these are, reckoned 
from above to below — carpus, metacarpus, and phalanges. 

The number of apparent digits varies from one to five ; and, however it may 
otherwise appear, philosophical anatomy has shown that the hand of all the 
domesticated animals may be considered as belonging to the pentadactylous 
type. When it does not appear to be so, this is due to more or less numerous 
or extensive atrophies or abortions always occurring according to fixed laws. (See 
remarks hereafter on the Hand in General.) 

1. Caepal Bones (Figs. 67, 68, 69). 

The carpus (or 'knee') forms the base of the hand. Situated between the 
inferior extremity of the radius and the superior extremity of the metacarpal bones, 
it is composed of several small bones joined to each other, in the fresh state, by 
extremely solid articular bands. Collectively, they form an almost quadrilateral 
mass, in which may be distinguished two faces and four borders. 

The anterior face is slightly convex from side to side, and irregular ; it is 
in contact with the tendons of the extensor muscles of the metacarpus and 
phalanges. 

1h.Q posterior face is very unequal, and converted — especially outwardly — into 
a groove, in which the tendons of the flexor muscles of the phalanges glide. 



108 



THE BONES. 



Fig. 67. 



The superior border articulates with the radius ; the inferior border with the 
metacarpal bones. 

The lateral borders are nearly flat ; above and behind the external border is 
remarked a considerable eminence, formed by the 
bone which will be hereafter studied as the super- 
carpal bene (pisiform or trapezium). 

In the carpus of the Horse are seven or eight 
bones, which are disposed in two superposed rows. 
The superior row comprises four bones placed side 
by side, and designated by the numerical names of 
Jirst, second, third, and fourth, viewing them from 
without to within. The inferior row has only 
three, which are named in the same manner. 

In applying to them the names proposed by 
Liser, we have, in the upper row — 

1. The pisiform, or supercarpal bone. 

2. The cuneiform bone. 

3. The lunar bone. 

4. The scaphoid bone. 
In the inferior row — 

1. The unciform bone. 

2. The magnum bone. 

3. The trapezoid bone. 

4. The trapeziimi (not constant). 
The description of these bones is most simple, 

and may be made in a general manner for all. Thus, 
with the exception of the supercarpal bone, they 
are solid, nearly cubical in form, and exhibit on 
their periphery : 1. Articular surfaces. 2. /Surfaces 
for insertion. 

The articular surfaces are small, flat, or slightly 
undulating facets, distributed on the superior, in- 
ferior, and lateral faces ; none are found in front 
or behind. The superior and inferior faces are 
entirely occupied by a single facet, which responds 
either to the radius, the metacarpals, or to the bones 
of the other row. The lateral facets are always 
RIGHT ANTERIOR FOOT OR HAND multiplc, aud iu coutact with the bones of the same 




OF A 



tier ; they do not exist, of course, on the outside 
of the bones at the ends of each row. 

The surfaces for insertion are absent on the 
superior and inferior faces ; they separate, in the 
form of roughened depressions, the lateral articular 
facets. Before and behind, they are covered by 
more or less marked rugosities. 

Bones of the Upper or Antibrachial Row 
(Figs. 68, 69). — The first, or os pisiforme, is outside 
the row ; it is situated above and behind the carpus, whence its name of super- 
carpal bone, by which it is usually known in veterinary anatomy. This bone, 
which merits a special description, represents a disc flattened on both sides. 



HORSE. 

1, Radius; 2, grooves for the ex- 
tensor of the phalanges; 3, 
scaphoid; 4, lunar; 5, cunei- 
form ; 6, pisiform ; 7, mag- 
num ; 8, unciform ; 9, great 
metacarpal; 10, small meta- 
carpal ; 11, sesamoid bone ; 12, 
suffraginis ; 13, coronary; 14, 
navicular; 15, pedal ; 16, basi- 
lar process. 



THE ANTERIOR LIMBS. 



109 



oflFering for study two faces and a circumference. The external face is convex, 
roughened, and channeled anteriorly by a groove that traverses it from above to 
below, in which glides the inferior tendon of the external flexor of the 





CARPUS OF THE HORSE (ANTERIOR FACE). 

1, Pisiform or supercarpal bone (first of the 
upper row); 2. cuneiform (second ditto) ; 
3, lunar (third ditto); 4, scaphoid (fourth 
ditto) ; 5, unciform (first of lower row) ; 
6, OS magnum (second ditto) ; 7, trape- 
zoid (third ditto) ; 9, inferior articular 
face of the radius; 10, groove for the 
oblique extensor tendon of the meta- 
carpus; 11, groove for the anterior ex- 
tensor of the metacarpus; 12, groove for 
the anterior extensor of the phalanges ; 
13, superior extremity of the large meta- 
carpal bone ; 14, tubercle for the inser- 
tion of the anterior extensor of the meta- 
carpus ; 15, superior extremity of the 
external small metacarpal bone. 



CARPUS OF THE HORSE (POSTERIOR FACE> 

1, 2, 3, 4, 5, 6, 7, Same bones as in preced- 
ing figure ; 8, trapezium (fourth bone of 
the lower row); 9, 9, inferior articular 
surface of the radius ; 10, transverse crest 
for insertion of common posterior liga- 
ment of the carpus; 11, superior extremity 
of large metacarpal bone; 12, rugosities 
in which are fixed the deep layer of the 
suspense) y ligament of the fetlock or 
superior sesamoid ligament; 13, external 
small metacarpal ; 14, internal ditto. 



metacarpus. Its internal face — smooth and concave — concurs in forming the 
external wall of the carpal sheath. The circumference presents, in front, two 
10 



110 THE BONES. 

articular facets : the superior, concave, corresponds to the radius ; the inferior, 
convex, is in contact with the second bone of the upper row. 

The other three bones of this row increase in volume from without to within. 

The second bone, os pyramidalis, or cuneiform, articulates with the radius, 
the first bone of the lower row, the third of the upper, and the supercarpal 
bone ; it has, in all, five articular facets. 

The third, or os lunctre, has six facets, and is united below to the first and 
second bones of the second row. 

The fourth, or os scajjhoides — the most voluminous of the row— has only four 
facets, and articulates by its inferior face with the os magnum and trctpezoides. 

Collectively, the second, third, and fourth bones of the upper row form two 
articular surfaces. 

The superior, or radial articular surface, is very irregular ; but in examining 
it from without to within, there may be observed : 1. A glenoid cavity on the 
cuneiform bone. 2. In front, a transversely elongated condyle on the lunar and 
scaphoid bones. 3. A groove placed behind the preceding condyle. 

The inferior articulating surface, which corresponds to the second row, is 
constituted by several undulated facets ; it is convex outwardly and in front, 
concave posteriorly and inwardly. 

Bones of the Infekior or Metacarpal Row (Figs. 68, 69). — The thick- 
ness of these bones decreases from without to within. 

The first, unciform, or hookbone {os hainatum), has four diarthrodial facets, 
and responds, above, to the two first bones of the superior row ; below, to the 
first and second metacarpals. 

The second, os magnum, or os capitatum — ^the largest — has seven articular 
facets, three of which are on the interno-lateral face. It articulates, above, with 
the lunar and scaphoides ; below, with the principal metacarpal and the internal 
rudimentary metacarpal. 

The third, or trapezoides — the smallest — is provided with five facets, and is 
in contact with the scaphoides above, and the middle and internal metacarpals 
below. 

Collectively, these bones of the lower row form two large diarthrodial 
surfaces. The upper surface responds to the bones of the upper row, and is 
constituted in front, and from without to within, by a small condyle and two 
glenoid cavities ; behind, by two isolated condyles, formed by the os magnum 
and the trapezoides. The inferior articular surface is only formed by more or 
less long and plane facets, which incline towards each other. It articulates with 
the three portions of the metacarpus. 

Structure and deveJopm£nt. — Each carpal bone is formed by a nucleus of 
close spongy substance, enveloped in a very thick layer of compact tissue. Each 
is developed from a single centre of ossification. 

The carpal bones of the Ass much resemble those of the Horse, but the 
upper face of the Junar is more concave ; the facet of the cuneiform, for the 
pisiform, is less concave, but larger and triangular, and is always separated from 
the superior articular surface by a rough, wide, and deep groove. The pisifot m 
is more circular than that of the Horse, and is modified in shape to correspond 
with the cuneiform ; while the inferior surface of the os magnum is almost plane 
in the Ass, but in the Horse it is cut into a condyle in front and a glenoid cavity 
behind. Lesbre states that the trapezium is more frequent in the carpus of the 
Ass than the Horse. 



THE ANTERIOR LIMBS. 



Ill 



The carpal bones of the Hinny are hke those of the Ass, but those of the 
Mule resemble the Horse. 



Fi^. 70. 



Differential Characters in the Carpal Bones of other Animals. 

A. Ox, Sheep, Goat. — In these animals the carpus is composed of only six bones — four 
in the upper and two in the lower row, where the os magnum and trapezoid are fused together. 
The pisiform bone is in shape as its name implies, has no groove, and has no relation with the 
radius. The cuneiform bone articulates with the radius and ulna. The bones of the lower 
row only articulate with the large metacarpal bone (Fig. 71). 

B. Camel. — Among tlie seven carpal bones of the Camel are seen : 
a pisiform bone, having on its external face a large smooth groove ; a 
lunar, flattened on each side, and deeply notched laterally ; an unciform 
having a pyramidal prolongation behind ; an os magnum, smaller than 
the latter ; and a trapezoid, little developed, and entirely removed to 
the posterior part of the carpus. 

C. Pig. — The carpus of the Pig, like that of Man, contains eight 
bones — four in each of the rows. The second bone of the upper row 
articulates with the ulna, and to a very small extent with the radius. 
In the bones of the lower row, it is observed that the first articulates 
witli the two external metacarpals, the second with the great internal 
metacarpal, the third with the preceding and the small internal meta- 
carpal. The fourth, or trapezium, terminates inferiorly by a blunt 
point, and has no relations with the metacarpal bones, because the thumb 
is entirely undeveloped in this animal (Fig. 76). 

D. Dog, Cat. — In the Cat and Dog there are also eight bones. 
Lesbre says, however, that the scaphoid and lunar are sometimes one 
bone, and that often a lenticular bone is found in the upper row. The 
cuneiform bone is very developed, and occupies all the external border of 
the carpus, articulating with the ulna, first bone of the second row, and 
the first metacarpal. 'J'he pisiform bone is elongated, prismatic, thick 
at both ends, and has in front two contiguous articular facets— one for 
articulation with tlie ulna, the other for union with the cuneiform bone. 
The bones of the lower row diminish in size from the first to the fourth, 
and articulate — the first, with the first and second metacarpals; the 
second, with the metacarpal of the third digit; the third, with the 
fourth digit ; and the fourth with the metacarpus of the thumb. 

E. Rabbit. — This animal possesses nine carpal bones; for it is 
stated that between the two rows there is a piece which Blainville has 
named the intermediate bone It really belongs to the upper row, and 
represents the scaphoid. There are, therefore, five bones in the first 
carpal row of the Rabbit, and in this respect the hand of this species 
more nearly approaches the typical hand than that of the other domestic 
animals (see the Hand in General). 




2. Metacarpal Bones (Figs. 67, 70). 



In Solipeds, the metacarpus is composed of three bones, 
named the " metacarpals," standing parallel to each other. 
These are the principal metacarpal and the two rudimentary 
metacarpals — an external and internal. 

Principal Metacarpal Bone {psmetacarpi magnum').— 
This is a long cylindrical bone, situated vertically between the 
carpus and the digital region. 

Bodij. — The body is a little depressed before and behind, which permits it to 
be described as having two faces and two borders. The anterior face is perfectly 
smooth and rounded from side to side. The posterior face is flat, and exhibits : 
1. Towards the upper third, the nutrient foramen of the bone. 2. On the sides, 



posterior view of 
right metacarpus. 
1, Head of large meta- 
carpal bone for ar- 
ticulation with the 
trapezoi'i, magnum, 
and unciform ; 2, 
inner splint, rudi- 
mentary, or small 
metacarpal bone,for 
articulation with 
the trapezoid ; 4, 
scabrous surface for 
the attachment of 
the suspensory liga- 
ment ; 5, nutrinnt 
foramen ; 6, median 
ridge separating tne 
two inferior con- 
dyles. 



112 THE BONES. 

two narrow, rousrhened surfaces, parallel and elongated vertically, commencing 
near the superior extremity, to disappear a little below the middle of the bone ; 
these surfaces are held in apposition to the rudimentary metacarpals, by an 
interosseous ligament which is often ossified in old Horses. The borders — external 
and internal — are very thick, round, and smooth, like the anterior face. 

Extremities. — The superior is flattened before and behind, and presents. 1. 
Above, an undulating articular surface, formed by the union of several flat facets 
more or less inclined towards each other ; they articulate with all the lower row 
of carpal bones. 2. Anteriorly and inwardly, a tuberosity for muscular insertion. 
3. Posteriorly — and directly above the roughened surfaces of the posterior face — 
four small diarthrodial facets in pairs, and running into the larger articular 
surface by their superior border ; they are adapted to similar facets on the 
rudimentary metacarpals. The inferior extremity, elongated transversely, articulates 
with the first phalanx and the sesamoid bones by an articular sm-face — convex 
from before to behind — which is composed of tivo lateral condyles separated by a 
median spine. The two condyles would be exactly alike, if the antero-posterior 
diameter of the external condyle were not less extensive than that of the opposite 
condyle. Both are hollowed on the sides by an excavation for the attachment 
of ligamentous fasciculi. 

Structure and development. — The principal metacarpal is one of the most 
compact bones in the body. It is developed from two centres of ossification, 
one of which is for the inferior extremity. 

RuDiMENTAEY METACARPALS (ossa metacctrpi pavva). — The two rudimentary 
(sm.aU) metacarpal (or splint) bones are elongated, and placed against the 
posterior face of the principal bone, one without, the other within. Each is in 
the form of an inverted pyramid, and exhibits a middle part and two extremities. 

Middle portion. — Prismatic and triangular, this ofl^ers : 1. Three faces — an 
external, smooth and rounded from one border to the other ; an internal, plane, 
and equally smooth ; an anterior, covered with asperities to give attachment to 
the interosseous ligament uniting the lateral metacarpal bone to the median. 
2. Three salient borders which markedly separate the faces from each other. 

Extremities. — The superior, the largest, is named the head, and shows : above, 
a diarthrodial facet which articulates with one or two bones of the inferior row 
of the carpus ; in front, other two small facets continuous with the preceding, 
and in contact with similar facets on the large metacarpal bone ; on the other 
points of its periphery are rugosities for the attachment of ligamentous and 
tendinous fibres. The inferior extremity only reaches to about the lower fourth 
of the large metacarpal bone, and terminates in a small button-shaped enlarge- 
ment, which is never fused with the latter. 

The two small metacarpals, although very much alike, may yet be easily 
distinguished from each other. For instance, the internal bone is always the 
thickest, and often the longest ; besides, the superior articular surface of its 
head results from the union of the two facets articulating with the two last 
carpal bones of the lower tier. 

Structure and development. — Of a somewhat compact texture, like all the long 
bones, these have no medullary canal, and are developed from only one ossifying 
centre. Not unfrequently, however, the tubercle is formed from a special centre. 

The metacarpus of the Ass is recognized by : 1. The great inequality of the 
small metacarpals. 2. The thickness of the large metacarpal (the width is to the 
thickness as 1-35 : 1 in the A&s, and as 1*53 : 1 in the Horse). 3. The depth of 



THE ANTERIOR LIMBS. 



113 



the depressions above the inferior articular surface, poste- 
riorly. 4. The level form of the facet articulating with the 
OS magnum of the second row. 5. The presence of a small, 
flat, vertical facet on the posterior contour of the upper 
articular surface of the large metacarpal. 

In the Mule and Hinny, the small metacarpals are nearly- 
alike, as in the Horse ; the large metacarpal is flattened, as 
in that animal, with marked depressions posteriorly. 



Differential Characters in the Metacarpus of other Animals. 

The number of metacarpal bones naturally varies with tliat of the 

digits : — 

In the Carnivora there are 5 

In the Pig there are 4 

In Ruminants there are 2 or 3 

With regard to their shape and form, they offer interesting differences, 

which will now be studied. 

A. Ox, Sheep, Goat. — In these animals the metacarpal bones are 
two in number — a principal, which itself results from the consolidation 
of the second and third metacarpals ; another, altogether rudimentary, 
situated outwardly; and a third— not constant — embedded in a fibrous 
cord passing along the inner border of tlie principal metacarpal. 

The principal metacarpal is channeled on its anterior face, and for 
its whole length, by a deep vascular fissure — a trace of the primitive 
separation of the bone into two pieces. Tliis fissure presents, inferiorly, 
the anterior orifice of a canal that completely traverses the bone. The 
posterior face is nlso marked by a very slight longitudinnl groove. The 
superior extremity exhibits, externally and posteriorly, a single diar- 
throdial facet for articulation with the rudimentary metacarpal. The 
inferior extremity is divided by a deep notch into two articular surfaces, 
which together resemble the single surface in the Horse ; each articulates 
with one of the digits ; the external is always smaller than the internal. 
In the foetus, the two long bones that form the great metacarpal are 
simply laid together, and their medullary canals are separated from 
each other by the double partition which results from this apposition ; 
after their coalescence, however, the partitions are completely destroyed 
by absorption, and in a short time there is only a single medullary canal 
for the entire bone. 

Tiie rudimentary metacarpal is only a small osseous stylet, articu- 
lating, by a diarthrodial facet, beiiind and to the outside of the superior 
extremity of the principal metacarpal; it is sometimes absent in the 
Sheep and Goat. 

B. Camel.— The metacarpus of the Camel is very long, quadran- 
gular in its upper two-thirds, and flattened behind and before in its 
inferior third. Its posterior face is converted into a kind of concave 
furrow, by the considerably raised borders of the bone. The superior 
articular surface is divided into two parts by a large roughened depres- 
sion ; the inner part is on a higher level than the outer. The inferior 
extn mity is also divided into two articular surfaces by a very deep 
notch ; each surface is condyloid in its anterior moiety, and is like 
that of the Horse in its posterior moiety. 

C. Dog, Cat, Rabbit.— The five metacarpals of the Dog and Cat 
articulate with each other, at their superior extremities, by lateral 
facets; they offer, at their inferior extremity, a condyle prolonged back- 
wards by an articular surface resembling that of the Horse. The 



forearm and foot 

OF THE ox (front 

view). 

1, Olecranon ; 2, body 

of the ulna ; 3, 

body of the radius; 

first and second bones 

rudimentary metacarpals; 10, principal inetacarpals ; 11, external digit; 



4, 5, 6, first, second, and third bones of the upper row of the carpus; 7, 

of the lower row ; " " ' ' 

12, internal digit. 



114 



THE BONES. 



middle two are always longer than the two lateral. The smallest belongs to the fifth digit, or 
thumb, and is terminated inferiorly by a trochlea. 

D. Pig. — The four metacarpals of the Pig articulate with each other, as in the Carnivora. 
The second and third are larger than the first and fourth. The fifth metacarpal is not 
developed (Fig. 76). 

3. Bones of the Phalangeal or Digital Region (Figs. 72, 73). 
Solipeds have apparently only one digit, supported by the principal metacarpal 
bone, and composed of three pieces placed end to end, one upon another. The 
first comprises three bones — a principal, the first phalanx — and two complemen- 



Fig. 72. 



Fig. 73. 





LATERAL VIEW OF THE DIGITAL 
REGION (OUTSIDE OF RIGHT LIMB). 

1, Large metacarpal bone ; 2, 3, outer and 
inner sesamoids ; 4, first, jiroximal, os suf- 
fraginis, or metacarpal phalanx ; 5, its 
posterior surface ; 6, tuberosity for liga- 
mentous insertion ; 7, inner condyle of 
ditto ; 8, eminences on second phalanx for 
attachment of lateral ligament; 9, smooth 
surface for passage of deep flexor tendon 
on second phalanx ; 10, median or second 
phalanx, os coronae, or small pastern bone ; 
11, navicular bone; 12, third phalanx, 
pedal, or coffin bone ; 13, its basilar process. 



POSTERIOR VIEW OF THE DIGITAL REGION. 

1, Large metacarpal bone ; 2, 3, outer and 
inner splint bones ; 4, 5, sesamoid bones ; 
6, suffraginis ; 7, 8, tuberosities for inser- 
tion of crucial ligaments ; 9, triangular 
space for insertion of short sesamoid liga- 
ment ; 10, anterior face of suffraginis ; 
11, 12, tuberosities for ligamentous inser- 
tion ; 13, articular depression separating 
condyles ; 14, 15, second phalanx ; 16, 
scabrous surface for ligamentous attach- 
ment; 17, smooth surface for gliding of 
deep flexor tendon ; 1 8, navicular bone ; 
19, pedal bone ; 20, basilar process ; 21, 
plantar foramen. 



tary ones, the sesamoids. The second is formed by the second phalanx, and the 
last, which terminates the limb, is constituted by the third phalanx, and an 
accessory bone which has received the name of the small sesamoid {navicular 



First (proximal) or Metacarpal Phalanx (Large Pastern Bone, or 
Os Suffraginis).— The first phalanx (Figs. 72, 73), the smallest of all the 
long bones, is situated in an oblique direction from above downwards, and 
behind to before, between the principal metacarpal and the second phalanx. 



THE ANTERIOR LIMBS. 115 

Body. — Flattened before and behind, this bone exhibits : an anterior face^ 
round from one side to the other, and slightly roughened above and below ; 
a posterior face, flat, covered with ligamentous imprints in the form of a triangle 
with the base reversed ; two lateral borders, thick, rounded, and provided with 
some imprints. 

Extremities. — The superior, the largest, presents : Above, an articular surface 
adapted to the inferior metacarpal surface, and consequently composed of two 
glenoid cavities separated by a groove running from front to back ; laterally, 
and a little posteriorly, a well-defined tubercle of iiisertion. The inferior extremity 
has a transversely elongated articular surface, to articulate with the second 
phalanx ; this surface is formed by tivo condyles separated by a middle groove, 
and surmounted laterally by a small tuberosity for ligamentous insertions. The 
external condyle is smaller than the internal, and when the bone is placed upon 
a horizontal plane, the anterior face turned upwards, it only touches by three 
points— the two tubercles of the upper extremity and the internal condyle ; by 
pressing on the external condyle, it is easy to make the bone oscillate. 

The first phalanx is a very compact bone, and is developed from two points 
of ossification, one of which is for the superior extremity alone. Professors 
Yachetta and Fogliata, of Pisa, assert that this bone, as well as the second phalanx, 
has three centres of ossification during uterine life. 

Sesamoids (Figs. 72, 7^). — These are two small, short bones placed side 
by side behind the superior extremity of the first phalanx, the articular sur- 
face of which it completes, as it has not extent enough to be exactly adapted to 
the metacarpal surface. Each of these bones represents a small, irregularly shaped 
polyhedron, or, rather, a short trifacial pyramid. It offers : an anterior face, 
which is articular, and corresponding to the inferior extremity of the principal 
metacarpal bone, moulded, as it were, on one of the condyles and one of the 
sides of the median ridge ; a posterior face, covered with cartilage in the fresh 
state, and forming, with that of the opposite bone, a gliding concave surface for 
the flexor tendons of the phalanges ; a latercd face, studded with ligamentous 
imprints ; a summit, directed upwards ; and a base, turned downwards, and 
serving for the attachment of several ligaments. 

Second (or Median) Phalanx (Os Coron.^, Small Pastern Bone (Figs. 
72, 73). — This is a short bone, situated in the same oblique direction as the 
first phalanx, and between it and the third. Its general form is that of a 
cube flattened before and behind, and offering the following features : an anterior 
face, covered with some slight imprints ; a posterior face, provided, above, with a 
transversely elongated gliding surface ; a superior face, channeled by two glenoid 
cavities, to match the inferior articulating surface of the first phalanx ; an inferior 
face, formed on the same plan as the last — being occupied by two unequal condyles, 
which articulate with the third phalanx and the navicular bone ; two lateral faces 
exhibiting a very marked imprint. In the interior of this bone is found a nucleus 
of very condensed spongy substance, enveloped in a layer of compact tissue. 

It is usually developed from a single centre of ossification, though in many 
subjects there is a complementary nucleus for the superior articular and the 
posterior ghding surface. 

Third (Distal or Ungual) Phalanx, Os Pedis (Pedal or Coffin Bone) 
(Figs. 72, 73, 74). — This is a short bone which terminates the digit, and sustains 
the hoof that incloses it and the navicular bone. When completed by a special 
tibro-cartilaginous apparidus, it represents the segment of a very short cone. 




116 THE BONES. 

obliquely truncated behind, from the summit to the base. It offers for study : 
three faces, three borders, and two lateral angles. 

Faces. — The anterior, convex from side to side, and cribbled by porosities and 
vascular openings, shows on each side: 1. The preplantar fissure — a horizontal 
groove more or less ramified, which commences behind, between the retrossal and 
basilar processes, terminating in front in one of the foramina that penetrate 
the bone. 2. The patilohe eminence — a roughened projecting surface, situated 
between the preceding fissure and the inferior border of the bone. The superior 
face is occupied by an articular surface formed by two glenoid cavities and a slight 
median ridge ; it comes in apposition with the inferior face of the second phalanx. 
The inferior (or solar) face, hollowed out like an arch, is divided into two regions 
by the semilunar crest, a salient line which describes 
^'-- '^^- a curve forwards. The anterior region is perforated 

with very fine porosities, and corresponds to that part 
of the hoof named the sole. The posterior region 
shows, immediately behind the semilunar crest, a 
median imprint, and two lateral channels designated 
the plantar fissures. These originate at the root of 
tlie basilar process, are directed obliquely downwards 
and inwards, and open into the plantar foramina, 
the external orifices of two large canals which enter 
PLANTAR SURFACE OF THIRD ^j^g jjQ^g ^ud uultc lu Its luterlor to form the semilunar 

PHALANX. 

« o sinus. 

1, Lower face, or sole \ 2, i, r, i n^^ • ^ ■^ -ii, 

wings, or retrossal pro- Borders.— ThQ Superior describes a curve, with 

cesses; 4. internal border; the convexity forward, and presents : 1. In its middle, 
5, plantar foramina. ^.j^^ pyramidal eminence of the OS pedis — a single tri- 

angular process, flat before and behind, roughened on its anterior aspect, and 
concurring, by its posterior surface, to form the articular surface which responds 
to that of the second phalanx. 2. Laterally, two facets of insertion which 
encroach on the anterior surface, and even advance, posteriorly, nearly to the 
preplantar fissure. The inferior border is thin, dentated, convex, and semicir- 
cular ; it is perforated by from five to ten large foramina, which pass into the 
bone. The posterior border is slightly concave ; on it is observed a very narrow, 
transversely elongated, diarthrodial facet, which becomes confounded with the 
superior large articular surface, and is adapted to a similar facet on the navicular 
bone. 

Lateral angles. — These are two projections directed backwards, on the summit 
of which the three borders of the bone unite, and which gives attachment to the 
lateral fibro-cartilages. A deep notch — the origin of the preplantar fissures — 
separates. each into two particular eminences: one, the superior, named by 
Bouley the basilar process ; the other, the inferior, prolonged behind, and desig- 
nated by Bracy Clark the retrossal process (from retro, behind, and ossa, bone). 

Sfructvre. — The os pedis exhibits in its interior the semilunar sinus — a cylin- 
drical, transversely elongated, and semicircular cavity resulting from the arching 
anastomoses of the two plantar canals. From this cavity pass off numerous 
channels, which anastomose frequently with each other, and open externally by 
the foramina on the anterior face of the bone, or by those on its inferior border. 
The OS pedis has for its base a nucleus of spongy substance, surrounded by a 
layer of compact tissue. The latter is thicker towards the pyramidal eminence 
than elsewhere, and sends into the interior numerous prolongations which form 



THE ANTERIOR LIMBS. 



11? 



the walls of the semilunar sinus, as well as the bony channels which spring 
from it. 

Development. — The third phalanx, formed from a single nucleus of ossifica- 
tion, undergoes numerous changes in its configuration during life. Thus, in the 
young animal the lateral angles are thick, obtuse,^ and but little prolonged 
posteriorly ; but as it grows older, they increase in length and become salient. 
The development they then assume, is due to the progressive ossification of the 
lateral cartilages implanted on their surface. It often happens, in very old horses 
that this ossifying process is carried to an extreme degree, and nearly the whole 
substance of these complementary organs is invaded. From the commencement, 
its inevitable result is to convert the notch which separates the basilar from the 
retrossal process into a foramen. 

The comple me atari/ Jihro-cartilaiiinous apparatus of the as pedis. — To under- 
stand properly the disposition of this portion of the .foot, it is necessary that a 
previous knowledge of the ligaments 
and tendons attached to the os pedis 
should have been acquired ; therefore 
a detailed description will be given 
when the Horse's foot is studied as a 
whole, in the article on the Sense of 
Touch. It will be sufficient here to state 
that this apparatus consists of two 
lateral pieces — the fibro-cartilages of the 
OS pedis, united behind and below by 
iheplantar cushion — a fibrous and elastic 
mass on which rests the navicular bone, 
through the medium of the perforans 
tendon. 

The Small Sesamoid or Navicular 
Bone (Figs. 72, 75). — This short bone 
is annexed to the third phalanx, behind 
which it is situated ; it is elongated 
transversely, flattened above and below, 
and narrow at its extremities. It offers : 
1. A superior face, on which are pro- 
longed the glenoid cavities and the 
median ridge of the articular surface 
of the OS pedis ; it articulates with the 

second phalanx. 2. An inferior face, dixided by a slight ridge into two undulated 
facets, and covered with cartilage to form a gliding surface. An anterior border, 
channeled lengthways by a groove of insertion, above which is remarked a diar- 
throdial facet that brings the small sesamoid into contact with the posterior border 
of the third phalanx. 4. A posterior border and two extremities, for ligamentous 
insertion. This bone, as well as the sesamoids, originates from a single centre of 
ossification. It is formed of a layer of compact tissue enveloping a nucleus of 
very condensed spongy substance. (For differences in the Ass, see Posterior 
Limb.) 




NAVICULAR BONE OF THE HORSE. 

Anterior Border and Inferior Face. 1, articu- 
lar facet for the facet on the po.stenor border 
of the OS pedis; 2, roughened groove on the 
anterior border ; 3, inferior face, smooth and 
undulated. B, Posterior Border and Superior 
Face. 1, Articular face for the lower end of 
the second phalanx; 2, posterior border, with 
many foramina. 



118 THE BONES. 

• 

Differential Characters in the Digital Region of other Animals. 
In the other domesticated animals, the number of complete digits is as follows : — 

Carnivora 5 

Pig 4 

Ruminants • .... 2 

A. Ox, Sheep, Goat. — These animals certainly possess four digits, but only two are perw 
feet— the mMius and annularis — and these articulate with the inferior extremity of the principal 
metacarpal (Fig. 71). The two others — the index and auricularis — are in a rudimentary con- 
dition, and are represented by two small bones situated above and behind the metacarpo- 
phalangeal articulation. 

In the Ox, Sheep, and Goat, each of the perfect digits comprises (like the single digit of the 
Horse) three phalanges and three sesamoids. 

The first phalanx fairly represents the moiety of this phalanx in the Horse. It has no 

Fig. 77. 
Fig. 76. y^ 

^- 

if' '' *~ 




ANTERIOR LIMB OF THE PIGi. 



FOREARM AND FOOT OF THE DOG (AN- 
TERIOR face). 

1, First digit ; 2, second digit ; 3, third 
digit ; 4, fourth digit ; 5, thumb ; 6, 
7, 8, 9, first, second, third, and fourth 
bones of the lower row of carpnl bones ; 
10, 11, first and second bones of the 
upper row; 12, supercarpal bone; 
13, body of the ulna ; 14, apex of the 
olecranon; 15, beak of the olecranon; 
16, body of the radius. 



posterior imprints, but shows them on its inner surface for the attachment of several ligaments. 
This internal face is plane, and the external convex ; these characters are repeated in the other 
two phalanges. It is also remarked in all the phalangeal bones, that the external articular 
facet of the extremities is always larger than the iuterual. Of the two sesamoids, the external 



THE ANTERIOR LIMBS. 



119 



Fig. 78. 



is wider and less elongated than tlie internal. They articulate with each other and with 
the first phalanx, by small diarthrodial facets. 

The second phalanx is hollowed internally by a small medullary cavity. 

The ungual phalanx, as a whole, resembles one of the lateral moieties of the os pedis of 
Solipeds. Tills phalanx has no complementary fibro-cartilage, basilar process, or retrossal 
eminence, nor yet a cavity for insertion on the sides of the pyramidal eminence. The semilunar 
crest is replaced by an obtuse, thick, and rugged ridge, which occupies quite the posterior limit 
of tlie inferior face of the bone. Three large canals penetrate the third phalanx— two to the 
base of the [lyramidal eminence, and one towards the origin of the preplantar fissure. They 
form, in the interior of the bone, a vast sinus, giving rise to several vascular canals which open 
on the surface. There is only one foramen at the base of the pyramidal eminence in the smaller 
Ruminants. 

B. Camel. — In this animal, there are in each digit only three phalanges and two large 
sesamoids. The direction and form of these phalanges 
differ notably from what is seen iu Ruminants. The 
first phalanx is long, very oblique, constricted in the 
middle, and very thick at both ends. On the superior 
articulating surface is a single glenoid cavity, dirided 
posteriorly by a median groove. The inferior surface is 
prolonged on the posterior face of the bone, which is 
converted into a kind of pulley. The second phalanx is 
nearly horizontal, and much flattened above and below. 
The ungual phalanx is somewhat like an irregular 
trifacial pyramid with a blunt summit ; near its base, 
on its upper face, it has a roughened tubercle. 

C. Pig. — The Pig has four complete digits articu- 
lating from the metacarpals ; the thumb is absent. The 
index and auricularis— or fourth and fifth digits — are 
short, and do not usually rest on the ground (Fig. 
76). 

D. Dog, Cat, Rabbit.— The five digits of the 
log and Cat are exactly analogous to those of Man. 
Thus, the external corresponds to the auricularis, the 
second to the annularis, the third to the medius, the 
fourth to the index, and the internal to the thumb. 
The latter, very small, has only two phalanges, and does 
not come into contact with the ground. Each of the 
first four is composed : 1. Of a first phalanx, to which are 
annexed two sesamoids. 2. A second phalanx, which 
represents a veritable long bone. 3. A conical phalan- 
gette, pointed, curved downwards, and hollowed at its 
base by a circular groove, in which is lodged the matrix 
of the claw. The small sesamoid (or navicular bone) 
la absent, but is replaced by a prominence of the ungual 
phalanx. The auricularis and index are alike, and not 
80 long as the annularis and medius, which are the same 
in length. 




HUMAN SCAPULA (EXTERNAL ASPECT). 

1, Supra-spinous fossa; 2, infra-spinous 
fossa ; 3, superior border ; 4, supra- 
sca|)ular notch; 5, anterior or axil- 
lary boi-der ; 6, head of the scapu- 
lar and glenoid cavity ; 7, inferior 
angle ; 8, neck of the scapula ; 9, 
posterior border; 10, spine; 11, 
triangular smooth surface, over 
which the tendon of the trapezius 
glides, with the tuberculum spinse 
scapulae between it and 10 ; 12, 
acromion process ; 13, nutrient fora- 
men ; 14, coracoid process. 



Comparison of the Thoracic Limb of Man with that of the Domesticated Animals. 

A. Shoulder. — The shoulder of man has for its base two well-developed bones — the scapula 
and clavicle. The scapula (Fig. 78) is more distinctly triangular than that of all the domesti- 
cated animals ; its vertebral border is also more extensive. The scapular spine, very elevated 
is continued by an acromion whose extremity reaches to above the scai)ulo-humeral articulation. 
The latter is separated from the remainder of the spine by a constriction called the pedicle of 
the acromion. The coracoid process is voluminous, and resembles a semi-flexed finger. The 
clavicle extends from the acromion to the sternum ; it is flattened above and below, and flexed 
like an italic S. This inflection of the clavicle is more pronounced in the male than the 
female. 

B. Arm. — The humerus (Fig. 79) of Man is much longer than that of animals. Its dia- 
physis is prismatic, and divisible into three faces ; the deltoid imprint has the form of a V with 
its point directed downwards. The voluminous articular head is turned inwards ; the bicipital 



120 



THE BONES. 



groove is single, and looks outwards. The inferior articular surface resembles that of animals, 
except that the condyle is more distinct. 

C. Forearm (Fig. 80). — The two bones of the forearm, as we have already seen, only articu- 
late by their extremities; they are separated from one another in their middle part. The 
superior extremity of the radius corresponds with the condyle of the humerus ; that of the ulna 
articulates with the humeral trochlea. The coroiioid process belongs to the ulna. At the 
lower extremity of the forearm, it is reiniirked : 1. That the radius corresponds with tlie greater 
portion of the cnrpus, while the ulna only articulates with the pyramidalis. 2. Tliat the radio- 
carpal articulation is protected outwardly and inwanlly by two small osseous prolongations — 
the styloid processes of thu ulna and radius. 

D. Hand. — 1. Carpus (Fig. 81). — The carpus of Man is composed of eight bones — four in 
each row. The three tirst of the upper row articulate with the radius ; the fourth responds to 



F.2. 



Fig. 8U. 




RIGHT HUMAN HUMERUS (ANTERIOR 
SURFACE). 

1, Shaft ; 2, head ; 3, neck ; 4, greater tu- 
berosity ; 5, lesser tuberosity ; 6, bici- 
pital groove ; 7, interior bicipital groove ; 
8, posterior bicipital ridge ; 9, rough sur- 
face for insertion of deltoid; 10, nutrient 
foramen; 11, eminentia capitata ; 12, 
trochlea; 13, external condyle; 14, in- 
ternal condyle ; 15, external condyloid 
ridge; 16, internal condyloid ridge; 17, 
fossa for the coronoid process of ulna. 



HUMAN ARM-BONES (FRONT VIEW). 

1, Shaft of ulna ; 2, greater sigmoid notch j 
3, lesser sigmoid notch ; 4, olecranon 
process ; 5, coronoid process ; 6, nutrient 
foramen ; 7, ridges for insertion of in- 
terosseous membrane ; 8, capitalum ulnae ; 
9, styloid process; 10, shaft of radius; 
11, its head ; 12, its neck ; 13, its tube- 
rosity ; 14, oblique line ; 15, lower end 
of bone ; 16, styloid process. 



the ulna. In the bones of the lower row, the trapezium responds to the metacarpal of the thumb 
and that of the index; the trapezoides to the latter only, the os magnum am unciform to the 
metacarpals of the medius, annularis, and little finger. The pisiform bone and the cuneiform 
process of the unciform convert the posterior face of the carpus into a channel. 

2. Metacarpus (Fig. 81).— The five metacarpals of Man are parallel to each other; they 
articulate by their superior extremities witli the bones of the carpus, and by their inferior ex- 
tremities witii the phalange-s. They are all concave in their middle portion, and tiiickened at 
their ends. Tlie metacarpal of the thumb is the shortest and strongest. The others diminish 
in volume from the fourth to the first. 



THE ANTERIOR LIMBS. 



121 



Fig. 81. 



3. Digital Region (Fig. 81). — Here we fiurl five digits, each compcsed of three bony colum- 
nettes, with tlie exception of the thumb, in which only the second and third phalanges are 
present. They decrease in length from the third to the first, and the third to the fifth. The 
first and second phalanges are small semi-cylindrical bones, slightly thickened at their ex- 
tremities. The ungual phalanges are constricted in their middle, and widened like a horse- 
slioe at their inferior extremity ; the palmar face is roughened, the dorsal face smooth. 

Article V. — The Hand in General. 

1. The limits of this region, as already mentioned, extend from the lower 
end of the forearm to the third phalanx, inclusive. If it is examined super- 
ficially, the diiferences it presents in the number and arrangement of the parts 
composing it are very striking. The digits that 
terminate the hand are pieces which, from the earliest 
times, have most occupied the attention of observers. 
Thus, when we do not go beyond simple appearances, 
it might be believed that, with regard to the number 
of digits, there were great diiferences in animals. 
From this point of view, the domestic animals form 
a nearly decreasing series, commencing with the Gar- 
ni vora and terminating with Solipeds. And in relying 
upon these appearances, some anatomists have dis- 
tinguished these animals as monodacti/les, didad ij.es, 
and. regular and irregular tetradadijUs ; but in the 
generalizations in this work, we have ignored these 
designations, as they are in complete disaccord with the 
teachings of philosophical anatomy. In fact, although 
the Horse appears to have only one digit, the Ox two, 
the Pig four, the Dog and Cat five, yet the hand in all 
these creatures may be referred to the pentadactylous 
type. To demonstrate this unity in composition, the 
laws promulgated by Grethe with regard to the vege- 
table kingdom, and developed and applied to animals 
by Geoff"roy Saint-Hilaire, are accepted ; and we have 
indicated in these few words the laws of analogy and 
harmony, the principle of relations, the elective affini- 
ties, the organic adjustments. 

These laws and these principles have been more 
particularly applied to the study of the 'hand of 
animals by Joly and Lavocat, Paul Gervais, Richard 
Owen, Delplanque, and Arloing. Comparisons, and 
the attentive study of normal conditions and anomalies, have served as a basis 
for the conclusions arrived at by these authorities. The anomalies that certain 
zoologists were tempted to regard as proper facts likely to mislead philosophical 
anatomists, have, on the contrary, been of assistance to the latter ; because, 
according to the expression of Geoffroy Saint-Hilaire, " an anomaly restores that 
which \ye term, in zoology, -normal conditions." 

2. The Archetypal Hand. The chief type is composed of five digits, 
and a complete digit in three sections — the carpus, -which has two bones ; the 
metacarpus, which has only one : and the phalangeal section, which has three. 
This constitution of the hand has been conceived by Joly and Lavocat, and 
reasoning would sanction its acceptance, if it were not presented in some animals 




PALMAR SURFACE OF LEFT 
HUMAN HAND. 

1, Scaphoid bone; 2, semilu- 
nare; 3, cuneiform ; 4, pisi- 
form ; 5, trapezium ; 6, 
groove in trapezium for ten- 
don of flexor car))i radialis; 
7, trapezoides ; iS, magnum ; 
9, unciform ; 10, 10, the 
five metacarpal bones; 11, 

11, first row of phalanges; 

12, 12, second row; 13, 13, 
third row; 14, first phalanx 
of the thumb; 15, second 
and last phalanx. 



122 



THE BONES. 




DESCRIPTION ON OPPOSITB PAGE. 



THE ANTERIOR LIMBS. 123 

—such as the 3Ioh, Marmot, and Guinea-pig— each, of which have five digits 
arising from the two carpal bones. In order to study the hand, these authorities 
place it in its natural position — pronation ; and the different pieces are reckoned 
from without to within by the numbers 1, 2, 3, 4, 5. 

3. Modifications in the Archetype. But the archetypal hand is not 
constantly realized, even when five digits— such as they are usually understood 
to be — are present. The hmnan hand, for instance, is formed by five digits and 
five metacarpal bones, with only eight bones in the carpus. When we go from 
Man, the number of bones in the three sections is more or less diminished ; and 
in the carpus of the domestic animals, as in that of Man, if the archetypal 
number does not exist in all the sections, it is because certain pieces have been 
fused with adjoining ones, or they are not developed. In several instances, 
certain bones become so atrophied that at the first glance they are not recog- 
nizable. Joly and Lavocat at first imagined that these atrophies took place 
according to some fixed law ; they believed that the atrophy operated on the 
middle part of the bones, extending downwards, and that the last piece to dis- 
appear, in an atrophied digit, was that of the carpus. 

But since the publication of their first memoires, Lavocat has had occasion 
to state that this law is not absolute. After these preliminary remarks, we 
will study the modifications in the archetypal hand in Man and the domestic 
animals, and demonstrate that in these it may easily be referred to the pentadacty- 
lous type. 

1. Man. — The human hand having five digits and five metacarpal bones, it 
is rational to admit the virtual existence of five pieces to each of the carpal rows. 
Materially, there are only four bones in each of these two rows ; but the com- 
parative study of the relations of each of these bones in the human carpus, and 
in that of animals which are in possession of the archetypal hand, leads to the 
belief that the scaphoid is the result of fusion of the fourth and fifth bones of 
the upper row, and the unciform the fusion of the first and second bones of the 

HAND OF MAN AND THE DOMESTIC MAMMALIA, NORMAL AND TERATOLOGICAL (Fig. 82). 

A, Human hand (dorsal face). 

B, Dog's hand (same position). 

C, Pig's hand (normal condition). 1, Trapezium. 

c', Pig's hand : the thumb (1) is completely developed from the trapezium (2). 

D, Sheep's hand (normal condition). 1, Principal metacarpal ; 2, rudimentary metacarpal, external ; 
3, ditto, mternal (not constant). 

E, Hand of the aquatic Chevrotain. 1, Double principal metacarpal; 2, 3, lateral metacarpals 
followed by phalanges. 

F, Lamb's hand, a. Carpus and superior extremity of metacarpus (seen in profile), on which the 
metacarpus of the thumb (1) was shown. 6, Ditto (face) : 1, internal rudimentary metacarpal 
completely developed ; 2, horny plate representing the thumb on the surface of the skin ; 3, horny 
plate representing the first digit on the surface of the skin. 

G, Lamb's hand on which are four complete digits. 1, Principal metacarpal ; 2, 3, lateral meta- 
carpals completely developed. 

H, Horse's hand (normal condition). 1, Principal metacarpal ; 2, 3, rudimentary metacarpals. 

I, Horse's hand, adult (teratological specimen, showing the division of the phalangeal section, 
1, 1, of the single digit of Solipeds). 

K, Foal's hand (teratological specimen described by Delplanque). 1, Principal metacarpal bifid in 
its lower third ; 2, e.\ternal rudimentary metacarpal ; 3, 4, phalangeal sections resulting from 
the division of the great digit. 

L, Horse's hand, adult (teratological piece), a. Carpus (inner aspect) : 1, trapezium ; 2, trapezoid ; 
3, principal metacarpal ; 4, internal rudimentary metacarpal transformed into a complete meta- 
carpal ; 5, styliform piece representing the metacarpal of the thumb. 6, Inferior extremity of 
the digital region (inner aspect): 1, principal metacarpal, followed by normal phalanges; 2, in- 
ternal rudimentary metacarpal transformed into a complete metacarpal, followed by normal 
phalanges. 



124 THE BONES. 

inferior row (Fio;. 82, a). It is easy, therefore, to refer Man to the most perfect 
pentadactylous type. 

2. Carnii'ora. — The hand of the Dog and Cat has five distinct digits, the 
internal of which — the thumb — smaller than the others, does not reach the 
ground (Fig. 82, b). By the metacarpus and the phalangeal section, these 
animals belong, then, to the pentadactylous type. They appear to be removed 
from it by the constitution of the carpus, for it has only seven (Dog) or eight 
bones (Cat) ; there has been fusion of the lunar and scaphoid, but the fifth bone 
of the upper row is free. The number of bones being thus raised to eight, we 
know how they may be referred to the archetype — by proceeding in the same 
manner as for the human carpus. 

3. Rodents. — The Rabbit has five digits, like the Cat, and nine carpal bones. 
Five of the latter are in the upper row, in consequence of the duplication of the 
fourth bone, which comports itself as in Carnivora. The scaphoid is between 
the two rows, as in the tarsus. 

The Rabbit, therefore, only differs from the archetype by the fusion of the 
first to the second inferior carpal bone, which sometimes is incomplete. 

We have thus demonstrated the pentadactylous composition of the hand in 
the domestic Carnivora and Rodents — an easy task, as these animals have five 
apparent digits. We will now pass to the Pig. 

4. Pig. — This animal has eight carpal bones and four complete digits, with 
metacarpals and phalanges — two large and two small (Fig. 82, c). There is no 
difficulty in referring the carpus of the Pig to that of Man or the Carnivora, and 
from these to the archetype. It suffices to find in this creature a trace of the fifth 
digit, in order to place it in the pentadactylous type. Normally, the fifth bone of 
the lower row — the trapezium — has no relation with the bones of the metacarpus ; 
which proves that the remainder of the thumb is absent. But this thumb has 
been found entirely developed, and having the appearance of the other digits. 
In Fig. M (c'), this has been shown in the teratological cases observed by 
Joly and Lavocat, and Goubaux and ourselves. Consequently, although the Pig 
has been classed among bisculcate animals by certain zoologists, yet it has in the 
anterior limb five digits, more or less completely developed. 

5. Ruminants. — Intended as an organ of support, the hand of Ruminants 
offers several fusions or abortions, which increase its solidity at the expense of 
its suppleness and flexibility. Thus, in the first place, it appears more difficult 
than in other animals to find, materially or virtually, the elements of the five 
digits. 

Only six bones are found in the carpus of the 0-r, Sheep, and Goat ; but the 
study of relations demonstrates that there are : abortion of the fifth bone of the 
upper row ; fusion between . the first and second, and between the third and 
fourth, and abortion of the fifth bone, of the lower row. So that, in reality, there 
are met with, in the carpus of the domestic Ruminants, the elements of ten 
bones, with the exception of two not developed (Fig. 82, d). 

The metacarpus comprises a principal metacarpal — the inferior articular face 
of which is double — and a stylif orm bone placed alongside its external and internal 
borders. For a long time, GeofFroy Saiut-Hilaire had demonstrated that the 
principal metacarpal is formed by two metacarpals brought together during foetal 
life, and separated by a more or less incomplete medullary septum during extra- 
uterine existence. Besides, the isolation of the two metacarpals — temporary in the 
Ox — is permanent in some other Ruminants, such as the Chevrotain of Guinea and 



THE ANTERIOR LIMBS. 125 

the Aquatic Chevrotain (Fig. 82, e). With regard to the external stylet, it is 
an atrophied metacarpal ; for in some teratological instances it becomes elongated, 
and supports a more or less perfect digit. In addition, in the Chevrotain it is 
replaced by the metacarpal and a complete digit (Fig. 82, e). It is the same 
with the internal stylet, which is usually smaller, and embedded in a fibrous cord 
running along the large metacarpal ; it may, like the external stylet, be converted 
into a perfect metacarpal (Fig. 82, P and g). 

It remains to demonstrate the virtual existence of a fifth metacarpal. Nor- 
mally, no traces of it are found in the domestic Ruminants, but it appears in 
some anomalies. The museum of the Toulouse Veterinary School possesses the 
hand of a Lamb, in which it can be seen, inside the internal stylet, which has 
been transformed into a long metacarpal — a small styliform bone which is 
assuredly nothing else than the metacarpus of the thumb (Fig, 82, f, i,). Here 
is the metacarpus brought to the pentadactylous type ; now for the phalangeal 
region. 

The digital region of Ruminants presents two perfect digits (the second and 
third. Fig. 82, d), and two rudimentary digits reduced to one or two small 
phalanges covered by a horny plate (ergot), situated behind the metacarpo- 
phalangeal articulation. The two rudimentary digits may, in certain cases, be 
reproduced— to the right and left of the normal ones — complete and suspended from 
real metacarpals. This was seen in a specimen from a young sheep (Fig. 82, g) ; 
and this condition is normal in the Chevrotain (Fig. 82, e), only the lateral 
digits are less voluminous than those appertaining to the principal metacarpal. 
The presence of the fifth digit is normally indicated, according to Joly and 
Lavocat, by a tuft or spike of hair inside the carpus, rather above than below it. 
Sometimes it is better marked ; for in the specimen sho^Ti in Fig. 82, f' a, 
where the metacarpal of the thumb had appeared, this digit was represented on 
the surface of the skin by a plate of horn in the form of an ergot (f, a and b, 
2). Otherwise, in order to dispel all doubts, it may be mentioned that Geoff roy 
Saint-Hilaire studied a new-born Lamb which had five digits in the anterior 
limb. 

6. SoUpeds. — In Solipeds, there is apparently only one digit enclosed in one 
hoof. Nevertheless, by the aid of analogous facts to those which have already 
assisted us in proving pentadactylism in Ruminants, we shall be able to demon- 
strate that the hand of the Horse, Ass, etc., is no exception to the general law. 
Many anatomists only describe seven bones in the carpus of the Horse — four in 
the upper row, three in the lower. But it is not rare to see a pisiform bone on 
the inner side of the trapezoid, which raises the number of carpal bones to eight. 
And Bourgelat, Girard, Rigot, and Goubaux have observed in the carpus of the 
Horse, in addition to the bones mentioned, a similar piece alongside the external 
bone of the second row. Lavocat considered this second piece as the first of the 
inferior carpal bones — the base of the external digit, and that the bone found 
beside the trapezoid was the trapezium or base of the internal digit or thumb, 
the trapezoid being the base of the fourth finger. The trapezium and trapezoid 
are shown, with the significance attributed to them by Lavocat, on the carpus 
represented in Fig. 82 (l a, 1, 2). 

The carpus of Solipeds does not differ, then, from the archetype, except in the 
frequent abortion of the fifth superior carpal bone, and the first and fifth of the 
lower tier. 

The metacarpus of Solipeds comprises a large bone articulating with the 
11 



126 THE BONES. 

digital section, and two rudimentary pieces on each side of it, and which are 
really atrophied metacarpals ; for in some teratological specimens they are as long 
as the principal bone, and terminate in a diarthrodial surface which articulates 
with a perfect digit (Fig. 82, l b). At first sight, there are, then, three meta- 
carpals in Solipeds. 

With several authorities, and particularly Joly and Lavocat, we have 
admitted the duplicity of the large median metacarpal bone, basing our admis- 
sion on several considerations with regard to form and relations, and especially 
on certain anomalies similar to those represented in Fig. 82, i, in which 
is seen the single digit of Solipeds divided like that of the Ox — the division 
extending to the lower end of that bone. But an attentive study of the 
metacarpal region in the Mammalia, and notably in Pachyderms, and of the 
arrangement it offers in the various fossil Equidfe, has caused us to abandon 
this opinion. "We consider the principal metacarpal of Sohpeds to be the analogue 
of the metacarpus of the medius of pentadactylous Mammals. With regard to 
the anomaly shown at i and k. Fig. 82, it should be interpreted as an example 
of division of an organ normally single. 

The Horse, then, has always three metacarpals — one for the medius, the 
index, and the annularis ; and it remains to prove the existence of two other 
metacarpals. Usually, the metacarpal of the thumb is completely aborted ; but 
yet the existence of these bones is indicated by the frequent presence of the 
trapezium at the inner side of the carpus. Lastly, as a continuation from the 
trapezium there may be found a conical prolongation (Fig. 82, L a, 5), parallel 
with the metacarpal bone of the index — a prolongation which, because of its 
connections, should be regarded as the metacarpal of the thumb. 

With respect to the metacarpal of the auricularis, or little digit, we do not 
know of one teratological example in which it can be distinctly seen. But its 
existence is virtually indicated by the presence of the small external carpal bone 
we have sometimes observed, and which was noted by Bourgelat, Eigot, and 
Goubaux. 

The phalangeal section only possesses the elements of a single digit. But 
besides the hoof, Soliped animals have a horny plate divided by a slight median 
groove, and resting on an elastic cushion behind the metacarpo-phalangeal articula- 
tion. This plate occupies the same position as the ergots in the Ox ; it has vessels 
and nerves from the same source as those of the principal digit ; it lies upon an 
elastic bed similar to that belonging to that organ ; and Joly and Lavocat regard 
it as the representative of the phalanges, which should be continued with the 
rudimentary metacarpals. Otherwise, when one of these metacarpals is developed 
into a perfect digit, the horny plate or ergot diminishes in volume, because 
a portion of its substance is carried to the extremity of the supplementary digit. 
It -is, therefore, easy to find three digits in these animals, but the thumb is more 
difficult to render evident. However, the presence of a trapezius, and, much 
more rarely, of an atrophied metacarpal succeeding it, would warrant the admis- 
sion that this digit exists, if it were not represented on the surface of the skin by 
the chestnut — the horny plate situated on the internal aspect of the forearm. 
The position of this small mass of horn above the carpus has been invoked 
against this signification ; but it is easy to overcome this objection in showing, by 
the ascending vessels and nerves of the chestnut, that this is a displaced organ ; 
the vessels and nerves arise from the same trunks that supply the other digits. 

The fifth digit is not absolutely represented except by its carpal base, which is 



TEE POSTERIOR LIMBS. 127 

often absent ; however, its presence in a certain number of instances allows it to 
be affirmed that Solipeds materially and virtually belong to the pentadactylous 
type. This conclusion applies a fortiori to all the domestic animals. 

According to statistics drawn up by Cornevin, the return to the pentadacty- 
lous type is much more frequently manifested, in Solipeds, in the anterior than 
the posterior limbs. 

Article YI. — Posterior or Pelvic Limbs. 

Each of these is divided, as already noted, into four secondary regions : the 
pelvis, thigh, leg, and foot. 

Pelvis (Figs. 83, 84, 85). 
The pelvis is a kind of bony cavity formed by the union of the sacrum with 
two lateral pieces — the ossa innominata, or coxae — which are consolidated with each 

Fig. 83. 




THE OSSA INNOMINATA (SEEN FROM BELOW). 

1, Iliac surface ; 2, auncular facet ; 3, angle or crest of the ilium ; 4, angle of the haunch ; 5, 
?eSs. r;^' V^"'\T '^'^'V*"' '\ °°^ ""^ '^' '"P'-'°'^ f""- tl^e insertion of the rec'tu 
rator) foramen ; 11, sciatic spine ; 12, 12, ischiatic arch, r ) , ^, 

Other in the inferior median line. The description of the sacrum having been 
ah:eady given, it now remains to speak of the os inn^ominatum of each side. 

A. Coxa, or Os Innominatum. 

The OS innominatum—2X^o designated os coxa, os iliacum, os innominatum-is 

a very irregularly shaped flat bone, double (with its fellow on the opposite side), 

and directed obhquely downwards and backwards. It is contracted in its middle 

part, which presents externally a deep cavity-the cotgloid ; anteriorly, where 



128 THE BONES. 

it rests on the sacrum, it becomes widened, as it also does in its posterior 
portion, which is inflected inwards to be united, on the median Hne, with the 
OS innominatum of the opposite side. 

It is divided, in the foetus, into three distinct pieces, joined by cartilage in 
the centre of the cotyloid cavity, which they concur in forming. Although they 
soon become consolidated into a single piece, it is customary to describe them as 
so many separate bones by the names of ilium, pubis, and ischium. 

Ilium (Figs. 83, 84). — The ilium — a flat and triangular bone, curved on itself, 
directed obliquely downwards, backwards, and outwards — forms the anterior 
portion of the coxa which corresponds with the sacrum. It is the most consider- 
able of the three divisions, and has two faces, three borders, and three angles or 
processes. 

Faces. — The external or superior face (Fig. 83), studded Avith some muscular 
imprints, is excavated on both sides, and is named the external iliac fossa. The 
internal or inferior face offers for study : 1. An external portion, smooth, and 
crossed by some vascular grooves ; this is the iliac surface, which is replaced in 
Man by an excavation called the internal iliac fossa. 2. An internal portion, 
roughened and uneven, presents, posteriorly, the auricular facet — an irregular 
diarthrodial surface, elongated from side to side, a little oblique in front and 
inwards, and responding to an analogous surface on the sacrum. 

Borders. — The anterior border, or crest of the ilium, is slightly concave, and 
bears a roughened lip for muscular insertion. The external border is thick, 
concave, and furrowed by vascular fissures ; it presents, inferiorly, the nutrient 
foramen. The internal border is thin and concave, particularly in its posterior 
part, which constitutes the great sciatic notch. 

Angles. — The externcd angle, or anterior and superior spinous 2)rocess, is thick, 
wide, and flat, and bears four tuberosities : two superior and two inferior. The 
internal angle, or posterior and siqjerior sp)inous j^rocess, represents a rugged tube- 
rosity curved backwards and upwards. The posterior — or cotyloid angle — is pris- 
matic and very volimiinous. It exhibits : 1. Behind, a wide concave articular facet, 
which forms part of the cotyloid cavity. 2. Above this cavity, the supra-cotyloid 
crest, represented in Man by the ischiatic spine. This is an eminence elongated 
from before to behind, sharp on its summit, smooth inwardly, roughened out- 
wardly, and continuous by its anterior extremity with the internal border of the 
bone. 3. Outwardly, two deep imprints for the insertion of the rectus femoris 
muscle. 4. In'front and inwards, the ilio-2^ectineal spine, a small elongated pro- 
minence forming the most salient point of a kind of ridge {linea ilio-pectinea) that 
insensibly subsides above on the inner face of the ilium, and is continued below 
by the anterior border of the pubis. 

Of the three angles of the ilium, the first is also termed the angle of the 
haunch, and the second the angle of the croup. 

Pubis (Fig. 83). — Situated between the ilium and ischium, elongated from 
side to side, flattened above and below, and irregularly triangular, the pubis — the 
smallest of the three divisions — is divided, for convenience of description, into 
two faces, three borders, and three angles. 

Faces. — The superior, smooth and concave, concurs in forming the floor of 
the pelvis. It shows one or two nutrient foramina. The inferior is roughened, 
and marked throughout its length by a wide channel which reaches the bottom 
of the cotyloid cavity. This fissure lodges the pubio-femoral ligament and 
a very large vein. 



THE POSTERIOR LIMBS. 



129 



Borders. — The anterior is constituted by a thin rugged lip, which is curved 
upwards. The posterior, thick and concave, circumscribes anteriorly a wide 
opening, the oval, suhpiiUc, or obturator foramen ; it is channeled near the coty- 

Fig. 84. 




PELVIS (ANTERO-LATERAL VIEW). 

1, Anterior iliac spine ; 2, posterior iliac spine ; 3, shaft of the ilium, with the ilio-pectineal crest ; 
4, cotyloid cavity ; 5, symphysis pubis ; 6, inferior ischiatic spine and tuberosity. 



loid angle by a fissure which runs obliquely inwards and downwards. The 
internal is united with that of the opposite bone, to form the pubic portion of 
the pelvic symphysis. 

Ayigles. — The ex- Fig- 85. 

ternal, also named the 
cotyloid angle, is the 
thickest of the three. 
To it chiefly belongs 
the rugged depressed 
surface that constitutes 
the bottom of the coty- 
loid cavity. The in- 
ternal unites with the 
analogous angle of the 
opposite bone. The 
•posterior is consolidated 
at an early period with 
the antero - internal 
angle of the ischium, to 
enclose, inwardly, the 
oval foramen. 

Ischium (Figs. 84, 
85). — This is the mean, 
in volume, of the three 
pieces of the coxa. Situated behind the pubis and ilium, it is flattened above 




PELVIS (LATERAL VIEW). 

1, External angle of the ilium, or anterior iliac spine ; 2, internal 
angle, or posterior iliac spine ; 3, shaft of the ilium and ilio- 
pectineal line ; 4, cotyloid cavity, or acetabulum ; 6, inferior 
ischiatic spine, with tuberosity behind. 



130 THE BONES. 

and below, and of a quadrilateral form. It offers for study : two faces, four 
borders, and four angles. 

Faces. — The superior is smooth and nearly plane, and forms part of the floor 
of the pelvic cavity. It has a small nutrient foramen directed outwards. The 
inferior presents some rugosities, clustered particularly about the symphysis. 

Borders. — The anterior, thick and concave, circumscribes the oval foramen 
posteriorly. The posterior, straight and directed obliquely forwards and inwards, 
forms, with the analogous border of the opposite bone, a large notch named tjie 
ischial arch. It exhibits, throughout its extent, a rugged depressed lip (the 
spine), arising from the side of the inferior face. The external, thick and 
concave, constitutes the lesser ischiatic notch. The internal is joined to the 
ischium of the other side, to constitute a portion of the pelvic symphysis. 

Angles. — The antero-externcd, or cotyloidean, is the most voluminous of the 
four, and affords for study : 1. An excavated diarthrodial facet, making part of 
the cotyloid cavity. 2. The posterior extremity of the supra-cotyloidean crest, 
limited by a small transverse fissure which separates from the external border of 
the bone. The antero-internal angle is consolidated with the posterior angle of 
the pubis. The poster o-external angle forms the ischial tuberosity. This is a 
large prismatic process which looks upwards, and is prolonged by a salient 
ridge, elongated from before to behind, with its sharp border turned outwards 
and downwards. The postero-internal angle forms, with that of the other 
ischium, the summit of the triangular space which constitutes the ischial arch, 
or pubic arch of some species. 

The Coxa in General. — This bone, the three constituent parts of which we 
have just been studying, presents for consideration, as a whole, a middle portion 
and two extremities. The middle, very much contracted, offers, outwards and 
downwards, the cotyloid cavity (or acetabulum), which has not yet been described, 
because its study does not properly pertain to either of the three regions of the 
coxa. This cavity is intended to receive the articulating head of the femur, and 
represents the segment of a hollow sphere ; it is circumscribed by a very salient 
rim, which is thin at its free margin, and widely notched on the inner side. The 
deeper portion is occupied by the roughened and depressed surface already 
designated as the bottom of the cotyloid cavity {fundus acetabuli), which 
communicates, by the internal notch of the rim, with the inferior groove of the 
pubis. The anterior extremity, flattened on both sides, and formed by the 
ilium, rests, as has been shown, on the sacrum. The posterior extremity, 
flattened in an inverse sense to the preceding, is constituted by the pubis and 
the ischium, and is traversed, from above to below, by the sub-pubic (or obturator) 
foramen — the large oval aperture which separates these two bones from one 
another, and perforates the floor of the pelvis ; this opening is closed in the 
fresh staie by muscles. 

The two coxae, by uniting in their posterior part, form the articulation to 
which has been given the name of ischio-pubic or pelric symphysis ; thus united, 
the two bones represent something like a V with the opening in front — a 
circumstance which makes the lateral diameter of the pelvis greater in front 
than behind. 

Structure and Development of the Coxa. — To the three centres of 
ossification which constitute the coxa, are added two complementary centres : 
one for the anterior spinous process and spine of the ihum, another for the 
ischial tuberosity. 



THE POSTEBIOB LIMBS. 131 

It must be added that there is, within and in front of the cotyloid cavity, a 
cotyloid nucleus analogous to the glenoid nucleus of the scapula. This nucleus, 
comprised between the three bones of the coxa, has been named by Serres the 
Y-shaped bone. 

In youth, the different parts of the coxa are very thick, and the spongy 
tissue is abundant, while the compact is rare. The pubis is always convex on 
its two faces, and the middle part of the coxa — that adjoining the cotyloid 
cavity — is of considerable thickness, a feature which much diminishes the extent 
of the pelvic cavity. As the animal advances in age, however, the layers of 
compact tissue increase in thickness, approaching each other as the spongy 
substance is lessened. The pubis becomes thinnest, and at an advanced period 
of life is sometimes even translucid. 

The compact tissue is always abundant in the neighbourhood of the cotyloid 
cavity, as this is the centre on which converge all the impulsive efforts com- 
municated to the trunk by the posterior limbs. It is also in this cavity that 
ossification commences. 

B. The Pelvis in Genekal. 

1. External and Internal Conformation of the Pelvis. — The pelvis 
is a kind of rear cavity in the form of a cone, which prolongs the abdominal 
cavity between the sacrum and coccygeal vertebrae. 

It occupies the posterior part of the trunk, and, with regard to its conforma- 
tion, presents for study an external and internal surface. 

External surface. — This may be resolved into four planes or faces. 

The superior plane is slightly oblique from above to below, and before to 
behind ; its degree of obliquity, varies. It is contracted from before to behind, 
and shows : 1. On the median line, the spinous processes of the sacral and the 
first coccygeal vertebrae. 2. On each side the sacral grooves, at the bottom of 
which open the supra-sacral canals. 

The inferior pla?ie is nearly horizontal. Formed by the pubes and ischial 
I)ones, it presents from before to behind : 1. In the middle, the ischio-pubic 
symphysis. 2. On each side the subpubic groove, the oval foramina, and the 
inferior face of the ischial bones. 3. Quite externally, the cotyloid cavities, by 
which the pelvis rests upon the posterior limbs. , 

The lateral faces are oblique downwards and outwards, and are wider in front 
than behind. They exhibit : 1. The spine of the ilium and the two anterior 
■spinous processes. 2. The external iliac fossa. 3. The ischial arch. 4. The 
supra-cotyloid crest or ischiatic spine, which presents, outwardly, the surface of 
insertion for the internal or deep gluteus muscles. 5. The lesser ischiatic notch. 
6. The ischial tuberosity. 

Internal surface. — The internal surface of the Horse's pelvis cannot be 
divided into two portions as in Man, because the inner surface of the iliac bones 
is not hollowed out to form an anterior cavity. 

The pelvis of Solipeds is, therefore, a simple conoid cavity, in which are 
distinguished four planes or faces, and two apertures called the inlet and 
outlet. 

The anterior openinq, or inlet, is nearly circular, especially in the Mare, and a 
little oblique downwards and backwards. It is limited above by the inferior face 
^f the first vertebra of the sacrum ; inferiorly, by the anterior border of the 



182 



TEE BONES. 



pubis ; and on the sides by a part of the inner face of the iliac bones, and also 
the internal aspect of the pectineal crests. 

The inlet presents four diameters, a knowledge of which is important in 
obstetrics — a vertical, horizontal, and two oblique. The first, the sacro-pubir, 
extends from the inferior face of the sacriun to the anterior border of the pubic 
symphysis ; its mean length is 8:^ inches. The second, the bis-iliac, is measured 
from one pectineal crest or eminence to another ; the mean of this is H^jj inches. 
The two last diameters, the ileo-sacral, are estimated from the inferior face of 
the sacro-iliac articulation of one side to the ilio-pectineal eminence of the 
other ; this is, on an average, SyV inches. These measurements irrefutably 

Fig. 86. 




PELVIS OF THE HORSE. 



demonstrate that the inlet is not elliptical in the vertical direction ; but it may 
happen that the transverse diameter is the greatest. 

The posterior aperture or outlet, situated at the posterior end of the pelvic 
cavity, gives exit to the rectum and genital organs. It is limited by the inferior 
face of the summit of the sacrum, the superior face of the ischial bones, the 
supra-cotyloid crest or ischiatic spine, and the internal face of the sacro-sciatic 
ligaments. At the outlet only two diameters are recognized — a vertical and a 
horizontal. The vertical, extending from the inferior face of the sacrum to the 
superior face of the ischial symphysis, measures on an average 6yV inches. 
The horizontal diameter, comprised between the two supra-cotyloid crests, is 
7-j^ inches. 

The superior face of the pelvic cavity is a little concave from before to 



THE POSTERIOR LIMBS. 133 

behind ; it has for base the sacrum, which presents on each side of the median 
line the subsacral foramina. This part is also called the sacral plane, or roof of 
the pelvis. 

The inferior region, or ischio-pubic plane, is formed by the pubes and the 
ischial bones. It is concave from side to side ; its anterior border is nearly 
straight, and its posterior border is scooped out by a wide notch to form the arch 
of the ischium. 

It has been remarked by Goubaux, that the portion of this plane correspond- 
ing to the pubis presents numerous varieties. The superior face of the pubis 
may be convex in its anterior moiety, and concave in its posterior ; or it may be 

Fifr. 87. 




PKLVIS OF Tllli MARE. 

ooncave before and convex behind, the concavity being separated from the 
convexity by a transverse ridge. This ridge is sometimes represented by a series 
of small conical eminences ; at other times this upper face is disposed as a 
smooth inclined plate, directed backwards and upwards, and a kind of rim 
surmounts the anterior contour of the oval foramen.^ 

With regard to the lateral faces, they are formed by a small portion of the 
inner face of the iliac bones, and in great part by the sacro-sciatic ligaments. 

The foetus must pass through the pelvic canal during parturition ; it is, 
therefore, important to know at any time if the female pelvis is of sufficient 
dimensions to allow the foetus to leave it. Pelvimetry is the name given to 

' It is necessary to be aware of the frequency of these asperities on the floor of the pelvic 
cavity, in order not to arrive at false inductions when exploring the bladder per re,etum. 



134 THE BONES. 

that section of obstetrics dealing with the diameters of the pelvis. These may 
be determined in several ways, which, in veterinary surgery, daily receive the 
sanction of experience. 

Some years ago we indicated one,^ which consists in measuring the horizontal 
distances between the two haimches and the two ischiatic tuberosities, and the 
vertical distance extending from the coxo-femoral articulation to the most 
salient part of the croup ; then to take a fourth of the total of the two first 
measurements, in order to obtain the transverse diameter of the inlet, and 
three-fourths of the third, to have the vertical diameter of this opening. 

Saint-Cyr and Violet have investigated the relation existing between the 
height of the Mare and the vertical diameter of the pelvis, then that of the 
width of the croup to the bis-iliac diameter ; and they have found that the first 
was equal to 0"1515 centimetres ; the second to 0'4654, in a well-bred Mare, to 
0*3945 in common-bred Mares. Consequently, according to the pelvimetric 
procedure of these authorities, it is sufficient to multiply the height of the Mare 
by 0-1515 to have the vertical diameter of the inlet, and the width of the croup 
by 0*4654 or 0"3945, according to circumstances, to find the transverse diameter. 
But this question rather appertains to obstetrics.^ 

2. Differences in the Pelvis of the Sexes. — The pelvis of the Mare 
exceeds that of the Horse in all its dimensions, but the difference is most, 
marked in the transverse diameters (Figs. 86, 87). 

The inlet forms a vast circumference, when compared with that of the male ; 
the pectineal crests are wide apart, and the distance separating the anterior 
border of the pubis from the lower face of the sacrum is considerable. 

If the pelvis be viewed in its superior plane, it is found that in the Mare the 
ischiatic notches are very deep ; that the internal border of the ilium forms a 
regularly curved and very concave line ; and that the supra-cotyloid crests, or 
ischiatic spines, are widely separated from each other. It is also noticed that 
the floor of the pelvis is wide, and that the bones composing it tend towards the 
same horizontal Hne. 

In the male, the ischiatic border is only represented by a very curved line ; 
this line is composed of two almost straight portions, which join at an obtuse 
angle at the origin of the neck of the ilium ; the supra-cotyloid crests are 
relatively near each other, and bent towards the longitudinal axis ; while the 
two moieties of the pelvic floor are directed very obliquely downwards and 
inwards. 

In the Mare, the ischial arch is larger than in the male, and forms a regular 
curve uniting the two tuberosities of the same name. In the Horse, the two 
ischial tuberosities are but little apart, and the ischial arch forms a somewhat 
acute angle, with its borders nearly straight. 

Lastly, when the pelvis is examined in its inferior plane, in addition to the 
features already indicated in the ischial arch, it is found that in the Mare the 
obturator foramina are large and nearly circular, while in the Horse they are 
elliptical ; the cotyloid cavities are also further removed from the ischio-pubic 
symphysis in the female than in the male. 

The sacrum of the Mare has appeared to us, in some individuals to be a little 
more arched from before to behind than that of the Horse ; but this character 
is not constant. 

' Arloing;, Journal Vet^rinaire de Lyon. 1868. 

= Saint Cyr and Violet, Trait€ cV Ohstetrique VitMnaire, Paris: 1888. 



Tn:E POSTERIOR LIMBS. 



135 



The following figures, relating to the capacity of the pelvis of the Mare and 
Horse, confirm what has just been enunciated : — 



Mare. 
Horizontal Diameters. 


Horse. 
Horizontal Diameters. 


Between the Pectineal 
Crests. 


Between the Supra-cotyloid 
Crest,. 


Between the Pectineal 
Cre^t8. 


Between the Supra-cotyloid 
Crests. 


Inches. 
9| 


Inches. 
7^ 


Inches. 
8t', 


Inches. 


Mare. 
Vertical Diameters. 


Horse. 
Vertical Diameters. 


Between the Sacrum and 
Pubis. 


Between the Sacrum and 
Ischium. 


Between the Sacrum and 
Pubis. 


Between the Sacrum and 
Ischium. 


Inches. 
8^ 


Inches. 


Inches. 
8 


Inches. 
6^ 



To recapitulate, there is observed in the pelvis of the Mare : — 

1. A great increase in the transverse diameters. 

2. A deep and regularly concave ischiatic notch. 

3. A wide and concave ischial arch. 

4. Circular obturator foramina. 

5. The cotyloid cavities distant from the pubic symphysis. 

In the Ass, the inlet of the pelvis is a longer oval than in the Horse. The 
coxse are distinguished by : 1. The less curvature of the anterior border of the 
ilium. 2. A slightly excavated external iliac fossa. 3. The triangular shape of 
the obturator foramina. 4. A short and deep notch separating the external 
border of the ilium from the angle of the haunch. 5. The direction of the 
tuberosities of this angle ; they approach more nearly the parallelism with the 
median plane of the trunk than in the Horse. 6. The disposition of the rugo- 
sities in tubercles for the insertion of the suspensory ligaments of the corpus 
cavernosum on the inferior face of the ischium. In the Ass, also, a line which 
would unite the inferior contour of the auricular facet to the most salient 
point of the angle of the haunch, would be parallel to the anterior border of the 
ihum, while it would be oblique on this border in the Horse. 

The inlet of the pelvis in the Hinny resembles that of the Ass ; in that of 
the Mule, it holds a middle place between the Ass and Horse. The pelvis of 
the Hinny resembles that of the Ass, also, by the form of the obturator foramina, 
the direction of the anterior border of the ilium, and the position of the auricu- 
lar facet ; while that of the Mule, on the contrary, resembles the pelvis of the 
Horse in these features. The reverse is noted with regard to the disposition of 
the angle of the haunch. 



Differential Characters in the Pelvis op other Animals. 

It is remarked : 1. That in all the domesticated animals, with the exception of Solipeds 
and the Camel, the direction of the coxse is nearly horizontal. 2. That in all, the ilium is 
more oblique than in Solipeds. 3. That in all, the transverse diameters of the pelvis are 
relatively less extensive. 

A. Ruminants. — In the Ox, the space between the two coxae is scarcely so great in front 



THE BONES. 



as behind ; the ilium is not voluminous, and has only three processes on the anterior and 
superior iliac spines. There is no furrow on the lower face of the pubes, and its upper face, 
like that of the ischium, is very concave. Thrt-e eminences are seen on the posteio-external 
angle of the ischium. In early life, the ischio-pubic symphysis shows an epiphysary nucleus 
in the middle of its inferior face. (The epiphysis on the inner border of the ischium has been 
considered by some anatomists as an independent bone, and described by them as the 
inter-ischial bone). 

Tiie ischio-pubic symphysis has, in the middle of its inferior face, a thick protuberance, 
flattened on each side and very pointed; in early life this is an epiphysis, and the epipliysary 
nucleus, bifurcated posteriorly, is continued along the posterior border of tlie ischial bones as 
far as the ischial tuberosity, in the form of two marginal bands. 

The rim of the cotyloid 
cavity has also three notches, 
and the supra-coryloid crest, 
or ischiatic spine, is very ele- 
vated and shiirp, and but little 
rou;<hened outwardly. 

lu the Sheep and Goat, the 
coxae are yet more horizontal 
and proportionately longer 
than in the Ox, but the upper 
face of ttie ischium and pubis 
i.s less concave ; the external ' 
iliac fossa is separated into two 
portions by a small longi- 
tudinal crest. 

The pelvis of the Camel ia 
remarkable for its great ob- 
liquity, its shortness, and its 
narrowness. The anterior 
border of the ilium is convex ; 
the pubis and ischium are 
very thick; the rim of the 
cotyhiid cavity is elevated and 
regular; the ischio-pubic sym- 
physis forms a rugged crest 
outside the pelvis; and the 
ischial tuberosity is disposed 
in the same manner as in the 
Horse. 

B. Pig.— Tlie pelvis of 
the Pig closely resembles that 
of the smaller Ruminants ; 
though the crest of the ilium 
is convex, and there is no pro- 
tuberance outside the ischio- 
pubic symphysis, 
height, and the ischio-pubic 




PELVIC BONES OF THE CAT AND RABBIT. 

1, Pelvis of the Cat. B, Pelvis of the Rabbit. 1, Sacrum ; 2, 
external iliac fossa; 3, great ischiatic notch; 4, external border 
of the ilium ; 5, supra-cotyloid crest ; 6, cotyloid cavity ; 7, 
crest above the shaft or neck of the ilium ; 8, small sciatic 
notch; 9, anterior extremity of the symphysis pubis; 10, 
ischium; 11, ischial tuberosity; 12, pubis; 13, obturator 
foramen. 



The pelvic cavity is vast, in proportion to the animal' 
symphysis is late in becoming ossified. 

C. Dog. — In the Dog, the transverse diameter of the pelvis is greater behind than in front ; 
it is smallest between the cotyloid cavities. The ilium is nearly vertical, and its external 
face is much depressed. The notch forming the ischial arch occupies no more than the 
internal moiety of the posterior border of the ischium ; between this arch and the ischial 
tuberosity, is a rugged lip directed downwards. There is no furrow on the lower face of the 
pubis. Ossification of the symphysis is even later than in the Pig. 

D. Cat. — In the Cat, tlie ilium is proportionately narrow, and the supra-cotyloid crest 
liigher, than in the Dog. The posterior border of the ischium is regularly convex from 
without to within, and the pubic symphysis has, inferiorly, a somewhat salient crest (Fig. 88). 

E. Rabbit. — Pelvis horizontal ; ischium nearly as long as the ilium ; external iliac fossa 
divided by a blunt longitudinal crest ; supra-cotyloid crest little elevated, straight, and ending 
abruptly behind by a kind of notch ; rim of the cotyloid cavity complete, or having a slight 
posterior notch; ischial tuberosities parallel and not divergent, as in the Dog: and posterior 
border of the ischium concave, and very obliquely directed forw-ards and inwards (Fig. 88). 



THE POSTERIOR LIMBS. 1S7 



Thigh. 
This has for its base one bone — the femur. 

Femur (Figs. 89, 90). 

The femur (os femoris) is a long, pair bone situated in an oblique direction 
downwards and forwards, between the coxa and the principal bone of the leg ; 
it is divided into a bodt/ (or shaft) and two extremities. 

Body. — It is irregularly cylindrical, and presents for study four faces. The 
external, internal, and anterior, confounded with one another, are regularly 
rounded and almost smooth, showing only some slight imprints and vascular 
grooves. The posterior, nearly . plane, and wider above than below, offers : 1. 
Outwardly and towards the superior third, an uneven circular surface. 2. On 
the same level, and inwardly, a shght crest, oblique downwards and outwards. 
3. In the middle, a very extensive roughened surface, having the form of an 
obliquely angular parallelogram, for the attachment of the great adductor muscle 
of the thigh. 4. Below this surface, a large vascular groove running obliquely 
outwards and downwards. 

On the limit of the posterior and external faces are found, towards the upper 
third, a large rugged, flattened eminence, curved in front, and termed the 
subtrochanterian crest (or external smcdl trochanter ^), because of its position under 
the trochanter ; below, a deep fossa, named the subcondijloid, garnished at its 
bottom with asperities, and bordered in front by an uneven lip. On the limit 
of the posterior and internal face, there are observed from above to below : 
1. The small trochanter — a large scabrous tuberosity, elongated in conformity 
with the bone, and situated near its upper fourth. 2. A marked longitudinal 
imprint for the attachment of the pectineus ; behind, it is confounded with the 
surface for the insertion of the great adductor muscle of the thigh, and presents, 
in front, the nutrient foramen of the bone. 3. The origin of the great posterior 
fissure. 4. Quite below, a collection of large tubercles which form the supra- 
condyloid crest. 

Extremities. — The superior extremit)/ is sensibly flattened before and behind, 
and shows : 1. Inwardly, an articular head which is received into the cavity of 
the acetabuluna. This head is separated from the other portion of the body by 
a neck, which is, however, not well marked in the Horse, and forms two-thirds 
of a sphere, excavated in its internal part by a very deep cavity for ligamentous 
insertion. 2. Outwardly, a very large eminence — the trochanter major, or great 
{external) trochanter, in which is recognized, as in the trochlea of the humerus : 
a summit, much more elevated than the articular head, and shghtly bent inwards ; 
a convexity, encrusted with cartilage, and anterior to the summit, from which 
it is separated by a narrow and deep notch ; a crest situated under the convexity, 
and formed by a tuberculated surface, on which one of the tendons of the middle 
gluteus muscle becomes inserted, after gliding over the convexity. 3. Posteriorly, 
the trochanteric or digitcd fossa — a deep cavity studded with imprints, and circum- 
scribed, outwardly, by a salient lip {trochanteric ridge), which descends vertically 

' This is tlie third trochanter of Cuvier, and takes the place of the external and superior 
branch of the linea axpera of Man. (It is the external small trochanter of Percivall, and the 
middle trochanter of Leyh ) 



138 



THE BONES. 



from the summit of the trochanter to the posterior face of the bone, where it 
gradually subsides. 

The [inferior extremity is flattened before and behind ; consequently, its laro-er 
axis crosses at a right angle that of the upper extremity. It is distinguished by 
the presence of tzvo condyles and a trochlea. The two condyles, placed behind, 
one beside the other, articulate with the superior extremity of the tibia. They 
are separated by a deep depression designated the intercondyloid fossa, which 
lodges the spine of the tibia and the interosseous ligaments of the femoro-tibial 



Fig. 89. 



Fig. 90. 




LEFT FEMUR (ANTERIOR VIEW). 

1, Head ; 2, 2, trochanter major, with its 
crest ; 3, trochanter minor, subtrochan- 
terian crest, or third trochanter; 4, in- 
ternal trochanter ; 5, notch for insertion 
of ligamentum teres ; 7, 8, tuberosities 
for tendinous and ligamentous insertion ; 
9, trochlea. 




LEFT FEMUR (POST^IOR VIEW). 

Head ; 2, trochanter major ; 3, trochanter 
minor ; 4, internal trochanter ; 5, fossa 
for insertion of ligamentum teres ; 6, 
trochanteric fossa; 7, 8, tuberosities; 9, 
fossa for the insertion of the external 
meniscus; 10, supra-condyloid fossa ; 11, 
condyles. 



articulation. The external condyle bears, outwardly, two fossag — one superior, for 
ligamentous insertion ; the other, inferior, for muscular attachment. The 
internal condyle presents, posteriorly and inwardly, near the posterior extremity 
of the intercondyloid notch, a roughened depression for the insertion of the 
fibro-cartilaginous meniscus interposed between the external condyle and the 
corresponding articular plane of the tibia. It is surmounted outwardly — on 
the side opposite to the intercondyloid notch — by a large tubercle for insertion. 
The trochlea, a wide pulley on which the patella glides, is situated in front of 



THE POSTERIOR LIMBS. 



139 



Fig. 91. 



the condyles. It is slightly oblique downwards and inwards, and appears to 
continue in front the intercondyloid notch. Of the two lips which border its 
cavity laterally, the internal is the thickest and the most prominent. Between 
the external and the corresponding condyle, is seen a digital fossa for muscular 
insertion. 

Structure and development. — The femur, very spongy at its extremities, is 
developed from four principal centres of ossification : one for the body, another 
for the articular head, the third for the trochanter, and the last for the inferior 
extremity alone. 

The femur of the Ass offers several differential characters, the principal of 
which have reference to the length of the neck, the development of the third 
trochanter (trochanter minor), and the curvatures of the 
diaphysis. The greater length of the neck causes the 
internal trochanter to be some distance from the hori- 
zontal plane on which the inner face of the bone lies ; 
in the Horse this trochanter is always in contact with 
the plane. The small trochanter is less developed than 
in the Horse, as may be seen on laying the bone on its 
external border ; for the femur of the Ass rests by the 
trochanter major and external condyle, while in the Horse, 
it lies on the latter and the subtrochanteric crest. With 
regard to the curvatures, there is remarked a slight 
diminution in that which carries the head of the bone 
backwards, and a slight increase in the twist of the 
diaphysis around its longitudinal axis, which alters the 
equilibrium of the bon* so that it is impossible to have 
it in stable equilibrium when it rests on the trochanter 
major, head, and inner lip of the trochlea ; this is easily 
accomplished with the femur of the Horse. 

By the dimensions of the neck and internal trochanter, 
the femur of the Hinny and Mule holds a middle place 
between their progenitors ; while in the development of 
the trochanter major, and the degree of torsion around 
its longitudinal axis, the femur of the Hinny much resembles that of the Ass, 
and the Mule that of the Horse, though the conditions of equilibrium always 
remain the same as in the latter. 




SECTION OF LEFT FEMUR, 
SHOWING ITS STRUCTURE. 



Differential Characters in the Thigh-bone of the other Animals. 

In all the domesticated animals except Solipeds, the femur tends to become curved longi- 
tudinally, prismatic, and triangular; the posterior face contracts, and the surfaces for insertion 
that it presents gradually approach each other, until they become confounded, and form a 
linea aspera in certain species. The head is more distinct ; the internal trochanter is a rough 
tubercle, and is joined to the large trochanter by an oblique ridge ; the large trochanter sub- 
sides, and forms a single mass, the summit and convexity of which are confounded ; the third 
trochanter, the fossa, and the supra-condyloid crest are more or less effaced. In addition to 
these modifications, there are others special to each species. 

A. Rvuninants.— In the Ox, there is no subtrochanteric crest ; the supra-condyloid fossa 
is shallow, and the crest little noticeable. The head is well detached, and has its centre 
excavated by a shallow fossa of insertion. The trochlea is narrow, and its inner border ascends 
much higher on the anterior face of the bone than the external. 

In the Sheep and Goat, the general form of the femur resembles that of the Ox. It is 
observed, however, that the body is slightly curved backwards ; that the supra-condyloid fossa 



140 



THE BONES. 



is nearly obliterated ; that the trochantir has subsiiled nearly to a level with the articulaJ 
head; and that the trochha is circumscribed by two equal-sized lips. 

The femur of the Camel more nearly resembles that of Man. It is long, slender, and curved 
backwards. The body is prismatic in its middle portion, and the two branches of the linea 
aspera meet in the middle and diverge towards the ends. Tlie articular head is very much 
separated from the trochanter major, which is below the level of tlie most prominent part of the 
head. Tiie internal condyle is smaller than the external, and the trochlea is narrow, while its 
lips are equal. 

B. Pig. — In the femur of the Pig, there is also noticed a supra-condyloid fossa, but it is 

wide and sliallow ; the rugosities of the posterior face are replaced by some salient lines ; the 

trochanter major is on a level with the heail; the latter is supported by a somewhat constricted 

neck,andissituated within, and in front of, the trochanter major. This hitter disposition changes 

the direction of the great axis of the superior extremity, 

which fibliquely crosses that of the inferior extremity. 

C. Camivora. — In the Dog and Cat, the femur is 
long and curved like a bow. Tlie rugged surfaces of the 
posterior face are confounded, and form two crests repre- 
senting the linea aspera of the human femur. These 
crests do not lie against each other in the middle portion 
of the bone — they are merely parallel ; tlien they diverge 
above and below, to terminate beneath the great and 
small trochanters, and above the two condyles. The 
trochanter major is not so high as the particular head. 
The femur of Carnivora is also distinguished: 1. By 
the complete absence of the third trochanter and the 
supra-condyloid fossa — this last being replaced by a 
small tubercle, which terminates below the external 
brinch of the linea aspera. 2. By the marked constriction 
and length of the neck supporting the articular head. 
3. By the depth of the digital fossa. 

In the Cat and Rabbit are found small bony nodules, 
embedded like sesamoids m the substance of the lateral 
ligaments of the femoro-tibial articulation. After mace- 
ration, liiey often adhere to the condyles of the femur. 

D. Rodents.— The femur of the Rabbit resembles 
that of the Dog. It is flat before and behind, and more 
bent inwards at its upper end. The internal trochanter 
appears as a crest, and not a tubercle ; and the sub- 
trochanteric crest is very developed, and placed im- 
mediately below the trochanter major. 

Leg. 

This has for its base three bones : the tibia, 
peroneus {pv fibula), and the rotiila {or patella). 




A. - B 

rEMtJR OF THE OAT AND RABBIT. 

L, Femur of the Rabbit. B, Femur 
of the Cat. 1, Diaphysis ; 2, head ; 
3, internal trochanter; 4, trochanter 
major ; 5, subtrochanteric crest ; 
6, trochlea; 7, internal condyle; 
8, sesamoid imbedded in the internal 
ligament of the femoro-tibial articu- 
lation. 



1. Tibia (Fig. 93). 

The tibia is a long prismatic bone, thicker at the superior than the opposite 
extremity, and situated between the femur and the astragalus, in an oblique 
direction downwards and backwards, constituting the principal portion of the 
leg. It has a body or shaft, and two extremities. 

Bod//.— Thk offers for study three faces and three borders. The faces are 
wider above than below. The external is almost smooth, and is concave in its 
superior part and convex below, where it deviates to become the anterior. The 
internal, slightly convex on both sides, presents, superiorly, deep imprmts for the 
attachment of the adductor muscles of the thigh and the semitendinosus. The 
posterior, nearly plane, is divided into two triangular surfaces : one, superior, 



THE POSTERIOR LIMBS. 



141 



Fig. 93. 



slightly roughened, serves for the attachment of the popliteus muscle ; the other 

inferior, much more extensive, is furrowed into numerous longitudinal crests, 

which give attachment to the perforans muscle. On the Hmit of these two 

surfaces is remarked the nutrient foramen of the bone. 

The borders are distinguished as anterior, external, and 

internal. The first is rounded, and not very sahent in its 

inferior two-thirds ; it forms, in its superior third, a 

curved crest, with the concavity external, which joins the 

anterior and superior tuberosity of the bone ; this has 

received the name of the tibial crest. The external border 

is very thick and concave above, where it constitutes, in 

common with the fibula, the tibial arch. The internal is 

also very thick, straight, and provided superiorly with some 

salient tubercles to which the popliteus is attached. 

Extremities. — The superior extremity, the most volumi- 
nous, is formed by three tuberosities — an anterior and two 
lateral, which are external and internal. The first, the 
smallest, is a rugged process continuous with the tibial 
crest, and separated from the external tuberosity by a 
wide and deep groove, into which passes a tendinous cord ; 
it is excavated, in front, by a vertically elongated fossa, 
which lodges the middle ligament of the patella. The 
externcd tuberosity, medium in size and the most detached, 
has outwardly an articular facet for the head of the fibula. 
The internal tuberosity, the largest and least detached, 
presents : on the sides, ligamentous imprints ; behind, a 
small tubercle which gives attachment to the posterior 
crucial ligament of the femoro-tibial articulation. The 
superior face of the two lateral tuberosities is occupied by 
two large, irregular, and undulated articular surf aces, which 
respond to the condyles of the femur, through the medium 
of the two meniscus-shaped fibro-cartilages interposed 
between the two bones. Of these two surfaces, the ex- 
ternal is always the widest, because it serves, by its posterior 
part, for the gliding movements of the popliteal tendon. 
They are separated from each other by the tibial spine — a 
conical articular eminence, divided into two lateral parts 
by a groove for insertion excavated at its base ; and in front 
by two lateral facets for the insertion, anteriorly, of the 
two inter-articular cartilages ; it is bordered behind by 
another fossa, which receives the posterior insertion of the 
internal meniscus. 

The inferior extremity, flattened behind and before, ex- 
hibits an articular surface moulded on the pulley of the 
astragalus, and two lateral tuberosities. The articular 
surface is formed by two deep cavities, oblique forwards and outwards, and 
separated by a median tenon which terminates posteriorly by a very prominent 
projection, on which the bone rests when it is made to stand vertically on a hori- 
zontal plane. The external tuberosity ^ projects but little, and is traversed in ItB 

* The external malleolus of Man. 
12 




POSTERIOR VIEW OP 
RIGHT TIBIA. 

Tibial spine ; 2, fossa 
for the insei'tion of the 
internal meniscus ; 3, 
external tuberosity 
with articulation for 
the fibula ; 4, fossa for 
the insertion of exter- 
nal meniscus ; 5, fibula, 
forming with the tibia 
the tibial arch; 6, shaft, 
or body of the tibia; 
7, 8, external and in- 
ternal malleoli, inferior 
tuberosities, or lateral 
processes of the tibia; 
9, articular trochleas 
with a median ridge, 
for articulation with 
the astragalus. 



142 



THE BONES. 




LEG-BONES OF THE MULE, WITH THE 
FIBULA COMPLETELY DETACHED. 

I, Nutrient foramen ; 2, insertion sur- 
face for the perforans ; 3, insertion 
surface for the popliteus ; 4, tibial 
ridge ; 5, fossa for the insertion of 
the anterior crucial ligament; 6, in- 
ternal articular surface; 7, external 
articular surface ; 8, tubercle for the 
insertion of the posterior crucial liga- 
ment ; 9, fossa for the insertion of 
the internal meniscus ; 10, tibial 
crest ; 11, internal and inferior tu- 
berosity; 12, external and inferior 
fissure of the tuberosity; 13, pos- 
terior prominence formed behind by 
the median spur of the inferior articu- 
lar surface ;' 14, superior extremity 
of the fibula articulating with the 
tibia; 15, the body ofthe fibula — com- 
pletely developed in this specimen. 



middle by a vertical fissure. The infernal 
tubcrosif//,^ better defined, is margined pos- 
teriorly by an oblique channel. 

Structure and development. — The tibia is 
very compact in its inferior portion, and is 
developed from five chief centres of ossifica- 
tion. The body is formed by one and the 
superior extremity by two, the anterior tuber- 
osity having one of these ; the last develops 
the whole of the inferior extremity of the bone, 
except the external tuberosity, which is de- 
veloped from a separate nucleus, that at an 
early period becomes fused with the principal 
one of the epiphysis. 

The tibia of the Ass is remarkable for 
the more or less perfect equality of the promin- 
ences around the inferior articular surface, so 
that this bone can sometimes lie in stable 
equilibrium on its inferior extremity. It is 
also distinguished from that of the Horse by : 

1. The more or less marked obliquity of the 
grooves which articulate with the astragalus. 

2. The disposition of the oblique prominence 
coursing the surface, for the insertion of the 
popliteus muscle. 3. The great development 
of the imprint for the semitendinosus muscle, 
and the crest above the groove for the oblique 
flexor tendon of the phalanges. 

The tibia of the Mule and Hinny more 
particularly resembles that of the Horse. 

2. Fibula, ok Peroneus (Fig. 94). 

A small, undeveloped bone, elongated and 
styloid in shape, situated outside the tibia, 
and extending from the superior extremity of 
that bone to the middle or lower third of its 
body. 

The middle portion of the fibula is thin 
and cylindrical, and forms above, in common 
with the external border of the larger bone, 
the tibial arch. Its superior extremity, wide 
and flattened on both sides, has received the 
name of head. It offers, on its internal face, 
a diarthrodial facet to articulate with the 
external and superior tuberosity of the tibia ; 
on its external face it shows ligamentous im- 
prints. The infei'ior extremity of the fibula 

* The internal malleolus. 



THE POSTEBIOB LIMBS. 



143 



terminates in a blunt point, and gives attachment to the ligamentous fibres that 
unite it to the tibia. 

The fibula is sometimes continued to the external inferior tuberosity of the 
latter bone, with which it is confounded ; and as this tuberosity always forms a 
special nucleus, particularly in the young Foal, it seems natural, having regard 
to the disposition observed in Pachyderms and the Carnivora, to consider it as the 
inferior extremity of the fibula fused to the tibia. In these animals, indeed, the 
tuberosity or external maleolus is formed by the inferior extremity of the fibula. 

Structure and development. — This bone is very compact, and apparently 
developed by a single nucleus of ossification ; though, in reality, there are two, 
one of which is for the head of the bone. 

3. Patella (Figs. 95, 96). 

A small, short, and very compact bone, situated in front of the femoral 
trochlea, and annexed to the tibia, to which it is attached by three extremely solid 
ligamentous bands. 

The small polyhedron which it represents only offers for study three faces : 




PATELLA OF THE HORSE (SUPERIOR AND 
POSTERIOR FACES). 

1, Superior face ; 2, posterior articular face ; 
3, external border. 



PATELLA OF THE HORSE (ANTERIOR FACE). 

1, Anterior face ; 2, external border ; 3, 
internal border. 



the superior, roughened, and serving for the insertion of the triceps cruralis and 
rectus muscles ; the anterior, convex and irregular ; and the third, the posterior, 
moulded on the femoral trochlea, to which it is but imperfectly adapted. In the 
fresh state, however, the articular surface formed by the latter face is completed 
by a fibro-cartilaginous apparatus, which will be noticed when describing the 
femoro-tibial articulation. This articular surface is composed : 1. Of a median 
ridge, which occupies the bottom of the trochlear cavity. 2. Of two depressed, 
gliding, lateral facets on the sides of this cavity ; the internal facet is always 
larger than the external — a disposition which permits the patella of one hmb to 
be distinguished from that of the other. 

The Patella of the Ass is usually narrower than that of the Horse, but this 
feature would scarcely permit of its being distinguished from that of the other 
domestic Equidae. 



144 



THE BONES. 



Fig. 97. 



Differential Characters in the Leg-bones op the other Animals. 

In the leg-bones there is observed, in the various domesticated animals, differences analo- 
gous to those mentioned as existing in the forearm of the pectoral limb. More particularly 
is til is the case with regard to the development of the fibula. The relations existing between 
the development of that bone and the number of digits, is less marked than that which exists 
between the development of the ulna and the division of the digital region. Thus, in Rumi- 
nanta the fibula is only represented by its inferior nucleus of ossification, although there are 
two apparent and free digits. In these animals the patella is also very narrow ; and in all the 

domesticated species except Solipeds, tlie articular 
grooves in the lower end of the tibia are directed im- 
mediately from before to behind. 

A. Ox, Sheep, Goat.— In the Ox, the tibia is 
short ; it is longer in the Goat and the Sheep. The 
tibia of these animals is remarkable for : 1. The absence 
of the lateral facet on the supero-external tuberosity. 
2. The absence of a vertical fossa on the anterior tuber- 
osity. 3. The absence of roughened lines on the pos- 
terior face. 4. The obliquity downwards and inwards 
of the inferior articular surface. The most salient point 
of this surface is the anterior extremity of the middle 
tenon. 

The body of the fibula and its upper extremity 
are replaced by a fibrous cord, which is sometimes 
ossified wholly or in part, and may then resemble the 
fibula of Solipeds. The inferior extremity forms a 
small isolated bone (the tamal coronoid bone of some 
authorities), articulating in one direction with the tibia, 
and in another with the calcis and astragalus. 

B. Camel The tibia of the Camd is very long. 

slightly bent outwards at its upper end, and inwards 
at the lower end. The tibial crest is high and sharp. 
The posterior face shows only one roughened line 
limiting the popliteal surface. 

C. Pig.— In the Pig, the fibula is flattened on both 
sides, extends the whole length of the leg, and is united 
to the tibia by its two extremities : above, by a diar- 
throdial facet ; below, by an interosseous ligament. 
It is developed from three ossifying centres; the in- 
ferior articulates with the calcis and astragalus. 

D. Dog, Cat. — In Carnivora, the tibia is long and 
slender, and presents a salient anterior crest. The 
fibula is also as long as the tibia, and is united to 
that bone at three points : at the two extremities by 
articular surfaces, in the inferior third and middle by 
an interosseous ligament. 

E. Rabbit. The leg-bones of this animal much 
resemble those of Carnivora, diflering only in : 1. More 
pronounced flattening of the tibia on each side at its 

upper end, and before and behind inferioily. 2. The slightly salient malleoli. 3. The fibula, 
which is fused with the tibia in its lower third. 




LEG-BONES OF THE RABBIT AND CAT. 

A, Boues of the Rabbit. B, Bones of 
the Cat. 1, Diaphysis of the tibia ; 
2, crest of the tibia; 3, internal 
malleolus or tuberosity of the in- 
ferior extremity of the tibia ; 4, 
anteiior extremity of the median 
tenon on the inferior articular sur- 
face of the tibia ; 5, fibula ; 6, ex- 
ternal malleolus or tubei'osity. 



Posterior Foot. 

This region, which bears the o;reatest resemblance to the same region in the 
anterior limb, comprises three subdivisions— the tarsus, the metatarsus, and the 
digital region. 

1. Bones of the Tarsus (Figs. 98, 99). 
These are short, very compact bones, six or seven in number, and situated 



THE POSTERIOR LIMBS. 



145 



between the inferior extremity of the tibia and the superior extremity of the 
metatarsal bones ; they are arranged, like the bones of the carpus, in two tiers — 
a superior and an inferior. 

The superior row only comprises two bones, 
the largest ; these are the astragalus and the 
calcaneum (or calcis). The inferior row is formed, 
outwardly, of the cuboides alone ; inwardly and 
anteriorly, it is subdivided into two secondary 
rows, the superior of which is constituted by the 
scaphoides, and the inferior by the large and small 
cuneiform bones. The last is sometimes divided 
into two, in which case there are three cunei- 
forms ; then the total number of the bones is 



Astragalus. — An irregular cubical bone, situ- 
ated in front of the calcis, between the tibia 
and the scaphoid, and divided into Jive faces : 
1. A superior and anterior, formed as an articular 
pulley to correspond with the inferior extremity of 
the tibia. This pulley — oblique from above down- 
wards, forwards, and outwards — may be considered 
as the type of the most perfect trochlea in the 
body ; it forms with the median plane of the body 
an angle of from 12° to 15°. Its borders are 
slightly spiral, the inner being more prolonged 
backwards than the external ; its groove receives 
the median tenon of the tibia, and its two ridges 
or lips fit into the lateral furrows of that bone ; 
the two lips are deeply implanted in the lateral 
grooves, and their two fossae are hollowed out of 
their lower extremity, to admit the end of the 
principal bone during flexion movements, 2. An 
inferior face, occupied by a slightly convex articu- 
lar surface articulating with the scaphoid ; this 
surface is notched outwardly by an excavation for 
ligamentous insertion ; behind the internal ex- 
tremity of this furrow, the articular face is cut 
in such a manner as to present two facets inclined 
towards each other, and separated by a sharp 
ridge. 3. A posterior face, irregular, cut into three 
or four diarthrodial facets adapted for similar 
facets on the calcis, and which are separated by 
a wide, rugged excavation ; the middle facet is 
elliptical, almost vertical, slightly convex, and is 
the largest. 4. An external face, covered with 
imprints for the tibo-tarsal ligaments. 5. An 
internal face, provided below with a small tubercle 
for insertion, and, posteriorly, with a badly defined 
sinuous furrow for the tendon of the oblique flexor 
muscle of the phalanges (Fig. 99). 




left hind foot (external 
aspect). 

1, Tibia ; 2, summit of calcis or cal- 
caneum ; 3, astragalus ; 4, cuboid; 
5, scaphoid ; 6, cuneiform mag- 
num ; 7, large metatarsal bone ; 
8, small metatarsal bone ; 9, suf- 
fraginis, proximal, or first pha- 
lanx ; 10, sesamoid bones; 11, 
coronary, second, or middle pha- 
lanx ; 12, pedal bone, or third or 
distal phalanx; 14, navicular 
bone ; 15, basilar process of pedal 
bone. 



146 



THE BONES. 



Calcaneum, or Calcis (Figs. 98, 99, 100, 101).-A bone vertically elongated, 
flattened on both sides, and presenting tivo faces, hvo borders, and two extremities. 

The external face is smooth and nearly plane. The internal face is excavated 
into a ghdmg groove to form the tarsal groove, in which passes the tendon of 
the perforans. The anterior border is slightly concave. The posterior border is 

Fig. 99. 




TARSUS OF THE 
INTERNAL ASPECT. 

1, Calcis; 2, astragalus (first and second bones of the 
upper row); 3, cuboid; 4, scaphoid; 5, cuneiform 
magnum; 6, vascular canal between the cuboid, 
scaphoid, and cuneiform magnum ; 7, smooth sur- 
face for the tendon of the gastrocnemius; 8, surface 
for insertion of latter ; 9, smooth surface for the 
tendon of the perforans ; 10, anterior extremity of 
the tibia; 11, superior extremity of the large meta- 
tarsal bone. A, Bones of the upper row. b. Bones 
of the lower row. T, Tibia, m, Metatarsus. ' 



ANTERO-EXTERNAL ASPECT. 

1, Calcis; 2, astragalus; 3, cunei- 
form magnum ; 4, scaphoid ; 5, 
cuboid; 6, cuneiform parvum ; 7, 
superior extremity of large meta- 
tarsal bone ; 8, superior extremity 
of inner small metatarsal bone. 
A, Bones of the upper row. b, 
Bones of the lower row. t, Tibia. 
M, Metatarsus, 



thicker, straight, and rugged. The superior extremity, slightly enlarged, con- 
Btitutes the summit of the calcaneum, and is divided into three parts : a middle 
which gives attachment to the tendon of the gastrocnemius ; the other the 
anterior, is a smooth surface on which this tendon rests when the foot is much 
flexed ; the third, altogether posterior, also constitutes a gliding surface for the 



TEE POSTERIOR LIMBS. 



147 



tendon of the perforatus. The inferior extremity, wide and voluminous, shows in 
front three or four articular facets which articulate with the astragalus, and are 
(Separated, like those of the last bone, by an irregular and slightly excavated sur- 
face for insertion. Below, it shows for articulation with the cuboid a fifth facet, 
continuous with one of the preceding. 

Developynent. — The calcaneum is developed from two nuclei of ossification, 
one of which is for the summit. 

Cuboid hone (Figs. 98, 99). — This little bone, situated at the external side of the 
scaphoid and the large cuneiform bone, between the calcis and two of the metatar- 
sals, does not resemble a cube, but a parellelopiped elongated from before to behind. 
It offers six faces : a superior, an articular face, in contact with the calcaneum ; 
an inferior, also articular, articulating with the principal and external rudimen- 
tary metatarsal hones ; an internal, furnished with three facets for contact with 
the scaphoid and great cuneiform, and crossed from before to behind by a fissure, 



Fig. 100. 



Fig. 101. 





LEFT HOCK (FRONT VIEW). 

1, Apex of calcaneum ; 2, astragalus, inner 
ridge ; 3, cuneiform magnum ; cunei- 
form medium ; 5, cuboid. 



LEFT HOCK (INTERNAL ASPECT). 

1, Apex of calcaneum ; 2, inner articular 
ride of astragalus ; 3, navicular, scaphoid, 
or cuneiform medium ; 4, cuneiform mag- 
num ; 5, cuboid ; 6, cuneiform parvum. 



which forms with these two bones a vascular canal ; an external, an anterior, and 
B> posterior, covered with imprints. 

Scaphoid hone (the large cuneiform of Percivall) (Figs. 98, 99). — Flattened above 
and below, it is described as having two faces and a circumference. The faces, both 
articular, are furrowed by a channel of insertion, and are distinguished as superior 
and inferior. The first is concave, and articulates with the astragalus ; the second 
is convex, and in contact with the two cuneiform bones. The circumference offers, 
outwardly, two small facets, which are adapted to similar facets on the cuboid 
bone. For the remainder of its extent, it is covered with imprints (Fig. 99). 

Oreat Cuneiform hone (the middle cuneiform of Percivall) (Figs. 99, 100, 101). — 
Flattened above and below, and triangular in shape, this bone is much smaller than 
the scaphoid, though resembling it in a striking manner. Its superior face is in 
contact with the latter bone, and its inferior face articulates with the middle and 
internal lateral metatarsal bones. Its external harder is provided with one or two 
facets to correspond with the cuboid bone ; and its internal herder also shows one. 



148 THE BONES. 

which is in contact with another on the small cuneiform. Its anterior border is 
roughened throughout its extent (Figs. 99, 100). 

Small Cuneiform hone (Figs. 99, 101). — Situated at the inner side of the tarsus, 
this bone — the smallest of any yet examined — is elongated from before to 
behind, flattened on both sides, and wedged in between the os scaphoides, the large 
cuneiform bone, and the large and internal small rudimentary metatarsal bones, 
with which it corresponds by four articular facets : a superior, two inferior, and 
one internal. When this bone is in two portions, there are then three cuneiforms, 
which may be distinguished, as in Man, by naming them //•«/, second, and third 
(Fig. 99). 

It is not very rare to find the scaphoid {cuneiform mafjnum) fused with the 
great cuneiform {cuneiform medium), and sometimes even the cuboid is joined to 
the cunean bones. 

Development. — All the bones of the tarsus, with the exception of the calcis, 
are developed from a single nucleus of ossification. 

The astragalus in the Ass is distinguished from that of the Horse by the 
external Hp of the trochlea, which is abruptly deviated outwards at its inferior 
extremity ; and by the disposition of the inferior articular surface, which is 
regularly convex from side to side, behind the groove for insertion ; in the 
Horse this part of the articular surface is formed by the union of two facets 
inclined towards each other. In the same animal, the scaphoid {cuneiform 
maffnum) is recognized by the shape of the superior diarthrodial surface, which 
is a hollowed reproduction of the inferior face of the astragalus ; and the g7-eat 
cuneiform {cuneiform medium) by the larger concavity of its scaphoid face. 

Differential Characters in the Tarsal Bones of the other Animals. 

In the domestic animals, the tarsus differs in the number and shape of the bones enteriug 
into its formation. 

A. Ox, Sheep, Goat. — The tarsus of these animals is slender, and has only five bones, 
the cuboid and scaphoid being fused into one. The astragalus i.s tlongated from above to 
below, and is united to the scaphoid by an antero-posterior groove, and to the calcis by a 
vertical groove ; so that it has tiiree trochleas. The principal trochlea has its external border 
thicker than the internal, and decreases from below to above. The posterior trochlea is not 
80 deep as the others. The calcis is lon^' and thin; the posterior gliding surface on the 
summit is excavated into a channel. The small cuneiform is pisiform, and but slightly developed. 

B. Camel. — In the Camel, there are six tarsal bones, two of which :ire cuneiform. The 
astragalus articulates, by means of a double groove, with the scaphoid and cuboid. The 
calcis is relatively short, and about equally excavated on its two faces. The cuboid ia 
voluminous. 

C. Pig. — The tarsus of this animal much resembles that of Ruminants in its general 
disposition, and in the astragalus ami calcis; but it lias seven bones, because the cuboid and 
scaphoid are separate, and there are constantly three cunfi/nrm bones. 

D. Dog, Cat. — There are seven bones in the tarsus of these animals. The astragalus 
articulates witli the scaphoid— almost as in Man— by means of a tiue In ad, separated from the 
rest of the bone by a constriction named the neck of the astragalus. The cuboid and the three 
cuneiform bones articulate with the five metatarsal bones. 

2. Bones of the Metatarsus (Figs. 98, 102). 

These bones are three in number — a median and two lateral — and offer the 
greatest analogy to the metacarpal bones. This enables us to dispense with a 
general description of them, and to confine ourselves only to indicating the 
differential characters which distinguish them from the corresponding bones in 
the anterior limb. 



THE POSTERIOR LIMBS. 



149 



The principal, large, or median metatarsal bone, is longer than the same 
metacarpal, and its body, instead of being slightly compressed before and behind, 
is nearly a regular cylinder. It presents, outwardly, a fissure which is directed 
at first obliquely backwards and downwards (Fig. 99), and afterwards descends 
vertically along the lateral external metatarsal bone. The articular surface of 
the superior extremity is excavated in its centre by a large fossa for insertion 
(Fig. 99). This surface presents, behind and outwards, a 
thick tubercle which appears to spring from the body of the Fig. 102. 

bone, and which has a facet against which the external rudi- 
mentary metatarsal rests. The inferior extremity is at the 
same time wider and thicker than that of the metacarpus. 
Above and in front of the articular surface, it is hollowed 
by a small transverse fossa, which is deeper than in the corre- 
sponding bone in the anterior limb. 

Of the tivo rudimentary {digital, splint), or lateral meta- 
tarsal bones, the external is always longest, if not thickest. 
The internal bears on the superior face of its head three 
articular facets, two of which articulate with the small 
cuneiform, and the third with the large bone of that name. 

The length of these rudimentary metatarsals is nearly 
equal to three-fourths that of the principal metatarsal. 

The metatarsus of the Ass is remarkable for the length 
of its rudimentary metatarsals, which are nearly five-sixths 
that of the principal bone. The latter is also notable, 
because of its length and fineness ; and if it is compared 
with that of the Horse, it is distinguished by : 1. The tri- 
angular shape of its upper extremity, due to the great 
development of the tubercle on which the external rudi- 
mentary metatarsal lies. 2. The flat diarthrodial facet which 
articulates with the antero-external part of the large cunei- 
form, 3. The marked inequality of its condyles. 



Differential Characters in the Metatarsal Bones of the 
OTHER Animals. 



posterior aspect op 
left metatarsus. 

1, Head of principal 
metatarsal bone ; 2, 

3, external and in- 
ternal splint bones, 
or metatarsals of the 
rudimentary digits ; 

4, rough surface for 
insertion of suspen- 
sory ligament ; 5, 
nutrient foramen ; 
6, middle ridge or 
tenon of inferior arti- 
cular surface. 



The metatarsus is also a region in which the number of bones varies 
in the domesticated animals. Tlius, in Ruminants there are two, and 
five in the Pig, Camivora, and Rodents. 

The metatarsals of the latter are exactly like the same bones in 
the anterior limb. Those of Ruminants are slightly different. 

A. Ox, Sheep, Goat.— In the Ox, Sheep, and Goat are found a 
principal and a rudimentary metatarsal bone. The latter is a small 
lenticular bone, articulating, posteriorly, with the head of the large 
metatarsal bone. The latter differs from the principal metacarpal 
bone, in being longer, quadrilateral in form, and having a vascular 
canal traversing the posterior face of its upper extremity. 

B. Camel. — The metatarsus differs from the metacarpus by its greater width and less 
thickness; the articular surface is divided by a depression into two parts, situated on the same 
horizontal plane. 

C. Pig.— The Pig has four perfect metatarsals, and an internal rudimentary one. The 
latter is a small bone flattened on both sides, articulating by means of a diarthrodial facet, and 
sometimes fused posteriorly with the upper end of the fourth metatarsal. 

D. Dog, Cat.— Ill the Dog and Cat are one rudimentarv and four perfect metatarsals. 
The former is articulated with the internal cuneiform, and represents the vestige of the thumb. 



150 THE BONES. 

3. Bones of the Digital REOrioN (Fig. 98). 

Id Man, the digits of the foot — known as toes — are very different to those of 
the hand ; but it is otherwise with the domestic animals. The phalangeal region 
of the posterior, closely resembles that of the anterior Hmb. The analogy in the 
conformation of these bones is even pushed so far, that it becomes very difficult 
to distinguish them from one another. 

There are some differential characters, however. For instance, it is remarked : 
1. That the first phalanx is not so long as in the anterior limb, and less wide 
and thick at its inferior extremity ; but it is, on the contrary, wider and thicker at 
its superior extremity. 2. That the lateral diameter of the second phalanx is 
shorter. 8. That the third phalanx, less expanded towards its inferior border, 
has more the shape of a V, and that its inferior face is more concave. 4. That 
the sesamoids are less voluminous. 5. That the navicular bone is shorter and 
narrower. 

In the Ass, the same differential features are observed between the posterior 
and anterior phalanges as in the Horse, and there are no very marked differences 
between the former in these two animals. The following may, however, serve to 
distinguish them. 

The ^rs^ phalanx of the Ass is proportionately longer than that of the Horse, 
and the rugosities are larger ; the principal nutrient foramen is usually on the 
anterior face, and the external glenoid cavity is much smaller than the internal. 

The second phalanx is also proportionately longer than that of the Horse. 
Its inferior median furrow is deep, especially behind ; it has generally numerous 
nutrient foramina below the posterior gliding surface ; the median tenon of its 
upper face terminates before and behind by a salient tubercle, which prevents the 
bone from resting in equilibrium when it is placed vertically on that face. 

The third phalanx of the Ass is higher than that of the Horse, owing to the 
development of the pyramidal process ; it is constricted above the preplantar 
fissure ; the surface of the sole is proportionately more extensive, and the 
concavity of the semilunar crest is less marked ; the extremities of that crest are 
saUent, and the plantar fissures very deep. 

The navicular bone shows very marked differences. In the Ass its thickness 
is very considerable, due to the median ridges on both faces. Its posterior 
border is very oblique downwards and backwards, and it is towards this border 
that it inclines when Ave attempt to make it lie horizontally on its upper face ; 
while its two extremities are more curved than in the Horse. 

In the Mule and Hinny, the two first phalanges much resemble those of 
the Ass, while the third shows the characters of that of their progenitors. 
Nevertheless, that of the Hinny is rather more like the third phalanx of the 
Horse than that of the Ass, while the contrary is observed in that of the Mule. 

Differential Characters in the Posterior Phalangeal Region of other Animals. 

In all the domesticated animals, the posterior digits comport themselves exactly like the 
anterior. The Carnivora alone offer a notable difference ; in them, in reality, the inner toe, 
the equivalent of the thumb, does not exist — or rather, it is only represented by tiie rudimentary 
metatarsal bone alluded to above. Nevertheless, it frequently occurs that a completely de- 
veloped thumb is found in this animal ; and in this case the rudimentary metatarsal is ordinarily 
followed by a ligamentous cord, to which is suspended a bony stylet that represents either the 
inferior extremity of the metatarsal bone, or the first phalanx ; it is to this stylet that are found 
articulated in succession the second and third phalanges. 

It is not rare to meet with a sixth floating toe in dogs of very large size. 



THE POSTEBIOR LIMBS. 



151 



Comparison of the Abdominal Limb of Man with that of Animals. 

A. Pelvis (Fig. 103). — The longitudinal axis of the pelvis of Man forms, with the horizon, 
an angle of about 40°. 

The bones which compose it are proportionately larger and stronger than in all the 
domesticated animals. 

The two faces of the ilium, and especially the inner face, are much hollowed ; the iliac 
crest has the form of an italic S. 

The pubis alone participates in the formation of the pelvic sympliysis, and the concavity 
which, in the domesticated animals, 

is called the ischial arch, is desig- Fig. 103. 

nated in Man the pubic arch. 

In consequence of the excavation 
on the inner face of the ilium, the 
pelvic cavity may be divided into 
the great and lesser pelvis. In the 
latter are lodged the genital and 
urinary organs, as well as the ex- 
tremity of the digestive tube. 

B. Thigh (Fig. 104).— The femur 
of Man is nearly vertical, and situ- 
ated in a direction sligiitly oblique 
downwards and inwards ; it presents 
a curvature forwards. The body of 
the bone is prismatic and triangular 
in its middle part; the posterior 
border of this prism forms a some- 
what salient cresf, which takes the 
place of all the insertion eminences 
on the posterior aspect of the femur 
in animals, and is designated the 
linea aspera. This line bifurcates 
above and below ; below, the branches 
margin a triangular or popliteal space. 

The head is supported by a long 
neck, inserted obliquely into the 
superior extremity. The two con- 
dyles are joined together in front by 
the trochlea, which is wide and* 
shallow. 

a Leg (Fig. 105) —Three bones : 




human pelvis (female). 

1, Last lumbar vertebra ; 2, 2, intervertebral substance ; 
3, promontory of the sacrum ; 4, anterior surface of the 
sacrum ; 5, coccyx ; 6, iliac fossae ; 7, antero-superior 
spinous process ; 8, antero-inferior spinous process ; 
9, acetabulum, a. Its notch ; 6, body of ischium; c, its 
tuberosity ; d, its spine ; e, pubis ; /, symphysis pubis ; 
g, arch of the pubes ; h, angle of os pubis; i, spine of 
pubes, with crest between it and h; k, k, pectineal line ; 
I, I, ilio-pectineal line, with its prolongation, m, m ; 
n, ilio-pectineal eminence ; o, smooth surface for femoral 
vessels ; p, p, great sacro-ischiatic notch. 



the tibia, fibula, and patella. 

The tibia is very long ; its crest (or spinous process) is much more developed than in any 
of the domesticated animals, and describes a kind of curve like an italic S. On the inner 
aspect of the inferior extremity is seen a voluminous process which occupies, inwardly, a 
portion of the tibio-tarsal articulation : this is the internal malleolus. The articular surface ia 
not exactly formed to correspond with the whole articular surface of the astragalus. 

The fibula is as long as the tibia. It is prismatic, and slightly twisted on itself. It articu- 
lates above and below with the tibia. The lower extremity responds to the astragalus, and 
forms a prominence named the external malleolus. 

There is nothing particular to note in the patella. 

D. Foot (Fig. 106). — The foot of Man is pLaced in a horizontal direction. Its upper 
aspect is convex; its inferior face is excavated, and it rests on the ground by its two 
extremities. 

1. Tarsus. — In the tarsus there are seven bones, three of which are cuneiform. The astra- 
galus articulates with the tibia and fibula ; it responds to the scaphoid by a well-detached 
convex articular surface, named the head. 

In the bones of the lower row, it is remarked that the cuboid responds to the fifth and 
fourth metatarsals; the first cuneiform to the third; the second cuneiform to the second 
metatarsal : and the third to the first. 

2. Metatarsus. — The metatarsus is composed of five bony columns, nearly parallel to each 



152 



TEE BONES. 



other. They are enumerated from without to within, and increase in length from the first to 
the fourth ; the fifth is the shortest and most voluminous. 

3. Digital region-— This comprises five digits or toes. The phalanges of these toes are 
analogous to those of the fiiigersi, from which they are distinguished by their small size. They 
increase in volume from tlie first to the fifth digit. 



Article VIL — The Foot in General. 

It would be useless to reproduce here the general considerations discussed 
when treating of the hand (p. 121), and it may therefore be sufficient to state 

Fig. 104. Fig. 105. Fig. 106. 





RIGHT HUMAN FEMUR 
(ANTERIOR ASPECT). 

1, Shaft ; 2, head ; 3, neck ; 
4, great trochanter ; 5, 
anterior intertrochanteric 
line; 6, lesser trochanter; 
7, external condyle ; 8, 
internal condyle ; 9, tu- 
berosity for attachment 
of external lateral liga- 
ment; 10, fossa for ten- 
don of origin of popliteus 
muscle ; 11, tuberosity 
for attachment of inter- 
nal lateral ligament. 



HUMAN TIBIA AND FIBULA 
OF RIGHT LEG (ANTERIOR 
ASPECT). 

1, Shaft of tibia; 2, inner 
tuberosity; 3, outer tu- 
berosity ; 4, spinous pro- 
cess ; 5, tubercle ; 6, in- 
ternal surface of shaft ; 
7, lower extremity of 
tibia; 8, internal malleo- 
lus; 9, shaft of fibula; 

10, its upper extremity; 

11, its lower extremity; 
between 1 and 6 is the 
sharp crest of the tibia. 



DORSAL SURFACE OF LEFT 
HUMAN FOOT. 

1, Astragalus ; 2, its anterior 
extremity articulating 
with the cuboid bone, 4 
3, 3, calcis ; 4, scaphoid 

5, internal cuneiform bone 

6, middle cuneiform bone 

7, external cuneiform 
bone ; 8, cuboid bone ; 9, 
metatarsal bones of first 
and second toes; 10, first 
phalanx of great toe ; 11, 
second ditto ; 12, 13, 14, 
phalanges of second toe. 



that the works of the anatomists already mentioned — and especially those of Joly 
and Lavocat — have demonstrated that the foot of animals is constructed on the 
same type as the hand. In it, as in the hand, three sections are remarked : the 



THE FOOT IN GENERAL. 153 

tarsus, metatarsus, and phalanges ,- and, in the archetype, each section comprises 
five parallel rows, each of which has two tarsal bones, one metatarsal, and three 
phalangeal. In the present fauna there is not, perhaps, a Mammal which has 
a perfectly typical pentadactylous abominal limb ; for this ideal disposition is 
modified in the sense already indicated for the hand. In the following- brief 
paragraphs, an attempt will be made to show the manner in which Man and the 
domestic animals may be allotted to the archetype. 

1. 31 an. — In Man the archetype is realized in the metatarsal and phalangeal 
sections, and it will now suttice to examine the tarsal section. This contains 
seven separate bones — three in the upper and four in the lower row. It must 
not be forgotten that the scaphoid, although situated between the two rows, 
nevertheless belongs to the upper, as happens in the carpus of certain species. 
Apparently, it is deficient in two bones in the upper row and one in the inferior. 
This deficiency arises from fusion of the apex of the calcaneum {first superior 
metatarsal hone) with the remainder of the bone {second hone), of the scaphoid 
with the fifth hone in the upper row, and of the first inferior tarsal bone with the 
cuboid in the second row. 

2. Carnivora. — The foot of Carnivora only differs from that of Man in the 
arrangement of the thumb ; as this digit has usually no phalanges, and its meta- 
tarsal piece is only a small, very short styliform bone. Notwithstanding this 
difference, the pentadactylous archetype is as easily recognized in the foot of 
these animals as in that of Man. 

3. Rodents. — The foot of the Rahhit and Hare is yet less complete than that 
of Carnivora, as the metatarsal of the thumb is absent ; but, by the constitution 
of the tarsus, Rodents resemble Carnivora and Man, and consequently they can 
be also classed in the pentadactylous type. 

4. Pig. — In this animal, the tarsus presents the same number of pieces and 
the same fusions, as in Rodents, Carnivora, and Man. The metatarsus and 
phalangeal section have four complete toes — first, second, third, and fourth ; 
and with regard to the fifth digit, it is represented by a short, flat, and irregu- 
larly triangular metatarsal, articulating posteriorly with the third metatarsal, and 
attached to the third cuneiform by some ligamentous fibres. 

5. Ruminants. — The foot of the Ox, Sheep, and Goat present numerous 
fusions, and even some abortions. The tarsus has only five distinct bones ; for, 
besides the fusions which exist as in the preceding animals, the scaphoid is united 
to the cuboid, and the third cuneiform is completely aborted. 

The metatarsus of these animals includes a principal metatarsal, provided, 
inferiorly, with a double diarthrodial surface, and an internal rudimentary 
metatarsal. Must we consider the principal metatarsal as the result of the fusion 
of the third and fourth, and admit, in Ruminants, the abortion of the first two 
digits ? Several anatomists have professed this opinion. Lavocat did so at first, 
and then abandoned it. He considered the principal metatarsal as due to fusion 
of the metatarsals of the first four digits, and he expressed himself on this point 
as follows : " The first and the fourth metatarsals are visible, and fused above 
and behind the united large metatarsals. Each of them has the shape of a thick 
pyramid, with its base uppermost, large, and about five centimetres long in the 
Ox. Above, they join to form an arch, which is the contour of a wide and short 
vascular canal running between them and the two large metatarsals, and which 
does not exist in the Goat and SheejJ. Their widened superior extremity is in 
contact with the bones of the tarsus, to wit : the first metatarsal with a facet of 



154 TEE BONES. 

the p-ototarsiis, or first portion of the cuboid ; the fourth metatarsal with all the 
inferior facet of the tetrofarsus, or second cuneiform. And each of them has, 
for this eminently normal connection, an articular facet well separated from the 
diarthrodial surface of the large metatarsals by a large fossa destitute of cartilage. 
In this way the first four metacarpals are gathered into a single bundle. . . . 
Lastly, the thumb, or fifth digit, is constantly represented in the foot by a 
distinct metatarsal bone — at least in the Ox, Goat, and Sheep.''' 

Notwithstanding the reasons on which Lavocat bases his last interpretation 
as to the metatarsals of the Ox, we prefer adopting the first. In fact, if some 
wild Rimiinants are examined — Deer, for example — there will be found a tarsus 
identical with that of the Ox, and a principal metatarsal provided with a vascular 
canal, with two inverted pyramidal expansions ; and, in addition, two styliform 
bones lying to the outside and the inside of the principal bone of the shank. 
These bones evidently represent the metatarsals of the second and fifth digits ; 
as they exist at the same time as the lateral ridges on the principal metatarsal 
bone, it appears to be impossible to give to the latter the same signification. 

The posterior phalangeal region of the Ox is almost identical with the an- 
terior ; it is, therefore, needless to again demonstrate its constitution. That of 
the Sheep and Goat has no rudimentary phalanges to serve as a base for the 
ergot, in the hand ; but the two ergots suffice to represent the first and fourth 
digits, and so to include these animals in the pentadactylous type. 

6. SoUpeds. — The tarsus of these animals has six or seven bones. In the 
second case, it is identical with that of Carnivora and Man ; in the first, the 
second and third cuneiforms are fused. The metatarsus and posterior phalangeal 
section having the same constitution as those of the anterior, the reader is 
referred to the description of the Hand in General. 

Article VIII. — The Limbs in General and their Parallelism. 

A. The Limbs in General. — The bony sections which compose the limbs, 
are destined not only to support the trunk in a stationary attitude, but also to 
transport it during progression. This double use gives rise to a difference 
between the anterior and the posterior members. The front limbs, being nearer 
the centre of gravity than those behind, have to sustain the largest share of the 
weight. They ought, consequently, to be specially organized as organs of sup- 
port. Therefore it is, that the four principal bones composing each of them — 
shoulder, arm, forearm, foot — although flexed, or disposed to be flexed, in an 
inverse sense to one another, oppose to the pressure of the weight of the trunk — 
which tends incessantly to throw them down — obstacles purely mechanical, and 
of such energy that we may still understand how the body can be sustained on 
the anterior limbs, if we suppose all the muscular masses surrounding these bony 
columns to be removed, except one. 

Thus, the weight of the body is transmitted to the scapula through the 
muscles that attach that bone to the trunk. It then passes to the humerus, and 
thence to the radius, to be thrown, finally, on the diflferent pieces composing 
the foot. Now, the humerus forming with the scapula an angle which is open 
behind, and with the bones of the forearm another angle open in front, the 
weight of the body pressing continually on these angles tends to close them, 
and thus cause the flexion of these bones. But this result is prevented by the 
combined action of two muscular powers — the biceps and the extensors of the 



THE LIMBS IN GENERAL AND THEIR PARALLELISM. 



155 



forearm. With regard to the radius, 
carpus, and metacarpus, owing to their 
vertical direction, they themselves sup- 
port the pressure of the weight of the 
body without requiring any muscular 
aid. But the digital region, being di- 
rected obliquely forward and downward, 
forms, with the principal metacarpal, a 
third angle open in front, for the main- 
tenance of which nature has given solid, 
inert, or contractile mechanical bands. 

The anterior limbs are also agents 
of transport, for they can elevate the 
trunk by the spring of their bony rays, 
and fix themselves on the ground by 
their free extremities. 

The posterior limbs are less favour- 
ably disposed than those in front to as- 
sume the function of columns of support ; 
as their rays are, for the most part, in a 
state of permanent flexion, and joined in 
an angular manner to one another, as 
may be seen by glancing at the skeleton 
(Figs. 107, 108, 1, 2, 4, 5, 6). It is, 
therefore, necessary that muscular agency 
should prevent the breaking-down of 
these columns. Though defective as 
supports, they are nevertheless admirably 
designed to serve as agents of locomotion. 
The slightest erection of these inclined 
bones propels the mass of the body for- 
ward, and this impulsion is almost wholly 
transmitted to the trunk, in consequence 
of the very intimate union of the pelvis 
with the vertebral column. 

B. Parallel between the An- 
terior AND Posterior Limbs. — After 
what has just been said, it will be seen 
that the anterior limbs are more par- 
ticularly destined for the support of the 
body, while the posterior ones more 
especially play the part of propelling 
agents in the locomotory acts. 

Notwithstanding this difference in 
the functions assigned them, these two 
limits offer in their conformation such 
striking resemblances to each other, that 
some authors have been inclined to con- 
sider the posterior as an exact repetition 
of the anterior limb. The followina: is 




ANTERIOR LIMB OF THE HORSE (ANTERO- 
EXTERNAL VIEW). 

0, Scapula ; H, humerus ; a, radius ; C, carpus ; 
M, metacarpus ; p, phalanges ; s, sesamoid 
bone. 1, Coracoid process; 2, head of the 
humerus; 3, external trochanter ; 4, deltoid 
ridge; 5, inferior articular surface of the 
humerus; 6, olecranon; 7, ulna; 9, pisi- 
form (trapezium), or supercarpal bone. 



156 



THE BONES. 



Fig. 108. 




POSTERIOR LIMB OF THE HORSE (ANTERO- 
EXTERNAL VIEW). 

C, Coxa ; F, femur ; J, tibia ; 8, tarsus ; M, meta- 
tarsus; p, phalanges; S, sesamoid. 1, Ischium ; 1', 
pubis; 2, head of the femur; 3, trochanter major; 
4, trochanter minor ; 5, condyle of the femur ; 
6, patella ; 7, fibula ; tibial ridge ; 9, calcis. 



a brief analysis of the analogies ex- 
isting between them. 

At the end of the last century, 
Winslow and Vicq-d'Azyr, and nearer 
our own time, Cuvier, Flourens, 
Paul Gervais, Martins, Gegenbauer, 
Lavocat, Foltz, and Sabatier, have 
occupied themselves with the homo- 
logy of the anterior and the posterior 
members. All these anatomists did 
not absolutely arrive at the same 
conclusion ; for several of them, for- 
getting that the question should be 
examined in the whole animal series, 
made Man alone the subject of their 
studies. 

Vicq-d'Azyr and Cuvier recom- 
mended that the anterior and pos- 
terior limbs of opposite sides should 
be compared. Martins and Gegen- 
bauer, allowing a torsion of the 
humerus of 180°, advised that the 
two members of the same side should 
be compared, care being taken to 
make allowance for the untwisting 
of the 180° contortion at the lower 
end of the humerus. Lastly, 
Flourens and Lavocat contrasted the 
two members of the same pair with 
each other, after placing the hand 
in a position of natural pronation 
by rotation of the radius on the ulna, 
and without turning either limb or 
bone, or even a portion of a bone, 
no matter what kind of animal may 
be under examination. We will 
adopt the latter proceeding, as it is 
the simplest and most natural. 

Parallel between the coxa and 
scapula. — The analogies existing be- 
tween these two bones are but little 
striking at first sight ; nevertheless, 
with attention there is no ditficulty 
in finding in the coxa the three pieces 
that enter into the composition of 
the shoulder (Figs. 107, 108). 

The ilium represents the scapula. 
The external iliac fossa reminds one 
of the supra- and subspinous fossae. 
Occasionally, there is met with in the 



THE LIMBS IN GENERAL AND THEIR PARALLELISM. 157 

Horse a rudiment of the crest dividing the ihac fossa into two parts, and in 
some animals — the Pig, Sheep, and Goat— this crest, which is the trace of the 
scapular spine, becomes constant and very evident. 

With regard to the cotyloid cavity, it repeats in the posterior limb the glenoid 
cavity of the scapula. There remains to determine, in the latter bone, the 
portions analogous to the ischium and pubis. If we rely upon the evidence 
afforded by the muscular insertions, we come to the conclusion that the ischium 
corresponds to the coracoid process, and the pubis to the clavicle of animals 
which are provided with one. It will also be remarked that the coxa is directed 
backwards, while the scapula inclines obliquely forwards ; this opposition in the 
direction of the bones in no way alters their analogies ; the functions of the 
members to which they correspond require this inverse position. 

Parallel hehveen the femur and hwiwus. — The resemblance between these 
two bones is remarkable. Thus there is found in the first. 1. An articular 
head, better detached than that of the humerus, but shaped in the same manner. 
2. A trochanter analogous to the great tuberosity, and also, like it, decomposable 
into three distinct parts — summit, crest, and convexity. 2. A lesser trochanter, 
representing the small tuberosity. 4. An eminence for the insertion of the 
superficial gluteus muscle, which takes the place of the deltoid imprint. 5. An 
inferior articular pulley continued between the two condyles by a non-articular 
groove ; this trochlea certainly corresponds to the median groove of the inferior 
humeral face. 

There are, no doubt, differences in the two bones, but they have no bearing 
upon the result just indicated. Thus, the linea aspera of the femur is situated 
behind ; that of the humerus in front. In the femui' the two condyles of the 
inferior extremity are placed behind the trochlea ; the contrary holds in the 
humerus. These modifications are necessary, in order to give the movements of 
the limbs a convenient direction. The leg is flexed backward on the thigh, while 
the fprear is flexed forward on the humerus. 

Parallel hetween the bones of the leg and those of the forearm. — It is more 
particularly in these two regions that the question of analogies has been resolved 
in a contradictory manner by anatomists. It would have appeared less compli- 
cated had it been studied in a large number of species. 

If we examine the leg-bones of certain Marsupials^ in which the tibia and 
fibula are apart as in the radius and ulna in Man, it will be found that : 1. These 
two bones articulate with the condyles of the femur. 2. The anterior face of the 
tibia has no ridge. 3. The patella is attached to the upper end of the fibula. 
From this it might be concluded that, in Man and the domestic animals, the 
tibia, with the exception of its anterior and external tuberosities, is the homologue 
of the radius, and the fibula and external and anterior tuberosities of the tibia 
are the homologues of the body and inferior extremity of the ulna. The patella 
corresponds to the olecranon ; the mobility of the first cannot be offered as an 
objection to this assimilation, for in Bactrians the olecranon forms, like the 
patella, an independent bony nucleus. 

Parallel between the bones of the posterior and those of the anterior foot. — The 
analogy becomes so marked when these two regions are compared, that it is 
scarcely necessary to allude to them. The tarsal bones are to the posterior limb 
what the carpals are to the anterior one ; it is even possible to compare, one by 
one, the several pieces in these regions. The metatarsals are but a repetition of 
the metacarpals ; while the digital bones are so much alike, that it is difficult to 
distinguish the anterior from the posterior phalanges. 



158 THE BONES, 

CHAPTER III. 

THE BONES IN BIRDS. 

These animals, destined for the most part to sustain themselves in the air, 
should exhibit in the conformation of their skeleton all the conditions which 
may favour aerial locomotion ; from this arise the differences which distinguish 
their skeleton from that of the Mammalia — differences which will now be rapidly 
traced. 

Veetebeal Column. Cervical vertebne. — The cervical spine represents in 
the Bird, as in the Mammal, a kind of balancing-pole curved like an S, which 
supports the head, and by its changes in form and direction varies the centre of 
gravity. When a Bird rises in the air and flies rapidly, it lengthens the neck 
and stretches out the head, to carry the centre of gravity forwards. But when 
it rests on the ground, it makes the balancing-pole assume the natural and more 
or less graceful inflection, by throwing the head backwards, and transferring the 
greater portion of the weight of its body to the columns of support formed by 
the posterior Hmbs. These displacements of the centre of gravity are executed 
in Birds on a more extensive scale than in Mammalia ; the vertebral limbs in the 
former are also longer, hghter, and enjoy an excessive mobility. 

The vertebrae composing it number fourteen in Fotvls, twelve in the Fir/eon, 
fifteen in the DmJc, aijd eighteen in the Goose ; in the Swan twenty-three have 
been counted ; — a curious variety, which singularly contrasts with the numerical 
unity noticed as one of the most remarkable characters in Mammalia ! These 
vertebras are generally longer than in the latter animals, and are particularly 
distinguished by the configuration of the articular surfaces of the inferior part or 
body. These are diarthrodial facets convex in one direction and concave in the 
other, articulating the vertebral bodies by a veritable and reciprocal clamping. 
In this manner, the anterior head of the body of each vertebra is replaced by a 
facet concave on both sides, and convex vertically ; while the posterior extremity 
of the bone bears, instead of a concavity, a facet convex in the lateral sense, and 
concave from above to below. The inferior crest of the body (Fig. 109, 2, 2') 
only exists in the first and last vertebrae ; but it forms a veritable spine, 
analogous to that observed in the lumbar vertebrae of the Rabbit. The spinous 
process (Fig. 109, 1, 1') only forms a simple crest in the middle part of the neck ; 
it becomes more salient in the vertebras which occupy the two extremities of this 
region. The transverse process represents on the side of the vertebra a thick, 
obtuse, and irregular tubercle, situated under the anterior articular process, and 
pierced at its base by a large vertebral foramen (Fig. 109, 4, 4'). It is most 
frequently furnished with a small styloid prolongation (Fig. 109, 3, 3') directed 
backwards and downwards, forming an epiphysis at an early period, and 
representing a real undeveloped rib. 

The atlas has no transverse processes. This vertebra is shaped like a thin 
ring, and is excavated on its anterior contour by a small cavity, into which is 
received the single condyle of the occipital bone. 

The axis shows a very marked odontoid process, with a single facet under 
that eminence. 

Dorsal vertebrce (Fig. 109, b, c). — These are seven in the Fotvl and Figeon, 



TEE BONES IN BIRDS. 



159 



and nine in the Goose and Duck; they are nearly always consolidated into a 
single piece to which the trunk is fixed, and which gives the wings a sohd 



Fig. 109, 




SKELETON OF A FOWL. 

From A to B, Cervical VertebrcE . 1, spiDous process of the third vertebra; 2, inferior ridge on body 
of the same ; 3, styloid prolongation of the transverse process of the same; 4, vertebral foramen 
of the same ; 1', 2', 3', 4', the same parts in the twelfth vertebra. From B to C, Dorsal Vertebrae: 
6, spinous process of the first ; 7, crest formed by the union of the other spinous processes. From 
D to E, Coccygeal Vertebrce. F, G, Head: 8, interorbital septum; 9, foramen of communication 
between the two orbits ; 10, premaxillary bone ; 10', external openings of the nose; 11, maxilla; 



160 



THE BONES. 



Fig. 110. 




support in the violent efforts that flight demands. The two or three last are 
often even covered by the wing-bones, and joined to them. The inferior crest 
of the body forms a very long spine, especially in the first vertebras. The 
spinous processes — flat, wide, short, and consolidated with each other by their 
opposite borders — constitute a long crest extending from the last cer\ical vertebra 
to the bones of the wings (Fig. lOD, 7). The trans- 
verse processes widen to their summit ; in the FovjI 
they are nearly constantly fused with each other. 

Lumbar and sacral vertebne. — All these vertebrae 
are formed exactly on the same type ; so that it be- 
comes difficult, if not impossible, to fix the point where 
the lumbar region ends or the sacral begins. At first 
independent of each other, these vertebra?, numbering 
fourteen, soon become consolidated with one another 
and with the ribs ; but their primitive separation is 
always indicated by the lateral septa, which form, on 
their inferior face, the vestiges of the transverse pro- 
cesses. The former are closely united to the latter in 
the dorsal region. 

Coccygeal vertebrce. — In the coccygeal region, the 
spine recovers its mobility. The tail of the Bird, 
indeed, fulfils the office of a rudder in directing it during 
flight ; and it is absolutely necessary that the vertebr* 
which serve as a base for the steering feathers should 
preserve their independence, so as to allow these to be 
carried to the right, left, downwards, or upwards. 
These vertebrje — seven in number — present spinous 
processes which are often bifurcated, transverse pro- 
cesses very developed, and sometimes even spines more 
or less long on the inferior surface of their bodies. The 
last vertebra is always the most voluminous ; it is 
flattened on both sides, and terminates in a curved-up 
point. 

Head (Fig. 110, f, g).— The head of the Bird is 
small, and of a conical form. The anterior extremity 
is elongated, and terminated by a pointed or flattened 
beak, which allows the animal to cut the air with more 
facility. 

Bones of the cranium. — The bones which compose 

the cranium are, as in Mammalia, an occipital, parietal, 

frontal, ethmoid, sphenoid, and two temporcds. These bones are not isolated from 

each other, excepting during early life in the shell ; and the ossifying process 

12. OS quadratum ; 13, malar bone. H, Sternum : 14, brisket or keel ; 15, episternal process ; 16, 
internal lateral process; 17, lateral external process; 18, membrnne which closes the internal 
notch ; 19, membrane of the exte^-nal notch, i. etc., Superior Ribs : 20, posterior process of the 
fifth. J, Inferior ribs. K, Scapula. L, Coracoid hone. M, Furculum : m, m, its two branches. 
N, Humerus. 0, Ulna : o. radius, p. p', Bones of carpus. Q, q'. Bones of metacarpus. R. First 
phalanx of th° large digit of the loinq : r. second phalanx of the same, r'. Phalanx of thumb. 
S, Hium. s'. Ischium, s". Pubis : 21. sciatic foramen : 22, foramen ovale. T, Femur, v. Patella. 
V, Tibia. X, Fibula : y, single bone of tarsus, y. Metatarsus : 23, superior process representing 
a united metatarsal bone ; 24, process supporting the claw. Z, etc.. Digits. 



HEAD OF AN OWL (NATURAL 
SIZE ; POSTERIOR VIEW). 

1, Occipital foramen ; 2, single 
occipital condyle ; 3, ptery- 
goid ; 4, inferior articular 
surface of the os quadratum ; 

5, anterior process of ditto ; 

6, 6, anterior face of the 
palatine bones, forming: the 
guttural orifice of the nasal 
cavities; 7, posterior ex- 
tremity of ditto; 8, zygo- 
matic ; 9. lachrymal ; 10. 
premaxilla ; 11, orbital pro- 
cess ; 12, right zygomatic 
process ; 12', zygomatic pro- 
cess on the opposite side, 
united to the orbital pro- 
cess. 



TEE BONES IN BIRDS. 161 

which unites them is so rapid, that the cranium, shortly after hatching, is already 
a single piece. No detailed description of the separate bones will be given here, 
but only a few brief observations which may be of some utility. 

Thus, the occipital bone shows for articulation with the spine only a single 
condyle, situated under the occipital foramen, and excavated by a slight gi'oove. 
In Palmipedes, this bone is pierced, behind the crests which give attachment to 
the extensor muscles, by two foramina which penetrate the cranium, and represent 
permanent fontanella. The parietal bone is feebly developed, and formed from 
only two primary nuclei. The frontal is the largest bone of the cranium ; its 
orbital process (Fig. 110, 1), incomplete, is supported by a particular piece 
(posterior frontal) fixed between the principal frontal bone, parietal, and posterior 
sphenoid, with which it is sometimes confounded. The perpendicular lamina of 
the ethmoid is considerable, and forms between the two orbits a thin vertical 
septum (Fig. 109, 8). Its posterior border is notched opposite to the optic 
foramen, and thus constitutes an opening which communicates between the two 
orbital cavities (Fig. 109, 9). It is also channeled, near its upper. border, by 
a fissm-e which terminates by two openings at its extremities, one entering the 
cranium, the other the nasal cavities. Tliis fissure and these foramina pennit the 
passage of the ethmoidal nerve, which in this way traverses the orbit before 
arriving at its destination. The ethmoidal cells are more membranous than 
bony : their base is attached to a very delicate transverse plate, which is often 
membranous and not cribbled, and forms part of the anterior orbital wall. These 
cells replace, at the same time, the lateral masses of the ethmoid and turbinated 
bones of MammaUa. The sphenoid appeal's to be formed of a single piece, and 
shows on its sides two diarthrodial facets corresponding to the pterygoids. It is 
pierced by one foramen for the passage of the optic nerves ; but this foramen 
opens on the outer and opposite side of the posterior notch of the interoi-bital 
septum, and thus allows each of the nerves passing through it to reach the eye 
for which it was intended. 

It is worthy of remark, that an analogous disposition is also noticed in the 
Rabbit.^ The temporal bones present at their base an articular surface correspond- 
ing to the square bone (os qimdratum) (Fig. 109, 12, 12'). In the Foivl species, 
the zygomatic process forms a small flattened tongue, directed forwards, sometimes 
free, and at other times united by its superior border to the summit of the 
orbital process. These two eminences are exceedingly short in Pigeons. In 
Palmipedes they are consolidated and confounded so intimately, that it becomes 
impossible to distinguish them from one another. From this union results a 
long and strong process, which inclines forward and meets a particular prolonga- 
tion of the OS unguis, forming with it a real bony arch. This arch limits, below 
and outwardly, the orbital cavity. 

Bones of the face. — The supermaxilla comprises : a premaxilla, two nasal, two 
lachrymal, two palatine, two pterygoid, two zygomatic hones, and a vomer. The 
inferior jaw has for its base a maxillary hone, which articulates with the cranium 
by means of two supplementary pieces named the square hones. The premaxillary 
hone (Fig. 110, 10) is formed, before hatching is completed, of two lateral pieces, 

' This analogy is really striking, and might, in our opinion, serve as a basis for a new 
ietermiuation of the interorbital septum. We are tempted, indeed, to consider this bony 
lamina as the inferior sphenoid and the middle portion of the ethmoid in Birds. This manner 
of viewing it tends to confirm the ideas of M. Tabourin on the inferior sphenoid and the 
ethmoid of Mammals. 



162 THE BONES. 

which represent the two small premaxillaries of Mammals. This bone is very 
considerable, and of itself forms the base of the upper beak, the form of which it 
determines ; it is pointed and conical in the GalUnacea, and wide and flattened 
above and below in Palmipedes. In front it circumscribes the external openings 
of the nose, and is prolonged superiorly into two lengthy processes which dovetail 
between the nasal bones. Two inferior processes belonging also to this bone 
concur in the formation of the palatine roof. The supennaxillaries, analogues of 
the supermaxillaries of Mammals, are two rudimentary bones situated on the sides 
and at the base of the beak. They form a part of the palatine roof and the walls 
of the nasal cavities. The nasal bones circumscribe above, inwardly, and even 
outwardly, the external orifices of these cavities. The palatine hones encircle, as 
in Mammals, the guttural openings of the nose, and constitute in great part the 
roof of the palate ; their posterior extremity lies against the pterygoids ; the 
anterior joins the supermaxillaries and the inferior process of the premaxillary 
bone. The pterygoids extend obliquely from the sphenoid to the square bones, 
and are united to the sphenoid by diarthrodial articulation. The zygomatic hones 
have the form of two very thin stylets, and are united to the square bone by their 
posterior, and consolidated with the supermaxillary by their anterior, extremity. 
The vomer separates the guttural openings of the nose from one another. 

The bones of the upper jaw are not fused to each other so rapidly as the 
bones of the cranium. The ascending processes of the premaxillary and nasal 
bones even remain for a long time tmited to the frontal bone by a simple 
synarthrodial articulation. This arrangement allows the upper beak to execute 
a certain elevating movement, of which we will speak when describing the 
articulations. 

The inferior maxillary hone is originally formed of a great number of distinct 
segments, which are soon united into a solid piece. The square, petrous., or hone 
of the tympanum ought to be considered as detached from the temporal. It is 
prismatic in shape, and provided on its upper surface with a diarthrodial facet 
which unites it to the temporal, and on its lower face with another facet articu- 
lating with the branch of the maxilla. Outwards it joins the zygomatic bone, 
and inwards the pterygoid. Behind, it gives attachment to the membrane of 
the tympanmn ; and in front it presents a small eminence of insertion, which 
Meckel considered a second zygomatic process. 

Thokax. — Sternum (Fig. 109, H 1). — The sternum of Birds, serving as a 
basis of support to the muscles moving the wings, should offer, and does in 
fact show, a remarkable degree of strength, because of the extraordinary volume 
of these muscles. And these being more powerful and energetic as the Bird 
exhibits a greater degree of aptitude for flight, it results that the structure of 
the sternum is solid in proportion as the creature is strong on the wing. For 
this reason, we may infallibly pronounce as to the extent and power of a bird's 
flight by an inspection of the sternum of individuals of its species. In this 
respect, however, we only announce what is well known to be a particular appli- 
cation of the rules established by the great law of concordance between the 
anatomical disposition of organs and their physiological finality. 

Studied in Palmipedes., which will serve as a type for description, the sternum 
presents itself in the form of a large rectangular cuirass, elongated from before 
to behind, of itself constituting the inferior wall of the thoracic cavity, and also 
largely protecting the abdominal cavity. Its superior face is concave, while the 
inferior is convex, and entirely occupied by the insertion of the pectoral muscles. 



THE BONES IN BIRDS. 1G3 

It presents, on the median line, a thin and very salient ridge, named the brisket 
{carina or keel) (Figs. 109, 14 ; 111, B. 2), which in a remarkable manner 
multiplies the points of attachment of these muscles. The anterior border 
offers in its middle a small eminence of insertion, the episternal (Figs. 109, 15 ; 
111, A 2). Laterally, two articular grooves are seen which correspond to the 
coracoids. The posterior border is cut by two notches which are often converted 
into foramina (Fig. Ill, b 3, 3). On the lateral borders are observed small 
double articular facets answering to the inferior ribs. The angles which separate 
these two borders from the anterior are both prolonged into a httle eminence, 
named by some authors the costal process (Fig. Ill, a 33). 

In the Fowl, the sternum is not so strong as in the Goose or Duck. On 
each side of the brisket it shows two wide notches, which greatly reduce its 
substance. These notches (Figs. 109, 18, 19 ; 111, a 6, 7), closed in the fresh 
state by membranes, are distinguished as external and internal. The latter, of 
greater size than the former, extends nearly to the extremity of the bone. 
From this division of the lateral plates of the sternum, result two long and 
slender processes directed backwards (Figs. 109, 16, 17 ; 111, a 4, 5). The 
external terminates by becoming widened, and forming a kind of bony plate, 
which covers the last inferior ribs. 

The sternum of Pigeons is distinguished by the enormous development of 
the brisket. The two notches of the Fowl are also met with in these birds, but 
the internal is nearly always converted into a narrow foramen. 

This comparative study of the sternum in the chief domesticated birds, leads 
us to appreciate the correctness of the principles just enunciated, with regard 
to the form and extent this bone may exhibit. The Gallmaceous Birds, properly 
so called, which fly little and badly, have the sterur.-n singularly weakened by 
the deep notches cut in its lateral parts. With Palmipedes, the sternum is wide 
and but slightly notched, so that the Goose and Duck, which waddle along so 
awkwardly in our poultry yards, are capable of sustaining long and rapid flight, 
like that of the wild individuals of the same species. With regard to Pigeons, 
which are well known to be swift and powerful flyers, may this advantage not 
be due to the extraordinary development of the keel which constitutes the 
brisket ? 

Ribs (Fig. 109, I, etc.).— In the Fowl and Pigeon there are seven pairs 
of ribs ; and in the Duck nine pairs. Articulated superiorly with the dorsal 
vertebrte, as in Mammals, these bones are provided, near their middle, with a 
flat eminence which commences at the posterior border, and is directed back- 
wards and upwards, to rest by its free extremity on the external face of the next 
rib. These eminences (Fig. 109, 20) form an epiphysis at an early period, and 
are usually absent in the first and last ribs. They concur in an efficacious 
manner to increase the solidity of the thorax. 

The costal cartilages of the Mammalia, are in Birds often transformed into 
veritable inferior ribs, joined to the superior ribs by a diarthrodial articulation 
(Fig. 109, J). These pieces are long and strong, and all terminate at their lower 
extremity by a double facet which articulates with the lateral border of the 
sternum ; they are nearly always absent in the two first ribs. It is not rare to 
see the last united to the one before it, instead of passing directly to the sternum ; 
in which case it comports itself like the asternal ribs of Mammals. 

Anterior Limbs. Shoulder-bone. — The shoulder comprises : a scapula ; a 
particular bone named the coracoid by Cuvier : and a clavicle, which forms, in 



164 



THE BONES. 



coalescing with that of the opposite side, a single bone called the /or A' (furcidum)^ 
or osfuradare. The scapula (Figs. 109, k ; 111, a 8) is narrow, elongated, and 
falciform, and shows no trace of a spine. Its anterior extremity only forms a 
portion of the glenoid cavity, and is united by means of a fibro-cartilage with 
the fork of the coracoid bone. The latter (Figs. 109, L ; 111 a 9) is so named 
because it represents the coracoid process of Mammals, and is a long prismatic 
bone, directed obliquely from above downwards, and before to behind. Its 
superior extremity is often fused with the scapula, and united at an acute angle 
with that bone to form a portion of the articular cavity which receives the head 
of the humerus. Its inferior extremity is flattened from before to behind, and 
responds by a diarthrodial articulation to the anterior border of the sternum. 
The coracoid is long in Birds which fly slowly ; it is, on the contrary, short, 
thick, and therefore very solid, in quick flyers. Th.^ fork (Figs. 109, M; 111,. 

Fig. 111. 




STERNUM AND BONES OF THE WING. 

A, Sternum and mng-bones of the Fowl {upper face). 1, Body of the sternum; 2, its episternal 
process; 3, 3, its costal proces>es ; 4, 4, its lateral external processes; 5, 5, its lateral internal 
processes; 6, 6, internal notches; 7. 7, external notches; 8, scapula; 9, coracoid; 10, fork; 
11, opening for the passage of the elevator of the wing; 13, humerus; 14, air-opening in that 
bone; 15, ulna; 16, radius; 17, ulna-cavpal bone; 18, radio-carpal bone; 19, large metacarpal ; 
20, small metacarpal ; 21, first phalnnx of the large digit ; 21', second phalanx of ditto ; 22, small 
phalanx lying beside the first bone of the large digit, and representing the remains of a third digit ; 
23, thumb. 

B, Sternum and shoulder-hone of a young Duck (inferior surface). 1, 1, Sternum ; 2, keel ; 3, 3, 
lateral notches ; 4, 4, coracoid •, 5, 5, fork ; 6, opening for the passage of the elevator of the wing. 



B 5, 5) is a single bone, shaped like a V or U, situated at the base of the two 
wings, in front of the trunk, and in an oblique direction downwards and back- 
wards. The two branches which form it represent the clavicles ; they meet and 
are united at their inferior extremities, where they describe a curvilinear angle 
more or less open, attached to the brisket by means of a membranous ligament. 



THE BONES IN BIRDS. 165 

Their superior extremity rests within and opposite to the glenoid cavity, against 
the scapula and coracoid, forming with these bones a remarkable foramen, 
through which passes the tendon of the elevator muscle of the wing (Fig. Ill, 
A 4, B 6). The forks play the part of an elastic spring, whose office it is to 
prevent the wings coming towards each other during contraction of the depressor 
muscles. The conformation of this bone is, therefore, like the sternum, related 
to the extent and power of flight ; and for this reason it is that, in swift flyers, 
the two branches of the furculum are thick, solid, widely separated, and curved 
like a U ; while in those which fly heavily and with difficulty, these branches 
are thin and weak, and joined at an acute angle. The latter formation greatly 
diminishes its strength, and lessens, in a singular manner, the reactionary power 
of the bony arch it represents. 

Bone of the arm. — The humerus (Figs. 109, n ; 111, a 13) offers an articular 
oval-shaped head, and an air-opening placed beneath this eminence. It is long 
in Palmipedes, ordinarily so in the Gallinaca, proper, and very short in Pigeons. 

Bones of the forearm (Figs. 109, o, o ; 111, A 15, 16).— The radius is much 
less voluminous than the ulna. The latter has an extremely short olecranon ; 
and the two bones are separated from one another in their middle part to meet 
again at their extremities, where they are united by ligamentous bands in such 
a way as to render the movements of pronation and supination impossible. This 
mode of union, which nevertheless does not prevent the two bones from gliding 
slightly on each other in the direction of their length, has been wisely adopted 
by nature in order that the wing might strike the air, like an oar, by its inferior 
face ; otherwise, the resistance of the aerial medium would make these two bones 
pivot, and cause the wing to present itself to the air in a wrong direction. 

Bones of the carpus (Figs. 109, p, p' ; 111, a 17, 17).— These are only two, 
and are distinguished by the names of radius and ulna, in consequence of their 
corresponding more particularly to these bones in other animals. 

Bones of the metacarpus (Figs. 109, q, q' ; 111, a, 19, 20).— These also 
number only two, and are separated at their middle portion, to be consolidated 
at their extremities. 

Bones of the digital region. — The wing of a bird is composed of three digits. 
One of them, which resembles the thumb and forms the basis of the false wing 
is composed of a single styloid-sliaped phalanx, articulated at the base of a small 
particular process belonging to the superior extremity of the largest metacarpal 
bone (Figs. 109, r' ; 111, A 23). The largest digit comprises two phalanges, 
which succeed the last bone (Figs. 109, R, r ; 111, a 21, 21'), The third digit 
is represented by a small rudimentary phalanx (Fig. 109, a 22), which corre- 
sponds to the inferior extremity of the small metacarpal bone, and lies beside 
the first phalanx of the large digit in the closest manner. 

It is well to remark that the hand and forearm are longer in proportion to 
the quality of flight ; those two regions of the Aving, for example, are very short 
in Gallinaceous Birds. 

Posterior Limbs, Coxa, or os iliac. — This is a voluminous and very 
solid piece, particularly in walking birds, and composed, as in the Mammalia, 
of an ilium, ischium, and pubis. The ilium (Fig. 109, s), very long, is con- 
solidated with the last two dorsal, the lumbar, and the sacral vertebrae ; it is 
excavated on its internal face. The ischium partly incloses the side of the pelvic 
cavity ; between its internal border and the external border of the ilium is an 
•orifice which replaces the great ischiatic notch. Its inferior border is united to 



166 THE BONES. 

the pubis. The latter (Fig. 109, s") is thin and elongated, and follows the 
direction of the inferior border of the ischium, with it circumscribing an oval 
opening more or less spacious (Fig. 109, 22). Its inferior extremity extends 
beyond the ischium, to curve inwards towards that of the opposite side, but 
without uniting with it. We do not, therefore, find the pelvic symphysis in 
Birds, and the pelvis is slightly open below, a circumstance which favours the 
passage of the egg through the cavity and out of the cloaca. The cotyloid cavity 
is perforated by an opening at the bottom, which passes through the bone. 

Thigh-bone. — The femur (Fig. 109, t) is articulated inferiorly with the 
patella, tibia, and fibula. In all walking Birds, Uke the Gallinacge, it is long 
and strong, as well as the bones below it. 

Leg-bones. — The patella (Fig. 109, u) is wide and thin. The tiUa (Fig. 
109, v) terminates, below, by two condyles separated by a groove, which becomes 
articular behind. The fibula (Fig. 109, x) articulates by its head with the 
external condyle of the femur, and is consolidated with the tibia ; it never 
descends to the inferior extremity of that bone. 

Tarsal bones. — The tarsus appears to be altogether absent in Birds. Never- 
theless, we may venture to consider, as a vestige of the bones of this region, a 
small bony nucleus buried in a fibro-cartilaginous mass which ghdes on the- 
posterior pulley of the tibia. This nucleus (Fig. 109, y) represents the calcaneum 
of Mammals. 

Metatarsal bone. — A single metatarsal bone Ls found in Birds, articulating 
superiorly with the inferior extremity of the tibia, and terminating inferiorly by 
three pulleys which support the three principal digits. This bone (Fig. 109, y) 
shows in the Fowl, near its inferior third, a conical process turned backwards, 
which serves as a base for the spur. Behind its superior extremity, it exhibits 
another which may be considered as a consolidated metatarsal bone (Fig. 
109, 23). 

Bones of the (ligital region (Fig. 109, z, etc.). — All the domesticated Birds have 
four digits on the inferior members : three principal, directed forwards, and one 
rudimentary, carried backwards. The first, designated as internal, median, and 
external, articulate with the inferior pulleys of the metatarsal bones. The in- 
ternal is formed by three phalanges, the second has four, and the third five. 
These phalanges are formed something like those of the Carnivora ; the last is 
pointed, conical, and enveloped in a horny sheath. The fourth digit, or thumb, 
is composed of three pieces ; one of these, the first, is generally considered as a 
rudimentary metatarsal bone. It is attached by fibro-cartilaginous tissue to the 
inner and posterior aspect of the inferior extremity of the principal metatarsal 
bone. 



THEORY OF THE VERTEBRAL CONSTITUTION OF THE SKELETON. 167 



CHAPTER IV. 

THEORY OF THE VERTEBRAL CONSTITUTION OF THE 
SKELETON. 

In the series of vertebrated animals, the bony pieces of the trunk bearing the 
name of vertebrse are those which offer the highest degree of fixity, and to which 
the existence or the arrangement of the others appears to be subordinate. This 
feature in organization, recognized by E. Geoffroy Saint-Hilaire and Professor 
Owen, has caused these authorities to assert that the type of construction of 
vertebrated animals is the vertebra. 

After E. Geoffroy Saint-Hilaire and Professor Owen, several German, English, 
and French anatomists have studied the vertebral composition of the skeleton ; 
and among the works published in France on this subject, must be specially 
noticed those of Lavocat. In principle, all the writers have arrived at the same 
conclusions, and only differ in some few details. 

It is certain that the base of the vertebral column is formed by a series of 
bony segments. Each of these segments is called an osteodesm, and each osteo- 
desm represents the bodi/ or centrum of a vertebra. 

In examining the dorsal region, it is evident that to the body or centrum of 
a vertebra are added two complete osseous arches — a superior and an inferior. 
The superior arch is formed by the vertebral laminae ; the inferior by the ribs, their 
cartilages, and a portion of the sternum. The first is designated the neural arch, 
as it furnishes a protective case for the nervous centres ; and the second, which 
more particularly protects the vascular system, is called the hcemal arch (see 
Figs. 112, 113). 

The hfemal arch may have prolongations or appendices more or less developed, 
and comparable to the apophysary prolongations of the ribs in Birds and some 
Fishes. 

Such is the general composition of a typical vertebra ; but there are also to 
be distinguished in the neural and htemal arches the following parts : — 



H^MAL ARCH. 

1. Haemal parapophysis = the tuberosity of 

the rib. 

2. Haemal metapophysis = the head of the 

rib. 

3. Haemal diapophysis = the rib proper. 

4. Hsemapophysis = the costal cartilage. 

5. Haemal spine = the corresponding sternal 

portion. 



NEURAL ARCH. 

1. Neural parapophysis = the posterior 

costal cupola. 

2. Neural metapophysis = the anterior costal 

cupola. 

3. Neural diapophysis = the summit of the 

transverse process. 

4. Neurapophysis = the vertebral lamina. 

5. Neural spine = the summit of the spinous 

process. 

The vertebrae sometimes depart more or less from the model just described. 
They may vary not only from one species to another, but also in the same 
animal, and even in the same region. Thus, the neural arch may be absent, as 
has been observed in certain coccygeal vertebrae ; or the hsmal arch is incom- 
plete or null, as in the cervical or lumbar vertebrae ; or, lastly, the arches are 
often unequal ; though this inequality is of no importance, since their size is in 
relation to the volume of the parts they should protect. 

Notwithstanding these differences and variations, or the transformations 



168 



THE BONES. 



experienced by certain parts, there is not a bone in the skeleton which cannot be 
included in the vertebral type. 



Fig. 112. 




THORACIC OR PECTORAL VERTEBRA 
OF A MAMMAL. 

C, Centrum ; n, neural arch ; h, hsemal 
arch. 



Fig. 113. 



CAUDAL VERTEBRA OF THE 
TURBOT. 

c, Centrum , n, neural arch ; 
h, hsemai arch. 



The vertebra being admitted as the type of construction of the skeleton, it 
is easy to find it in all the regions of the bony framework. In the thoraco- 

Fig. 114. 




CRANIAL VERTEBRiE OF THE DOG. (AFTER LAVOCAT.) 

1, Occipito-hyoideal vertebra; 2, parieto-maxillary vertebra; 3, fronto-mandibular vertebra; 
4, naso-turbinal vertebra. 



THEORY OF TEE YERTEBRAL CONSTITUTION OF THE SKELETON. 169 

abdominal region, the centrum, neural arch, and hsemal arch are readily per- 
ceived ; for in the lumbar vertebrae, the enormously developed transverse process 
indicates the existence of an intra-vertebral arch. 

In the sacral region, the bony girdle of the pelvis represents the hsemal arch. 
The posterior limbs, articulating with the bones of the pelvis, also belong to the 
hsemal arch, and should be considered as appendices of this arch, analogous to 
the costal appendices of birds. 

The cervical region may be compared to the sacral region ; as in it the 
inferior haemal arch is represented by the osseous ring supporting the anterior 
hmbs — the scapulo-clavicular girdle. The limbs themselves are appendices of 
the cervical haemal arch. 

Difficulties begin to appear when the extremities of the trunk — the head and 
coccyx — come to be examined. Nevertheless, the composition of the coccyx is 
revealed when the caudal vertebrae of certain Fishes, especially those of the 
Pleuronectidae, in which the neural and hsemal arches are complete, are examined 
(Fig. 113). But the vertebral constitution of the head remained for a long time 
an insoluble question, or it was solved in a contradictory manner by the 
naturalists who attempted it. Some admitted a single cranial vertebra ; others 
included three or four ; while others, again, found six or seven. 

These difficulties and contradictory results may be understood, when it is 
borne in mind what profound modifications the vertebra must have undergone 
to constitute the bones of the head. 

At present the problem appears solved. The head is composed of four 
vertebrae, in which are found the various parts enumerated in the description of 
the typical vertebra. 

In the four classes of vertebrata, the head is constantly formed of four 
vertebrse, which are determined as follows, according to Lavocat : — 



Vertebra. 


Centrum. 


Neural arch. 


Hjemal arch. 


Occipito-hyoideal. 


Basilar process 
of the occipi- 
tal. 


Occipital (3 pieces). 
Mastoid walls of the 
tympanum. 


Hvoideal apparatus 
('five pieces). 


Parieto-maxillary. 


Body of the 
posterior sphe- 
noid. 


Wing and pterygoid 
process of the pos- 
terior sphenoid. 

S(iiiamnus portion and 
zygomatic process of 
the temporal. 

Parietal. 


Inferior maxilla (five 
pieces). 


Froiito-manflibular. 


Body of the 
anterior sphe- 
noid. 


Wing and pterygoid 
pr<'cess of the anterior 
splienoid. 

Posterior Frontal and 
its (irhital process. 

Frontal. 


Malar. 

Laclirvnial. 

Palatine. 

Supermaxillary. 

Preriiaxillary. 


Naso ttnbinal. 


Vomer. 


Ftlimoid. 

Nasal. 


Turbinated. 
Sub-ethmoidal. 



170 THE ARTICULATIONS. 

The number of cranial vertebrae is invariable, as each is destined to lodge 
the organs of one of the four senses. The occipito-hyoideal receives the principal 
organs of hearing ; the parieto-maxillary osteodesm protects the sense of taste ; 
finally, the organs of vision are sustained by the fronto-mandibular vertebra, 
while the naso-turbinal contains the sense of smell. 

Several anatomists, at the head of whom are Huxley and Gegenbauer, do not 
entirely share these views. They certainly admit the existence of the occipital 
vertebra, but it appears to them to be impossible to recognize the others. They 
remark that all the bones which constitute the spine are found in the primary 
cartilaginous skeleton ; so that, in order to establish the vertebral constitution 
of the head, it would be necessary to allot to the same cranial vertebra : 1. The 
pieces that are found in the cartilaginous cranium. 2. The other pieces which are 
developed in the fibrous tissue — those skeletal tegumentary pieces (temporals, 
parietals, etc.). It must also be observed that the division into vertebral bodies 
of the parts which form the base of the cranium, far from being easy in the lowest 
animals, is, on the contrary, only possible, with some trouble, in the highest classes. 
So that if the vertebral constitution of the head were a fact, it must be admitted 
that the differentiation of the bones at the base of the cranium is less advanced 
in Mammals than in the lower vertebrates. 

The vertebral type is not, therefore, universally accepted by all anatomists. 



SECOND SECTION. 

The Articulations. 

THE ARTICULATIONS IN GENERAL. 

The different pieces constituting the solid framework of the animal body are, a-s 
has been said, united in such a manner that they can move one upon the other. 
From this union results the articulations, or articular joints, the construction 
of which will now be referred to in a general manner, before commencing a 
particular description of each. 

Arthrology, or Syndesmology , is the name given to that division of anatomy 
which treats of the articulations. To form articulations, the bones correspond 
with each other by certain determined points of their periphery, which are named 
articular surfaces. Every articulation is, therefore, essentially constituted by two 
opposite osseous surfaces, simple or complex, which are moulded to each other. 
These are either contiguous, independent, and very movable — continuous with 
each other by means of a cartilaginous substance which confines them, if not to 
total immobility, at least to very limited movements ; or united by a fibro- 
cartilage, the elasticity of which permits a certain degree of displacement between 
the bones in contact. 

In the first case, the articulations are classed as diarthroses, or movable 
articulations. 

In the second, they are designated synarthroses, sutures, or immovable 
articulations. 



THE ARTICULATIONS IN GENERAL. 



171 



In the third, they are amphiarthroses, or mixed articulations; so termed 
because they participate in the movements of the other two classes : synarthroses, 
by the continuity established between the articular surfaces ; and diarthroses. by 
the extensive motion they permit. 

The general characters that distinguish each of these three great classes of 
articulations will be successively studied. 

Fig. 115. 



u 



rammiQ 



1^ 





a/ 




/ 




e 




V 












pn 


4 — 






fefjfjft 










PLANS OF THK DIFFERENT CLASSES OP ARTICULATIONS. 

A, Suture: 1, periosteum ; 2,sutural ligament. B, Amphiarthrosis : a, first degree— 1, periosteum; 
2, articular cartilage ; 3, interarticular ligament : b, second degree — 4, single cavity in the 
interarticular ligament : c, third degree — 5, double cavity in the interarticular ligament. C, 
Diarthrosis: b, simple diarthrosis — 1, periosteum; 2, articular cartilage; 3, epithelial layer of 
the synovial membrane (dotted line) ; 4, fibrous capsule ; 5, cul-de-sac of the synovial membrane ; 
6, fibrous layer of the synovial membrane : c, double diarthrosis— 7, interarticular meniscus ; 8, 
9, cavities of the two synovial membranes. 



General Characters of Diarthroses. 

"We ought to consider, in the diarthrodial articulations (Fig. 115, c, 6 and c) : 
1. The contiguous boni/ surfaces which form them. 2. The cartilaginous layers 
(cartilages of incrustation) which cover these. 3. The fibrous or fibro-cartilagi- 
nous tissue {articular fihro-cartilages) which complete them, when they are not 
shaped so as to be reciprocally adapted to each other. 4. The ligaments which 



172 



THE ARTICVLATIONS. 



maintain them in contact. 5. The serous membranes {synovial capsules) that 
cover the internal face of the latter, and which secrete the synovia, a kind of 
animal oil that facilitates the gliding of the articular surfaces. 6. The movements 
of which these articulations may be the seat. 7. Their methodical classification. 
8, Their nomenclature. 

Articular Surfaces. — These surfaces have the common character of being 
destitute of asperities, so that they can glide with the greatest facility on each 
other. They are designated, according to their form, by the names of facets, 
heads, condijles, cotyles, glenes, pulleys, etc. There is no need to revert to their 
general description, as they have already been suihciently studied in the osteo- 
logy ; so we will confine ourselves to repeating that they are found at the 
extremities of long bones, on the faces of short bones, and on the angles of wide 
bones. We may mention, also, that they are often excavated by one or several 
depressions named synovial fossce, or hollows for the insertion of ligaments. The 
first are a sort of natural reservoirs which receive the unctuous fluid secreted by 
the interarticular serous membranes ; the second give attachment to interosseous 
ligaments. 

Cartilages of Incrustation. — This designation is given to the layers of 
cartilaginous matter which, as it were, varnish the articular surfaces they adhere 

to by their inner face ; their free surface 
is distinguished by a remarkable polish 
and brilliancy. Thicker towards the 
centre than at the circumference when 
they cover bony eminences, these carti- 
lages show an inverse disposition when 
they line cavities. They are elastic, of 
a pearly whiteness, and resisting — though 
they are soft enough to be cut by a sharp 
instrument ; in a word, they possess all 
the physical characteristics of the primary 
cartilage of bones. They appear to be 
formed of parallel fibres placed perpen- 
dicular to the bony surfaces, and im- 
planted in these by one of their ex- 
tremities ; the opposite extremity corre- 
sponding to the free surface of the 
cartilage. Viewed by the microscope, 
they are found to present the characters 
of true or hyaline cartilage. 
The fundamental matter is amorphous and homogeneous ; but under the 
influence of slight dessication, there appears in the hyaline substance a partition- 
ing formation, which may be regarded as an agent in the distribution of the 
nutritive juices in the substance of the cartilaginous tissue (Renaut). 

The cavities (cartilage capsules) are irregular, and more or less wide. They 
contain from one to five cells without walls, and their contents — slightly granular 
— have in the centre of each cell one or two nuclei with nucleoH (Fig. 1 IG). These 
cavities are elongated, and are directed almost perpendicularly towards the osseous 
articular surface in the deep layer ; in the middle layer they are round ; and 
they are lenticular, and parallel to the surface of friction, in the superficial layer. 
(It has been stated that a membrane lines these spaces. In addition to the 




SECTION OF BRANCHIAL CARTILAGE OF 
TADPOLE. 

, Group of four cells separating from each 
other ; b. pair of cells in apposition ; c, c, 
nuclei of cartilage-cells ; d, cavity contain- 
ing tiiree cells. These cells are embedded 
in the finely granular matrix, or funda- 
mental substance. 



THE ARTICULATIONS IN GENERAL. 



173 



granular matter observed in the cells, it is not rare to find fat globules. The 
nuclei of the cells vary from ^^V? *o Wmj o^ 8,n inch in diameter. The cells 
multiply eudogenously.) 

The cartilage cells are insoluble in boiling water ; consequently, so far as 
their chemical composition is concerned, they are distinct from the fundamental 
substance. 

The diarthrodial cartilages have no vessels or nerves. 

The presence of cartilages of incrustation in the articulations is of the greatest 
importance. When they are worn, absorbed, or transformed into bone in con- 
sequence of certain articular maladies, the movements become painful and very 
difficult. With regard to the part they play in the economy, it may be said that : 

1. They favour, by their smoothness, the gliding and displacement of the bones. 

2. They attenuate, by their suppleness and elasticity, the violent shocks to which 
the articulations are exposed. S. They resist the wear and deformation of the 
articular surfaces. 

Complementary Fibro-caetilages. — There are two kinds of complementary 
fibro-cartilages. Some (interosseous) represent circular cushions which pad the 
margins of certain cavi- 
ties, filling up the notches ^' S- ^ ^ '^• 
that might render these 
imperfect. They in- 
crease the depth of these 
cavities, and protect their 
borders from in j ury — for 
example, the coxo-femo- 
ral articulation. Others 
(infer-articular) are in- 
terposed between arti- 
cular surfaces when these 
do not exactly fit each 
other — as when two opposing extremities are convex. It may be remembered 
that the lateral tuberosities of each tibial surface present, for articulation with the 
condyles of the femur, two convex diarthrodial faces, the coaptation of which is 
rendered perfect by the interposition between each condyle and corresponding 
tibial surface, of a crescent-shaped fibro-cartilage, which for this reason has been 
named a meniscus. In other joints, these interarticular fibro-cartilages are 
shaped like discs or biconcave lenses. There then result double diarthroses (Fig. 
115, C, e) : example, the temporo-maxillary articulation. (Fibro-cartilage also 
covers bony surfaces over which the tendons play, as on the trochlear surface of 
the humerus, postero-inferior face of the navicular bone, and elsewhere. In 
these situations it is named stratiform fibro-cartilage.) These organs are formed 
sometimes by fibrous, at other times by cartilaginous tissue ; their mode of 
association need not be referred to here, though it may be observed that the 
cartilage is more particularly found in all those points where there is most 
articular friction. They receive very few vessels, and it is questionable if they 
have nerves. 

Ligaments. — These are bands which unite contiguous diarthrodial surfaces. 
They are sometimes formed of white fibrous tissue, and sometimes of yellow ; 
hence their division into two great classes of white and yeUoiv ligaments. 

a. The white ligaments are distinguished by the pearly whiteness of their 
14 




FIBRO-CARTILAGE, MAGNIFIED 155 TIMES. 

Showing interlacement of fibrous fasciculi, with scattered 
groups of cartilage-cells. 



174 



THE ARTICULATIONS. 



tissue and want of elasticity. Those which are found around the margin of 
articulations are termed peripheral, and those in their interior are designated 
interosseous or interarticular ligaments. 

The peripheral ligaments are g^erallj composed of parallel fibres collected in 
fasciculi, or spread out as membranes. In the first they are called funicular, or 
riMon-shaped ; in the second, they are termed membraniform, or capsidar. The 
funicular ligaments are short, round, or flattened bands, attached by their 
extremities to the two bones they unite ; they are lined on their inner aspect 
by the synovial capsule, and are covered .externally by tendons, aponeuroses, 
muscles, vessels, or nerves. The capsular ligaments are often complete — that is 



Fig. 118. 






Fig. 119. 




^^S 


Wl^m^^UJSlfmije'^^M^KplMwMl'' 





WHITE OR NON-ELASTIC FIBBOUS 

TISSUE. 



YELLOW OR ELASTIC FIBROUS TISSUE, 
THE LIGAMENTUM NUCH^E. 



to say, they envelop the whole articulation like a sack. At other times they are 
incomplete, and then they are simple membranes, binding together the different 
funicular ligaments of a joint. 

The interosseous ligaments — less numerous than the preceding — are often formed 
of interlacing fibres ; they are always funicular, and fixed by their extremities 
into excavations in the centre of articular surfaces. 

J. Hhe yellow ligaments are 2k[[ perijyheral, funicular, or 7nembranous, and enjoy 
a marked degree of elasticity, which permits them mechanically to bring back to 
their usual position the bony levers that have been momentarily displaced. These 
ligaments, which are powerful auxiliaries to the muscular forces, give permanent 
equilibrium to the weight in certain parts of the body, which incessantly tend to 
fall to the ground ; for instance, the cervical ligament of Solipeds and large 
Ruminants. The ligaments are always assisted in their action by atmospheric 
pressure, which is exerted over all the surface of the body ; and also frequently by 
the tendons and aponeurosis of muscles, and even by the muscles themselves, 
when they pass over an articulation or are inserted in its vicinity. In several 
regions the ligaments are more or less confounded w^ith tendons or aponeiu-oses — 
as in the anterior extensor tendon of the phalanges and superior sesamoid liga- 
ment, the ligaments of the femoro-tibial articulation, and the aponeuroses of the 
posterior portion of the superficial gluteal muscle. 

Synovial Capsules. — These are very thin membranes of a serous character, 
intended to secrete the synovia. They are composed of two layers : a deep, 
formed by fasciculi of connective tissue ; the other, superficial, formed by an 



THE ABTIGULATIONS IN GENERAL. 175 

endothelium. The first sometimes adheres intimately to the inner face of the 
funicular or membranous ligaments of the articulation ; at other times it is loosely- 
attached to them by an abundance of connective tissue. The second layer is con- 
stituted by a single row of flattened polygonal cells, except at the bottom of 
certain grooves, where they are more or less crowded. Though belonging to the 
serous membranes, the synovial membranes do not form complete sacs, as, after 
lining the internal surface of the ligaments, they cease at the articular margins. 

Direct observation demonstrates that the cartilages have no covering, and 
that there is no synovial membrane on their surface. The anatomists who 
imagined that the thin pellicle, which can be rendered evident in cutting the 
surface of cartilage obliquely and separating it by teazing, was a membrane, were 
deceived, as this pellicle has not the texture of a serous membrane ; and it is not 
vascular, for it has never been possible to inject vessels on the surface of such 
cartilages, nor yet in their substance. Neither is it covered with epithelium, and, 
if submitted to microscopical examination, it has all the characters of cartilage. 

Pathological facts prove nothing in favour of the existence of a synovial 
membrane on cartilages. 

It may be accepted, then, that the synovial membrane never extends to the 
surface of articular cartilage ; but, after being fixed around the margin of a 
diarthrodial surface, it is reflected in every direction to line the internal surface 
of the ligaments, and become attached to the periphery of the diarthrodial surface 
in contact with the other, so that it entirely isolates the interior of the joint from 
the peri-articular connective tissue. 

There are generally found within articulations, little masses of fat which push 
the synovial membrane enveloping them inwards. Erroneously considered by 
Clopton Havers as glands for the secretion of synovia, these accumulations of fat 
have been named synovial fringes,- ot villi. They are more particularly numerous 
in the neighbourhood of the articular margins — that is, on the border of diarthro- 
dial surfaces. They are formed by a prolongation of the synovial membrane, 
which covers some connective tissue fibres associated with adipose cells, or an 
amorphous substance provided with nuclei. 

The synovial membrane, after lining the inner surface of ligaments, sometimes 
escapes between these, forming a hernia. The term synovial culs-de-sac has been 
given to these external prolongations of the articular serous membrane. This 
membrane often covers the inner surface of a tendon or ligament, in order to 
facilitate their gliding over a bony eminence. 

The synovia is a viscid, colourless, or slightly yellow fluid, in its physical 
characters somewhat resembling oil ; it does not possess them, however, so far as 
its composition is concerned, for chemical analysis has not demonstrated the 
presence of fatty principles. It is the albumen it contains which gives to it its 
viscidity, and which fits it for lubricating the articular surfaces over which it is 
spread. Its use in the animal economy is absolutely identical with that of the 
greasy substances employed to luliricate the axles of carriages. 

To the means of union described under the names of ligaments and synovial 
membranes, may be added atmospheric pressure, the influence of which is 
relatively considerable, as the experiments of Weber have demonstrated. 

Movements. — The movements peculiar to diarthrodial articulations are 
divided into seven principal classes : 

1. Simple gliding, the only movement possible between two plane or undu- 
lating facets. 



176 THE ARTICULATIONS. 

2. Flexion, which brings two bony pieces nearer each other, by closing more 

or less their angle of union. 

3. Extension, the inverse movement, during which the bones are straightened 

on each other. 

4. Adduction, which brings the inferior extremity of the movable bone towards 

the median line. 

5. Abduction, the contrary movement to the preceding. 

6. Circumduction, or the sling movement, during which the bone passes 

successively through the last four positions. 

7. Rotation, in which one bone pivots on another. 

Classification of the Diarthroses. — The basis of this classification is 
founded on the configuration of the articular surfaces and the nature of the 
movements they permit. This double base serves to establish five kinds of 
diathrodial articulation : 

1. Enr/rfhrosis, characterized by the reception of an articular head within a 
cavity of appropriate form. This articulation, the surfaces of which are derived 
from a sphere, may be the seat of the most extensive and varied movements — 
flexion, extension, abduction, adduction, circumduction, and rotation. Example : 
the coxo-femoral articulation. 

2. The trochlea?!, angular ginglymoid, or perfect hinge articulation, when the 
articular surfaces are formed into trochlea, reciprocally fitting into each other, 
and the movements of which — flexion and extension only — are executed, from 
before to behind, with the precision of a hinge. Example : the tibio-tarsal 
articulation. 

3. The piiwt, trochoid, or lateral ginglymoid articulation, is a diarthrosis formed 
by a pivot which turns in a semi-cylindrical cavity. Rotation is the only move- 
ment. Example : the atlo-axoid articulation. • 

4. The condyloid, or imperfect hinge articulation, which permits, like the 
preceding, the two principal movements of extension and flexion, and the acces- 
sory movements of rotation or lateral inclination. The articular surfaces, though 
very diversely shaped, nevertheless exhibit in all the articulations one or more 
condyles opposed to an equal number of oval excavations. Example : the femoro- 
tibial articulation. 

5. Arthrodia, or 'plamform diarthrosis, is constituted by plane or nearly plane 
iacets. Gliding is the only possible movement. Example : the carpo-metacarpal 
articulation. 

Nomenclature. — The names of the articulations are usually those of the 
bones which form them. For instance, the scapulo-humeral articulation is the 
joint between the scapula and humerus ; the intervertehrnl articulations join to 
each other the various bones constituting the spine. When the qualifying name 
of an articulation is composed of two elements, as in the first instance, it is well 
to place first the word which indicates the bone usually most fixed. 

General Characters of the Synarthroses. 

Sutures (Fig. 1 1 5, a) are the temporary articulations which exist only at an early 
period of life. They nearly all disappear in the adult animal, in consequence of 
the bones forming them becoming consolidated. They belong almost exclusively 
to the bones of the head. 

Articular Surfaces. — The bones forming these come in contact by their 



THE ARTICULATIONS IN GENERAL. 177 

borders or angles, which, for this purpose, generally present very uneven 
surfaces. 

Sometimes they arc cut perpendicularly and simply roughened ; at other times 
they are bevelled, and joined by means of fine laminse or trifling inequalities ; 
again, they are notched into deep and sinuous dentations ; and lastly, one bone 
is fixed into a groove cut in the other. It will be understood that such formations 
of the articular surfaces will limit their movements, and assure the solidity of 
their union. 

Modes of Union, — A fibrous tissue interposed between these synarthrodia! 
surfaces, unites them closely to each other. It has absolutely the same texture as 
the primary cartilage of the bones, and, like it, possesses the property of becoming 
ossified after having been vascularized. This ossification, which causes the 
disapppearance of the sutures, occurs earlier inwards than outwards. The 
periosteum, in passing from one bone to another, also concurs in bringing about 
a more complete synarthrosis. It should, therefore, be included in their means 
of union. 

Movements. — These are very obscure, and only noticeable in young animals, 
by the elasticity they communicate to the bony walls of the cranium or face. In 
the adult, they may be said to be null. 

Classification. — Tliere are four principal descriptions of sutures .- 

1. When two wide bones correspond by means of denticulations fitting into 
each other, the suture is named frup, Umhosa, serrated, or dentated. Example : 
the articulations unitmg the three portions of the parietal bone. 2. If the opposite 
borders of two bones in contact are widely bevelled, one inwards, the other out- 
wards, it forms a scaly or squamous suture {squamosa). Example : the parieto- 
temporal articulations. 3. When the union of bones takes place by plane or 
roughened surfaces, cut perpendicularly on their borders or angles ; this constitutes 
the harmoaia suture, or suture hij juxtaposition (or apposition). Example : the 
occipito-temporal articulations. 4. The schiruii/Iesis, mortised suture, synchron- 
drosis, or gomphosis, results from the reception of a bony plate into a groove more 
or less deep in another bone. Examples : the spheno-frontal and supermaxillo-nasal 
articulations ; the teeth in the alveolar cavities. 

General Characters of the Amphiarthroses or Symphyses. 

Articulae Surfaces. — They are frequently smooth, and formed almost on 
the same model as the diarthrodial surfaces. They are covered by a thin layer of 
cartilage ; but, instead of being smooth and polished, they are more or less rugged, 
without, however, presenting the anfractuous disposition of the majority of synar- 
throdia! surfaces. 

Modes of Union. — The organs which perform this office are : 1. Fibro- 
cartilage, which establishes continuity between the articular surfaces. 2. Ribbon- 
shaped and peripheral ligaments (Fig. 115, b a). These latter do not differ from 
the analogous bands attaching the diarthrodial articulations. With regard to the 
fibro-cartilage, it is distinguished from the complementary discs of these same 
articulations, by a less intimate mixture of the cartilaginous and fibrous elements 
entering into its composition. The last may be sometimes absent, as well as the 
peripheral bands ; and then the articulation only differs from the synarthroses by 
the extent of motion it permits. Occasionally, the interarticular fibro-cartilages 
are excavated by one or two little narrow cavities (Fig. 115, b b, c) ; but these 
are never lined by a synovial membrane, like the diarthrodial cavities. 



178 THE ARTICULATIONS. 

Movements. — The amphiarthroses only permit of a see-saw or swinging 
movement, the extent of which depends on the thickness of the intermediate 
fibro-cartilage. 

Classification. — Only one kind of amphiarthrosis is recognized in the Horse, 
the most, remarkable of which is found in the articulations between the bodies of 
the vertebrae. 



CHAPTER II. 

ARTICULATIONS OF MAMMALIA IN PARTICULAR. 

In the special study of the articulations, the same order will be followed as for the 
bones ; the articulations of the spine will be first noticed, then those of the head, 
thorax, and anterior and posterior limbs. 

Preparation. — The preparation of the bones which have been described, has not been made 
the subject of any particular recommendation, because it suffices, in order to study them, to 
remove the soft parts by which they are surrounded, either by boiling, maceration, or scraping. 
But when we come to examine the soft textures, in order to do so profitably it is necessary to 
learn beforehand the rules whicli should be followed in their preparation. The following 
directions are given with regard to the study of the articulations : — 

1. To prepare the articulations, young subjects are cliosen in preference to those advanced 
in years, because the density of tlie connective tissue in them is not so great, and this tissue is 
easily removed from around the ligaments. As tiiese are prepared with difficulty when the 
external surface is in a dry state, care should be taken, before dissecting them, to have them 
excluded from the air by covering them with damp cloths, or with the skin of the animal. 

2. It is convenient to separate the articulation we wish to dissect, by sawing through the 
bones at a certain distance from the articular surfaces. The manipulation of the part is then 
rendered easier, and its dissection can be made under the most favourable conditions. 

3. It is necessary to preserve, as carefully as possible, the muscles surrounding the articula- 
tions, in order to be able to study their relations with the ligaments which bind these. If it 
be absolutely requisite to remove them, their insertions corresponding to the articulation 
should always be retained. 

4. The capsular ligaments should be first studied, as they have soon to be removed, the 
better to show the funicular ligaments. Tliese, in their turn, must be sacrificed in order to 
display, by different sections, the interosseous ligaments, when they are present. Lastly, the 
two articular surfaces should be completely separated, so as to examine their conformation. 

5. The synovial membranes, with their different cuU-de-sac, being a very important study — 
with reference to the diagnosis and treatment of articular tumours — it is convenient to devote a 
special piece to the examination of these serous membranes. It is very useful to inject their 
interior with plaster or tallow coloured black, in order to distend their cavities, and thus aid 
the study of their relations with ligaments, tendons, or muscles. 

6. When an articulation is completely dissected, it may be left exposed to the air for some 
time. When the ligaments begin to dry, they are more visible and easier studied. 

For the preparation of each articulation it is not necessary to give any directions ; a glance 
at the figures accompanying the description will suffice to dispel any embarrassment the 
student may experience, while he always requires particular indications. 

Article I. — Articulations of the Spine. 
These articulations comprise all those of the vertebrse with each other. 

Preparation. — In order to properly study the vertebral joints, the spine of one subject 
should be freed from all tlie muscles surrounding it; this being done, portions consisting of at 
least two vertebrse from the cervical, dorsal, and lumbar regions, should be detached trum it. 
In the portions from the cervical regions, the interlamellar ligaments and the capsules of the 



ARTICULATIONS OF TEE SPINE. 179 

articular processes are easily dissected ; and on the dorsal region portions, the interspinous, 
Bupra-spinous, interlamellar, and common inferior ligaments, can be examined. On those 
portions from the lumbar region, in a horizontal section through the spinal canal, the inferior 
face of the interlamellar ligaments and the common superior vertebral ligament will be seen ; 
while in those from the dorsal region, a good idea will be derived of the common inferior 
vertebral ligament. The intervertebral ligaments can be studied in vertical and horizontal 
eections of the bodies of the vertebrae from any region. 

A second subject, which should be fixed in the third position (see Preparation of the 
Muscles), is necessary for the dissection of the supra-spinous, dorso-lumbar, and cervical 
ligament. This may be eflPected by removing the muscles which occupy the vertical channels 
above the cervical vertebrse (see Preparation of the Cervical Kegions). 

Intervertebral Articulations. 

The vertebrae articulate : 1. By their bodies. 2. By their spinal or annular 
portion. There results from this union two kinds of articulation, which must be 
studied separately, as they do not belong to the same class. It is well to mention, 
however, that the general details into which this study leads us, apply only to 
the articulations uniting the last six cervical vertebrae, all the dorsal and lumbar 
vertebrae, and the first sacral vertebra. 

Union op the Vertebra by their Bodies. — The articulations forming 
this union are so many amphiarthroses. 

Articular surfaces. — The vertebral bodies come into contact by the surfaces 
which terminate them before and behind. In the cervical region these surfaces 
represent, anteriorly, a real head ; posteriorly, a cotyloid cavity which receives the 
head of the next vertebra. Beginning from the first dorsal vertebra and passing 
on to the sacrum, these surfaces tend to become effaced and more and more 
plane, though they still preserve their convexity and concavity. 

Means of union. — 1. By fibro-cartilages interposed between the articular 
surfaces. 2. By a common superior vertebral ligament. 3. By a common 
inferior vertebral ligament, 

a. Intervertebral fihro-cartilages (Fig. 121, 1, 1). — These are circular or 
elliptical discs, convex in front, concave behind, and soUdly fixed by their faces 
to the articular planes which they separate. The fibro-cartilaginous substance 
composing them consists of concentric layers, which become denser and closer to 
each other as they near the circumference ; they even disappear towards the 
centre of the disc, where this substance becomes pulpy, and assumes the histo- 
logical characters of pure cartilage. It may be remarked, that each of these 
layers is made up of a collection of thick parallel filaments, which cross with 
those of other layers Hke an X, and are attached by their extremities to the 
articular surfaces. From this aiTangement results so intimate an adherence 
between the vertebral bodies and their intermediate fibro-cartilages, that an 
attempt to disunite them is more likely to cause a fracture of the former. The 
fibro-cartilages, thicker in the cervical and lumber regions than in the dorsal, 
respond by their circumference to the two common ligaments. Those which 
separate the vertebrte of the back concur to form the intervertebral cavities, 
intended for the reception of the heads of the ribs, and give attachment to the 
interosseous costo-vertebral ligaments. 

h. Common superior vertebral ligament (Fig. 126, 1). — This ligament extends 
from the axis to the sacrum, and is lodged in the spinal canal. It is a long 
fibrous band cut on its borders into wide festoons. By its inferior face, it is 
attached to the intervertebral discs, and the triangular imprints on the upper 
faces of the bodies of the vertebrte. Its superior face is in contact with the dura 



180 THE ARTICULATIONS. 

mater, tlirough the medium of an abundant cellulo-adipose tissue. Its borders 
are margined by the intra-vertebral venous sinuses (venm basium vertehrarium). 

c. Common inferior vertebral ligament (Fig. 127, 5). — Situated under the 
spine, this ligament is absent in the cervical, and the anterior third of the dorsal 
region. It only really begins about the sixth or eighth vertebra of the latter 
region, and is prolonged in the form of a cord — at first narrow, then gradually 
widening until it reaches the sacrum, on the inferior surface of which it 
terminates by a decreasing expansion. From its commencement, it is attached to 
the inferior crests of the bodies of the vertebrae and the intervertebral discs. By 
its inferior face, it is in contact with the posterior aorta. 

(Leyh commences this ligament at the seventh cervical vertebra, and says 
that it adheres to the crests on the bodies of the dorsal and lumbar vertebrae, as 
well as to the lower face of the sacrum and coccyx. At the fifth dorsal vertebra 
it widens and thickens, and in the lumbar region is bound up with the pillars 
of the diaphragm, and confounded on each side with the large ligaments of the 
pelvis.) 

Union of the Vertebra by their Spinal Portions. — Each vertebra, in 
uniting by its annular portion with that which follows or precedes it, forms a 
double arthrodial joint. 

Articular surfaces. — These are the facets cut on the anterior or posterior 
articular processes, and which have been described when speaking of the vertebrse 
themselves. They are covered by a thin layer of cartilage. 

Means of union. — 1. A common supra-spinous ligament. 2. Interspinous 
ligaments. 3. Interlamellar ligaments. 4. Ligamentous capsules, proper to the 
articular processes. 

a. Capsules proper to the articular processes (Fig. 124, 5). — Each anterior 
articular process is maintained against the corresponding posterior process, by a 
direct band. This is a peripheric capsule attached around the diarthrodial facets, 
lined by a synovial membrane which facilitates their gliding, and covered, 
outwardly, by the insertions of some spinal muscles. These capsules, yellow and 
elastic in the cervical region, are composed of white fibrous tissue in the dorso- 
lumbar region. Very developed at the neck, in consequence of the thickness of 
the articular tubercles they envelop, they become reduced, near the middle of 
the back, to some fibres which cover, outwardly, the diarthrodial facets in 
contact. 

b. Common supraspinous ligament. — This ligament, the name of which suffi- 
ciently indicates its situation, extends from the sacrum to the occipital bone, and is 
divided into two portions — one posterior, or supraspinous dor so-lumbar ligament ; 
the other anterior, or supraspinous cervical ligament. These two ligaments, 
although continuous with one another, yet differ so strikins^ly in form and 
structure that they are best described separately. 

1. Supra-dorso-lumbar ligament (Fig. 127, 2). — This is a cord of white 
fibrous tissue, which commences behind on the sacral spine, and ceases in front, 
about the inferior third of the dorsal region, by insensibly assuming the texture 
and elasticity of the cervical ligament, with which it is continuous. It is attached 
in its course to the summits of all the lumbar spinous processes, and to the ten or 
twelve last dorsal. On the sacral spine, it is confounded with the superior 
ilio-sacral ligaments. In the lumbar region, it is united on each side to the 
aponeuroses of the longissimus dorsi muscles. 

2. Supraspinous cervical, or simply cervical ligament {ligamentum nucha, liga- 



ARTICULATIONS OF THE SPINE. 



181 



mmtum colli) (Fig. 120, 1, 2). — This ligament is entirely formed of yellow 
fibrous tissue, and constitutes, in the median plane of the body, a very remarkable 
elastic apparatus, which separates the superior cervical muscles of the right side 
from those of the left, and plays the part not entirely of an articular band, but 
rather of a permanent stay, charged to balance the weight of the head. 

In the cervical ligament there is distinguished a fumriiJar and a lamellar 
portion. The first, usually called the cord {funicular or cordiform portion) of the 
ligament, is a wide funiculus which extends directly from the first dorsal spinous 

Fig. 120. 




CERVICAL LIGAMENT AND DEEP MUSCLES OF THE HORSE S NECK. 

1, Lamellar portion of the cervical ligament ; 2, funicular portion of the same. 



processes to the summit of the head. Divided into two lateral lips by a median 
groove, this cord is continued posteriorly by the dorso-lumbar ligament, and is 
inserted, anteriorly, into the tuberosity of the occipital bone. It is covered above 
by a mass of fibro-adipose tissue, which, in certain common-bred horses, is very 
abundant. Below, it gives rise, in its posterior two-thirds, to the majority of the 
fibres belonging to the lamellar portion. On the sides, it receives the insertions 
of several cervical muscles. The lamellar portion — comprised between the funicular 
portion, the spinous processes of the second dorsal vertebra, and the cervical 



182 



THE ARTICULATIONS. 




vertebrae, constitutes a vast triangular and vertical septum, which itself results from 
the apposition of the two laminae that lie back to back, and are united by 
connective tissue ; they are bordered above by the two lateral lips of the cord. The 
elastic fibres which enter into their composition are given off either from the 
latter, or from the spinous processes of the second and third dorsal vertebrae ; 
they are directed downwards or forwards, and reach the spinous processes of the 
last six cervical vertebrae, into which they are inserted by so many digitations, 
becoming confounded with the interspinous ligaments of the neck. The fibres 
of the two last digitations are few in number, widely separated from one another, 
and united by many anastomosing branches, which make them appear as a kind 
of wide network. The lamina of the cervical ligament are in relation, outwardly, 
with the superior branch of the ilio-spinal ligament, the intertransversalis colli 
muscles, and the complexus muscle. 

(This important structure, which is, in reality, 
the mechanical stay and support of the heavy head 
and neck of quadrupeds, and is usually temied the 
ligamentvm nucJm, is all but absent in Man, being 
represented in him by a tliin narrow band — or rather 
two thin planes of fibres, the ligamenta suhflava. It 
is described by Leyh as if there were not two portions, 
and that excellent anatomist does not appear to insist 
suificiently on the difference between the dorso-nuchal 
and the dorso-lumbar divisions. Percivall, who almost 
entirely neglects the ligaments, also makes no distinc- 
tion. The difference in structure, elasticity, and 
situation, wairants the distinction made by Chauveau. 
As already indicated, the function of this ligament — 
and more particularly of its nuchal division — is to 
maintain the head and neck in their natural position 
during repose, and to allow the most extensive move- 
ments at other times.) 

c. Interspinous Ugaments (Fig. 121, 3). — Fibrous 
laminae fill the interspinous spaces, and are attached, 
before and behind, to the opposite borders of the spinous 
processes, which they unite. They are confounded 
superiorly with the supra-spinous hgament, and are continued inferiorly by the 
interlamellar ligaments — forming two lateral planes which are applied against each 
other, hke the laminae of the cervical ligament, and covered outwardly by the inter- 
transversalis colli muscles. 

In the region of the neck, the interspinous ligaments are yellow and elastic. 
In the dorso-lumbar region, they are formed by fasciculi of white fibrous tissue, 
loosely united to each other at their extremities, and directed very obliquely 
backwards and downwards. In consequence of this disposition, and notwith- 
standing their inextensibility, they permit the separation of the spinous processes. 
Their lateral surfaces are divided by a layer of grey elastic fibres, which cross hke 
an X the direction of the preceding fasciculi. Very abundant in the anterior 
moiety of the dorsal region, these fibres operate, by their proper elasticity, in 
bringing the spinous processes towards each other. 

d. Interlamellar, or interannular ligaments. — Situated, as their name indicates, 
between the vertebral laminae, and divided into two lateral moieties, these 



INTERVERTEBRAL ARTICULA- 
TIONS. 

A, B, C, Bodies of three dorsal 
■vertebrse divided longitudi- 
nally ami vertically to show 
(1, i) a section of the inter- 
vertebral discs ; 2, supra- 
spinous dorso-lumbar liga- 
ment ; 3, interspinous liga- 
ment ; 4, fibrous fascia, con- 
stituting the proper capsule 
of the articular processes in 
the dorsal region. 



ARTICULATIONS OF THE SFINE. 183 

ligaments appear to be produced by the two fibrous planes of the preceding 
ligaments, which, on arriving at the base of the spinous processes, separate from 
one another to be carried outwards. Their anterior border is inserted into the 
posterior margin of the vertebral lamina in front. Their posterior border is fixed 
to the anterior border and inferior face of the lamina behind. Their superior 
face is in relation with some spinal muscles, and their inferior face is in contact 
with the dura mater. Outwardly, they are confounded with the capsules proper 
to the articular processes. Yellow and elastic in the cervical region, these 
ligaments are Avhite and inelastic in the dorso-lumbar region. 

Ohaeactees proper to some Intervertebral Articulations. 1. Inter- 
coccygeal ana sacro-coccijgeal articulations. — These articulations are adapted to the 
rudimentary type of the vertebrae they unite. The coccygeal bones only come in 
contact by their bodies — their spinal laminse being reduced to the merest traces, 
or are altogether absent. The anterior and posterior articular surfaces of each 
vertebra are convex, and the interarticular fibro-cartilages, hollow on both faces, 
resemble a biconcave lens. With regard to the peripheral bands, they are repre- 
sented by a bundle of longitudinal fibres spread over the surface of the bones, 
which they envelop in a common sheath. 

2. Intersacral articulations. — The sacral vertebras being fused into one piece 
— the OS sacrum — there is no occasion to study the true articulations in this 
region. It may be remarked, however, that the supra-spinous dorso-lumbar liga- 
ment is continued on the sacral spine, and that there exist between the processes 
formed by this spine, true interspinous ligaments. 

3. Sacro-lumhar articulation. — In this articulation, the great thickness of the 
fibro-cartilage is to be remarked ; and, in addition, that the last lumbar vertebra 
corresponds with the sacrum not only by its body and articular processes, but 
also by the oval and slightly concave facets shown on the posterior border of its 
transverse processes, which are adapted to analogous slightly convex facets on the 
sides of the base of the sacrum. The bundles of fibres thrown from one bone to 
another from around these sacro-transversals (real planiform diarthroses) maintain 
the articular surfaces in contact, and cover, outwardly, the synovial membrane 
which facilitates their gUding. 

4. Articulation of the tivo last lumbar vertebrce. — This is distinguished by the 
presence, between the transverse processes, of a planiform diarthrosis, like that of 
the sacro-transversal just noticed. These two articulations are only found in 
Solipeds. 

5. Atlo-axoid articulation. — This is so far removed by its conformation and 
special uses from the other intervertebral articulations, that it will be described 
as an extrinsic articulation of the head and spine. (See Articulations of the Head.) 

The Movements of the Spine in general. — Each intervertebral articula- 
tion is the seat of very obscure movements, the separate study of which offers 
little interest. But these movements, when conjoined with those of the other 
articulations, result in bending the whole spine in a somewhat marked manner, 
and producing either the flexion, extension, or lateral inclination of this flexuous 
column. 

When flexion takes place, the spine is arched upwards, the common inferior 
ligament is relaxed, the spinous processes separate from one another, and the 
supra-spinous ligament, becoming very tense, soon imposes limits to this movement. 

Extension is effected by an inverse mechanism, and is checked by the tension 
of the common inferior ligament and the meeting of the spinous processes. 



181 



THE ARTICULATIONS. 



Lateral inclination takes place when the spine bends to one side. This 
movement is very easily executed in the cervical and coccygeal regions, but is 
arrested by the ribs and the costiform processes in the dorso-lumbar region. 

A circumflex movement is possible at the two extremities of the vertebral 
column— neck and tail ; for they pass easily from extension to lateral inclination, 
and from tliis to flexion, etc. 

Owing to the elasticity of the intervertebral fibro-cartilages, the spine is 
endowed with a very limited amount of rotation, or rather of torsion. 

For the special study of the movements of each spinal region, reference must 
be made to what has been already said (,p. U) regarding tlie mobility of this 
part. 

Fig. 122. 




CERVICAL LIGAMENT OF THE OX. 

L, l', The two laminse which form the cord of the cervical ligament : 1, 2, 3, 4, the four anterior 
digitations of the cordiform portion. R, Its accessory portion : 5, first dorsal vertebrae ; 6, 6, 6, 
interspinous ligament of the dorsal region. 



Differential Characters in the Vertebral Articulations and Ligaments in the 

OTHER Animals. 
A. In the Ox the intervertebral discs are much thicker than in the Horse. The common 
inferior vertebral ligament is very strong in the lumbar region. The supraspinous dorso-lumhar 
ligamsnt is composed of yellow elastic tissue. The cervical ligament is much more developed 
than in Solipeds,in consequence of the greater weight of the head ; and it presents a conforma- 
tion altogether special, which M. Lecoq has made known in the following terms : " On lenving 
the withers, the stipra- spinous ligament ceases to cover the head of the spinous processes, and 
extends from each side in a wide and strong band, taking points of attachment on the sides of 
the processes, and becoming separated, on leaving that of the first dorsal vertebra, into two 
parts — a superior and inferior. The first reaches the cervical tuberosity in the form of a thick 
cord united to the cord of the opposite; the other thins off into a band, which is attached to 
the posterior half of the spinous process of the axis, and to that of the third and fourth vertebrae. 
A production of the same kind — an auxiliary to the principal portion — leaves the anterior border 
of the spinous process of the first dorsal vertebra, and is attached to that of the fourth, fifth, 



ARTICULATIONS OF THE SPINE. 



185 



sixth, and seventh vertebrae. The superior border of this auxiliary ligamentous production, is 
concealed between the two lamiua of the principal ligament." ' 

B. Camel. — In this animal, the common supraspinous ligament is entirely composed of 
yellow elastic tissue ; it is therefore impossible to distinguish, physically, a dorso-lumbar and a 
cervical portion. It is remarkable for its thickness and width ; and its dimensions increase 
from behind to before, especially from the second lumbar vertebra. At the fifth, sixth, seventh, 
eighth, ninth, and tenth dorsal vertebrae an elastic band is given off fi om its borders ; as this 
descends, it gradually becomes thinner until it reaches the external intercostal muscles. 

From the ninth dorsal vertebra, the supraspinous ligament divides into two layers, which 
are placed against the lateral faces of the spinous processes. In the cervical region, the layers 



Fig. 123, 




kt^i^l^^-^ 



^i 



x\\\-^ 



CERVICAL LIGAMENT OF A YOUNG CAMEL. 



become rounded, are joined to each other by means of connective tissue, and describing an S- 
shaped curve, become inserted into the occipital bone. 

They give oflf, from their inferior border, six digitations, which are attached to the spinous 
processes of tlie last six cervical vertebrae. An accessory leaf is situated between the two 
portions just described : it is detached from the anterior border of the spinous process of the 
first dorsal vertebra, and is fixed anteriorly into the two last cervical vertebrae. 

C. Pig. — The Pig, remarkable for the shortness of its neck and the limited movements of 
this region, does not show any cervical ligament, properly so called. It is replaced by a super- 
ficial fibrous raphe', extending from the occipital bone to tlie spinous process of the first dorsal 
vertebra. 



^Journal de MMecine VeW-inaire, p. 122. Lyons, 1848. 



186 TEE ARTICULATIONS. 

D. Camivora. — The Cat has no cervical ligament, and shows, instead, a raphe like the 
Pig. In the Dog, the ligament is reduced to a simple cord, continued from the dorso-lumbar 
ligament, and goes no further than behind the spinous process of the axis. In the Cat, the 
interspinous ligaments are replaced by small muscular fasciculi ; in the Dog, this substitution 
only takes place in the xiervical region. The laminae of the first coccygeal vertebrae possess 
the principal characters which distinguish perfect vertebrae, and are united by vestiges of the 
articular bands which exist in the other regions of the spine. 

Aeticle IL — Articulations of the Head. 

We will first study the two extrinsic articulations which are the centre of the 
movements of the head on the spine — the atlo-axoid and occipito-athid articula- 
tions. Afterwards, we will pass to the examination of the joints which unite the 
different bones of the head. 

1. Atlo-axoid Articulation (Fig. 124). 

Preparation. — It suffices to remove the soft parts from around the articulation, to expose 
the interannular, the interspinous, and the inferior odontoid ligament. To examine the superior 
odontoid ligament and the synovial membrane, one half the atlas and axis must be separated 
by sawing longitudinally through them from oue side to the other. 

This may be considered as the type of the trochoid articulation. 

Articular surfaces. — To form this articulation, the axis offers its odontoid 
pivot and the undulated diarthrodial facets at its base. The atlas opposes to the 
pivot the concave semi-cylindrical surface hollowed on the superior face of its 
body ; and for the lateral undulated facets it has analogous facets cut on the 
transverse processes, on each side of the vertebral canal. 

Mode of union. — 1. An odontoid, or odonto-atloid ligament. 2. An inferior 
atlo-axoid ligament. 3. A superior ditto. 4. A fibrous capsule. 

a. Odontoid ligament (Fig. 124, 3). — Continuous with the common superior 
vertebral ligament, very short and strong, flattened above and below, and triangu- 
lar in shape, the odontoid ligament is composed of glistening white fibres, fixed 
behind in the superior channel of the odontoid process, and inserted in front on 
the transverse ridge which separates the superior face from the inferior arch of 
the atlas, as well as on the imprints situated in front of this ridge. It is covered, 
on its lower face, by the synovial membrane of the articulation ; and its upper 
surface is in contact with the spinal dura mater. It sends some bands within the 
condyles of the occipital bone. 

b. Inferior atlo-axoid ligament. — This is a wide, thin, and nacrous-looking 
band, extending from the inferior face of the axis to the inferior tubercle of the 
atlas, and is covered by the longus colli muscle ; it is united to the synovial mem- 
brane by its deep face, and confounded on its bordei-s with the fibrous capsule to 
be immediately described. It represents the common inferior vertebral ligament. 

c. Superior atlo-axoid ligament. — This exactly represents the interspinous liga- 
ments of the other cervical articulations. Yellow, elastic, and formed like the 
two lateral bands, it is continuous, laterally, with the capsular Ugament. It 
represents the interspinous and interlamellar ligaments. 

d. Capsular ligament. — This, it may be said, is only the interlamellar ligament 
proper to the atlo-axoid articulation. It commences from the sides of the pre- 
ceding ligament, and becomes united to the inferior atlo-axoid, after contracting 
adhesions with the borders of the odontoid Ugament. In this way it encloses the 
articulation and the spinal canal. Before and beliind, it is attached to the anterior 
or posterior margin of the bones it unites. Its external face is in contact wiih 



ARTICULATIONS OF THE HEAD. 



187 



the great oblique muscle of the head ; its internal responds, in its inferior half, 
to the articular synovial membrane, and its superior moiety to the spinal dura 
mater. It is analogous to the capsules in other regions. 
(Leyh describes this Ugament as the interannular). Fig. 124. 

Synovial membrane. — This lines the odontoid ligament 
and atlo-axoid ligaments, and the articular portion of the 
peripheral capsule. 

Movements. — Rotation, the only movement possible in 
the atlo-axoid articulation, is effected in the following 
manner : the axis remains fixed, and the first vertebra, 
drawn to one side chiefly by the great oblique muscle, 
rotates on the odontoid pivot, carrying the head with it. 

The rotation movements of the head have, therefore, 
this diarthrosis for a centre, and not the atloido-occipital 
articulation. 

In the Dog and Cat, the odontoid ligament is replaced by three 
particular ligaments : 1. Two lateral cords, rising in common from the 
summit of the odontoid process, and inserted, each on its own side, 
within the condyles of tlie occipital bone. 2 A transverse ligament, 
passing over the odontoid process, which it maintains in its place 
against the itiferior arch of the atlas, and is attached by its extremities 
to the superior face of the latter. A small synovial capsule facili- 
tates the gliding of the odontoid process beneath this ligament. The 
articular synovial membrane always communicates with that of the 
occipito-atloid articulation. 

In the Pig, the disposition is nearly the same as in the Caruivora. 



2. Occipito-atloid Articulation (Fig. 124). 

(^Preparation. — Dissect away all the soft parts that pass from the 
neck to the head and cover the articulation, and more particularly 
the flexor, the recti, and the small oblique muscles of the head. To 
expose the synovial membranes, open the sides of the capsular 
ligament.) 




This is a condyloid articulation. 

Articular surfaces. — In the atlas, the two cavities which 
replace the anterior articular processes and the heads of the 
other vertebrfe ; in the occipital bone, the two condyles 
flanking the sides of the occipital foramen. 

Mode of union. — A single capsular ligament envelops 
the entire articulation ; it is attached by its anterior border 
to the margin of the occipital condyles, and by its posterior 
to the anterior contour of the atlas. Thin and slightly 
elastic in its inferior half, this ligament presents, supe- 
riorly, four reinforcing fasciculi : two middle, which inter- 
cross in X — whence the name "cruciform," sometimes 
given to this ligament (Fig. 124, 1, 1) ; and two lateral, 
which pass from the sides of the atlas to the base of 
the styloid processes (Fig. 124, 2, 2). It is lined by 
the synovial membranes, and is enveloped externally by a 

large number of muscles, which protect the articulation and greatly strengthen 
it everywhere. Among these may be particularly noticed the recti muscles of 



ATLO-OXOID AND OCCIPI- 
TO-ATLOID ARTICULA- 
TIONS (the upper arch 
of the atlas has been 
removed to show the 
odontoid ligament). 

1, 1, Middle accessory fas- 
ciculi ; 2, 2, lateral 
fasciculi of the capsular 
ligament of the occipi- 
to-atloid articulation ; 

3, odontoid ligament ; 

4, interspinous liga- 
ment uniting the second 
and third vertebrae of 
the neck ; 5, fibrous 
capsule uniting the 
articular processes of 
these vertebrae. A, 
Anterior internal fora- 
men of the atlas con- 
verted into a groove by 
the section of the bone; 
B, B, vertebral foramina 
of the atlas ; C, C, fora- 
mina replacing the an- 
terior notches of the 
axis. 



188 



THE ARTICULATIONS. 



the head, the small oblique, and the complexus. There is also the cord of the 
cervical ligament, 

Sijiiovial membranes. — These membranes are two in number — one for each 
condyle and coiTesponding atloid cavity. Sustained above, below, and outwardly 
by the capsular ligament, they are related inwardly to the dura mater and the 
fibrous tractus which, from the odontoid ligament, is carried to the internal face 
of the occipital condyles. 

Movements. — Extension, flexion, lateral inclination, and circumduction, are the 
movements of the occipito-atloid articulation. 



In the Pig, Dog, and Cat, this articulation— strengthened, as it is, by the capsular and 
odontoido-occipital ligaments already mentioned — has only one synovial capsule. 

3. Aeticulation of the Bones of the Head with each other. 
If we except the articulation which unites the inferior jaw to the cranium — 
the temporo-maxillary — and the hyoideal articulations, it will be found that all 
the bones of the cranium and face are united to each other by synarthrosis, 
forming the different kinds of sutures already generally described (p. 170). 
Nothing is to be gained by entering into more detail with regard to these articu- 
lations, as it will be found sufficient to call to mind the topographical description 
of each bone entering into their formation. 

4. Temporo-maxillary Articulation (Fig. 125). 

{Preparation. — Remove the masseter muscle and the parotid gland. Saw through the 
head about the middle liue. Open the articulation externally, to exhibit the interarticular 
meniscus.) 

The lower jaw, in its union with the cranium, constitutes a double condyloid 
articulation. 
F'g 125. Articular surfaces. — With the temporal bone, 

these are the condyle, the glenoid cavity, and the 
supra-condyloid process at the base of the zygomatic 
process. The glenoid cavity is not lined by cartilage, 
and appears to be merely covered by synovial mem- 
brane. On the maxillary bone is the oljlong condyle 
situated in front of the coronoid process. 

Interarticular fihro-cartilage. — The articular sur- 
faces just named are far from fitting each other 
accurately ; this is only accompUshed by the inter- 
position of a fibro-cartilaginous disc between the 
temporal and maxillary bones. This disc is a kind 
of irregular plate, flattened above and below, thicker 
before than behind, and moulded on each of the 
diarthrodial surfaces it separates. Its superior face, 
therefore, presents : in front, a cavity to receive 
the condyle of the temporal bone ; behind, a boss 
which is lodged in the glenoid cavity. The inferior 
face is hollowed by an oblong fossa, in which the 
maxillary condyle is lodged (Fig. 125, 1). 

Mode of union. — A fibrous envelope — a true capsular ligament — surrounds the 
articulation, aiid is attached by its borders to the margin of the articular surfaces 
it unites. Formed, outwardly, by a thick fasciculus of white vertical fibres (Fig, 




TEMPORO-MAXILLARY ARTICU- 
LATION . 

1, Interarticular fibro-cartilag;e ; 
2, external fasciculus of the 
capsular ligament. A, Base of 
the coronoid process ; B, neck 
of the maxillary condyle; C, 
mastoid process ; D, external 
auditory hiatus. 



ARTICULATIONS OF THE HEAD. 189 

125, 2), this ligament becomes greyish-coloured and elastic for the remainder of 
its extent, and greatly diminishes in thickness, especially in front. Its inner 
face IS covered by the synovial capsules, and adheres to the circumference of the 
interarticular fibro-cartilage. Its external face is related, in front, to the temporal 
and masseter muscles ; behind, to the parotid gland ; inwardly, to the external 
pterygoid muscle ; and outwardly, to a fibrous expansion which separates it from 
the skin. (Leyh mentions a lateral external and a posterior ligament for this 
articulation, but Chauveau and Bigot evidently look upon these as portions of 
the capsular.) 

Synovial membranes. — This articulation has two synovial sacs — one above the 
other — which are separated by the fibro-cartiiaginous disc. 

Movements. — The temporo-maxillary articulation is the centre of all the 
movements performed by the lower jaw. These are : depression, elevation, lateral 
motion, and horizontal gliding. 

The lower jaw is depressed when it separates from the superior one, and is 
elevated when it approaches this. These two opposite movements are executed by 
a mechanism of such great simplicity, that it need not be described here. Lateral 
movements take place when the inferior extremity of the jaw is carried alternately 
to the right and left. It then happens that one of the maxillary condyles, taking 
with it the fibro-cartilage, is brought into contact with the temporal condyle, 
while the other is embedded in tiie glenoid cavity of the opposite side. The 
horizontal gliding is effected from behind to before, or vice veisd. In the first 
case, the two maxillary condyles are carried at the same time under the temporal 
condyles, bearing with them the fibro-cartilages. In the second case, they are 
drawn into the glenoid cavities, and rest against the supra-condyloid eminence, 
which prevents their going further. It will be understood, after this brief 
description, that the presence of the fibro-cartilages singularly favours the lateral 
movements and horizontal gliding of the lower jaw. 

In the Pig, the temporo-maxillary articulation is formed after the same type as that of 
Rodents, and allows very extensive movements from before to behind — a circumstance due to 
the complete absence of the supra-condyloid eminence. 

In the Dog and Cat, the maxillary condyle is exactly fitted to the temporal cavity. This 
disposition, in giving great precision to the movements of depression and elevation, restrains in 
a singular manner the lateral and horizontal gliding motions. The interarticular fibro-cartilage 
is extremely thin in these animals. 

In the Rabbit, the narrow condyle of the maxilla moves from before to behind and to 
each side, on the temporal bone, the articular surface of which is very elongated and destitute 
of a subglenoid eminence. 

5. Hyoideal Aeticulations. 

(Preparation. — Disarticulate the lower jaw, and dissect away from the right of each 
articulation the muscles that may conceal the view.) 

These are of two kinds — extrinsic and intrinsic. The first comprise the two 
tempo ro-hyoideal articulations ; to the second belong the joints which unite the 
different pieces of the hyoid bone — the interhyoideal articulations. 

Temporo-hyoideal Articulations. — These are two amphiarthrodial joints, 
in the formation of which each great cornu of the hyoid bone opposes its upper 
extremity to the hyoideal prolongation lodged in the vaginal sheath of the 
temporal bone. An elastic cartilage, from -^q to i%- of an inch in length, unites 
the two bones in a solid manner ; and it is owing to the flexibility of this 
cartilage that the hyoid bone can move entirely on the temporal bones. 
15 



190 THE ARTICULATIONS. 

Inter-hyoideal Articulations. — A. The great cornu articulates with the 
small one, by an amphiarthrosis analogous to the preceding. To form this articu- 
lation, these two pieces of bone are joined at an acute angle, through the medium 
of a more or less thick cartilaginous band, in the centre of which there is often 
a little bony nucleus— the styloid nucleus, or kerato-hyal bone. This cartilage is 
elastic and flexible, and permits the opening and closing of the articular angle at 
the summit of which it is placed. 

B. Each styloid cornu is united to the body of the hyoid bone, or basihyal, 
by an arthrodial articulation. The articular surfaces are : for the hyoideal 
branch, the small cavity terminating its inferior extremity ; for the body, the 
convex lateral facet situated at the origin of the thyroid cornua. These surfaces 
are covered by cartilage, and enveloped by a small synovial sac and a peripheral 
fibrous capsule. They can ghde on each other in nearly every direction. (Median 
and superior hyoideal capsular ligaments are described by Leyh as sometimes 
present. The latter unites the upper and middle branches, and the former the 
middle with the inferior branches. They are absent when these branches are 
confounded with the superior ones.) 

Article III. —Articulations of the Thorax. 

These are also divided into extrinsic and intrinsic. The first — named costo- 
vertebral— unite the ribs to the spine. The second join the different bones of the 
thorax together ; they comprise : 1. The chondro-sternal articulations, 2. 
Chondro-costal articulations. 3. The articulations of the costal cartilages with 
each other. 4. The sternal articulation perculiar to the larger Ruminants and 
the Pig. All these joints will be first studied in a special manner, then examined 
in a general way as to their movements. 

Extrinsic Articulations. 

Articulations of the Ribs with the Vertebral Column, or Costo- 
vertebral Articulations. 

(Preparation.— This is simple. No difficulty need be experienced except in exposing the 
interartieular ligament, and this is efifected by sawing tlirough one of the dorsal vertebra 
transversely, close to the posterior intervertebral joint formed by that bone. A few cuts of the 
bone forceps will then show the whole extent of the ligament.) 

Each rib articulates with the vertebral column by two points — its head and 
its tuberosity. The first is received into one of the intervertebral cavities 
hollowed out on the sides of the spine, and is therefore in contact with two doi-sal 
vertebrfe ; the second rests against the transverse process of the posterior vertebra. 
From this an'angement arises two particular articulations belonging to the 
arthrodial class, which are named costo-vertehral and costo-transverse. 

Costo-vertebral Articulations. — Articular surfaces. — Pertaining to the 
rib, we have the two convex facets of the head, separated from each other by a 
groove of insertion, and covered by a thin layer of cartilage. On the vertebras, 
the concave facets which, by their union, form the intervertebral cavity ; these 
facets are also covered with cartilage, and separated, at the bottom of the cavity, 
by the con'esponding intervertebral disc. 

Mode of union. — 1. An interartieular ligament (Figs. 126, 2 ; 127, 1), fixed 
in the groove in the head of the rib, and attached to the superior border of the 



ARTICULATIONS OF THE THORAX. 



191 



intervertebral disc, Avhich it encii-cles upwards and inwards, to unite on the median 
line with the ligament of the opposite side. 2. An inferior peripheral ligament 
(Fig. 127, 2, 3, 4), flat above and below, thin and radiating (whence it is often 
named the stellate ligament), formed of three fasciculi, wliich are fixed in common 
on the inferior face of the head of the rib, and in diverging are carried over the 
bodies of the two vertebrte and the intervertebral disc. Lmed above by the 
synovial membranes, this ligament is covered below by the pleura. (Leyh includes 
a capsular ligament for the head of the rib, and another for the costal tuberosity. 
He probably considered the synovial membrane of these articulations as such.) 

Synovial membranes. — These are two in number — an anterior and posterior, 
lying against each other, and separated in part by the interarticular ligament 
they cover. Supported below by the stellate ligament, above they are directly in 
contact with the levatores costarum muscles, and with vessels and nerves. 

CosTO-TRANSVERSE ARTICULATIONS. Avticular surfttces. — In the rib, the 



Fig. 127. 



Fig. 126. 





articulations of the ribs with the ver- 
tebra, and of these with each other 
(upper plane). 

1, Spinal canal, upper face, showing the common 
superior ligament; 2, interarticular costo- 
vertebral ligament ; 3, interosseous costo- 
transverse ligament ; 4, posterior costo-trans- 
verse ligament. 



ARTICULATIONS OF THE RIBS WITH THE 
VERTEBRA, AND OF THESE WITH EACH 
OTHER (INFERIOR PLANE). 

1, Interarticular costo-vertebral liga- 
ment ; 2, 3, 4, fasciculi of the stellate, 
or inferior costo-vertebral ligament; 5, 
common inferior vertebral ligament. 



diarthrodial facet cut on the tuberosity. In the vertebra, the analogous facet on 
the outside of the transveree process. 

Mode of union. Two ligaments bind this articulation : 1. The posterior costo- 
transverse ligament (Fig. 126, 4), a white fibrous band attached by its extremities 
behind the transverse process and the costal tuberosity, lined by synovial mem- 
brane, and covered by the transverse insertions of several spinal muscles. 2. The 
anterior costo-transverse., or interosseous ligament (Fig. 126, 3), a fasciculus of 
short, thick, white fibres, fixed on the anterior surface of the transverse process 
near its base, and in the rugged excavation on the neck of the rib. This liga- 
ment is invested, posteriorly, by the synovial membrane, and covered in front by 
pads of adipose tissue which separate it from the costo-vertebral articulation. 

Synovial membrane. — This is a small particular capsule, kept apart from the 
posterior synovial membrane of the costo-vertebral articulation by the costo-trans- 
verse interosseous ligament. 

Characters peculiar to some Costo-vertebral Articulations. — 1. 
The first, and sometimes the second, costo-vertebral articulation has no inter- 
osseous ligament, and only exhibits one synovial membrane. The intervertebral 



192 THE ARTICULATIONS. 

cavity which concurs in forming the first is often excavated between the last 
cervical and first dorsal vertebras. 

2. The two or three last costo-transverse articulations are confounded with 
the corresponding costo-vertebral joints. They have no proper serous membrane, 
but the posterior synovial membrane of the latter is prolonged around their 
articular surfaces. 

Intrinsic Articulations. 
A. The Chondro-sternal or Costo-sternal Articulations. 

{Preparation. — To show the articulation of the ribs with the cartilages, these with the 
sternum, and the cartilages with each other, carefully remove the pleura, the triangularis 
sterui muscle, the diaphragm, tlie transverse muscle of the abdomen, then the pectorals, the 
great oblique, the transversalis of the ribs, and the intercostal muscles.) 

The first eight ribs, in resting upon the sternum by the inferior extremity of 
their cartilages, form eight similar arthrodial articulations. 

Articular surfaces. — Each sternal cartilage opposes to one of the lateral cavities 
of the sternum, the convex and oblong facet at its lower extremity. 

Mode of union. — The diarthrosis resulting from the union of these two surfaces 
is enveloped everywhere by bundles of white, radiating, fibrous tissue, which con- 
stitute a veritable ligamentous capsule. The superior part of this capsule — known 
as the stellate or superior costo-sternal ligament, is covered by the triangularis 
sterui muscle ; it is joined to a fibrous cord lying on the superior face of the 
sternum, and which is confounded in front with that of the opposite side. The 
inferior portion — the irtferior stellate or costo-sternal ligament — is in relation 
with the pectoral muscles. 

Synovial ccqysule. — There is one for each articulation. 

Characters proper to the first costo-sternal articulation. — The first costo-sternal 
articulation is not separated from its fellow of the opposite side ; so that these two 
joints are, in reality, only one, and the two cartilages lying close to each other 
correspond by a small diarthrodial facet, continuous with that for the sternum. 
The two sternal facets are inclined upwards, and confounded with one another. 
Only one synovial cavity exists for this complex articulation, which unites the 
two first ribs to each other and to the sternum. 

B. Chrondo-costal Articulations uniting the Ribs to their 

Cartilages. 

These are synarthrodial articulations, the movements of which are very 
obscure. They are formed by the implantation of the cartilages in the nigged 
cavities the ribs present at their inferior extremities. The solidity of these articu- 
lations is assured by the adherence of the fibro-cartilages to the proper substance 
of the ribs, and by the periosteum which, in passing from the bone to the cartilage, 
plays the part of a powerful peripheral band. 

In the Ox, the sternal ribs, in uniting with their oartilages, form a true ginglymoid diar- 
throsis, the movement of whicli is facilitated by a small synovial capsule. 

C. Articulations of the Costal Cartilages with each other. 

The ribs, attached to each other by means of the intercostal muscles, are not 
united by real articulations ; neither are their cartilages of prolongation. But 



ARTICULATIONS OF THE THORAX. ■ 193 

the asternal cartilages are bound together by a small yellow elastic ligament, which 
is carried from the free extremity of each to the posterior border of the preceding 
cartilage ; the anterior border of the first asternal cartilage is directly united to 
the posterior border of the last sternal cartilage, through the medium of the 
perichondrium and very short Kgamentous bands. This same asternal cartilage 
is also bound to the inferior face of the xiphoid appendage by a small white 
ligament (the chondro-xiphoicl), under which passes the anterior abdominal 
artery. 

D. Sternal Articulation peculiar to the Ox and Pig. 
It has been already shown that in these animals the anterior piece of the sternum is not 
consolidated with the second portion. Tlie two are united by a diurthrodial articulation ; and 
for this purpose the anterior presents a concave surface, the posterior a convex one. Bundles 
of peripheral fibres firmly bind tliem to each other, and a special small synovial capsule facili- 
tates their movements, which are very limited. 

The Articulations of the Thorax considered in a General Manner, 
with Regard to Movements. 

The thorax can increase or diminish in diameter, in an antero-posterior and 
a transverse direction ; whence arise the dilatation and contraction of this cavity — 
the inspiratory movements accompanying the entrance of the external air into 
the lungs, and the expiratory movements expelling the air contained in these 
organs. 

The variations in the antero-posterior diameter of the chest being due to 
changes in the figure of the diaphragm, need not be noticed here. But the 
transverse variations being the result of the play of the costal arches on tjie spine 
and sternum, it is advantageous to study the mechanism which presides in the 
execution of theii' movements. 

The costal arches, being inclined backwards on the middle plane, the space 
they enclose in their concavity is not nearly so extensive as if they were perpen- 
dicular to this plane. Owing to their double arthrodial joints, the ribs are 
movable on the spine ; and their inferior extremity, also movable, rests either 
directly or indirectly on the sternum. Therefore it is that, when they are drawn 
forward by their middle portions, they pivot on theii' extremities, and tend to 
assume a perpendicular direction, which is the most favourable for the largest 
increase of the space they limit ; then there is enlargement of the lateral diameter 
of the thorax, which signifies dilatation of its cavity. The inverse movement, by 
an opposite mechanism, causes contraction of the chest. 

The ribs are said to be elevated during the forward movement, and depressed 
when they fall backwards. These expressions, though perfectly applicable to Man, 
who stands in a vertical position, are not correct when employed in veterinary 
anatomy. 

Besides the enlargement of the thorax in the transverse and the antero-posterior 
directions, it is necessary to remark on an increase in a vertical direction, caused 
by the displacement of the sternum forward, due to elevation of the ribs. In this 
movement, the costal arches are erected not only on the median plane, but also 
on the spine. The inferior extremity, carried forward, also takes the sternum 
with it ; and this movement cannot take place without that piece being farther 
removed from the vertebrae above. In Man, the displacement of the sternum is 
very marked. 



194 THE ARTICULATIONS. 

AeTICLE IV.---AETICULATIONS OF TRE ANTERIOR LiMBS. 

1. SCAPULO-HUMERAL ARTICULATION (Fig. 128). 

(Preparation. — Detach the limb from the trunk. Remove from the upper extremity those 
muscles which are inserted in the vicinity of the glenoid cavity of the scapula ; turn down from 
its lower extremity those which are inserted into the superior end of the humerus or a little 
below, preserving the attachments of their tendons with the capsular ligament. The seapulo- 
humeralis gracilis muscle may be allowed to remain, in order to show its relations.) 

To constitute this enarthrodial articulation, the scapula is united to the 
humerus, and forms an obtuse angle which is open behind. 

Articular surfaces. — In the scapula there is the glenoid cavity — the shallow, 
oval fossa, elongated in an antero-posterior direction, notched inwardly, and 
excavated at its centre, or near the internal notch, by a small synovial f ossette. A 
ligamentous band, attached to the brim of the cavity, fills up this notch, and is 
the vestige of the glenoid ligament of Man. In the humerus, the articular head, 
fixed between the large and small tuberosities, is often excavated by a shallow 
synovial f ossette. 

Mode of union. — One capsular ligament (Fig. 128, 1), a kind of sac having two 
openings — one inferior, embracing the head of the humerus ; and a superior, inserted 
into the margin of the glenoid cavity. This capsule presents, in front, two sup- 
porting fasciculi, which diverge as they descend from the coracoid process to the 
great and small tuberosities. The aponeurotic expansion thus formed is very 
thin and loose, so as to allow the two bones to separate to the extent of from 
-f*Q to y^o of an inch ; but it is far from being sufficiently strong to bind them 
firmly together. The articulation is, therefore, strengthened by the powerful 
muscles which surround it, among which maybe noticed : 1. In front, the coraco- 
radialis (flexor brachii), separated from the fibrous capsule by an adipose cushion. 
2. Behind, the large extensor of the forearm and scapulo-humeralis gracilis (or 
teres minor) muscles, the use of which appears to be to pull up this capsule during 
the movements of flexion, so as to prevent its being pinched between the articular 
surfaces. 3. Outwards, the short abductor of the arm and the infra-spinatus (postea 
spinatus) tendon. 4. Inwards, the wide and strong tendon of the subscapularis 
muscle. In addition to this powerful retaining apparatus, there is the atmospheric 
pressure, the influence of which is of a certain importance. This may be proved 
by removing all the surrounding muscles, when it will be found that the capsule 
is not relaxed, nor are the articular surfaces separated ; to effect this, it is neces- 
sary to make an opening in the capsule, so as to allow the air to enter its cavity, 
when the surfaces immediately fall apart. 

Synovial capsule. — This is very loose, and entirely enveloped by the peripheral 
capsule, the internal surface of which it lines. 

Movements. — Like all the enarthrodial articulations, the scapulo-humeral 
permits extension, flexion, abduction, adduction, circumduction, and rotation. These 
various movements, however, are far from being so extensive as in Man, the arm 
in the domesticated animals not being detached from the trunk, but, on the 
contrary, is fixed with the shoulder against the lateral parietes of the thorax. 
Flexion and extension are the least limited, and the most frequently repeated 
movements ; their execution always demands a displacement of the two bones, 
wliich are almost equally movable. In flexion, the scapulo-humeral angle is 
closed, not only because the inferior extremity of the humerus is carried back- 
wards and upwards, but also because the scapula pivots on its superior attach- 



ARTICULATIONS OF TEE ANTERIOR LIMBS. 1S5 

merits in such a manner as to throw its glenoid angle forward and upward. 
Extension is produced by an inverse mechanism. During the execution of the 
other movements, the scapula remains fixed, and the humerus alone is displaced, 
bringing with it the inferior bones of the limb. If it is carried outwards, we 
have abduction, or inwards, adduction ; if the leg passes successively from flexion 
to abduction, and from that to extension, etc., in describing a circle by its lower 
extremity, then there is circumduction ; if it pivots from left to right, or right to 
left, we have rotation. 

In the Pig, Dog, and Cat, the synDvial membrane is not exactly enclosed by the fibrous 
capsule, but forms in front a cul-de-sac, which descends in the bicipital groove to favour the 
gliding of the coraco-radialis tendon. 

In Man, the scapulo-humeral articulation is disposed as in animals, but it is also protected 
above by the coraco-acromion arch. For the reasons noted above, this articulation allows of 
more extensive motion than in animals. As remarked by Cruveilhier, of all the joints in the 
human body, tlie scapulo-humeral is that which has the most extensive motion; in movements 
forward and outward, the humerus can become horizontal; in those of circumduction it 
describes a complete cone, which is more extensive in front and laterally than behind and 
inwardly. 

2. HuMERO-RADiAL, OE Elbow Aeticulation (Fig. 128). 

(^Preparation. — Turn down the inferior extremity of the flexors of the forearm, remove the 
•olecranian, epicondyloid, and epitrochlean muscles, taking care not to damage the ligaments 
to which they somewhat closely adhere.) 

Three bones concur to form this articulation, which presents a remarkable 
•example of an angular ginglymus : the humerus, by its inferior extremity, and 
the two bones of the arm by their upper extremities. 

Artkidar surfaces. — The humeral surface, already described at page 102, is 
transversely elongated, and convex from before to behind. It presents : 1. A 
median groove excavated by a synovial fossette. 2. An external groove (humeral 
trochlea) not so deep as the preceding. 3. A kind of voluminous condyle wliich 
borders, inwardly, the internal pulley, and whose antero-posterior diameter is 
much greater than that of the external lip of the trochlea of the opposite side. 
The antibrachial surface, divided into two portions, is moulded to the humeral 
surface ; it is, therefore, concave before and behind, and is composed : 1. Of a 
double external groove. 2. Of an internal glenoid cavity, both excavated, on the 
superior extremity of the radius. 3. A middle ridge for the middle groove of 
the humerus, separating the two preceding surfaces, and prolonged on the ulnar 
beak, where it forms the sigmoid notch. This ridge shows a small synovial 
fossette hollowed out on the radius and ulna. 

Mode of union. — Three ligaments : two lateral and an anterior. 

a. The external lateral ligament (Figs. 128, 8) is a thick, short, and strong 
funicle, attached above to the crest limiting outwardly and posteriorly the musculo- 
.spiral groove, and in the small cavity placed at the external side of the humeral 
articular surface. Below, it is inserted into the supero-external tuberosity of the 
radius. Its anterior border is confounded with the capsular ligament, and is 
margined by the principal extensor of the phalanges, which derives from it 
numerous points of attachment. By its posterior border it is in contact with 
the external flexor of the metacarpus. Its internal face is lined by synovial 
membrane, and its external face is only separated from the skin by the anti- 
brachial aponeurosis, and some of the fasciculi from the origin of the lateral 
extensor muscle of the phalanges. Its superficial fibres are vertical, and are 



196 



THE ARTICULATIONS. 



continuous, behind, with the arcif orm ligamentous bands which stretch from the 
ubia to the radius. Its deep fibres are shghtly obUque downwards and forwards. 
b. The lateral internal ligament — also funicular — is longer, but not so strong 

as the preceding. It arises from 
Fig. 128. the small tuberosity on the inner 

side of the superior articular face 
of the humerus, and, widening as 
it descends, reaches the radius. Its 
median fibres, which are the longest, 
are directed vertically downwards 
to reach the imprints situated below 
the bicipital tuberosity ; its anterior 
fibres, curved forwards, are united 
to the tendon of the coraco-radialis 
muscle, or are confounded ^^■ith the 
anterior ligament ; the posterior are 
turned backwards, near their in- 
ferior extremities, to join the arci- 
form fibrous fascicuU, which in- 
wardly unite the ulna to the radius. 
The middle fibres of this Ugament 
cover the inferior insertion of the 
short flexor of the forearm, and — in 
part only — that of the long flexor. 
It is covered by the ulna-plantar 
nerve and the posterior radial artery 
and vein. 

c. The anteiior or capsular liga- 
ment (Figs. 128, 9) is a membrani- 
form band, attached by its superior 
border above the humeral articular 
surface, and by its inferior to the 
anterior margin of the radial sur- 
face. By its lateral borders, it is 
confounded with the funicular Uga- 
ments. Its internal half is formed 
of vertical fibres which descend from 
the humerus and expand over the 
radius, where they become united 
with the inferior tendon of the 
coraco-radialis muscle. In its exter- 
nal moiety it is extremely thin, and 
composed of fibres crossed in various 
directions. Lined internally by 
synovial membrane, this ligament is 
in contact, by its external surface, 
with the anterior radial vessels and 
nerves, the two flexor muscles of 
the forearm, the anterior extensor of 
the metacarpus, and the anterior extensor of the phalanges. The two latter muscles 




6capul0-humeral and humero-radial articula- 
tions, with the muscles surrounding them 
(external face). 

1, Scapulo-humeral capsular ligament ; 2, short ab- 
ductor muscle of the arm ; 3, its insertion in the 
humerus; 4, insertion of the infra-spinatus muscle 
on the crest of the great tuberosity; 5, coraco-radialis 
muscle; tj, its tendon of origin ;ittached to the 
coracoid process; 7, its radial insertion confounded 
with the anterior ligament of the ulnar articula- 
tion ; 8, 8, external lateral ligament of that articu- 
lation ; 9, anterior ligament ; 10. aconeus, or small 
extensor of the forearm ; 11, origin of the external 
flexor muscle of the metacarpus; 12, short flexor 
muscle of the forearm. A, Tuberosity of the scapii- 
lar spine; B, supra-spinous fossa; C, infra-spinous 
fossa : D, convexity of the small trochanter ; E, 
summit of the ti-ochanter. 



ABTICDLATIONS OF THE ANTERIOR LIMBS. 197 

are even attached to it in a very evident manner. The elbow articulation, closed 
in front and on the sides by the tliree ligaments just described, has no particular 
ligaments posteriorly ; but it is powerfully strengthened there by the olecranian 
insertion of the extensor muscles of the forearm, and by the tendons of origin of 
the five flexor muscles of the metacarpus or phalanges. 

Synovial membrane. — This membrane is very extensive, and, stretched out 
on the internal face of the before-mentioned hgaments, forms, behind, three great 
culs-de-sac of prolongment : a superior, occupying the olecranian fossa, and 
covered by a fatty cushion, as well as by the small extensor muscle of the fore- 
arm ; ^ two lateral, which descend from each side of the ulnar beak, and are 
■distinguished as internal and external — the first lines the tendon of the external 
flexor of the metacarpus, the second facilitates the play on the upper radial 
extremity of the four flexor muscles of the foot or digits, and which are attached 
in common to the epitrochlea. This synovial sac also furnishes the radio-ulnar 
articulation with a diverticulum, which descends between the bones of the fore- 
arm to below the adjacent diarthrodial facets. 

Movements. — Flexion and extension. 

In flexion, the two bones do not approach each other directly, the inferior 
extremity of the radius deviating a little outwards. This is due more to the 
.sHght obliquity of the articular grooves, than to the difference in thickness 
between the external and internal extremities of the humeral surface. 

Extension is limited by the reception of the beak of the olecranon in its fossa, 
and by the tension of the lateral ligaments ; so that the two bones cannot be 
straightened on one another in a complete manner, or placed on the same line. 

In the Dog and Cat, tlie external lateral ligament is very thick, and forms in its inferior 
moiety a fibro-cartilaginous cap wliich is fixed on the ulna and radius, and united in front to 
the annular ligament of the superior radio-ulnar joint. This cap, with the last-named liga- 
ment, completes the osteo-fibrous ring in wliich the superior extremity of the radius turns. 
The internal lateral ligament is inserted, by two very short fasciculi, into the ulna and inner 
side of the head of tlie radius. A third fasciculus, deeper and median, much more developed 
than the first, and covered by the inferior insertion of the flexors of tlie forearm, descends 
between the radius and ulna to the posterior face of the former, and is there inserted near the 
inferior attachment of the external ligament, which it appears as if about to join. 

In Man, the elbow articulation is formed nearly on the same plan as that of the Dog and 
Cat. The radius and ulna move together when the forearm is flexed and extended on the 
humerus. 
• 

3. Radio-ulnar Articulation. 

Jirticular surfaces. — The two bones of the forearm articulate by diarthrodial 
'and synarthrodial surfaces. 

a. The diarthrodial surfaces consist of four undulated, transversely elongated 
facets, two of which are radial and two idnar. The first border, posteriorly, the 
great articular surface forming the elbow- joint ; the second are situated beneath 
the sigmoid notch. 

h. The synarthrodial surfaces are plane and roughened, and are also two on 
each bone : one, superior, extends below the diarthrodial facets to the radio-ulnar 
arch ; the other, inferior, more extensive, occupies all the anterior face of the 
ulna from this arch ; on the radius it forms a very elongated triangular imprint, 
which descends to the lower fourth of the bone (see pp. 104, 105). 

' Some grey elastic fibres which cover this cul-de-sac externally, have been wrongly 
described as a posterior membraniform ligament. 



198 THE ABTICV LATIONS. 

Mode of union. — Two interosseous and two peripheral ligaments. 

a. The interosseous ligaments, interposed between the synarthrodia! surfaces,, 
are composed of extremely short white fibres passing from one to the other 
surface, and which are endowed with a very remarkable power of resistance. The 
inferior always ossifies a long time before the animal is full grown — a circum- 
stance which caused the older veterinary anatomists to describe — and with some 
show of reason — the radius and ulna as a single bone. Ossification of the superior 
ligament is very rare. 

b. The peripheral bands are bundles of arciform fibres which, from the beak 
of the olecranon to the radio-ulnar arch, leave the lateral faces of the ulna to 
pass — some inwards, others outwards — to the posterior face of the radius. The 
fibres of the external ligament are confounded with the external humero-radial 
ligament. The internal fibres are united to the internal humero-radial ligament,. 
and to the small ulnar tendon belonging to the short flexor of the forearm. 
Analogous fibres are found beneath the radio-ulnar arch ; but they are much 
shorter and less apparent. (This is the external transverse radio-idnar ligament 
of Leyh.) 

Movements. — Very obscure in youth ; nearly null when the two bones are 
fused together. 

In the Ox, ossification of the superior interosseous ligament is constant at adult age. 

In the Dog anti Cat, we have already seen (p. 107) that the radius and uhia are not fused 
to each other, but remain independent during life. They are united in their middle portion 
by an interosseous ligament, and join by diarthrosis at their two extremities. These animals 
therefore exhibit; 1. An interosseous ligament. 2. A superior radio-ulnar articulation. 3. 
An inferior radio-ulnar articulation. 

Interosseous ligament. — It is composed of very resisting white fibres, attached by their 
extremities to the bodies of the bones. Notwithstanding their sliortneas, they are loose enough 
to allow movements taking place between the radio-ulnar articulations. 

Superior radio-ulnar articulation. — This is a trochoid articulation, which only allows 
movements of rotation or pivoting. 

The articular swr/'aees which form this articulation are: in the ulna, the small sigmoid 
cavity — a surface excavated in the lateral sense, and semicircular; in the radius, a cylindrical 
half-liinge received into the preceding cavity. 

To unite these there is an annular ligament — a kind of fibrous web thrown around the 
superior extremity of the radius, fixed inwardly on the ulna near the inner extremity of the 
small sigmoid cavity, attached outwardly to the external lateral ligament of the elbow^ 
articulation, and confounded superiorly with the anterior ligament of the same articulation. 
This fibrous web, in uniting with the fibro-cartilaginous cap of the external humero-radial 
ligament, and joining the small sigmoid cavity by its iiiternal extremity, transforms this last 
into a complete ring, covered with cartilage in its bony portion. The head or superior 
extremity of the radius is also encrusted, over its entire contour, with a layer of cartilage — a con- 
dition which pt-rmits it to glide not only in the concave face of the small sigmoid cavity, but 
also on the internal face of the two ligaments which complete this cavity. 

Inferior radio-ulnar articulation. — This is also a trochoid articulation analogous to the pre- 
ceding, but inversely disposed. Thus, the concave articular surface is hollosved on the radius, 
outside tlie inferior extremity; the convex surface lies within the ulna. These two facets are 
very small, and are maintained in ctmtact by a diminutive peripheral fibrous capsule. A 
strong interosseous ligament, situated beneath the articular facets, also consolidates this 
diatlirosis, and concurs by its inferior border to form the antibrachial surface of the radio-carpal 
articulation. A small synovial capsule is specially devoted to this articulation. 

Mechanism of the radio-ulnar joints. — The play of these two articulations is simultaneous,, 
and tends to the same end— that is, to the execution of the double rotatory movement which 
constitutes supination and pronation. 

Supination is when the ulna remains fixed, and the radius pivots on it in such a manner as 
to carry its anterior face outwards. Its superior extremity then turns from within forwards — 
and even from before outwartls if the movement is exaggerated, in the articular girdle formed 



ARTICULATIONS OF THE ANTERIOR LIMBS. 199 

by the small sigmoid cavity of the ulna and the ligaments which complete it. The inferior 
extremity also rolls on the ulnar facet in describing a similar movement, and the internal 
tuberosity of this extremity is carried forwards. 

In the movement of pronation, this tuberosity is brought inwards, and the anterior face of 
the radius comes forward by an opposite mechanism. 

The inferior bone of the anterior limb being articulated in a hinge-like manner with the 
radius, it follows this bone in its rotatory movements, the anterior face of the metacarpus 
looking outwards during supination and forwards in pronation. 

The radio-ulnar articulation in Man resembles that of the Dog and Cat, the articular 
surfaces only being larger and the movements more extensive. In supination, the palmar face 
is turned forward, and the radius, situated on the outer side of the ulna, is in the same direction 
as the latter. In pronation, on the contrary, the palmar face of the hand looks backwards, and 
the radius — remaining outwards in its upper part — crosses the ulna in front in such a manner 
that its lower extremity is placed witliiu the ulna. 

4. Articulations of the Carpus (Figs. 129, 130) 

Preparation. — After removing the tendons surrounding the carpus, the ligaments cbmmon 
to all the carpal articulations can be studied. The anterior and posterior membraniform 
ligament can tben be removed, and the ligaments proper to each row, as well as those uniting 
the two rows, and these to adjoining bones, can be dissected. Some time is required for this 
dissection, which is not difficult. 

These comprise : 1. The articulations uniting the carpal bones of the first 
row to each other. 2. The analogous articulations of the second row. 3. The 
radio-carpal articulation. 4. The articulation of the two rows with each other. 
5. The carpo-metacarpal articulation. 

Articulations which unite the Bones of the First Row to each 
other. — These bones, four in number, are joined by the diarthrodial facets on 
their lateral faces, and form small arthrodial articulations.^ They are maintained 
in contact by six ligaments, three anterior, and three interosseous. The anterior 
ligaments are small flattened bauds carried from the fourth bone to the first, 
from the first to the second, and from that to the third. The first, placed 
outside rather than in front of the carpus, is covered by the external lateral 
ligament and the inferior tendon of the external flexor of the metacarpus ; the 
others adhere to the capsular ligament. The interosseous ligaments are implanted 
in the grooves of insertion which separate the diarthrodial facets. One of them, 
derived from the common superior ligament, unites the first to the second bone. 
The two others, situated between the three last carpal bones, are confounded 
with the corresponding anterior ligaments. 

Articulations uniting the Carpal Bones of the Second Row. — 
These are arthrodial articulations, like the preceding, but numbering only two. 
They are fixed by two anterior and two interosseous ligaments. One of the 
anterior ligaments joins the first bone to the second, and strongly adheres to the 
capsular ligament ; the other is entirely covered by the lateral internal ligament, 
and attaches the two last bones to each other. Of the two interosseous ligaments, 
the second alone is confounded with the corresponding anterior ligament. That 
which is situated between the two first bones is separated from the anterior 
hgament by one of the diarthrodial facets between these bones. 

Radio-carpal Articulation. — The inferior extremity of the radius, in 
becoming united to the upper row of carpal bones, constitutes a diarthrosis 
which, from the nature of the movements it permits, may be considered as 
an imperfect hinge- joint. 

' The facet uniting the supercarpal to the first bone is not situated on one of its faces, but 
rather on the anterior part of its circumference. 



200 THE ARTICULATIONS. 

Articular surfaces. — The radial surface, elongated transversely and very 
irregular, presents : 1, Outwardly, a wide groove, limited in front by a small 
glenoid cavity, and bounded, posteriorly, by a non-articular excavation which 
receives a prolongation of the second bone in the movement of flexion ; 
2, Inwardly, a condyle with a more extensive curvature than that of the pre- 
ceding groove, and, like it, completed by a small anterior glenoid cavity. The 
carpal surface, moulded exactly on the radial, offers depressions corresponding 
to the projections on it, and rice verm. 

Mode of union. — The radio-carpal articulation is bound by three ligaments 
which entirely belong to it ; and by four stronsf ligaments that are common to 
it and articulations which will be studied hereafter. 

Of the three ligaments proper belonging to the radio-carpal articulation, 
one forms a thick, rounded funicle, extending from the radius to the fourth 
bone in an oblique direction downwards and inwards, and concealed by the 
common posterior ligament. The second (Fig. 130, 5), much smaller, is carried 
from the supercarpal bone to the external side of the inferior extremity of the 
radius, and is partly covered by the common external ligament. When the 
synovial capsule is distended by dropsy, it may form a hernia at the outer side 
of the carpus, by passing between this small ligament and the common posterior 
ligament. The third, very delicate, but always present, is deeply situated beneath 
the last ; it is inserted, for one part, into the radius near the first proper 
ligament, and for the other, into the second bone and the interosseous ligament 
which unites the supercarpal to that bone. 

tSi/norial membrane. — After lining these three ligaments, and the four great 
ligaments yet to be described, this membrane is prolonged between the three 
first carpal bones, to cover the superior face of the interosseous ligaments which 
unite them. It even more frequently descends into the articulation which joins 
the supercarpal to the first bone ; though it also sometimes happens that this 
has a particular synovial capsule of its own. 

Akticulation of the Two Rows between each other. — Like the pre- 
ceding, this is an imperfect hinge articulation. 

Articnlar surfaces. — These are two, and are both transversely elongated, very 
irregular in their configuration, and divided into three portions. The inferior 
shows : behind, three small condyles placed side by side ; in front, two slightly 
concave facets. The superior corresponds to the first by three glenoid cavities 
and two convex facets. 

3Io(le of anion. — For this articulation, besides the common great ligaments, 
there are three particular ligaments. Two of these are very short, and are 
situated behind the carpus, underneath the great common posterior ligament. 
They are readily perceived by removing the capsular ligament, and strongly 
flexing the carpus. " The strongest extends vertically from the internal bone of 
the superior row to the second and third bones of the metacarpal row ; the other 
descends obliquely from the first bone of the antibrachial row to the second 
of the inferior row " (Rigot). The third ligament proper, much stronger than 
the other two, reaches from the supercarpal to the first bone of the inferior row 
and the head of the external metacarpal bone. It is confounded, outwardly, 
with the great external lateral ligament ; inwardly, with the common posterior 
ligament. Its posterior border gives attachment to the fibrous arch which 
completes the carpal sheath. This ligament has also a branch which is fixed on 
the second bone of the upper row (Fig. 130, 4). 



ARTICULATIONS OF THE ANTERIOR LIMBS. 



201 



Fig. 129. 




Synovial membrane. — This lines all the ligaments, and is prolonged above 
and below, between the carpal bones, to facilitate the gliding of their articular 
facets. Two upper prolongations ascend between the three first bones of the 
antibrachial row, to cover the inferior face of the interosseous ligaments uniting 
them. Two other prolongations descend between the carpal bones of the second 
row ; the external, after covering the first interosseous ligament, passes between 
it and the corresponding anterior ligament, and communicates with the synovial 
capsule of the carpo-metacarpal articulation. The internal 
forms a cul-de-sac which rests on the interosseous ligament. 

Carpo-Metacarpal Articulation. — The carpal bones of 
the second row articulate with the superior extremity of the 
metacarpal bones, constituting a planiform diarthrosis. 

Articular surfaces. — These are, on each side, plane facets 
more or less inclined one on the other, and continued between 
each other. The largest is in the middle, and is generally 
hollowed by a small, shallow, synovial fossette. 

Mode of union. — There are the four great common liga- 
ments, and also six specicd ligaments .- two anterior, two posterior, 
and two interosseous. 

Of the two anterior ligaments (Fig. 129, 2, 2), one is divided 
into two distinct bands, and unites the second bone to the 
principal metacarpal ; the other, concealed by the external 
lateral ligament, attaches the first bone to the head of the ex- 
ternal metacarpal bone. 

The two posterior Hgaments described by Rigot do not 
appear to us to be suificiently distinct from the great ligament 
to merit a special description. 

The two interosseous ligaments, completely overlooked by 
that able anatomist, start from the interstices which separate 
the median metacarpal bone from the lateral metacarpals, and 
join the interosseous ligaments of the second row ; they are 
thick and short. We have sometimes noted one or other of 
them to be absent. 

Synovial membrane. — This communicates, as indicated above, with the 
synovial capsule of the preceding articulation. It furnishes a superior cul-de-sac, 
which rests on the interosseous ligament interposed between the two last cai-pal 
bones of the second row. Two inferior culs-de-sac descend into the inter- 
metacarpal arthrodial articulations. 

Ligaments common to the three preceding Articulations. — As before 
mentioned, these are four in number : two lateral, one anterior, and one 
posterior. 

a. The externcd lateral ligament (Figs. 129, 3 ; 130, 3) is a thick funicular cord 
composed of two orders of fibres — a deep-seated and a superficial order, slightly 
crossed. It leaves the external and inferior tuberosity of the radius, descends 
vertically to the side of the carpus, transmits a fasciculus to the first bone of the 
upper row, gives off another fasciculus which stops at the external bone of the 
second row, and terminates on the head of the corresponding metacarpal bone. 
Traversed obliquely by the lateral extensor of the phalanges, this ligament covers 
the external carpal bones. In front, it is united to the capsular ligament ; near 
its inferior extremity, it is confounded with the strong ligament which joins the 



carpal articula- 
tions (front 
view). 

1, 1, Anterior liga- 
ments uniting the 
carpal bones of 
each row ; 2, 2, an- 
terior ligaments 
proper to the 
carpo -metacarpal 
articulation ; 3. 
common external 
ligament ; 4, com- 
mon internal liga- 
ment. 



ao2 



THE ARTICULATIONS. 



Fig. 130. 




supercarpal bone to the first bone of the inferior row and to the head of the 
external metacarpal bone. 

b. The internal lateral ligament (Fig. 129, 4), analogous to the preceding 

and situated on the opposite side, is wider and thicker than it. It commences on 

the internal tuberosity of the radius, and terminates on the upper extremity of 

the middle and internal metacarpal bones, after being attached, by two distinct 

fasciculi, to the third carpal bone of the upper row, and 

the two last of the metacarpal row. In contact by its 

external face with the tendon of the oblique extensor muscle 

of the metacarpus, this ligament responds, by its deep face, 

to the synovial membranes of the carpus and to the bones 

to which it is attached. By its anterior border it is united 

to the capsular ligament ; the opposite border is intimately 

confounded with the posterior ligament, from wliich it is 

impossible to distinguish it. 

c. The anterior, or capsular ligament, is a membranous 
band covering the anterior face of the carpal articulations. 
Its superior border is attached to the radius ; the inferior 
is inserted into the superior extremity of the principal 
metacarpal bone. The two right and left borders are 
united with the lateral ligaments. Its external face is in 
contact with the tendons of the anterior extensor muscles 
of the metacarpus and phalanges. The internal face is 
lined at certain points by synovial membrane, and adheres 
in others to the carpal bones and the anterior ligaments 
binding these to one another. This ligament is composed 
of transverse fibres more or less oblique, and arranged cross- 
wise ; by its amplitude it can adapt itself to the movements 
of flexion of the knee. 

d. The posterior ligament, one of the strongest in the 
animal economy, covers the posterior face of the carpus, 
filling up the asperities which roughen it. It is inserted : 
above, on the transverse crest surmounting the articular 
surface of the radius ; by its middle portion into all the 
carpal bones ; below, into the head of the principal meta- 
carpal bone. Confounded inwardly with the internal 
lateral ligament, united outwardly to the band which at- 
taches the supercarpal to the external metacarpal and the second carpal bone of 
the upper row, this ligament is continued, by its inferior extremity, with the carpal 
stay (or check ligament) which sustains the perforans tendon. Its posterior face 
is perfectly smooth, and is covered by the synovial membrane of the carpal 
sheath. 

Movements of thf Carpal Articulations. — The carpus is the seat of 
two very extensive and opposite movements— flexion and extension; to wliich 
are added three very limited accessory movements — adduction, abduction, and 
circumduction. 

All the carpal articulations do not take an equal part in the execution of 
these movements ; for it is easy to discover that they are chiefly performed in the 
radio-carpal diarthrosis, and in the imperfect hinge articulation uniting the two 
rows of carpal bones. Each of these articulations participates in the movements 



LATERAL VIEW OF THE 
CARPAL ARTICOLATIONS. 

1, 1, Anterior ligaments 
uniting the two rows 
of carpal bones; 2, 2, 
anterior ligaments pro- 
per to the carpo-meta- 
carpal articulation ; 3, 
common external liga- 
ment; 4, one of the 
ligaments proper to the 
articulation of the two 
rows (metacarpo-supra- 
carpal) ; 5, one of the 
ligaments proper to 
the radio-carpal articu- 
lation (radio-supercar- 
pal). A, Groove on the 
external surface of the 
supercarpal bone, for 
the passage of the ex- 
ternal flexor of the 
metacarpus. 



ARTICULATIONS OF THE ANTERIOR LIMBS. 203 

of the carpus in nearly the same proportions, and both act in an identical manner. 
Their mechanism is most simple. 

In flexmi, the first tier of bones rolls backwards on the radius, the inferior 
row moves in the same sense on the upper, the metacarpus is carried backwards 
and upwards, the common posterior ligament is relaxed, the capsular ligament 
becomes tense, and the articular surfaces, particularly those of the second joint, 
separate from each other in front. In extensmi, the metacarpus is carried down- 
wards and forwards by an inverse mechanism. This movement stops when the 
ray of the forearm and that of the metacarpus are in the same vertical line. In 
flexion, these bones never directly approach each other, the inferior extremity of 
the metacarpus being always carried outwards. It may also be remarked, that 
the slight movements of abduction, adduction, and circumduction of the carpus are 
only possible at the moment when the foot is flexed on the forearm. 

With regard to the planiform diarthroses articulating the carpal bones of the 
same row, they only allow a simple gliding between the surfaces in contact ; and 
with the carpo-metacarpal arthrodia it is absolutely the same. The restricted 
mobility of these various articulations has but a very secondary influence on the 
general movements of the carpus ; but it nevertheless favours them by permitting 
the carpal bones to change their reciprocal relations, and adapt themselves, during 
the play of the radio-carpal and intercarpal hinges, to a more exact coaptation of 
the articular planes which they form. 

In the other animals, the carpal articulations have the same essential characteristics we 
have noticed in Solipeds. The four principal peripheral bands differ but little in them; 
though in the Dog and Cat they are lax enough to allow somewhat extensive lateral 
movements. 

5. Intermetacarpal Articulations. 

Each lateral metacarpal bone articulates with the middle one, by means of 
diarthrodial and synarthrodial surfaces, for the description of which refer to page 
112. An interosseous ligament, composed of very short and strong fasciculi, is 
interposed between the synarthrodial surfaces, and binds them firmly together. 
Its ossification is not rare. The diarthrodial facets are maintained in contact by 
the preceding ligament, and by the carpal ligaments inserted into the head of the 
lateral metacarpal bones. The intermetacarpal articulations only allow a very 
obscure, vertical, gliding movement. 

In the Ox, there is only one intermetacarpal articulation, which is much simpler than 
those in the Horse. 

In the Pig, the four metacarpal bones correspond, at tlieir upper extremity, by means of 
small diarthrodial facets on their sides. Fibrous fasciculi, derived from the great anterior and 
posterior ligaments of the carpus, protect these intermetacarpal articulations before and 
behind. Other fibres, situated between the adjacent faces of the metacarpal bones, are real 
interosseous ligaments. 

In the Dog and Cat, the four great metacarpal bones articulate with each other in 
almost the same manner as in the Pig, but their mobility is greater 

6. Metacarpo-phalangeal Articulation (Figs. 131, 132). 

Preparation.— In order to study the whole of this articulation, it is well to have an anterior 
limb from the lower fourth of the forearm. From this the tendons of the flexors and extensors 
of the phalanges are to be removed, and then the suspensory ligament of the fetlock, anterior 
capsular ligament, lateral ligaments, and the superficial inferior sesamoid ligament, can be 
dissected. To study the ligaments which bind the bones forming the inferior articular 
surface, the first phalanx and sesamoid bones should be removed, which allows of the dissection 



2M 



THE ARTICULATIONS. 



of the inter-, lateral, and inferior sesamoid middle and deep ligaments. An injection of the 
eynovinl capsule brings into relief some features which are interesting, from a surgical point 
of view. 

This is a perfect hinge-joint, formed by the inferior extremity of the median 
metacarpal bone on the one part, and the superior extremity of the upper phalanx 
and sesamoids on the other. 

Articular surfaces. — For the metacarpal bone, there are two lateral condyles 
and a median antero-posterior eminence ; for the first phalanx, two glenoid 
cavities and an intermediate groove prolonged posteriorly on the anterior face of 
the two sesamoids. Divided in this manner into three portions, the digital 
surface is well constituted for solidity, because the pressure transmitted to this 

region is diminished and. 

Fig. 131. diffused by the natural 

-*- ^ elasticity of the bands 

which unite these three 
pieces to each other. 

3Iode of union. — The 
means of union may be 
divided into two cate- 
gories : 1. Those which 
join together the several 
bones of the inferior sur- 
face. 2. Those which 
maintain in contact the 
two opposed articular 
surfaces. 

A. The firet have re- 
ceived the generic name 
of sesamoid ligaments, 
and are six in number : 
an intersesamoid ligament y 
which holds together the 
two complementary bones 
of the digital surface ; 
three inferior and two 
lateral sesamoid ligaments, 
which unite these bones 
to the first phalanx. 
a. The intersesamoid ligament is composed of fibro-cartilaginous substance, 
that appears to be the matrix in which the two sesamoids were developed ; as it 
is spread around these bones, after being solidly fixed on their internal face. 
Behind, this ligament, in common with the posterior face of the sesamoids, forms 
the channel (Fig. 131, 5) in which the flexor tendons glide. In front, it occupies 
the bottom of the intersesamoid articular groove. 

h. The inferior sesamoid ligaments, situated at the posterior face of the first 
phalanx, are distinguished as superficial, middle, and deep. 

The superficial ligament (Figs. 131, 14 ; 134, 8), the longest of the three, is a 
narrow band flattened before and behind. It arises from the middle of the 
fibro-cartilaginous mass which completes, posteriorly, the superior articular surface 
of the second phalanx, and, shghtly widening, ascends to the base of the sesamoids. 




DETAILS OF THE METACARPO-PHAI.ANGEAL ARTICULATION OF 
THE HORSE. 



A. Middle inferior sesamoidean 
ligaments. P. First phalanx 
(posterior face). 1, Inter 
sesamoidean ligament (pos- 
terior fnce); 2, 2, lateral 
sesamoidean ligaments ; 3, 
middle inferior sesamoidean 
ligament. 



B. Deep inferior sesamoidean 
ligaments. P. First phalanx : 
1, Inter-sesamoidean liga- 
ment ; 2, 2, lateral sesa- 
moidean ligaments; 3, in- 
ferior deep sesamoidean liga- 
ment. 



ARTICULATIONS OF THE ANTERIOR LIMBS. 

Fie;. 1 
into which it is inserted by becoming 
confounded with the intersesamoid liga- 
ments. Its posterior face, lined by the 
synovial membrane of the so-called sesa- 
moid sheath, is covered by the flexor 
tendons ; it partly covers the middle 
ligament. 

The middle ligament, triangular and 
radiating, is composed of three particular 
fasciculi : two lateral (seen on each side 
of the superficial ligament in Fig. 131, 
A 8), and a median which has been 
generally confounded with the superficial 
ligament, although it is clearly distin- 
guished from it by its inferior insertion. 
Fixed in common to the posterior imprints 
of the first phalanx, these three fasciculi 
diverge in ascending to the base of the 
sesamoids, where they have their upper 
insertion. 

The deep ligament is constituted by 
two small bands concealed beneath the 
middle ligament. Thin, short, flattened 
before and behind, and intercrossed (Fig. 
131, B 3), these bands are fixed to the 
base of the sesamoids in one direction, 
and in the other to the superior extremity 
of the first phalanx, near the margin of 
its articular surface. This ligament is 
covered on its anterior face by the synovial 
membrane of the articulation. 

CARPAL, METACARPAL, AND INTER-PHALANGEAL 

ARTICULATIONS OF THE HORSE (POSTERO- 
LATERAL view). 
R, Radius ; c, carpus ; M, metacarpus ; s, navicular 

bone ; P, third phalanx. 1, Supercarpal bone ; 

2, its proper ligament ; 3, external lateral liga- 
ment of the carpal articulations (superficial 

layei'); 3, ditto (deep layer); 4, groove for the 

tendon of the external Hexor of the metacarpus; 

5, common posterior ligament of the carpal 

articulations; 6, superior sesamoidean, or sus- 
pensory ligament of the fetlock ; 7, an originating 

branch of ditto ; 8, 8, terminal branches of ditto ; 

9, band given off by ditto to the anterior extensor 

of the phalanges ; 10, tendon of the anterior 

extensor of the phalanges ; 11, groove formed by 

the posterior face of the intersesamoidean liga- 
ment; 12, lateral metacarpo-phalangeal ligament 

(superticial layer); 12', ditto (deep layer) ; 14, 

inferior superficial sesamoidean ligament ; 15, 

ditto (deep layer); 16. elenoidal fibro-cartilage of 

the second phalanx ; 17. 18, 19, superior, middle, 

and inferior bands of that fibro-cartilage ; 20, 

lateral ligament of the first inter-phalangeal 

articulation; 21. lateral posterior ligament of 

the second inter-phalanceal ai'ticulation ; 22, 

anterior lateral ligament of ditto. 
16 



20» 




206 THE ARTICULATIONS. 

e. The lateral sesamoid ligaments are two thin layers, extending from the 
external face of each sesamoid to the tubercle of insertion on the side of the 
superior extremity of the first phalanx (Fig. 131, a 2). They are covered by the 
digital vessels and nerves, by the fibrous stay detached from the suspensory liga- 
ment to the anterior extensor tendon of the phalanges, and by the supei-ficial 
fasciculus of the lateral metacarpo- phalangeal ligament ; they are covered by 
synovial membrane on their internal face. 

B. The ligaments destined to unite the two articular surfaces of the meta- 
cai-po-phalangeal joint are four : tivo lateral, one anterior, and one posterior . 

a. Each lateral ligament comprises two fasciculi — a supei-ficial and a deep — 
firmly united by their adjacent faces. The superficial fasciculus (Fig. 132, 12) 
commences on the button of the lateral metacarpal bone, attaches itself to the 
median metacai-pal, and descends vertically to terminate at the superior extremity 
of the first phalanx. It covers the phalangeal insertion of the lateral sesamoid 
ligament and the deep fasciculus. The latter, attached superiorly in the lateral 
excavation of the inferior extremity of the principal metacarpal, radiates as it 
reaches the sesamoid and the superior extremity of the first phalanx, where it is 
fixed by mixing its fibres with those of the lateral sesamoid ligament. The inner 
face of this fasciculus is lined by the articular synovial membrane (Fig. 132, 12'). 

I. The anterior ligament (Fig. 132) belongs to the class of capsular ligaments. 
It is a veiy resisting membraniform expansion, which envelops the anterior face 
of the articulation. Attached by its upper border to the anterior margin of the 
metacarpal surface, and by its inferior border to the first phalanx, this expansion 
is confounded at its sides with the lateral ligaments. It is covered by the extensor 
tendons of the phalanges, which glide on its surface by means of small serous 
sacs. Its internal face adheres throughout its whole extent to the synovial 
capsule. 

c. The posterior ligament,^ very appropriately named the suspensory ligament 
of the fetloch (Figs. 132, 6 ; 133, 134, 4), is a long and powerful brace, composed 
of white fibrous tissue, and often containing fasciculi of fleshy fibres in its textm-e. 
Lodged behind the median metacai-pal, and between the two lateral metacarpal 
bones, this brace is quite thin at its origin, but it soon becomes enlarged, and pre- 
serves its great thickness to the extent of its upper fourth. Examined in section, 
it appears to be formed of two superposed portions which are closely adherent to 
each other. The superficial portion, the thinnest, commences by three small 
branches, which are fixed to the first and second bones of the lower carpal row 
(Figs. 132, 133, 5) ; the deep portion, much thicker, is attached to the posterior 
face of the principal metacai"pal for about ^ of an inch. It has been 
wrongly asserted that the suspensoiy ligament of the fetlock is continuous with 
the common posterior ligament of the cai-pus ; it is, on the contrary, quite distinct 
from it. The carpal stay {deep palmar aponeurosis of Man) is alone in direct 
continuity mth the common posterior ligament of the cai'pus (133, 3). The 
suspensory ligament of the fetlock is bifid at its inferior extremity ; its two 
branches, after being fixed into the summits of the sesamoid bones, give origin to 
two fibrous bands which pass downwards and forwards to become united on each 
side to the anterior extensor tendon of the phalanges (Fig. 132, 9). It is in relation, 
by its posterior face, Avith the perforans tendon and its carpal stay ; by its anterior 
face, with the median metacarpal bone, and arteries and veins ; by its borders, 

' It coiresponds to the two muscles which, in Mun, lie alongside the interosseous meta- 
carpal muscles. (See Muscles of the Foot.) 



ARTICULATIONS OF THE ANTERIOR LIMBS. 



207 




with two small interosseous muscles, the lateral metacarpal bones, and the digital 
vessels and nerves. 

Synovial membrane. — Tliis membrane is prolonged as a cul-de-sac between the 
terminal branches of the preceding ligament. It is the distension of this sac 
which causes the articular swellings vulgarly designated 
" windgalls." Fig. 133. 

Movements. — The metacarpo-phalangeal articulation 
permits the extension and flexion of the digit, and some 
slight lateral motion when the movable osseous segment 
is carried to the limits of flexion. 

In the Ox, Sheep, and G-oat, this articulation constitutes a 
dotible hinge, which resembles the simple ginglymus of Solipeds. 

They have three intersesamoid ligaments : two lateral, to unite 
the large sesamoids of each digit ; and a median, which unites 
the interual sesamoids. The inferior sesamoidean ligamentous 
apparatus is far from showing the same degree of development 
as in the Horse. It is reduced for each digit to four small bands, 
which remind one very much of the deep ligament of the latter 
animal, as it has been described by Rigot : two lateral bands pass 
directly from the sesamoids to the upper extremity of the first 
phalanx ; the other two, situated between the first, intercross 
and are confounded with the latter by their extremities. A lateral 
tesamoid ligament unites the first phalanx to the exterual sesamoid. 

For each digit there are two lateral metacarpo-phalangeal 
ligaments— a,n external, analogous to that of the Horse, but less 
complicated, is attached by its inferior extremity to the first 
phalanx only ; the other, internal, fixed superiorly in the bottom 
of the inter-articular notch of the metacarpal bone, is inserted 
into the inner face of the first phalanx in mixing its fibres with 
those of the superior interdigital ligament. This latter is situated 
between the two first phalanges, and is composed of short, inter- 
crossed fibres, attached to the imprints which in part cover the 
internal face of the two first phalangeal bones. In the Sheep 
there are only traces of this interdigital ligament, and each internal 
metacarpal-phalangeal gives rise, near its phalangeal insertion, to 
a fibrous branch which is directed backwards from the interdigital 
Bpace, and is terminated in the bone of the ergot (or posterior 
rudimentary digit), which it sustains. The anterior or capsular 
ligament, single as in Solipeds, unites the two external lateralliga- 
ments. The suspensory ligament, single superiorly, is divided inferiorly into eight branches, two 
of which are joined to the periuratus tendon, to form with it the double ring through which the 
two branches of the perforans pass. Four other branches, in pairs, extend to the summits of 
the sesamoids. That which is sent to each external sesamoid gives off, on the side of the first 
phalanx, a reinforcing band to the proper extensor of the digit. The two last, profound and 
median, descend into the inter-articular notch of the metacarpal bone, after becoming a single 
fasciculus ; afterwards, they pass between two internal metacarpo-phalangt-al ligaments, and 
separate from each other in passing downwards and forwards on the inner side of the first 
phalanx, to join the proper extensor tendon of each digit. 

In the Pig, Dog, and Cat, for each metacarpo-phalangeal there is: a proper synovial 
membrane; an intersesamoid ligament; an inferior sesamoid ligament composed of two cross- 
bands; two small lateral sesamoid ligaments; two lateral metacarpo-phalangeal ligaments, 
attached inferiorly to the first phalanx and the sesamoids ; an anterior capsular ligament, in 
the centre of which is found a small bony nucleus — a kind of anterior sesamoid— over which 
glides one of the branches of the common extensor of the digits. The suspensory ligament is 
replaced by real palmar interosseous muscles (see the Muscles of the Anterior Foot). Some 
fibres situated between the first phalanges in the great digits of the Pig, resemble the superior 
interdigital ligament of the Ox. 

In Man, the cavity in the upper extremity of the first phalanx is completed by a glenoid 



SECTION OF THE INFERIOR 
ROW OF CARPAL BONES, 
THE METACARPAL, AND 
THE SUSPENSORY LIGA- 
MENT OF THE FETLOCK. 

1, Os magnum ; 2, common 
posterior ligament of the 
carpus ; 3, stay, or band 
for tlie perforans tendon , 
4, suspensory ligament of 
the fetlock ; 5, its super- 
ficial layer ; 6, its deep 
fasciculus ; 7, principal 
metacarpal bone. 



TEE ARTICULATIONS. 



ligament. The prenoid ligaments of the four first digits are united to each other by a trans- 
verse ligament of the metacarpus. The articulations are cousolidated by two lateral ligaments. 

The metaciirpo-plialaiigeal articulations allow flexion and ex- 
Fig. 134. tension movements, as well as those of abduction and adduction; 

but the latter are limited by the lateral ligaments. 



M 



rosterior view of the 
metacarpo-phalangeal 
and inter-phalangeal 
articulations (right 
limb). 

1, 3, Outer and inner 
rudimentary metatarsal 
bones ; 2, perforans tea- 
don and its check liga- 
ment ; 4, suspensory liga- 
ment ; 5, gliding surface 
or sheath for the flexor 
tendons, f'rmed by the 
posterior face of the sesa- 
moid bones, and interse- 
samoid. transverse, and 
annular ligaments; 6, 
section of lateral sesamoid 
ligament ; 7, lateral fasci- 
culus of the middle infer 
lateral ligament of the fir 
of the perforatus tendon; 
surface of navicular bone; 
14, perforatus tendon, 15, 



7. Abticulation of the Fibst with the Second 
Phalanx, or First Interphalangeal Articulation. 

(Preparation. — Kemove the extensor tendon ; throw open the 
metaearpo-pnalangeal sheath, and turn down the flexor tendons.) 

This is an imperfect hinge-joint. 

Articular surfaces. — On the inferior extremity of the 
first phalanx are two lateral condyles, separated by a 
groove. On the superior surface of the second phalanx 
are two glenoid cavities, and an antero-posterior ridge. 

The latter surface is completed behind by a glenoidal 
fihro-cartilage, very dense and thick (Fig. 132, 16), which 
also acts as a ligament. It is attached, in one direction, 
to the second phalanx, between the superior articular 
surface and the kind of fixed sesamoid which margins it 
behind ; in the other, it is inserted into the first phalanx 
by means of six fibrous bands (Fig. 135, 4, 5, 6) : two 
superior, which embrace the inferior, middle, and super- 
ficial sesamoid ligaments ; two middle, and two inferior, 
which extend to the sides of the inferior extremity of 
the first phalanx. This fibro-cartilage is moulded, in 
front, to the articular surface of the latter bone, and 
forms, by its posterior face, a gliding surface for the 
perforans tendon (Figs. 132, 16 ; 134, 5). It is con- 
founded, laterally, with the two branches of the per- 
foratus, and receives, in the middle of its superior border, 
the insertion of the inferior superficial sesamoid liga- 
ment. 

Mode of union. — Two lateral ligaments (Fig. 135, 
7), to which are added, behind, the fibro-cartilage just 
described, and in front the tendon of the anterior extensor 
of the phalanges. These ligaments are large and thick, 
and, passing obliquely downwards and backwards, are 
inserted, superiorly, into the lateral tubercles of the 
inferior extremity of the first phalanx. They are at- 
tached, beneath, to the sides of the second phalanx. 
Their most inferior fibres are even prolonged below that 
point to reach the extremities of the navicular bone, and 
constitute the posterior lateral ligaments of the pedal 
articulation. 

Synovicd membrane. — This covers the tendon of the 

•ior sesamoid ligament; 8, inferior superficial sesamoid ligament ; 9, 
st interphalangeal articulation ; 10, section of the terminal branch 

11, section of the lateral cartilage of the foot; 12, postero-inferior 
13, section of lateral cartilage, plantar cushion, and wing of pedal bone; 

perforans tendon. 



ARTICULATIONS OF THE ANTERIOR LIMBS. 209 

anterior extensor of the phalanges, the lateral ligaments, and the glenoid fibro- 
cartilage. Behind, it forms a cul-de-sac, which extends between the latter and the 
posterior face of the first phalanx (Fig. 137). 

Movements. — This imperfect hinge is the seat of two principal movements : 
extension and flexion. It also allows the second phalanx to pivot on the first, and 
permits some lateral movements. 

In the Ox, Sheep, and Goat, the glenoid fibro-cartilage is confounded with the perforatus 
tendon, and is only attached to the first pliahmx by two lateral bands. The internal lateral 
ligament comprises two fasciculi : one, very short, which terminates in the st-coml phalanx ; 
and another, very long, descending to the internal face of the third phalanx. The external is 
very thin, and is also prolonged to the terminal phalanx ; so that the two last inteiphalangeal 
articuhitions of each digit are fixed by two common lateral li'j;aments which correspond exactly, 
by their position and inferior attachments, to the anterior lateral ligaments of the pedal joint 
of Solipeds. 

In the Dog and Cat, the glenoid cartilage, also confounded by its posterior face with the 
perforatus tendon, only adheres to the first phalanx by some cellular bands. The two lateral 
ligaments pass from the inferior extremity of the first phalanx to the superior extremity of the 
second. 

In the Pig, there is somewhat the same arrangement as in Carnivora. The external 
lateral ligament is, nevertheless, more like that of the Horse, in its most anterior fasciculi being 
prolonged lo the external extremity of the navicular bone. 

8. Aeticulation of the Second Phalanx with the Third, Second 
Interphalangeal Articulation, or Articulation op the Foot. 

Preparation. — Eemove the hoof according to the directions given hereafter, when treating of 
the muscles of the forearm ; then the plantar cushion, the flexor tendons, and one of the lateral 
cartilages. A section like that shown in Fig. 137 is useful to show the relations between the % 
synovial capsule of this joint and the bursae, behind the second phalanx. 

To form this imperfect hinge-joint, the second phalanx is opposed to the tliird, 
and to the navicular bone. 

Articular surfaces. — On the inferior face of the second phalanx there are two 
lateral condyles and a median groove. On the superior face of the third phalanx 
and the navicular bone, are two glenoid cavities separated by an antero-posterior 
ridge. The two bones which form tliis last surface, articulate with each other by 
arthrodia ; the navicular bone presents for tliis purpose an elongated facet on its 
anterior border ; the os pedis also offers an analogous facet on the posterior contour 
of the principal articular surface. 

Mode of union. — Five ligaments : a single interosseous one, which joins the 
navicular to the pedal bone ; and four lateral bones, distinguished as anterior and 
posterior. 

a. Interosseous ligament (Fig. 136, 2). — This is formed of very short fibres, 
which are inserted, behind, into the anterior groove of the navicular bone ; and 
in front, into the posterior border and inferior face of the third phalanx. This 
ligament is lined, on its superior surface, by the synovial membrane, and on its 
inferior face is covered by the navicular sheath. 

h. Anterior lateral ligaments (Figs. 132, 22 ; 135, 9).— These are two thick, 
short, and wide fasciculi, attached by their superior extremities to the lateral 
imprints of the second phalanx, and by their inferior extremities into the two 
cavities at the base of the pyramidal eminence of the os pedis. Each ligament is 
partly covered by the complementary fibro-cartilage of that bone, and appears to 
form a portion of it. Its anterior border is continuous with the common extensor 



210 



TEE ARTICULATIONS. 



tendon of the phalanges ; its internal face is covered by the synovial membrane, 
which adheres closely to it. 

c. Posterior lateral ligaments (Figs. 132, 21 ; 135, 8). — These have been 
already noticed. Each is composed of the lowermost fibres of the lateral ligament 
of the first interphalangeal articulation ; these fibres, after being attached to the 
?econd phalanx, unite into a sensibly elastic fibrous cord, which is chiefly fixed 



Fig. 1^5. 





M E r ATARSO - PHALANGEAL 
AND INTER-PHALANGEAL 
ARTICULATIONS OF THE 
HORSE. 

These are almost the same 
as in the anterior limb. 
1, Superficial layer of the 
external lateral ligament 
of the metatarso-phalan- 
geal articulation ; 2, sesa- 
moid branch of the deep 
layer; 3, phalangeal branch 
of the same ; 4, superior 
branch of the glenoidal 
fibro-cartilage; 5, middle 
branch of ditto; 6, inferior 
branch of ditto ; 7, lateral 
ligament of the first inter- 
phalangeal articulation ; 8, 
posterior lateral ligament 
of the pedal articulation ; 
9, anteiior lateral ligament 
of ditto. 



ARTICULATION OF THE FOOT (INFERIOR FACE). 

P, Inferior face of the third phalanx. S, Infe- 
rior face of the navicular bone. 1, Semilu- 
nar crest ; 2, interosseous ligament. 



into the extremity and superior border of the navicular 
bone, where the Ugaments join each other, and in this 
way form a kind of complementary cushion that in- 
creases the navicular articular surface. It also sends 
off a short fasciculus to the retrossal process, and a 
small band to the internal face of the lateral fibro- 
cartilage. Partly concealed by the latter and the plantar 
cushion, this ligament is covered inwardly by the articu- 
lar synovial membrane. 

Synovial memlrane. — This descends below the facets 
which unite the navicular to the pedal bone. It offers, 
posteriorly, a vast cul-de-sac which reaches the posterior 
face of the second phalanx, and hes against the two 
sesamoidean bursse (Fig. 137, 13). It also forms another 
much smaller, by being prolonged between the two lateral 
ligaments of the same side. This is very often distended, 
and it is liable to be opened in the operation for diseased lateral cartilages. 
Movements. — The same as those of the first interphalangeal articulation. 

In the Sheep are found : 1. An interosseous ligament to unite the navicular bone to the 
third phalanx. 2. Two anterior lateral ligaments commencing:, as already stated, at the first 
phalanx. 3. Two lateral posterior ligaments, passina: to the posterior face of the second phalanx 
and the navicular bone (the internal is yellow and elastic). 4. A single, anterior, elastic liga- 
ment, attached above to the superior extremity of the second phalanx, and fixed below into the 
third, between the insertion of the common extensor of the digits and that of the internal 
anterior lateral ligament; an inferior interdigital ligament, situated between the ungueal 
phalanges, whose separation from each other it limits This ligament is compose<l of parallel 
fibres, whicii extend transversely from the one navicular bone to the other, and is covered on 



ARTICULATIONS OF THE ANTERIOR LIMBS. 



211 



its inferior face by the skin of the interdigital Bpace. Its upper face is in contact with an 
adipose cushion. 

In the Ox, the external anterior lateral ligament, wide and expanding, is almost entirely 
covered by the long branch of the proper extensor of the digit, to which it is intimately 
adherent. The interdigital ligament has a much more complicated character than that of the 
Sheep. It is formed of fibres intercrossed on the median line, and divided at its extremities 
into two fasciculi : a superior passes over the perforans tendon, to which it serves as a restrain- 
ing band, and is fixed to the outside of the inferior extremity of the first phalanx, after con- 
tracting very close adhesions with a strong fibrous web which descends from the posterior 
metacarpal region, and which will be more fully noticed when describing the muscles; an 
inferior, shorter than the preceding, attached to the internal extremity of the navicular bone 
and the internal face of the third phalanx, becoming confounded with the perforans tendon, 
the plantar cushion, and the dermis of the keratogenous membrane. 



Fig. 138. 



Fig. 137. 




JffJO i 

LONGITTIDrNAL AND VERTICAL SECTION OF THE 
DIGITAL REGION IN THE HORSE, SHOWING THE 
ARRANGEMENT OF THE ARTICULAR AND TENDI- 
NOUS SYNOVIAL APPARATUS. 

1, First phalanx ; 2, second phalanx ; 3, third pha- 
lanx ; 4, semilunar sinus of ditto ; 5, navicular 
bone ; 6, tendon of the anterior extensor of the 
phalanges ; 7, its insertion into third phalanx ; 8, 
tendon of the perforatus ; 9, ditto perforans ; 10, 
its insertion into the third phalanx; 11, inferior 
sesamoid ligaments ; 12, posterior ctd-de-sac of 
the first synovial interphalangeal capsule; 13, 
ditto of second ; 14, infeiior cul-de-sac of the 
sesamoid bursa; 15, superior ditto of navicular 
bursa ; 16, inferior ditto of same ; 17, station of 
the coronary cushion; 18, ditto of plantar 
cushion. 




TENDONS AND LIGAMENTS OF 
THE POSTERIOR FACE OF 
THE DIGITAL REGION OF 
THE OX. 

1, Perforatus tendon ; 2, 2, 
its terminal tendons ; 3, 

3, theii- bifurcation ; 4, 

4, perforans tendon ; 6, 6, 
superior branches of the 
inferior interdigital liga- 
ment attached to the first 
phalanx ; 7, inferior inter- 
digital ligament ; 8, 8, 
suspensory ligament of 
the fetlock. 



In the Pig, for the maintenance of the second interphalangeal articulation, there are: 
1. Two lateral ligaments, carried from the lateral faces of the second phalanx to the external 
and internal faces of the third. 2. A third ligament, exactly resembling one of the posterior 
lateral ligaments of the pedal articulation of the Horse; this ligament descends from the 
inferior extremity of the first phalanx to the internal extremity of the navicular bone. Its 
analogue of the inner side appears to be altogether absent ; but in the large digits there is an 
anterior yellow elastic ligament like that of Ruminants. 

In the Dog, the two last phalanges are united by two lateral ligaments, very simply 
arranged. A third ligament, formed of elastic tissue, divided into two lateral portions, and 
situated in front of the articulation, plays the part of a spring, which mechanically produces 
the retraction of the claw when the flexor muscles cease to contract. In the Cat, this yellow 
ligament is very strong; and this animal also exhibits a very striking obliquity of the articular 



212 TEE ARTICULATIONS. 

pulleys by which the two phalanges correspond : an arrangement that permits the claw to be 
lodo'ed between two digits wlien they are raised, and tlius favour its retraction. 

Tlie second iuteiphalangeal articulation of the Dog and Cat is also distinguished by another 
essential arrangement. The articular surface of the third phalanx is completed by a glenoid 
fibrocartiiage analogous to that of the first articulation, but much thicker. This fibro-cartilage 
(see Muscles of the Hand) is fixed into the posterior projection of the third phalanx, and 
serves, by its inferior face, as a pulley for the perforaus tendon and, with the projection just 
named, plays the part of the navicular bone in other animals. 

The interphalangeal articulations of Man are formed on the same plan as the metacarpo- 
phalangeal articulations They are consolidated by a glenoid and lateral ligaments, and 
possess only the two movements oi flexion and extension. 

Article V. — Articulations of the Posterior Limbs. 
1. Articulations of the Pelvis. 

{Preparation.— These ligaments are all exposed to view by carefully removing the soft parts 
connected with the sacrum and coxae.) 

A. Sacro-iliac Articulation (Figs. 139, 140).— This is a pair articulation 
which establishes the union of the posterior limb with the spine, and is formed 
by the sacrum and coxa. It belongs to the arthi'odial class. 

Articular surfaces. — On the sacrum, the irregular diarthrodial facet named 
the " auricular," cut on the sides and near the base of the bone. For the coxa, 
the analogous facet on the internal face of the ilium. 

3fode of union. — By four ligaments, which, after the example of Rigot, we 
will name sacro-iliac, superior ilio-sacral, inferior ilio-sacral, and the sacro-sciatic. 
The first is situated immediately around the articular surfaces, and the others are 
only in mediate relations with them. 

a. Sacro-iliac ligament (Fig. 140, 1). — This is composed of thick fibrous 
fasciculi, which envelop the whole articulation in being firmly attached by their 
extremities, to the imprints around the diarthrodial facets. The inferior moiety 
of this ligament is covered by the iliacus muscle. Its posterior half ^ is much 
stronger, is hidden by the ilium, and gives attachment to the longissimus dorsi 
muscle. 

h. Superior ilio-sacral ligament (Fig. 139, 13). — A thick and short funicle, 
which, rising from the internal angle of the ilium, is carried backwards to be 
fixed to the sacral spine, where its fibres are confounded with those of the super- 
spinous dorso-lumbar ligament. 

c. Inferior ilio-sacral ligament (139, 14).— This is very resisting, triangular, 
membranous band, formed of parallel fibres passing obliquely downwards and 
backwards. It is attached, by its anterior margin, to the upper half of the 
sciatic border and the internal angle of the ilium, in becoming confounded with 
the preceding ligament. Its inferior margin is inserted into the rugged lip which 
borders the sacrum laterally. Its posterior border is united to the aponeurosis 
covering the coccygeal muscles, and its external face is in contact with the 
principal gluteal and the long vastus muscles ; while the internal lies against the 
lateral sacro-coccygeal muscle. 

d. Sacro-sciatic or ischiatic ligament (Fig. 140, 2).— This is a vast membranous 
expansion situated on the side of the pelvis, between the sacrum and the coxa. 
It serves more as a means for enclosing this portion of the pelvic cavity, than to 
assure the solidity of the sacro-iliac articulation. Its form is irregularly quadri- 

' It represents the interosseous sacro-iliac ligament of Man. The inferior half corresponds 
to the anterior sacro-iliac ligament. 



ARTICULATIONS OF TEE POSTERIOR LIMBS. 



213 



lateral, and permits its circumference to be divided into four borders : a suj^erior, 
attached to the rugged lateral ridge of the sacrum ; an inferior, fixed to the supra- 
cotyloid ridge, as well as the ischial tuberosity, and forming by the portion 
comprised between these two insertions, with the small ischiatic notch, the opening 
by which the internal obturator and pyramidalis muscles leave the pelvis ; an 
anterior, imperfectly limited, along with the great sciatic notch, circumscribes 
the opening through which the ghiteal vessels and nerves, and the sciatic nerves 
pass ; a posterior, doubled in the form of two layers which embrace the semi- 
membranosus muscle, and is confounded superiorly with the aponeurosis envelop- 
ing the coccygeal muscles. The external face of this ligament is traversed by the 
sciatic nerves, and is covered by the long vastus and the semitendinosus muscles, 
which derive numerous insertions from it. Its internal face is covered, in front, 




SACRO-ILIAC AND COXO-FEMORAL ARTICULATIONS, WITH THEIR SURROUNDIHG MUSCLES. 

11, Sacro-sciatic ligament; 12, great sciatic notch; 13, superior ilio-sacral ligament; 14, inferior 
ilio-sacral ligament. 



by the peritoneum, and, posteriorly, is in contact with the ischio-coccygeal and 
ischio-anal muscles, to which it gives attachment. 

Si/novial memhrane. — This lines the sacro-iliac ligament, but only furnishes a 
small quantity of synovia. 

MovemenU. — The two sacro-iliac articulations, being the centres towards which 
all the propulsive efforts communicated to the trunk by the posterior limbs con- 
verge, do not offer much mobility, as that would oppose the integral trans- 
mission of the propulsion. So that they permit only a very restricted gliding of 
the articular surfaces ; while the union of the sacrum and coxa by diarthrosis, 
appears to be exclusively designed to prevent the fractures to which these bones 
would be incessantly exposed, if they were fixed together in a more intimate 
manner. 

B. Articulation of the two Cox^, or Ischio-pubic Symphysis. — The 
two coxffi are united to each other throughout the whole extent of the inner border 
of the pubis and the ischial bones. In youth, this is a veritable amphiarthrosis, 
fixed by an interosseous cartilage and bundles of peripheral fibres. 

The cartilage is solidly fixed to the small rugged eminences which cover the 
adjacent articular surfaces, and becomes ossified, like the sutural cartilages, as 



214 



THE ARTICULATIONS. 



the animal advances in age. In adult Solipeds the coxae are constantly tused to 
each other. 

The peripheral fibrous fasciculi extend transversely from one bone to the 
other, above and below the symphysis ; those on the inferior face are incom- 
parably stronger and more abundant than the others. 

The movements of this articulation are most restricted, and depend solely 
upon the elasticity of the interosseous cartilage. They cease after its ossification. 

The fusion of the two coxsb proceeds very slowly in the female of the Cat, Dog, Pig, Ox, 
Sheep, and Goat species. 



2. COXO-FEMORAL ARTICULATION (Fig. 140). 

(Preparation. — Remove the muscles surrounding the articulation. To view the interior, 
divide the capsular ligament by a circular incision.) 

This is an enarfchrosis, formed by the reception of the head of the femur into 
the cotyloid cavity of the coxa. 

Articular surfaces. — As already shown, the cotyloid cavity represents the 

segment of a hollow sphere, 
deeply notched on the inner 
side, and provided at the 
bottom with a wide depres- 
sion, the internal moiety of 
which is destined for the 
insertion of one of the inter- 
osseous ligaments, wliile the 
external half plays the part 
of a synovial fossa. This 
depression is not covered by 
cartilage, and communicates 
by the internal notch with 
the inferior furrow on the 
pubis. The Up of the cotyloid 
cavity is covered by a com- 
plementary fibro-cartilage — 
the cotyloid ligament. This 
fibro-cartilage is not inter- 
rupted at the notch just 
mentioned, but passes over it, 
forming a remarkable band 
(Fig. 140, 5) that converts 
it into a foramen, through 
which pass the pubio- or ilio- 
femoral ligament and the 
vessels of the articulation. 
Fixed by its adherent border 
to the margin of the cotyloid 
cavity, this ligament is lined 
It is thickest in front and 




sacro-iliac and coxo-femoral articulations, with the 
small deep muscles surrounding the latter (inferior 
surface). 

1, Sacro-iliac ligament; 2, sacro-sciatic ligament; 3, great 
sciatic notch ; 4, anterior portion of the capsular ligament 
of the coxo-femoral articulation ; 5, internal band of the 
cotyloid ligament ; 6, coxo-femoral ligament ; 7, pubio- 
femoral ligament ; 8, its insertion into the femui-. 



by synovial membrane on its faces and free border, 
within. 

With regard to the head of the femur, it will be remembered that it is exactly 



ARTICULATIONS OF THE POSTERIOR LIMBS. 215 

moulded to the cavity, and, like it, is excavated by a nigged fossa which is entirely 
occwpied by the insertion of the interarticular Ligaments. 

llode of union. — This joint is maintained by a peripheral capsule, and by an 
interarticular band constituting the coxo-femoral ligament. 

a. Capsular ligament (Fig. 140, 4). — This is a membranous sac, like that of 
the scapulo-humeral articulation, embracing the head of the femur by its inferior 
opening, and attached by its opposite border to the margin of the cotyloid cavity 
and its surrounding fibro-cartilage. This Ugament is composed of intercrossed 
fibres, and is strengthened in front by an oblique fasciculus which descends to the 
body of the femur, along with the crureus muscle, near which it is fixed. Its 
internal face is covered by the articular synovial membrane, and its external face 
is in contact, through the medium of adipose cushions, with : in front, the crureus 
and the rectus femoris ; behind, the gemini, the internal obturator, and the 
pyramidalis muscles ; outwards and upwards, the small gluteal muscle ; within 
and below, the external obturator. 

h. Coxo-femoral ligament {ligammtum teres. Fig. 140, 6). — A thick and short 
funicle of a triangular shape, deeply situated between the two bony surfaces, which 
it cannot, notwithstanding its shortness, maintain exactly in contact without the 
other muscular or ligamentous stiiictures enveloping the articulation. In Solipeds, 
it is divided into two portions — a cotyloid and a puhic. The cotyloid portion is 
short and entirely concealed in the interior of the articulation (Fig. 140, 6). Its 
upper insertion occupies the internal moiety of the bottom of the cotyloid cavity ; 
and its inferior extremity is fixed into the rough fossa in the head of the femur. 
It is enveloped by the synovial membrane, 

T\iQ puhic portion (Fig. 140, 7, 8) arises, like the preceding, from the fossette 
in the head of the femur, and, passing upwards and outwards, enters the internal 
notch of the cotyloid cavity, is inflected downwards on the fibrous band Avhich 
converts that notch into a foramen, and is at last lodged in the inferior fuiTow on 
the pubis, becoming confounded with the prepubic tendon of the abdominal 
muscles, at the anterior border of the pubis. Longer and stronger tlian the cotyloid 
portion, this fasciculus is included, in its pubic part, between the two branches of 
the pectineus ; its interarticular part is covered by synovial membrane. 

Synovicd membrane. — This membrane is very extensive ; it lines the intemal 
face of the capsular and cotyloid ligaments, and is reflected on the interarticular 
ligaments, to form around them a serous vaginal covering. It is even prolonged 
into the synovial fossa occupying the centre of the cotyloid cavity. 

Movements. — The coxo-femoral articulation is one of the joints which are 
endowed with the most varied and extensive movements. It permits the flexion, 
extension, ahduction, adduction, circumduction, and rotation of the thigh on the 
pelvis. The mechanism of these movements is so simple, that they need no 
particular consideration.- 

The domesticated animals other than Solipeds, are distinguished by the com- 
plete absence of the pubio-femoral Ligament ; so that in them the movements of 
abduction, which are limited in Solipeds by the tension of this ligament, are much 
more extensive ; and it is the absence of the ligament in question which explains 
the facility with which the larger Ruminants are enabled to strike sideways — a 
movement known as a " cow's kick." 

In Man, the head of the femur is more detached than in the domesticated animals, and 
the cotyloid cavity, encircled by the cotyloid ligament, is deeper. The femur is united to the 
coxa: 1. By a capsular ligament. 2. By a triangular ligament, fixed above, to the cotyloid 



216 THE ABTICVLATIONS. 

ligament at the notch, and below, into the depression in the head of tlie femur. Also, as the 
brothers Weber have shown, the atmospheric pressure is a powerful adjuuct to tliese means 
of union. 

The coxo-femoral articulation of Man permits more extensive movements than that of 
animals, and especially abduction and adduction, which can be carried to 90 degrees. 

3. Femoro-tibial Articulation (Fig. 141). ^ 

Preparation. — Remove the soft parts surrounding the articulation, taking care not to wound 
the synovial membrane. To expose the crucial ligaments, make au antero-posterior vertical 
section of the femur in such a way as to separate the condyles. 

This is the most comphcated joint in the body, and is formed by the union of 
the femur with two of the thigh-bones — the tibia and patella. It represents an 
imperfect hinge-joint. 

Artuular surfaces. — To form this articulation, the femur opposes its two con- 
dyles to the wide, conve.K, and undulated facets on the superior face of the lateral 
tuberosities of the tibia, and its articular pulley to the posterior face of the patella. 

The femoral faces have already been described in detail (p. 137) ; but it may 
be repeated that the two condyles, placed side by side, are elongated in an antero- 
posterior direction, and are separated by a non-articular notch called the inter- 
condyloid ; also, that the femoral trochlea, situated in front of these two condyles, 
appears to continue the preceding notch, and that its internal border is much more 
elevated than the external — an arrangement which explains why it is so difficult, 
if not impossible, for the patella to be dislocated inwards. 

The tihial facets ascend on each side to the lateral faces of the tibial spine. 
They are separated from one another by the antero-posterior groove cut on the 
summit of that bone, and by the fossae of insertion situated at its base before and 
behind. The external facet, wider than the internal, is devoted in part to the 
gliding of the originating tendon of the popliteal muscle. 

The patellar surface, moulded on the femoral pulley, fits it in an imperfect 
manner. It is bordered, outwardly, by a small fibro-cartilaginous ring, which is 
united to the fibrous capsule of the femoro-patellar ariiculation (Fig. 141, 1). 
Inwardly, it is completed by the insertion of the internal patellar ligament, to be 
noticed immediately. 

Tnterarticular nieniscii {semilunar fihro-cartUages) (Figs. 141, a 1, 2, 3, 4 ; 
and 142, 5, G, 7, 8). — By this designation are known the two fibro-cartilages 
interposed between the condyles of the femm- and the tibial facets, to assure their 
coaptation. They are crescent-shaped bodies, and present : an internal, concave, 
thin, and sharj) border, embracing the tibial spine ; an external, thick, and convex 
border ; a superior face, excavated and moulded to one of the condyles ; an inferior 
face, nearly plane, gliding on the tibia ; and two extremities terminated by liga- 
ments, and fixed to the bones in apposition. The articular surfaces are not entirely 
separated throughout their extent by these complementaiy meniscii, for the tibial 
spine rubs directly against the inner sides of the femoral condyles. The internal 
semilunar fihro-cartilage, the widest and thickest, is inserted by its anterior 
extremity into one of the excavations situated in front of the spine ; its posterior 

1 By this name is understood the joint uniting the femur to the tibia, and that which 
articulates it with the patella. Following the example of anthropotomists, it has not been 
deemed necessary to describe a femoro-patellar articulation distinct from the femoro-tibial, 
properly so called. This innovation appears to be justified by the community of the principal 
articular bands which bind these two joints, and by the reciprocal dependence of their 
movements. 



ABTICULATIONS OF THE POSTERIOR LIMBS. 



217 



extremity is attached in the fossa behind that eminence. The external semilunar 
fiiro-cartilage is fixed, in front, near the anterior insertion of the opposite fibro- 
cartilage ; its posterior extremity gives origin to two slips or cords, one superior, 
the other inferior. The first, the strongest and longest, terminates in the fossa 
near the posterior extremity of the intercondyloid notch. The second, thin and 
■flat, is inserted on the posterior outline of the external tibial facet. The external 
border of this meniscus is separated from the external lateral ligament by the 
tendon of the popliteus muscle, and acts, with regard to this tendon, as a pulley. 
Mode of union. — The bands which bind this complicated articulation are veiy 



Fig. 141. 





FEMORO-TIBIAL ARTICULATION'. 

A. — Posterior face : the posterior lignment has been removed. 1, External meniscus ; 2, fibrous 
fasciculi fi.xiug it to the femur ; 3, fibrous fascia which attaches it to the posterior contour of the 
tibial surface ; 4, internal meniscus ; 5, tibial insertion of the posterior crucial ligament ; 6, 
external lateral ligament ; 7, mternal lateral ligament. 

B. — External face : the external condyle of the femur and the meniscus have been removed to 
show the crucial ligaments. 1, Anterior crucial ligament; 2, posterior ditto; 3, fibular insertion 
of the external lateral ligament ; 4, anterior patellar ligaments. A, Internal meni.^^cus ; B, anterior 
insertion of the external meniscus ; C, passage for the tendinous cord common to the flexor of the 
metatarsus and the anterior extensor of the phalanges ; D, anterior and superior tuberosity of 
the tibia; E, tibial crest. 

numerous. They will be successively described as : 1 . Those which attach the 
patella to the tibia. 2. Those which unite the femur with the tibia. 

A. Ligaments attaching the -patella to the tibia. — The patella is bound to the 
tibia by three funicular ligaments, designated by the generic epithet of " patellar." 
They are situated in front of the articulation, and transmit to the leg the action 
of the muscles which are attached to the patella. They are distinguished accord- 
ing to their position, as external, internal, and middle (Fig. 142, 2, 3, 4). 

a. The external patellar ligament, the largest and most powerful, is a flattened 
band, attached, by its lower extremity, to the culminating point of the anterior 
tuberosity of the tibia. Its upper extremity is fixed to the anterior face of the 
patella, and is confounded with the patellar insertion of the superficial gluteus. 
It is joined to the internal ligament by a veiy resisting aponeurotic extension, a 
dependency of the fascia lata. 



218 THE ARTICULATIONS. 

b. Tlie interna] patellar ligament also forms a flattened band, longer, but not 
80 wide or thick as the preceding. Its inferior extremity is attached to the inner 
side of the anterior tuberosity of the tibia. Its superior extremity becomes much 
thickened and fibro-cartilaginous, and is inserted into a prominence inside the 
patella. This fibro-cartilaginous portion (Fig. Ii2, 3) of the ligament ghdes on 
the internal border of the femoral trochlea, and may justly be considered as a 
complementary apparatus of the patellar surface. The ligament, joined to the 
preceding by the hbrous fascia ab-eady mentioned, is confounded, inwardly, with 
the aponeurosis of the adductor muscles of the leg. 

c. The middle patellar ligament is a round cord, situated, as its name indicates, 
between the other two, concealed beneath the aponeurosis which unites these, and 
in the middle of the adipose tissue protecting the synovial capsules in front. It 
leaves the anterior face of the patella, and descends vertically to the tibia, to be 
lodged in the fossa in the middle of the anterior tuberosity, where a small synovial 
bursa facilitates its movements. Its inferior extremity is inserted into the most 
decUvitous part of this excavation. 

B. Ligaments which attach the leg and thigh hones. — These are six in number : 

1. A femoro-patellar capsule maintaining the patella against the femoral trochlea. 

2. Five femoro-tibial ligaments, as follows : two lateral, two external and 
internal ; a posterior ; and two interarticular, distinguished with reference to 
their inferior insertion into anterior and posterior. 

1. T\\Q femoro-patellar capsule is a membranous expansion which covers, above 
and laterally, the superior synovial membrane. This capsule is attached by its 
borders around the femoral trochlea and the periphery of the patellar surface. 
It is extremely thin in its superior part ; but laterally it is thicker, and consti- 
tutes two wide fibrous fasciculi which bind the patella to the eccentric sides of 
the two condyles, and is described in several works as two special ligaments. Its 
external face is covered by the insertion of the superficial gluteus and the triceps 
cruralis. 

2. Femoro-tibicd ligaments. — a. The lateral ligammts are two ribbon-shaped 
cords situated at the extremities of the transversal axis of the articulation, more 
behind than before ; they are relaxed during flexion, and very tense in ex- 
tension. 

The external, the shortest and strongest, proceeds from one of the hollow 
facets on the external condyle of the femur, and is inserted into the head of the 
fibula by its inferior extremity, after gliding over the external tuberosity of the 
tibia by means of a special synovial bursa. It is covered by the crural or tibial 
aponeurosis, and covers the tendon of the popliteus, from which it is sometimes 
separated by a vesicular synovial membrane. 

The internal is attached, superiorly, to the eminence of insertion that sur- 
mounts the eccentric face of the internal condyle, and descends vertically to the 
tibia, gliding over the margin of its articular surface by means of a small facet 
covered with cartilage, and a nd-de-sac prolongation of the internal synovial 
membrane. It is fixed by its inferior extremity to the imprints which cover the 
internal tibial tuberosity. 

Its fil)res are disposed in two layers, which slightly intercross in X fashion ; 
those passing downwards and forwards adhere to the border of the internal 
meniscus. Covered by the aponeurosis of the adductor muscles of the leg, this 
ligament adheres by its deep face to the internal meniscus. 

b. The posterior ligament belongs to the class of membranous or capsular 



ARTICULATIONS OF TEE POSTERIOR LIMBS. 219 

ligaments. It is formed of two aponeurotic layers separated superiorly, but 
confounded inferiorly. The superficial layer is composed of strong, fibrous, 
intercrossed fasciculi, perforated with vascular openings. It is fixed, above, to 
the posterior face of the femur, below the external gastrocnemius muscle. The 
deep lamina envelops, like a cap, the femoral condyles. After becoming united, 
these two laminse are attached to the posterior face of the tibia, close to the 
superior articular face of that bone. Its external face is in contact with the 
popliteal vessels, and the gastrocnemius muscle. Its internal face is covered 
throughout nearly the whole of its extent by the lateral synovial membranes, 
embraces the condyles of the femur, and adheres to the posterior crucial liga- 
ment, as well as to the interarticular meniscii. 

c. The interosseous ligaments are two funicular bands lodged in the inter- 
condyloid notch. They are more commonly designated crucial ligaments, because 
they cross each other at their middle part, like the letter X (Fig. 141). 

The anterior, oblique downwards and forwards, is attached by its superior 
extremity to the bottom of the intercondyloid notch, and inwardly to the external 
condyle. Its inferior extremity is fixed in the groove on the summit of the tibial 
spine. The fibres entering into its formation are not parallel, but slightly twisted 
in a spiral manner. 

The posterior,\ongeY than the preceding, and oblique in the opposite dii-ection, 
is inserted, inferiorly, into the little eminence behind the internal tibial facet ; 
whence it goes to the bottom of the intercondyloid notch, to be attached by its 
superior extremity within the internal condyle. 

Sgnovial membranes. — For this articulation there are three synovial mem- 
branes : a superior and two lateral. The first, very large and strengthened by 
the femoro-patellar capsule, facilitates the gliding of the patella on the femoral 
pulley ; it is prolonged in a cul-de-sac below the insertion of the crural triceps. 
The other two, which lubricate the articular surfaces of the proper femoro-tibial 
joint, include the crucial ligaments between them, and cover the posterior 
ligament, the lateral ligaments, and the fibrous fasciculi for the attachment of 
the meniscii. The external lines, in addition, the tendon of the popliteus muscle, 
and furnishes a vast cul-de-sac which descends in the anterior groove of the tibia, 
to envelop the tendon common to the anterior extensor of the phalanges and the 
flexor of the metatareus. These two femoro-tibial synovial membranes lie against 
that of the femoro-patellar articulation, in front of the condyles and the notch 
which separates them, and if not always, at least not unfrequently, they com- 
municate with it. The three are separated from the ligaments of the patella by 
a considerable mass of adipose tissue, which is prolonged into the inter-condyloid 
notch, at the bottom of which it appeal's to be fixed. 

The synovial cavities sometimes communicate with each other, but, according 
to Lesbre, this is rare. 

Movements— 'T\m imperfect hinge-joint can execute the two principal and 
opposite movements of flexion and extension, and a somewhat limited accessory 
movement of rotation. The mechanism of these movements being simple enough 
to be readily understood without any preliminary explanation, they will not be 
detailed here ; but some remarks will be made with regard to the displacement 
the fibro-cartilages undergo, when the articulation is in motion. 

During flexion and extension, these bodies, fixed on the tibial facets, which 
they transform into glenoid cavities, move with them on the condyles of the 
femur, from before to behind, or behind to before, according to the movement 



THE ARTICULATIONS. 



No. 1. 



No. 2. 



executed. But at the same time they also glide in an inverse direction, and 
to a very appreciable degree, on the superior extremity of the tibia. Therefore, 
during flexion, they pass from behind forward on this extremity, and are drawn 
backwards during extension. 

In rotation — which may take place from within to without, or from without to 
within — the movement is produced not only 
Fig. 142. by the pivoting of the condyles in their 

glenoid cavities, but also by a fusible dis- 
placement of the meniscii on the tibial sur- 
faces. 



In the Dog and Cat, the meniscii are joined 
together, near their anterior insertion, by a trans- 
verse fibrous band. There is only one patellar liga- 
ment, and the posterior ligament shows in its sub- 
stance, two !<mall sesamoid bones against which the 
condyles of the femur play inwardly, and which give 
attachment, outwardly, to the originating branches 
of the gastrocnemius muscle. There is no femoro- 
patellar capsule, and only one synovial membrane 
for the whole articulation. 

In the Pig and Sheep, there is also only one 
ligament ;iud one synovial capsule. 



4. TiBIO-FIBULAR ARTICULATION. 

This articulation represents a small plani- 
form diathrosis, the movements of which are 
very limited and obscure. It is formed by 
the union of the irregular diathrodial facet 
which occupies the internal face of the head 
of the fibula, with the analogous facet on the 
external superior tuberosity of the tibia. 
Short and strong interosseous or peripheral 
fibres envelop these facets on every side, 
and maintain them firmly in contact. 

The fibula is also attached to the tibia : 
" 1. Above, by two small ligamentous fasci- 
culi crossed like the letter X, wdiich form the 
superior part of the great arch through w^hich 
pass the anterior tibial arteiy and vein (Fig. 
142, 12). 2. In the middle, by a kind of 
aponeurotic membrane, the wddth of which 
diminishes from above to below, like that of 
the space it fills (Fig. 142, 13). 3. Below, 
by a ligamentous cord (Fig. 142, 14) which 
prolongs the fibula to the external tuberosity 
of the inferior extremity of the tibia, where 
to the two external lateral ligaments of the 




LIGAMENTS ATTACHING THE THREE BONES 
OF THE LEG. 

No. 1. Posterior face. No. 2. Anterior face. 
1, Complementary fibro-cartilagiuous 
pad of the patellar surface ; 2, e.\ternal 
patellar ligament; 2', insertion of the 
superficial gluteal into this ligament; 3, 
internal patellar ligament ; 3', its upper 
insertion transformed into a comple- 
mentary apparatus of the patellar sur- 
face ; 4, midijle patellar ligament; 5, 
external meniscus of the tibia; 6, its 
branch of insertion into the femur cut 
off at its origin ; 7, its posterior tibial 
insertion ; 8, external meniscus ; 9, in- 
sertion of the anterior crucial ligament 
into the fossa of the tibial spine ; 10, 
tibial insertion of the posterior crucial 
ligament; 11, inferior insertion of the 
external femoro-tibial ligament ; 12, 13, 
14, tibio-fibular ligaments. A, Tibial 
arch ; B, surface of insertion of the 
popliteus muscle ; C, surface of insertion 
for the perforans muscle. 



this cord bifurcates, and is united 
tibio-tarsal articulation " (Rigot). 



In the Ox, Sheep, and Goat, the fibula being replaced by a ligament, there 
tibio-fibular articulation. 



no proper 



ARTICULATIONS OF THE POSTERIOR LIMBS. 221 

In the Dog and Cat, the two principal bones of the leg are united at their extremities 
and middle part : • 

1. At their superior extremity, by means of a small arthrodial articulation, analogous to 
that of the Horse, and, like it, provided witli a particular synovial bursa; 

2. At their inferior extremity, by means of a second artiirodial articulation, whose action is 
facilitated by a prolongation of the tibio-tarsal synovial membrane; 

3. By their middle part, through the interposition, between the two bones, of an inter- 
osseous ligament, which is wide and membranous in its upper two-thirds, and formed of 
extremely short and strong fibres at its lower third. 

5. Aeticulations of TttE Tarsus or Hock (Figs. 141, 144). 

Preparntion. — Commence by cutting off the tendons, and so exposing the lateral ligaments 
of the tibio-tarsal diathrosis. Tlien the procedure should be as for the carpus — dissect suc- 
cessively the ligaments proper to each row, those uniting the two rows, and those binding the 
lower row to the metatarsus. 

These comprise : 1. The tibio-tarsal articulation. 2. The articulation of the 
first row of bones — the astragalu3 and calcaneum or calcis. 3. Those which unite 
the bones of the lower row. 4. The articulation of the two rows with each other. 
5. The tarso-metatarsal articulation. The first is a perfect ginglymoid, and the 
only joint really movable ; all the others are aythrodial, and their action is so 
restricted that they appear to be condemned to almost absolute immobility. 
This intimate union of the tarsal and metatarsal bones, is evidently chiefly intended 
to guarantee precision in the movements of the tibio-tarsal articulation. 

Tibio-tarsal Articulation. — Two bones alone concur in the formation 
of this angular ginglymoid joint : these are the tibia and astragalus. 

Articular surfaces. — For the tibia : 1. The two deep grooves, oblique forwards 
and outwards, channeled in the inferior extremity of the bone. 2. The salient 
tenon which separates these grooves, and on which there is often a small synovial 
fossette. For the astragalus, the pulley occupying its anterior face (see p. 145). 

Mode of union. — Seven ligaments bind these articulations : two external 
lateral, three internal lateral, an anterior, and a posterior. 

a. External lateral ligaments. — These are distinguished, according to their 
relative position, into superficial and deep. 

The external superficial ligament (Figs. 143, 2 ; 144, 2) is a thick funicular 
cord, flattened in its inferior half. It commences above on the external tube- 
rosity of the tibia, behind the groove which divides this tuberosity into two 
parts ; from thence it descends almost vertically, fixing itseU" successively to the 
astragalus, calcaneum, cuboides, middle metatarsal bone, and the external rudi- 
mentary metatarsal bone. Passing in front with, and partly covered by, the 
lateral extensor of the phalanges, to which it supplies a retaining band (Fig. 
143, 2), this ligament is confounded behind, and near its inferior extremity, 
with the calcaneo-metatarsal ligament. It covers the external and deep ligament, 
the short band which constitutes the external calcaneo-astragaloid ligament, the 
insertion of one of the branches of the flexor of the metatarsus, and the small 
cuboido-cunean (cuneiform) ligament. 

The external deep ligament (Figs. 143, 1 ; 144, 1), much shorter than the pre- 
ceding, is attached, superiorly, to the anterior part of the external tuberosity of 
the tibia, and is directed obliquely backwards and downwards, to be fixed by two 
fasciculi at the external side of the astragalus and calcis. This ligament, covered 
by the preceding, which crosses it like an X, is lined on its inner face by a 
synovial membrane of the articulation. 
17 



222 



THE ARTICULATIONS. 



b. Internal lateral ligaments. — These are also three funicular bands superposed 
on one another, and arb consequently designated as superficial, middle, and deep. 
The internal superficial ligament (Fig. 14.3, 6), the strongest and longest of 
the three, proceeds from the internal and inferior tuberosity of the tibia, 
diminishing as it descends on the inner side of the tarsus. It is fixed, in mixing 
with the astragalo-metatarsal ligament and with the posterior tarso-metatareal 
ligamentous arrangement, to the tuberosity of the astragalus, the scaphoid, the 
two cuneifoi-m, the superior extremity of the principal metatarsal, and that of the 
internal rudimentary metatarsal bones. 

The internal middle ligament (Fig. 143, 5) is com- 
posed of two funicular cords, attached in common beneath 
the preceding ligament to the internal tibial tuberosity. 
These two fasciculi, exactly resembling those of the ex- 
ternal deep ligament, are directed downward and back- 
ward, and terminate, one at the astragalus, the other 
at the calcis. 

The internal deep ligament (Fig. 144, 4) is an extremely 
slender fasciculus, enveloped by the synovial membrane ; 
it is often reduced to a thin shred, scarcely distinct from 
the serous covering surrounding it. It is attached, in one 
direction, to the tibia below the middle ligament ; in 
the other, to the astragalus, and nearly at the same point 
as the superior fasciculus of the middle ligament. 

c. Anterior ligament. — This is a membraniform band 
formed of intercrossed fibres, stronger outwards than in- 
wards, attached by its upper border above and in front 
of the tibial surface, fixed by its inferior border to the 
astragalus, the scaphoid and great cuneiform bones, and 
the astragalo-metatarsal ligament ; it is confounded at its 
sides with the two superficial lateral ligaments. Its internal 
face is lined by articular synovial membrane, while the ex- 
ternal is covered by the flexor of the metatarsus, the anterior 
extensor of the phalanges, the anterior tibial arteiy, and 
several large anastomosing veins, from the junction of 
which arises the anterior tibial vein. 

d. Posterior ligament. — This is the second membrani- 
form or capsular band, which protects the articulation 
posteriorly. It presents, in its centre, a fibro-cartilaginous 
thickening, on which gUdes the perforans tendon. It is 
attached, above, to the tibia ; below, to the astragalus and 
calcis ; at its sides it is mixed with the two superficial 

lateral ligaments, and the astragalian fasciculus of the middle internal ligament. 
Its internal face is lined by articular synovial membrane ; the external is covered 
and lubricated by the vaginal serous membrane, which facilitates the gliding of 
the perforans tendon in the tarsal sheath. 

Synovial membrane. — This membrane is developed at the internal face of the 
two capsular ligaments, lines the greater part of the three internal ligaments, 
and also the external deep ligament. It communicates, in front and below, with 
the synovial membrane proper to the articulation of the two rows of tarsal bones. 
When it becomes the seat of dropsical effusion, it is always distended forwards 




parsal articitlations 
(front view). 

, External deep ligament 
of the tibio-taisal ar- 
ticulation ; 2, 2, ex- 
ternal superficial liga- 
ment ; 4, internal deep 
ligament ; 5, internal 
middle ligament ; 6, In- 
ternal superficial liga- 
ment ; 7, astragalo- 
metatarsal ligament ; 8, 
small cuboido-cunean 
ligament. A, Pulley of 
the astragalus; B, cu- 
boidal insertion belong- 
ing to tne tendinous 
cord of the flexor of the 
metatarsus ; C, vascular 
canal of the tarsus. 



ARTICULATIONS OF THE POSTERIOR LIMBS. 223 

and inwards, because it is only sustained at that place by the anterior capsular 
ligament. But the effusion may also elevate the posterior- ligament, and produce 
hernia in the hollow of the hock, behind the lateral ligaments. It is not, there- 
fore, absolutely correct to attribute all the synovial tumours in the hollow of the 
hock to dilatation of the tarsal tendinous sheath. (See the figure of the tendons 
and synovial capsules of the posterior limb, in the description of the perforans 
muscle.) 

Movements. — Nothing can be less complicated than the mechanism of the 
tibio-tarsal articulation, this joint only permitting two opposite movements — 
those oi flexion and extension — which are so simple and precise that we may dispense 
with a description of the manner in which they are executed. It may only be 
remarked that, in order to prevent contact between the leg and foot during flexion, 
the latter fraction of the limb deviates a little outwards, owing to the marked 
obliquity of the articular grooves. 

Articulation of the Bones of the First Row, or Calcaneo-astraga- 
LOiD Articulation. — This is a compound arthrodial joint, resulting from the 
coaptation of the three or four articular facets of the posterior face of the astragalus 
with the analogous facets of the calcis. 

This joint is maintained by the lateral ligaments of the tibio-tarsal articulation, 
and by four cakaneo-astragaloid ligaments — a superior, external, internal, and the 
last interosseous. 

The superior calcaneo-astragaloid ligament is formed of short parallel fibres 
thrown across from one bone to the other, and is situated towards the superior 
extremity of the pulley of the astragalus ; it is lined superiorly by the synovial 
membrane of the tibio-tarsal articulation. 

The lateral ligaments are two very thin fasciculi concealed by the ligaments 
which bind, laterally, the tibia to the tarsal bone. 

The interosseous ligament is very strong, and occupies a great portion of the 
rugged excavation which separates the articular facets. 

This articulation does not usually possess proper synovial capsules. Two 
prolongations of the synovial membrane of the two rows, in ascending between 
the calcis and astragalus, facilitate the gliding of the two inferior facets. An 
analogous prolongation of. the tibio-tarsal synovial membrane is effected for the 
superior facets, and it is not rare to find this prolongation form a distinct 
capsule. 

Movements nearly null. 

Articulation of the Bones of the Second Row with each other. — 
These bones, four in number, are brought into contact in the following manner : 
The cuboides responds to the scaphoid by two facets — one anterior, the other 
posterior ; it articulates with the great cuneiform by two similar facets, the 
posterior of which is not always present. The scaphoid is united to the two cunei- 
forms by the large convex facet occupying its entire lower face. The two cunei- 
forms are joined by means of a small articular surface. 

The fibrous fasciculi which maintain the diarthrodial surfaces in contact are 
somewhat numerous. They are as follows : — 

1. The astragalo-metatarsal ligament and tarso-metatarsal apparatus, which 
will be described hereafter ; these two bands do not properly; belong to the articu- 
lations of the second row of bones. 

2. Two anterior ligaments, named cuhoido-scaphoid and cuboido-cunean (Figs. 
143, 8 ; 144, 5), which are carried from the cuboid to the scaphoid and to the 



224 



THE ARTICULATIONS. 




great cuneiform bone, one above, the other below the vascular channel formed 
between these three bones. 

3. Two interosseous ligaments analogous to the preceding two. forming the 
superior and inferior walls of the aforesaid channel. 

4. An interosseous scaphoido-cunean ligament, passing from the scaphoid to 
the two cuneiform bones. 

5. An interosseous ligament, named the intercunean, is directed from one 
cuneiform bone to the other, and is confounded with 
the preceding ligament. 

The disposition of the lubricating membranes 
varies with that of the articular facets. The follow- 
ing is what is most generally observed : A proper 
synovial membrane is specially destined for the facets 
by which the scaphoid and gi'eat cuneiform bones 
correspond ; this synovial membrane belongs also to 
the two cuboido-scaphoid and posterior cuboido- 
cunean arthrodiae. The anterior cuboido-scaphoid 
diarthrosis receives a prolongation from the synovial 
membrane of the two rows. The play of the anterior 
cuboido-cunean and intercunean facets is facilitated 
by two prolongations of the tarso-metatai'sal synovial 
membrane. 

Movements almost null. 

Articulation of the two Rows with each 
OTHER. — This arthrodial joint is formed by the union 
of the calcis and the astragalus, on the one side, with 
the scaphoid and cuboid bones on the other. Its 
solidity is assured by six principal bands : 

1. The two lateral superficial ligaments of the 
tibio-tarsal articulation. 

2. The calcaneo-metatarml ligament (Fig. 144, 
3), a strong fibrous brace which unites the posterior 
border of the calcis to the.cuboides, and to the head 
of the external rudimentaiy metatarsal bone. It is 
confounded, outwardly, with the external and super- 
ficial tibio-tarsal ligament ; inwardly, with the pos- 
terior tarso-metatarsal band. 

3. The astragalo-metatarsal ligament (Fig. 143, 
7), a radiating fasciculus, the fibres of which leave the 
internal tuberosity of the astragalus, become mixed 
up with the internal and superficial tibio-tarsal liga- 
ments in diverging downwards to the scaphoides, the great cuneiform bone, and 
the upper extremity of the principal metatarsal bone. 

4. The posterior tarso-metatarsal ligament is a vast, very strong, and very 
complicated fibrous arrangement, which binds, posteriorly, all the tarsal bones, 
and also fixes them to the three portions of the metatarsus. This band, which is 
crossed by several tendons and by the artery and vein lodged in the cuboido- 
scaphoido-cunean canal, is continued below by the tarsal stay of the perforans 
tendon. It therefore closely resembles the posterior carpal ligament. Its posterior 
face is covered by the tendinous synovial membrane lining the tarsal sheath for 



ARTICULATIONS OF THE TARSUS 
(LATERAL VIEW). 

1, External deep ligament; 2, 
external superficial ligament ; 
2', ring furnished by the latter 
ligament for the passage of the 
lateral extensor tendon of the 
phalanges; 3, calcaneo-meta- 
tarsal ligament ; 4, astragalo- 
metatarsal ligament ; 5, small 
cuboido-cunean ligament. A, 
Cuboidal insertion of the flexor 
muscle of the metatarsus ; B, 
anterior orifice of the vascular 
conduit of the tarsus ;C, groove 
on the external tuberosity of 
the tibia for the gliding of the 
lateral extensor of the pha- 
langes ; D, insertion of the gas- 
trocnemius tendon of the leg 
into the os calcis ; E, gliding 
surface for that tendon. 



THE ARTICULATIONS IN BIRDS. 22S 

the passage of the perforaiis tendons. It is confounded, on its sides, with the 
calcaneo-metatarsal, and the internal and superficial tibio-tarsal ligaments. 

5. An interosseous liyamenf, attached to the four bones composing this 
articulation. 

It is provided with a particular synovial membrane which always communi- 
cates, in front, with the tibio-tarsal capsule. This membrane is prolonged, 
superiorly, between the calcis and astragalus, to lubrify two of the facets by 
which these bones come into contact ; and, in addition, it descends between the 
cuboid and scaphoid bones, to form a third prolongation for the anterior cuboido- 
scaphoid arthrodia. 

Movements almost null. 

Takso-metataesal Aeticulation. — This joint, formed by the meeting of 
the three tarsal bones — the cuboid and the two cuneiforms — with the three bones 
of the metatarsus, is fixed by the lateral superficial ligaments of the tibio-tarsal 
articulation, the calcaneo-metatarsal hgament, those which have been named the 
astragalo-metatarsal and tarso-metatarsal, and by a strong interosseous ligament 
which naturally forms three fasciculi. 

The synovial membrane proper to this joint ascends into the small anterior 
cuboido-cunean arthrodia, and into that which unites the two cuneiform bones ; it 
descends to the intermetatarsal articulations. 

Movements nearly null. 

In all the domesticated animals except Solipeds, the tarsal articulations offer some differen- 
tial peculiarities, the study of which is without interest, as it is without utility. It is only 
necessary to remark that the immobility of the tarsal joints, properly so called, is less absolute 
than in Solipeds, owing to the peculiar configuration of the articular surfaces of some of the 
bones composing them. Thus, in the Ox, Sheep, Goat, and Pig, the calcis is joined to the 
astragalus by a real trochlear articulation, and the latter bone is united to the scaphoid by a 
diarthrodial joint of the same kind — a mode of articulation much more favourable to motion 
than that of the planiform diarthrodial joint. In the Dog and Cat, the same result is 
obtained by the reception of the head of tlie astragalus into the superior cavity of the scaphoid. 

In Ruminants and the Pig, it is also observed that the tibio-tarsal articulation is formed 
by the tibia and fibula in the one direction, and by the astragalus and os calcis in the other. 

Lemoigne, who has been again recently studying the mechanical arrangement of the Ox's 
hock, remarks that, if the mobility of all the tarsal articulations deprive the posterior limb of 
that animal of the rigidity necessary fur speed, yet the nature of the astragalo-calcanean articu- 
lation gives it great power. In fact, the posterior trochlea of the astragalus acts as an eccentric 
on the calcis during movement, and gradually separates this bone in such a manner that the 
tendon of the gastrocnemius always remains nearly perpendicular on the lever arm — no matter 
to what degree the hock may be open or closed. But this mechanism may perhaps be disputed. 



CHAPTER III. 
THE ARTICULATIONS IN BIRDS. 

The study of the articulations in birds will only arrest us for a few moments ; as 
it will be confined to some remarks on the intervertebral occipito-atloid and 
temporo-maxillary joints, the only ones exhibiting a special conformation worthy 
of attention. 

Intervertebral articulations. — The great mobility of the neck of Birds is not 
only due to the fact of its length, relati^'ely considered, but also to the peculiar 
manner in which the vertebrae of this portion of the spine are articulated. It will 



226 THE ARTICULATIONS. 

be remarked that these do not unite by their bodies in the form of a continuous 
series of amphiarthroses, as in the domesticated Mammals ; but that, instead of 
these mixed articulations, there are real diarthroses, which may be included in the 
class created by Cruveilhier under the title of articulation hij reciprocal ball-and- 
socket — each vertebra becoming connected with the adjacent vertebra by means of 
facets, convex in one sense and concave in the sense perpendicular to the firat. 
These facets are manifestly covered by cartilage of incrustation ; and it appears 
that, instead of their being applied dii'ectly against the opposite facets, which 
present a precisely inverse conformation, they are separated by an extremely thin 
fibro-cartilaginous disc, which resembles the interosseous meniscus of the temporo- 
maxillary articulation in the Carnivora of the Cat species. Two loose synovial 
capsules, separated by this interarticular lamina, complete the framework of each 
articulation, and favour the play of the vertebrae on one another. This arrange- 
ment has only, so far as we are aware, been observed in the Swan, and that very 
imperfectly ; but it probably belongs to the entire class of Birds, for until now 
we have met with it in all the individuals submitted to examination. 

In its dorso-lumbar and sacral portion, the spine is a single piece, in con- 
sequence of the consolidation of the vertebrae, and does not show any proper 
articulations. 

In the coccygeal region, the mobility of the spine reappears, but it is far 
from being so marked as in the cervical region ; the vertebrae here are united by 
amphiarthrosis, and not by reciprocal ball-and-socket. 

Occiinto-atloid articulation. — It has been shown that there is only one more or 
less spheroidal condyle of the occipital bone, and a single cavity on the anterior 
margin of the spinal canal of the atlas. The occipito-atloid articulation is there- 
fore a true enarthrosis, with varied and very extensive movements — a disposition 
which accounts for the facility with which Birds can pivot their heads on the 
superior extremity of the vertelbral stalk. 

Temporo-maxillary articulation. — The play of this articulation offers one pecu- 
liarity, in that it causes, during the separation of the mandibles, not only the 
depression of the inferior, but also the elevation of the superior mandible. The 
arrangement which permits this movement has been already alluded to (p. 189) ; 
but yet it is difficult to understand, because there is no active agent, no proper 
muscle to directly effect it. Nevertheless, the mechanism which executes it is 
most simple, and may be given in a few words. Thus, we know that the square 
bone, interposed between the temporal and maxillary bones, like the interarticular 
meniscus of Mammals, is united outwardly with the malar bone, and inwardly 
with the pterygoid. We know also that the latter rests, by means of a diarthrodial 
facet, on the body of the sphenoid, and that it abuts against the posterior extremity 
of the palatine bones (Fig. 109) ; while the first, the zygomaticus, is joined 
directly to the supermaxillary bone. The upper jaw, it is also known, is movable 
on the cranium, because of the flexibility of the cartilages or bony plates uniting 
these two portions of the head. It may then be added, that the square bone 
receives on its anterior process one or two small muscles, which are attached to 
the base of the cranium, and that these bones may be pushed, or rather drawn 
forward, by the contraction of these muscles. It is this projecting or pushing, 
transmitted to the upper mandible through the medium of the malar bone on the 
one side, and the pterygoid bone on the other, that produces the elevation of that 
mandible. Nothing is easier than to prove it ; it is only necessary to take the 
head of a Bird, denude it of all its soft parts, and press with the fingers behind 



GENERAL CONSIDERATIONS ON TEE STRIPED MUSCLES. 227 

the two square bones, to imitate the action of the elevator muscles ; we then see 
the internal extremity of the pterygoid bone glide on the facet of the sphenoid, 
and push before it the palatine bone, during which the zygomatic bone acts in the 
same manner on the maxillary ; and in this way is produced, through the influence 
of this postero-anterior propulsion, the ascending movemeijit we undertook to 
explain. 



THIED SECTION. 

The Muscles. 

After the study of the bony levers and their articulations, comes the description 
of the agents whose function it is to move them. These are the muscles — fibrous 
organs possessing the property of contracting under the influence of a stimulus. 

They are distinguished as striped or striated, and smooth or non-striated 
muscles, according to the character of the anatomical element composing them. 

The striped muscles differ from the smooth, in that, with the exception of 
the tissue of the heart, their contractile power is immediately placed under the 
influence of the will. They are more particularly concerned in the functions of 
relation, which cause them to be also named the external muscles, or muscles 
of animal life. These muscles are nearly all attached to the skeleton, and are 
the active agents in moving the bony framework ; they will, therefore, be the 
only ones referred to in this place, in studying the locomotory apparatus. 

The unstriped muscles are removed from the influence of the will, and belong 
to the organs of vegetative life. They are also designated internal muscles^ 
involuntary muscles, or muscles of orgastic life. 

But before entering upon the particular description of each muscle, we will 
allude to the general considerations relating to their history. 



CHAPTER I. 

GENERAL CONSIDERATIONS ON THE STRIPED MUSCLES. 

THE STRIPED MUSCLES IN GENERAL. 

In this first paragraph, we will survey, in a general manner, the volume, situation, 
form, direction, attachments, relations, and names of the muscles belonging to 
the locomotory apparatus. 

A. Volume. — Nothing is more variable than the volume of the external 
muscles. What a difference there is, for example, between the small scapulo- 
humeralis muscle and the biceps femoris or longissimus dorsi, and what a 
number of intermediate sizes between these three points of comparison ! There 
are consequently very great, great, medium, small, and very small muscles. 

The weight of the total mass of these organs varies according to the species. 



228 THE MUSCLES. 

age, sex, and state of health ; but on taking a general average, it will be found 
that it represents nearly one-half the entire weight of the body. 

B. Situation. — There is no need to insist upon the fact, that a knowledge 
of the situation of the muscles is one of the firet objects to be acquired with 
regard to their arrangement. 

They may, like the bones, be described in two ways. 

1. In relation to the median plane of the body ; whence their division into 
pairs and single muscles. The last, very few in number, are far from exhibiting 
the symmetry which exists in the bones of the same order, as may be seen in the 
diaphragm. 

2. In relation to the other organs ; such as the bones and surrounding 
muscles. 

C. FoEM. — With regard to their absolute form, the muscles, again, like the 
bones, are classed as long, wide, and short. 

Long muscles. — These muscles are more particularly met with in the limbs. 
Provided with a principal axis, to which we may ascribe the effect of their 
contraction, they present a middle portion — usually thick, and tivo extremities of 
unequal thickness ; the most voluminous, always turned upwards, is metaphori- 
cally designated the head, the other the tail. They are most frequently /i<s?/o/7«, 
sometimes conical, but rarely cijlindrical, prismatic, ov flattened into thin bands. 

Thus, as Bichat remarked a long time ago, there are muscles which have no 
other analogy with the long muscles of the limbs than in their external appear- 
ance. These are the long muscles lying above or below the spine, and which are 
composed of a series of fasciculi indistinguishable at their origin and distinct at 
their termination ; or fasciculi, each of which has a distinct origin or termination 
on the vertebrfe. 

Wide muscles. — Wide muscles are those which have two principal axes, and 
are stretched beneath the skin, or around the great cavities of the trunk, which 
they concur in enclosing and separating from one another. They are ellipticaly 
quadrilateral, triangidar, trapezoid, etc. 

Short muscles. — These are found chiefly around the short bones, or at the 
periphery of the articulations which are deeply buried under enormous muscular 
masses. Although their name indicates that their three axes offer nearly the 
same dimensions, yet there is most frequently one, and even two, which pre- 
dominate. They may therefore be assimilated, in this respect, to the long or 
wide muscles. 

D. Direction. — Cruveilhier has justly remarked, that the direction of a 
muscle is one of the most important features in its history ; for it allows the 
determination of the angle of incidence of the muscle on its arm of the lever, its 
power, and its uses. 

With regard to the direction of muscles, we may observe : 1. The form of 
their principal axis. 2. The relation of this axis to the vertical line. 3. Its 
comparison with the axis of the bony levers which the muscles surround or moves. 

a. A muscle is termed rectilinear when its principal axis is straight ; it is 
curvilinear, or circular, if this axis describes a curve more or less marked ; it 
becomes inflected when it proceeds in a certain direction, and afterwards turns 
on a bony or cartilaginous pulley in another direction — that is to say, when its 
principal axis is broken into several lines. If the muscle offers two axes, it will 
\)Qflat or concave, these being one or the other, or straight or curvilinear. 

J. With regard to the direction of the muscles to that of the plumb-line, it 



GENERAL CONSIDERATIONS ON THE STRIPED MUSCLES. 229 

is either vertical, horizontal, or oblique — expressions which carry their own definition 
and require no explanation. 

c. If the direction of the muscles be compared with that of the bones they 
surround and move, it will be found that they are either parallel to these levers, 
or form with them angles more or less acute. The proper direction of the bones 
being known, it is sufficient to indicate that of the muscles to clearly establish 
this comparison. For instance, in saying that the majority of the muscles of 
the shoulder are oblique from above to below, and from before to behind, it is 
understood that these muscles are parallel to the scapula, and that their incidence 
•on the humerus takes place at a right angle. 

E. Attachments or Insertions. — This is undoubtedly the most essential 
part of the study of the muscles ; for with a knowledge of their insertions, we 
may determine then- extent and direction, and even their relations and uses. 

By the term attachment, fixed insertion, or „ origin, is meant the point of the 
muscle which usually remains fixed while the muscle itself contracts ; the attach- 
ment, movable insertion, or terminatio?i is the name given to that portion which 
is fixed to the lever displaced by the muscular contraction. Muscles are fre- 
quently met with the two insertions of which are alternately fixed or movable ; 
and in such cases care is taken not to give these insertions one or other of the 
•designations. 

The fixed insertion is often confounded with that of other muscles ; the 
movable insertion is generally free and independent. 

The muscles are sometimes directly attached to the bones by the ends of their 
fleshy fibres ; but most frequently they are fixed to these inert levers through the 
medium of a tendon or an aponeurosis, the volume of which is less considerable 
than that of the fibres. But for this arrangement, the surface of the skeleton 
would not be sufficiently extensive to give insertion to all the external muscles. 

F. Relations. — The indication of the relations of the muscles completes the 
idea of their situation, and is of great importance from a surgical point of view. 
They should, therefore, be studied with all the precision possible. 

The muscles entertain relations either with the skin, the bones, other muscles, 
■or with vessels and nerves. 

a. It is only, properly speaking, the subcutaneous muscles — such as the 
panniculus carnosus and the muscles of the face — which are really in inmiediate 
contact Avith the skin. The others are separated from it by the aponeurotic -^^^-^*' 
fas(^a^ which will be described as the appendage of the muscular system. '''^^ 

The superficial muscles are only related to the bones by their extremities. 
Those which are deeply situated are immediately applied by their bodies against 
the bones of the skeleton. 

c. The muscles are related to each other in a more or less intimate manner. 
Sometimes they adhere closely to one another ; and at other times they are 
separated by interstices filled with fat or connective tissue, and which are generally 
traversed by vessels and nerves. 

d. The connections of the muscles with the latter organs sometimes assume 
a remarkable character ; this is when one of them accompanies, like a satellite, 
the vascular and nervous trunks concealed beneath its deep face. There is in this 
circumstance an important fact with regard to surgical anatomy. The borders of 
these muscles are usually visible on the surface of the region, and for this reason 
may become valuable guides in seeking for important organs in their vicinity. 

G. Nomenclature. — a. Before the time of Sylvius, the muscles had not 



280 THE MUSCLES. 

received particular names. Since the days of Galen they had been distinguished 
by the numerical epithets of first, second, third, etc., to indicate their place and 
their order of superposition in the regions to which they belonged. It is in this 
fashion that they are designated in the Italian work on the Anatomy of the 
Horse by Ruini. 

b. Sylvius was the fii*st to give the muscles real names ; and, his example 
being followed by succeeding anthropotomists, the nomenclature ot these organs 
was soon completed. But no general view, no methodic spirit, guided Sylvius 
and his successoi-s ; it was sometimes their form, and sometimes their direction 
(oblique, straight, transverse muscles), position {intercostal muscles), uses (adductory 
abductor tnusctes), etc., to which the muscles owed their names. Bourgelat 
applied this nomenclature to the Horse, but modified it in many points. 

c. Chaussier, stnick by the imperfections of the nomenclature introduced into 
science by Sylvius, sought to substitute for it another, much more methodical. 
This anatomist gave to each muscle a name formed by two words, indicating the 
insertions of the organ. Girard imported this ingenious idea into veterinary 
anatomy. It was in applying this nomenclatm'e to the muscles of the Horse 
that he gave the name of supra-acromio-trochanteriiis to the supra-spinatns of 
Sylvius and Bourgelat, and subscapulo-trochanterius to the subscapular of these 
authorities. When two muscles have the same attachments, they are distin- 
guished by adding to the names which indicate their insertions, another which 
signifies the relative position or size of these organs. Thus, we distinguish the 
long abductor of Bourgelat from the short abdudor, both of which would merit 
the name of scapulo-humeral, according to the nomenclature of Chaussier, by 
the epithets of great scapulo-humeral and small scapido-humeral. The binary 
nomenclature of Chaussier is a useful aid to the memory of students, for a 
knowledge of the name of a muscle implies that of its attachments and uses ; 
but, nevertheless, notwithstanding its advantages, this new nomenclature did not 
supersede the old one ; because it ceased to be correct when applied to com- 
parative anatomy, the same muscles not having the same insertions in all the species.^ 

* It is not, however, that the ancient nomenclature has more advantages in this respect 
than the new. What can be more improper, for example, than the names of deltoid, spleuius, 
soleus, digastrieus, etc.? Do the muscles which receive these designations, considered in 
Mammals only, offer in all species the form or the structure which justifies the employment 
of these names in tlie human species? Are the distiuctive epithets of great, medium, little,, 
etc., given to many of them, reasonably applicable in every case? May not the same objectiou 
be urged against tiie majority of the names derived from their uses, complications, etc. ? 

No system of myological nomenclature is really philosophical, and we are of those who 
believe it to be indispensably necessary to create one; indeed, we are inclined to think tliat it 
would be simple and easy to attain this result in starting from a basis the fixity and invari- 
ability of which should be well defined. And this basis is, in our opinion, already discovered ; 
it is the principle of connections founded by E. Geoffroy Saint- Hilaire in his immortal Phihsophie 
Anatomique — a principle to which modern science certainly owes its finest conquests. 

We are desirous that the myolngical nomenclature should rest entirely, in the first place, on 
the relations of the muscles with the bones of the skeleton, or with other organs equally fixed and 
very important ; in the second place, on the reciprocal connections of the muscles. 

Such is our rule ; and it is not precisely new, fur the older anatomists were often inspired 
by it, though unwittingly, as the principle on which it is founded was to them entirely 
unknown; this circumstance, however, immediately leads us to an appreciation of its value. 
For instance, what could be happier than the name of intorcostals given to the inuscleB' 
situated between the ribs, and their distinction into external and internal ? Here we have 
names which indicate the relations of the muscles tliey designate, with the portions of the skeleton 
and the reciprocal connections of these muscles. It can also be applied in an equally rigorous 
manner to every species. We may also cite the supra-costals, the intertransverse, the trans- 



GENERAL CONSIDEEATIONS ON THE STRIPED MUSCLES. 231 

In this work we will follow the nomenclature of Bourgelat, which will, how- 
ever, be submitted to some change. But as the names given by Girard are, in 
our opinion, of some assistance to students, care will be taken to include them in 
the synonymy. 

(It only remains for me to add that Chauveau's nomenclature will be followed 
as closely as possible. It possesses advantages which are greatly superior to that 
adopted by Percivall ; and as, in my opinion, the names and terms imported into 
science should be as nearly alike in all languages as may be compatible with cir- 
cumstances, in order to facilitate study, comparison, and reference, I the more 
readily venture to take this course. Percivall's nomenclature will, however, be 
added in brackets to the synonyms, as well as that of Leyh and Gurlt, when 
occasion appears to demand it. 

Structure of the Striped Muscles. 

There enter into the structure of muscles : 1. Muscular tissue, properly 
so called. 2. Connective tissue in the form of deUcate lamellse, aponeuroses, or 
tendons. 3. Vessels and nerves. 

A. Muscular Tissue. — This tissue is composed of prismatic fasciculi, which 
it is possible to divide and subdivide into several smaller and smaller fasciculi, 
until the muscular fibre or primitive fasciculus is reached. 

The muscular fibre is a kind of irregular cylinder, from O'OIO to 0-008 milli- 
metres in length. It is sometimes straight, sometimes slightly \\Tinkled, but 
always striped either in a longitudinal or transverse direction, or both at once ; 
the transverse striae, being usually more marked, gives the fibril a very elegant 
scalariform aspect. 

This fibre is formed by an envelope and contents. 

The envelope is a very delicate, structureless membrane of an elastic nature, 
named the sarcolemma or myolemma (Fig. 146). Flat or oval nuclei in greater 
or less number can be seen on its inner face. 

The contents, or muscular substance, can easily be resolved into parallel fibrillce, 

verse spinous, the subscapularis, the eupra-spinatus, the infra-spinatus, etc., as they are found in 
a greater or less marked degree in identical conditions. 

Other muscles have received names derived in part from their situation, and in part from 
their volume. These names are far from being as convenient as the first ; as may be judged 
from the following examples : — 

In the majority of vertebrate animals, there are three important muscles situated above 
and behind the pelvis, and forming the base of the croup ; they have been designated gluteals, 
and this name is convenient, because it designates their situation. But to distinguish them 
from each other, regard has been had to their volume ; so that there is a great, a medium, and 
a small gluteus. This is an error, however, for the volume of the muscles is subject to the 
greatest variations, and a voluminous muscle in one species may be a very small one in 
anotlier, and vice versa. The muscle analogous to the gluteus maximus in Man has been 
described by Bourgelat as the minimus, and by Lafosse and Rigot as the medius. With regard 
to the gluteus medius of Man, its representative in the lower animals has been designated as 
the maximus by the majority of veterinary anatomists. What confusion ! And how easy it 
was to evade it by distinguishing these muscles, not by their volume, but by their reciprocal 
connections, which are the same in every species ! Is it not, indeed, more natural to substitute 
the names of superficial, middle, and deep gluteals, for those of great, etc. ? 

The same remark is applicable to the muscles which, in Man, cover the anterior aspect of 
the chest. Designated in common, and justly so, as pectorals, tliese muscles are wrongly 
distinguished into great and little ; for the last, which is already an enormous muscle in the 
smaller Ruminants, is represented in Solipeds by two considerable muscles, much more 
voluminous than the muscle analogous to the great pectoral. It is only necessary, in this 
case, to change their names into superficial and deep pectorals. 



232 



THE MUSCLES. 




B, ULTIMATE FIBRIL OF 
MUSCLE (according 
TO BOWMAN). 

C, Muscular fibre more 
highly magnified, its 
myolemma being so 
thin and transparent 
as to allow the ulti- 
mate fibrillae to be 



in the fresh muscles of insects ; in the higher animals, this disassociation into 
parallel fibrillae is generally only possible in muscles subjected to the action of 
certain reagents. Other reagents favour the breaking up of the fibre into super- 
posed discs ; hence it has been concluded that the fundamental element of the 
primitive muscular fibre was not a fibril, but a discoid segment of fibrillae, to which 
Bowman gave the name of sarcous elements (Fig. 143). 

Bowman considered that the transverse striae represent the lines of union of 
the sarcous elements. But nowadays the striation of the fibre is explained by 
the striation of the primitive contractile cylinder ; in 
fact, each of these is divisible into a series of thick, dark- 
coloured, contractile discs, joined by bright bands which 
play the part of a tissue framework in the cylinder. In 
the majority of Mammals, the thick discs are traversed in 
their middle by a pale streak named the intermediate band 
or streak of Hensen ; in the middle of each bright band is 
a thin disc dividing it into two parts. In the Invertebrata 
the situation is more complicated, as is seen in Fig. 147. 
Kanvier has remarked that there is, in the Skate and 
Rabbit, pale and dark striped muscles. The pale muscles 
are recognized by the predominance of the transverse 
striation and the rarity of nuclei ; wliile the fibres of the 
dark muscles present, on the contrary, a great number of 
nuclei and prevailing longitudinal striation. Lavocat and 
Arloing have examined these difl'erences in the muscular 
apparatus of some Fishes, Birds (Fowls, Guinea-fowls), 
and domestic Mammals (Dog, Ox, Horse), and their 
observations confirm those of Ranvier, apart from some secondary differences 
special to the varied species on which they made their investigations. 

The muscular fibres are united parallel to each other to form secondary 
fasciculi, which are surrounded by a connective sheath — the internal pei'imysium. 
The secondary fasciculi are laid together to constitute more voluminous fasciculi, 

which, in their turn, form the entire 
muscle. The connective sheath enveloping 
the muscle is named the external perimy- 
sium. 

B. Tendons and Aponeuroses. — 
The tendons are white, nacreous, round, 
or flattened cords fixed to the extremities 
of the long muscles. They are composed 
of fasciculi of connective-tissue fibres, 
covered by a layer of flat cells ; they have a parallel direction, and are united to 
one another by loose connective-tissue sheaths. 

The elementary fibres succeed the primitive striped fibres ; the latter terminate 
in rounded extremities, and are fused to the fibrous fasciculi— hollowed into a kind 
of cup — by an intermediate and very solid amorphous substance. 

The aponeuroses belong almost exclusively to the wide muscles; they are 
foi-med of several planes of parallel fibres which are not intercrossed in their 
middle part ; at their superficies, however, the fibrous fasciculi are matted together 
in a more or less inextricable manner. 

It is very interesting to study the mode of union of the muscular fibres with 



Fis;. 146. 





MUSCULAR FIBRE BROKEN ACROSS, SHOWING 
THE UNTORN SARCOLEMMA CONNECTING 
THE FRAGMENTS. 



GENERAL CONSIDERATIONS ON THE STRIPED MUSCLES. 



233 



the tissue of the aponeuroses and tendons, as well as the reciprocal relations of 
these two parts. 

The muscular fibre may be found passing in the same direction as the tendon, 
or it may fall upoji the latter obliquely. In both cases there is no insensible 



Fig. 147. 



Fig. 148.' 





TORN MUSCULAR FI- 
BRE : THE TWO 
FRAGMENTS ARE 
HELD TOGETHER 
BY THE SARCO- 
LEMMA. 

transition between the muscular fibre and the fasci- 
culus of the fibrous tissue ; on the contrary, the con- 
tractile fibre terminates by a rounded extremity, 
which is buried in a corresponding depression in the 
tendon or aponeurosis. The union of the muscular 
with the fibrous tissue appears to be effected by means 
of a kind of amorphous cement, which is very solid ; 
so much so, that when the muscles are submitted to a 
degree of traction sufficient to cause a rupture, this 
never happens at the point of union. 

The tendons commence sometimes by a hollow 
cone, which receives on its internal face the insertions 
of its muscular fibres ; and sometimes by a thin point, 
often divided, which is plunged into the substance of 
the muscle. It is worthy of remark, that a muscle 
provided with two tendons shows the first-named 
arrangement at one of its extremities, and the other 
at its opposite extremity ; so that all the fibres which 
compose the muscle offer nearly the same length, those 
which leave the summit of the internal tendon being 
fixed to the bottom of the hollow cone formed by the 
second tendon, and so on reciprocally. 

Tendons are not necessarily placed at the ex- 
tremities of muscles. Sometimes the muscle is divided into two bodies or bellies 
by a middle tendon ; it is then named a digastric muscle, 

', * These figures are from Renaut's work, Trailed' Histologie. Just publisiiedby Lecrosnier, 
Paris. 



PRIMITIVE FIBRE OF THE RED 
MUSCLE OF A RABBIT, MADE 
TENSE BY THROBBING. 

NS, Superficial nuclei ; np, 
deep nuclei ; n, nuclei in 
profile beneath the sarco- 
lemma; GS, sarcodic drop 
resulting from the expression 
of the muscular plasma, due 
to the contraction of the 
muscle under the influence 
of alcohol ; G, G, G, proteic 
granules from the muscular 
plasma, pressed out and united 
beneath the sarcolemma, or 
squeezed outside of it. 



THE MUSCLES. 



The muscular fibres which are continued by the fibrous fascicuK may be 
divergent or parallel. In the first case — the diaphragm, for example — the con- 
nective fibres run in the same direction as the muscular fibres. In the second 
case several arrangements may be observed : 

1. Tendons may pass in the same direction as the muscular fibres. This is the 
most simple manner (Fig. 152, A). 

Fig. 150.' 
Fig. 149. 




PRIMITIVK MUSCCTLAR FIBRE FROM 
THE FOOT OF THE LUCAN03 
STAG-BEETLE —A COMPLICATED 
CONTRACTILE SEGMENT, MADE 
TENSE BY THE INTERSTITIAL 
INJECTION OF STRONG ALCOHOL. 

K, Muscular nucleus ; 8, sarcolem- 
ma; SM, limits of a contractile 
segment of muscular substance ; 
DE, limits of a thick disc system 
enclosing discs ; Ep, principal 
thick disc ; Ea, Ea, thick acces- 
sory discs ; Bi, intervening 
bright bands of the thick discs ; 
BC, limits of the system of the 
bright band containing — Mp, 
the thin principal disc, and Ma, 
Ma, the two thin accessory discs ; 
/, /, /, lines of longitudinal 
striation indicating the limits 
of the fibrillar fasciculi. 




RELATION OF THE PRIMI- 
TIVE MUSCULAR FIBRE3 
WITH THE TENDON OF 
THE STERNO - HYOID 
MUSCLE OF THE FROG. 

F, Ordinary primitive 
fibres ; f', muscular 
prolongation ; T, ten- 
don of insertion. 



2. Muscular fasciculi, passing altogether from the same side to become united 
into a tendinous cord (Fig. 152, B and C), constitute a semi^enmfonn muscle. 

3. Muscular fasiculi maybe implanted to right and left of the tendon, and 
form ^pennated ov penniform muscle (Fig. 152, D). 

These various aiTangements of the muscular fibres with their tendons demon- 
strate the necessity of not confounding the length of the fleshy body of a muscle 

' From Eenaut's work already mentioned. 



OENEEAL CONSIDERATIONS ON TEE STRIPED MUSCLES. 



235 



Fig. 151. 




with the length of its fibres ; for the latter alone give an indication of the possible 
degree of shortening it is capable of — this shortening being estimated at one- 
fourth the length of its contractile fibres. In glancing at the different an'ange- 
ments shown in Fig. 152, it will be seen that, with muscles which have the same 
total length, that of the contractile elements varies within extensive limits. 

C. Vessels and Nerves. — The muscular 
tissue receives much blood ; the fibrous tissue 
very little. The arteries are large and numerous, 
and each is accompanied by two veins. The 
capillary vessels anastomose in such a manner 
as to form rectangular meshes, the greatest 
diameter of which is directed towards the length 
of the muscle. 

Ranvier has remarked that, in the dark 
muscles of the Rabbit, the vascular network has 
varicose formations which retain a considerable 
mass of blood in the interior of the muscles. 

The lymphatic vessels of the muscles are 
few ; they sometimes penetrate their interior in 
following the capillaries ; at other times they 
remain on the sm-face, in the external perimy- 
sium. The existence of lymphatics has not yet 
been demonstrated in tendons, aponeuroses, or 
synovial membranes. 

The nerves emanate from the cerebro-spinal 
centre. At their tenninal extremity they offer 
a small enlargement, called by Rouget the motor 
end plate, and by Doyere and Kiihne the nervous 
colline (hillock). It is admitted that the motor 
tube traverses the sarcolemma, there losing its 
envelope ; and that the substance of the axis- 
cylinder is spread over the surface of the muscular fibrillae to form the motor 
plate. 

Physico-chemical Properties of Striped Muscles. 

Muscles are soft organs, remarkable for their more or less deep-red colour, 
which varies with the species, and even with the age and health of animals of the 
same species. 

By desiccation, muscles become hard and brown ; by repeated washing they 
assume a straw-yellow tint. 

Muscles are extensible, elastic, and tenacious ; and their tenacity is more 
marked during life than after death. 

It has been remarked that the juice impregnating the muscular tissue has a 
marked acid reaction when extracted from a muscle which has been actively con- 
tracting. (The fluid or " muscle plasma " obtained by pressing flesh, is either 
neutral or slightly alkaline. It soon coagulates and separates into two portions — 
a semi-solid portion, " myosin," and the fluid serum that at ordinary temperatures 
quickly acquires an acid reaction.) It holds in solution a variable quantity of 
albumen, casein, fat, a little creatine, creatinine, and a somewhat large proportion 
of sarco-lactic acid. The solid substance of the muscle may be partly transformed 



TRANSVERSE SECTION OF FROZEN MUS- 
CLE, MAGNIFIED 400 DIAMETERS. 

N, Nerve. M, Muscular fibre, sur- 
rounded by portions of six others : 
a, nucleus of the nerve-sheath ; 
6, nucleus of the sarcolemma ; c, 
section of nucleus of terminal plate 
of nerve ; cf, transverse section of 
terminal plate, surrounded by gran- 
ular material; e, transverse section 
of muscle nuclei ; /, fine fat-drops. 
The angular dark particles are sec- 
tions of sarcous elements ; the clear 
intervening spaces represent the 
fluid isotropal part of the muscle 
substance. 



236 THE MUSCLES. 

into gelatine by boiling in water ; but its largest portion is a nitrogenous sub- 
stance, soluble in dilute hydrochloric acid, called myosine, or muscular fibrine ; it 
differs but little from the fibrine of the blood. 

Physiological Properties of the Striped Muscles. 

In this paragraph will be discussed the development of the muscles, muscular 
contractility, and the part the muscles play in locomotion, 

A. Development of the Muscles. — A muscle is derived from a mass of 

Fig. 152. 



T' 



ARRANGEMENT OF THE FIBRES OF A MUSCLE. 



153- 



M, Body of a muscle. T, t', Tendon, a, b, Length of the body of the muscle. A, B, C, D, Various 
modes of arrangement of the muscular fibres. (From Beaunis and Bouchard's Anatomiff 
descriptive.) 

embryonic cells. Each cell becomes considerably elongated, and its nucleus 
multiplies, the nuclei extending along the course of the fibre. The cellular mem- 
brane, enormously developed, forms the sarcolemma ; while the contents of the cell, 
becoming more dense, divide longitudinally, and give 
rise to the sarcous elements. When the muscles are 
formed, they grow by the augmentation in length 
and thickness of their primitive fibres. 

B. Muscular Contractility. — Muscles pos- 
sess the property of contracting under the influence 
of a natural or artificial stimulus. Muscular con- 
traction is the phenomenon resulting from the opera- 
tion of this property. Muscles in a state of contrac- 
tion are the seat of physical and chemical phenomena ; 
they change their form and consistence, and produce 
a relatively abundant quantity of carbonic acid, 
creatinine, and inosinic acid. During contraction, it has been remarked that the 
muscular fibres contract by increasing in volume, like an india-rubber tube left to 




distribution of CAPILLARIES 
IN MUSCLE. 



GENERAL CONSIDERATIONS ON THE STRIPED MUSCLES. 



237 



itself after being inflated, and that the transverse striation becomes much closer ; 
though the zigzag doubling mentioned by Prevost and Dumas has not been 
observed. 

But these physical and chemical modifications, important as they are from a 
physiological point of view, cannot longer be dwelt upon here. It is particularly 
important to speak of muscular contraction. 

A muscle that contracts becomes shortened ; its two extremities approach each 
other if they are free ; or one draws near 



Fig. 154. 



rT%^^--<i-^ 



m^^'^mx 



i 




the other if the latter is fixed to an im- 
movable point. If the extremities of a 
muscle are attached to two movable 
levers, its contraction will bring about the 
displacement of one or other of these ; 
from this a movement is produced. 

The degree of shortening of a muscle 
varies, according to its being entirely 
free, or having a resistance to overcome. 
The mean limit of this shortening is 
about one-fourth the length of the 
muscular fibres. From this it will be 
understood, that the movement produced 
by the contraction will be in proportion 
to the length of the fibres ; though in 
this appreciation it will be necessary to 
keep in mind the density and energy of 
the fibre, as well as the intensity of the 
stimulation which induces the con- 
traction. 

As each fibre represents a force 
independent in its action, it results that the power of a muscle may be inferred by 
the number of its fibres, or its volume. 

Muscles are often aided in their action by mechanical conditions : such as the 
disposition of the levers on which they act, the direction of the muscular fibres 
in connection with these levers, and, lastly, by the presence of bands or elastic 
cords. 

C. Uses of Muscles. — There are flexor, extensor, abductor, adductor, rotatory 



PORTION OF AN ELEMENTARY MUSCULAR FIBRE, 
WITH FOUR DARK-BORDERED FIBRES (a) 
CROSSING ITS SURFACE. 

b, Capillary blood-vessel, with fine nerve-fibres 
(a few only of the transverse markings of the 
muscle are represented); c, two of the dark- 
bordered nerve-fibres passing over the ele- 
mentary fibre to be distributed to adjacent 
fibres. This arrangement, in which a dark- 
bordered nerve-fibre, distributed to muscle, 
divides into branches, one of which passes to 
a vessel, while the other ramifies upon a 
muscle, is frequent. Magnified 700 diameters. 




MUSCULAR FIBRE IN A STATE OF CONTRACTION IN THE CENTRE ; THE STRI^ APPROXIMATED, 
THE BREADTH OF THE FIBRE INCREASED, AND THE MYOLEMMA RAISED IN VESICLES ON ITS 



and other muscles, for all the movements of which the articulations are the 
centre. 

To determine the uses of the muscles, it is sufficient to know their insertions 
and the mode in which the bones furnishing these insertions articulate with each 
other. • 

18 



238 TEE MUSCLES. 

For example, if a muscle is situated in an angle formed by two bones which 
have a trochlean articulation, it will be a Jlexar ,- but if it is placed behind the 
(Summit of the angle, it becomes an extensor ; if it be located on the external side 
of an enarthrosis, it is an abductor ; and when on the inner side of the joint, or 
between it and the middle plane of the body, it is then an adductor. A muscle 
may be rolled obliquely round the joint it controls — in passing, for instance, from 
the inner face of one bone to the outer face of another forming an articulation — and 
in such a case the/ea;ors and extensors become also rotators if the diarthroses they 
move permit rotation. 

Lastly, muscles applied more or less obliquely on bones united by a trochoid, 
will pivot one of the bones on the other — for instance, the great oblique muscle 
of the head. 

It is useless to multiply examples, for, the principle being once understood, it 
is easy in nearly every case to determine the uses of a muscle when its situation, 
and the number and kinds of articulations included between its insertions, are 
known. 

The result of the contraction of muscles being influenced by the form of their 
principal axis, and the length and direction of their levers, it is necessary to 
briefly examine these two points : 

1. The immediate effect of the contraction of rectilinear muscles is the approxi- 
mation of the bones to which they are attached. This approximation is usually 
brought about by the displacement of a single bone — that which receives the 
movable insertion of the muscle. Sometimes, however, the two bones move simul- 
taneously, or they are alternately fixed and movable. 

The first result produced by a curvilinear muscle, is the straightening of its 
component fibres ; after which it may act on the bony levers as do the rectilinear 
muscles, if its contractile power be not entirely expended. When a muscle is quite 
circular, its only action is to contract the opening it circumscribes. 

With regard to the inflected muscles, their action can only be estimated from 
their point of inflection ; they operate as if this point represented their origin or 
fixed insertion, 

2. The muscular powers are submitted to the statical and dynamical laws 
which govern the theory of levers ; for the bones are only levers moved by the 
muscles. 

In the locomotory apparatus we find the three kinds of lever recognized by 
physicists. Thus the head, extended by the great complexus muscle, represents 
an interfixed, or lever of the first class ; the foot, extended by the gastrocnemius 
muscle, offers an example of the inter-resisting, or second kind, when the limb 
remains fixed on the ground ; lastly, the lower jaw, raised towards the upper by 
the masseter muscle, forms an interpuissant, or third kind. 

It is worthy of remark that the arm of resistance in the bony levers is always 
extremely long ; a circumstance which favours speed and the extent of movement, 
but at the expense of power. 

On the other hand, muscles are rarely perpendicular to the arm of their levers — 
at least at the commencement of their action ; a second circumstance which 
diminishes their energy. 

Appendages of the Muscles. 

These are : 1. The enveloping or containing aponeuroses. 2. The serous or 
mucous hursse. 3. The tendinous and synovial sheaths. 



GENEBAL CONSIDERATIONS ON TEE STRIPED MUSCLES. 239 

A. Containing Aponeukoses. — These are layers or fascia of white fibrous 
tissue, which envelop, in common, all the muscles of one or several adjoining 
regions — principally those of the inferior bones of the limbs, where they constitute 
a kind of hollow cylinder. 

The aponeuroses are formed of very resisting interwoven fibres, which are 
attached to the bones at numerous points. At their periphery they receive the 
insertion of one or several muscles, which keep them more or less tense. Their 
external face is in contact with a thin connective-tissue layer that separates them 
from the skin. The internal face sends lamellar prolongations between the 
muscles, which enclose these in special sheaths. 

The aponeuroses maintain the muscles in their position, and sustain them 
during their contraction. 

B. Sekous Burs^. — The serous or mucous bursae are small cavities, filled 
with a serous fluid, which are met with at those points where the muscles glide 
over resisting surfaces. They are generally orbicular or circular, and their interior 
is often divided by fibrous bands. 

Their walls are formed by slightly condensed connective tissue, and may be 
lined by a pavement epithelium ; in which case it is believed that the serous 
bursa is produced by the simple dilatation of one of the connective-tissue meshes. 

They become much enlarged when pressure or friction is great at the points 
where they are situated. They may appear in any region, when the conditions 
which preside at their physiological development are accidentally produced. 

C. Tendinous Sheaths and Synovial Membranes. — Tendinous sheaths is 
the name given to the half-bony, half-fibrous, sometimes exclusively fibrous, 
gliding grooves in which tendons play when they are inflected to change their 
direction, or when they glide over movable articulations. 

The tendinous synovial sheaths are serous membranes lining the tendinous 
sheaths, and covering the tendons at the points where these two parts are in con- 
tact. They secrete a synovial fluid quite like that of the articulations. 

When they almost completely envelop the tendon, and are afterwards carried 
to the walls of the sheath, they are termed vaginal. 

Their walls are composed of : 1. A very fine connective-tissue membrane, 
confounded on its external face with the tendinous sheath, by the other face with 
the tendon. 2. A simple layer composed of pavement epithelium, extended over 
the whole or a part of the internal face of the membrane. 

Manner of Studying the Muscles. 

A. Classification. — To facilitate the study of the muscles, two methods may be employed 
in grouping them. The first consists in classifying them according to their uses ; describing, 
for example, all the flexors, extensors, etc., of the same region. In the second method, the uses 
of the muscles are not taken into account, their relations only being considered ; and they are 
divided into groups or regions, which include all the muscles situated around a bone. The 
latter is the method now adopted, because it is the most convenient, useful, and rational. 

B. Preparation. — We will limit ourselves to some general remarks on the following 
points : — 

Choice of a mibject. — If there is for disposal a certain number of subjects from among which 
it is possible to make a selection, the preference should be given to those which have the mus- 
cular system best developed; not that large, soft, lymphatic Horses with enormous masses of 
muscle should be chosen, for these animals are always less convenient than small or middle- 
sized, well-bred Horses. Asses and Mules, when very emaciated, answer well for the prepara- 
tion of the muscles. 

Position of the subject. — It is necessary to place the subject, immediately after death, in a 
convenient position, in order that the cadaveric rigidity may set in while it is in that attituda 



240 



THE MUSCLES. 



Without this precaution, the various parts of the body may assume an inconvenient shape oi 
direction, and all attempts to amend them will prove almost unavailing, particularly in the 
larger animals. 

Three principal positions may be given to subjects: 

1. The animal is in the first position when it is placed on its back, the four extremities in 
the air, and maintained in that posture by means of long cords passed round the pasterns, and 
fixed to the movable rings which terminate the extremity of the four bars of the wheeled table 
on which the subject is laid. The head should be beyond the end of the table and rest upon a 
stool. The animal should always be placed in such a manner that the head be opposite the 
fore-part of the table, so that the movements of the pole or shaft be not impeded during the 
displacement of the apparatus. In order that the neck be not twisted to the right or left, in 
attaching the fore limbs tiie subject i-hould be raised so that the withers rest lightly on the 
table. According to the bulk of the animal and the length of the bars, the ropes should be 
passed around either the pasterns, above the fetlocks, or even above the knees (Fig. 156). 

2. To place the animal in the second position, it is turned on the belly, the two thighs 
flexed, the extremities carried beyond the table, and the head fixed between two bars by meana 

Fig. 156. 




HORSE FIXED IN THE FIRST POSITION ON ONE OF THE WHEELED TABLES IN USE AT THE 
LYONS VETERINARY SCHOOL. 



of a rope passed under the zygomatic arches; or better, two cords with metal hooks may be 
employeil, a hook being fixed into each orbital arch, or through the skin and masseter muscle 
to beneatii the zygomatic arch, the cords being tied short to the uprights of the table (Fig. 
157). A block of wood or small stool may be employed to prop the trunk by placing it in the 
Bublumbar region (Fig. 157). 

3. The hubject is in the third position when it rests on its side. 

Rules to he observed during the preparation. — 1. By no means, if possible, remove the skin 
from the regions to be dissected until quite ready to begin the dissection. If this is impossible, 
then take the precaution of enveloping these regions in damp cloths, or in the animal's skin, 
to prevent desiccation of the aponeuroses and tiie superficial muscles. 

2. To rlissect a muscle, it is necessary to remove the aponeuroses or the other muscles which 
cover it, the eonnective tissue enveloping it, and the fat, glands, vessels, and nerves lodged m the 
neigiibouring interstices. The aponeuroses should be removed in shreds by making them very 
tense with the forceps, but without raising them, and causing the blade of tlie scalpel to glide 
between the fibrous and muscular surfaces, keeping it always parallel to these two planes. The 



GENERAL CONSIDERATIONS ON THE STRIPED MUSCLES. 241 

coverin- muscles sliould not be entirely excised, but ought to be cut through tlie middle, across 
tbeir fibres and the euds thrown back ; in this way it is always pc^sible to replace a muscle 
bv brlDcring the two portions together ; the study of its relations is then much more easy. The 
cellular^issue is got rid of by removing it with the forceps, and carrying the edge of the 
scalpel in the re-entering angle formed by the cellular layer and the surface of the muscle. 
This method also suffices for removing aponeuroses when they are slightly adherent to the 
muscular fibres. But when they give attachment to these by their under face, as may be 
noticed in the external scapular aponeurosis, it is necessary to have recourse to the method 
indicated above. To remove fat, glands, etc., scissors will be found very advantageous. 

Order tofolloio in preparing all the muscles of the same subject, so as to derive most advantage 
therefrom 1. Place the subject in the first position, and commence by studying the muscles of 
the inferior abdominal region. Then excise them, leaving the posterior extremity of the 
deep pectoral muscle, the prepubic tendon, and the crural arch intact. The abdommal cavity 
having been emptied of the viscera it contains, dissect and study successively the diaphragm. 



Fig. 157. 




HORSE FIXED IN THE SECOND POSITION ON A WHEELED TABLE. 



the internal crural region-^xcept the deep muscles-the sublumbar region, the femoral and 
posterior crural regions, the superficial muscles of the inferior cervical region, and the pectoral 

'^^^ 2'°After detaching for future use one of the anterior limbs, the animal is placed in the second 
position, and one after another may be dissected the muscles of the ear, those of the superior 
cervical region, the croup and costal regions-except the triangularis sterni-and the spinal 
region of the back and loins. . ,. . , 

3. The regions of the anterior limb may be prepared at the same time, or immediately 

* ^I'^Separate the two posterior limbs by sawing the femurs through their middle, and proceed 
to the dissection of the muscles of the posterior leg and foot. 

5. By means of another application of the saw across the middle of the loms, the pelvis is 
completely isolated for the preparation of the coccygeal muscles, and the deep muscles of the 
internal crural region, nearly as they are represented in figures 39 and 40. 

6. The animal being placed on its side, the pectoral cavity is opened by sawing through 
the ribs near their extremities ; on the two particular portions thus obtained may be 
studied, in one part, the triangularis sterai, and in the other the deep muscles of the inferior 



242 TEE MUSCLES. 

cervical region, including the longus colli and the anterior and lateral straight muscles of the 
head. 

7. Lastly, tlie head is disarticulated and the muscles of this region are prepared. 

The subject may afterwards serve for the study of nearly all the articulations. 

Preservation of the muscles.— The muscles may be preserved by immersing them in appro- 
priate fluids, and the muscular preparations by drying them. 

A large number of liquids preserve muscles from putrefaction. We may mention alcohol ; 
a mixture of alcohol and oil of turpentine; alcohol, water, and chloroform; a solution of 
sulphate of iron, bichloride of mercury, or arsenious acid. The best preservative fluid, how- 
ever, is nitric acid diluted with water, in the proportion of one of the former to three of the 
latter. The acid hardens the muscles and softens the connective tissue ; this allows all the 
interstices to be completely cleared out, and even permits the primitive muscular fasciculi 
which have been concealed by the white tissues, to be exposed. 

Desiccation, after immersion in a bath of arsenious acid or sulphate of iron, causes the 
muscles to become hardened and distorted. It is therefore a bad procedure, though it preserves 
the muscles. Steeping in carbolized glycerine is sometimes resorted to. 

(A careful dissection of the muscles, with regard to their origin, insertion, action, and 
relations, is of infinite importance to the student of human anatomy ; to the Veterinary Student 
it is no less important, and more particularly with reference to the muscles of the limbs. A 
correct knowledge of their situation, attachments, and functions is often the only guide the 
Veterinary Surgeon can rely upon in the diagnosis of those apparently obscure cases of lameness 
whicli are of such comparatively frequent occurrence. In the words of Mr. Henry Gray, we 
may repeat that " an accurate knowledge of the points of attachment of the muscles is of great 
importance in the determination of their action. By a knowledge of tiie action of the muscles, 
the surgeon is able at once to explain the causes of displacement in the various forms of 
fracture, or the causes which produce distortion in the various forms of deformities, and, con- 
sequently, to adopt appropriate treatment in each case. The relations also of some of the 
muscles, especially those in immediate apposition with the larger blood-vessels, and the surface 
markings they produce, should be especially remembered, as they form most useful guides to 
the surgeon in the application of a ligature to these vessels" (^Anatomy, Descriptive and 
Surgical). 

An accurate knowledge of the muscular system is also of great service to the Veterinary 
Surgeon, in estimating the value to be placed upon the external conformation presented by 
animals intended for diflferent kinds of labour. 

" In dissecting," says Mr. Holden, " there are four principal objects to be constantly borne 
in mind by the student : 1st, The impression on the memory of those facts of general anatomy 
taught in tiie lectures. 2nd, Tlie study of those parts of the body more especially concerned 
in surgical affections and operations. 3rd, The education of the sense of touch, and of the 
hand in the use of instruments; and 4th, The education of the eye in the knowledge of the 
several tissues of the body, in various positions, and varying circumstances. . . . The education 
of the eye is a gradual and tedious process, but one which is pretty certain to be satisfactorily 
accomplished if the student do but use his hands properly, and therefore a few words on the 
manual part of dissection may not be out of place. 

" First, as to the instruments requisite for dissection. A case, containing six or eight 
scalpels, two pairs of scissors, a pair of dissecting forceps, a set of chain-iiooks, a blow-pipe, 
and a probe, will enable the student to make all requisite dissections, supposing that he is 
allowed the use of a saw and chisel in the dissecting-room. Great variety exists in dissecting- 
cases, both as to form and expense, but so long as the instruments themselves are strong and 
good, the simpler the case the better. Scalpels for dissection are made of two principal shapes ; 
in one, the edge is bevelled to the point, the back being straight; in the other, both back and 
edge are bevelled to a point midway between the two. The latter form is preferable for most 
purposes. The blade should not be more than an inch and a half long, and never double 
edged ; but the material of which the handle is constructed is a matter of indifference. 

" For all ordinary dissection, it will be found most convenient to hold the scalpel like a 
pen ; but for cleaning the fascia off muscles and following out small nerves, it is better to hold 
it reversed, so that the back of the knife may be against the tissue which is to be preserved. 
In making the first incision through the skin of a limb, or in any otlier position where a long 
incision is required, the knife may, with advantage, be held under the hand, by which the 
wrist has more play, and the student has the opportunity of practising a mode of holding the 
knife which he will find very useful when operating on the living body. 

" The forceps should be broad at the extremities and coarsely serrated, so that it may 
retain a firm hold on small portions of tissue. It is very important that the forceps sliould not 



MUSCLES OF THE TRUNK. 243 

be too strong in the spring, for in that case it becomes so fatiguing to the hand that it is 
impossible to continue its use for any lengtii of time. The forceps should be held lightly 
between the thumb and the first and second fingers of the left hand, which may be steadied by 
resting the little finger on a neighbouring part. 

" The chain-hooks should be strong, and bent in the direction of the thickness and not of 
the breadth of the steel, as is sometimes done. These Litter are very inferior, being liable to be 
unbent under any considerable strain. Care should be taken that tlie chains are firmly linked, 
and that the central ring is sufficiently stout to bear any force that may be applied. The 
scissors should be large and strong, and it will be found advantageous to have one curved pair, 
which is very useful in preparing the ligaments. 

" The student will do well to bear in mind that he will probably be called upon in after life 
to operate on the living body, the only preparation for which is careful dissection: he 
should therefore, as far as possible, conduct all his dissections as methodically, and with as 
much care, as if operating on the living body. 

"The student should bear in mind that his manual labour is only a part of his duty, and 
will be thrown away, unless he at the same time study the description of the part upon which 
be is engaged ; he should not, therefore, carry the dissection further than he can learn the 
description on the same day, and at the subject, and should, if possible, re-peruse the description 
in the evening, and always on the next morning, before carrying the dissection any further.") 



CHAPTEE II. 

THE MUSCLES OF MAMMALIA IN PARTICULAR. 

Article I. — Muscles of the Trunk. 

Subcutaneous Region. 

This only comprises a single muscle, the /leshi/ panniculus (panniculus cartiosus), 
which moves the skin covering the trunk. Strictly speaking, however, we may 
describe as dermal muscles all those which are attached to the inner surface of 
the superficial integument — the muscles of the face, for example. 

Fleshy Panniculus (Panniculus Carnosus). 

Preparation. — Place the animal on its side, and carefully remove the skin, allowing the 
panniculus muscle to remain on the subjacent muscles. It may also be easily prepared on 
the subject placed in the first position. 

Situation — Form — Extmt. — Situated on the inner surface of the skin covering 
the sides of the thorax and abdomen, this is an immense wide muscle, UTegularly 
triangular in shape, thin at its borders, and thicker in the middle than elsewhere. 

The upper border corresponds to a curved line, convex superiorly, and 
extending obliquely from the flank to the withers. The inferior border is carried 
horizontally from the flank to the posterior border of the olecranian mass of 
muscles, passing along the upper margin of the deep pectoral muscle, which it 
covers, and to which it adheres somewhat closely. The anterior border descends 
from the superior extremity of the shoulder on to the muscles of the forearm. 

Structure — Attachments. — The fibres of this muscle are directed forwards 
for its posterior two-tliirds ; but on arriving on the shoulder they gradually 
become vertical. They are continued, on the margins of the muscle, by aponeu- 
roses which attach it either to the internal surface of the skin, or the fibrous 
fascia of the superficial muscles. 

This muscle has, besides, a very remarkable insertion into the humerus, which 



244 THE MUSCLES. 

was noticed by G-, Cuvier, in his ' Le9ons d'Anatomie Comparee,' and which 
appears to have been omitted, at least so far as SoHpeds are concerned, in every 
treatise on Veterinary Anatomy. The following is what we have often observed 
in this respect : On reaching the posterior border of the ulnar mass of muscles, 
the panniculus divides into two superposed layers — one, superficial, is carried 
to the muscles of the anterior limb ; the other, deep, soon terminates by an 
aponeurosis, which is united to the deep pectoral muscle, and is bordered at 
its . upper margin by a nacrous aponeurotic band that penetrates between the 
thorax and the muscles of the arm, to be fixed to the small trochanter. 

Relations. — By its superficial face, with the skin, to which it closely adheres ; 
by its deep face, with the latissimus dorsi, the dorsal portion of the trajjezius, the 
abdominal tunic, the great oblique muscle of the abdomen, the serratus magnus, 
some external intercostals, the spur vein, and the superficial muscles of the 
shoulder and arm. 

Action. — The animal, in contracting this muscle, shakes the whole of the 
cutaneous integument which covers it ; thus preventing insects from alighting on 
the surface of the body, or tormenting by their bites or stings. 

In the Dog, tlie panniculus carnosus is prolonsed over the croup, and is united along the 
dorso-lumbar spine to that of the opposite side. It is very developed in the Cat. 

Cervical Region. 

This region comprises all the muscles grouped around the cervical vertebrae — 
muscles which are conspicuous by their volume, and the important part they play 
in the animal economy. There are described a superior and an inferior cervical 
region. 

A. SuPERioE Cervical, or Spinal Region of the Neck. 
This includes seventeen pairs of muscles, arranged in four layers on each side 
of the cervical ligament, as follows : — 

First Layer. 
Cervical portion of the Trapezius. 

Second Layer. 
Rhomboideus. Angularis scapulm. Spleniv^. 

Third Layer. 
Complexus. Trachelo-Mastoideus. 

Fourth Layer. 

Spinalis or Semispinalis Colli. Six Intertransversales Colli. Obliquus 
Capitis anticus or inferioris. Obliquus Capitis posticus or superioris. Rectus 
Capitis posticus major. Rectus Capitus posticus minor. 

These occupy the triangular space circumscribed by the upper border of the 
cervical hgament, the transverse processes of the vertebrae of the neck, and the 
spinous process of the second dorsal vertebra. 

Preparation. — Place the subject in the second position, and dissect in succession the four 
layers of the region. To study the first layer, which is formed by the cervical portion of 
tlie trapezius, remove the skin, connective tissue, and the fascia covering that muscle (see 
Fig. 1.59). The preparation and study of the second layer, composed of tlie rhomboideus, 
angularis, and splenius, is carried out in two stages. In the first, the trapezium and the 



MUSCLES OF THE TRUNK. 



245 



mastoido-humeralis is removed, leaving only the cervical insertions of the latter muscle ; then 
the limb is removed by sawing through the scapula beneath the insertions of the angularis 
and serratus magnus, as in Fig. 162. But as neitlier the cervical or dorsal insertions 
of the splenius are exposed, it is necessary to proceed to the second part of the operation by 
removing the rhomboideus, angularis, and the superior extremity of the shoulder. To prepare 
the third layer, which comprises the great and small complexus, it is sufficient to excise the 
splenius, in following the direction of the neck, and to turn upwards and downwards the two 
portions of the muscle (see Fig. 162). Lastly, the deep layer — the semispinalis and iutertrans- 
versalis, oblique, and posterior straight muscles, as well as the cervical ligament — is 
by removing the complexus and longissimus dursi muscles (see Fig. 162). 

First Layer. 

Cervical Portion of the Trapezius. 



for description of this muscle, see 



Region of the Back and Loins. 



Second Layer. 
Rhomboideus (Figs. 158, 6 



162, 1, 2.) 



Synonyms. — Described by Bourgelat as two muscles, the "proper elevator of the shoulder and 
the rhomboideus, these were termed by Girard the cervico-subscapularis and dorso-subscapularis. 
(This is the rhomboideus longus and brevis of Percivall, and the dor so- scapular is and cervico- 
euhscapularis of Leyh.) 

Form — Situation — Direction. — This muscle has the form of a very elongated 
triangle, and is situated at the inner aspect of the cervical trapezius and the 

Fig. 158. 




LATERAL VIEW OF THE NECK; SUPERFICIAL MUSCLES. 

1, 1, Parotid gland ; 2, sterno-maxillaris, and, 14, its junction with its fellow of the opposite side, 
3, 4, mastoido-humeralis, or levator humeri; 5. splenius; 6, rhomboideus; 7, funicular portion 
of the cervical ligament, or ligamentum colli; 8, angularis of the scapula; 9, supra- or antea- 
spmatus; 10, trapezius; 11, infra- or postea-spinatus ; 12, jugular vein; 13, subscapulo- 
hyoideiis; 15, trachea. 

scapular cartilage, beneath the cervical ligament, the direction of which it follows. 

Structure— Attachments.— It is composed of thick fleshy fasciculi, the anterior 

of which are obhque downwards and backwards, the posterior passing directly 



246 THE MUSCLES. 

downwards. These fasciculi are fixed by their superior extremity to the funicular 
portion of the cervical ligament and the summits of the spinous processes of the 
four or five dorsal vertebrae succeeding the first— Jixed insertion ; by their inferior 
extremity, to the inner aspect of the scapular cartilage, where the anterior 
fasciculi are confounded with those of the angularis. 

Relations. — Covered by the cervical portion of the trapezius, the scapular 
cartilage, and the alponeurosis of the latissimus doi-si muscle, the rhomboideus 
covers the sphenius, which is excavated near its superior border for its reception, 
as well as the aponeurosis of the sen-atus auticus muscle through the medium of a 
yellow elastic layer. 

Action. — It draws the shoulder upwards and forwards. 

2. Angularis Scapula (Levator Anguli Scapula) (Figs. 159, 4 ; 162, 3). 

Synonyms. — Trachelo-subscapularis — Girard. Portion of the serratus ma.gnvis—Bourgelat. 
Elevator of the scapula — Cuvier. (Anterior portion of the serratus magnus of Percivall. The 
levator anguli scapulx of Man.) 

Situation — Form — Structure. — This is a very strong muscle, situated in front 
of the shoulder, triangular, flattened on both sides, thin at its superior border, 
thick behind and below, and almost entirely fleshy. 

Attachments. — It takes its origin from the transverse processes of the five last 
cervical vertebras by five distinct portions, which are directed towards the scapula 
in converging towards each other, and soon join to form a single muscular body, 
which is inserted into the internal face of the scapula, on its anterior triangular 
surface. 

Relations. — This muscle is confounded at its inferior border with the serratus 
magnus. It is covered by the cervical trapezius, the mastoido-humeralis, and the 
small pectoral muscle. It covers the splenius, the inferior branch of the latissimus 
dorsi, and transversalis costarum. Near its junction with the serratus magnus, its 
internal face adheres very closely to the transverse processes of the three first dorsal 
vertebrae . 

Action. — It draws forward the superior extremity of the scapula, while the 
humeral angle is carried backwards. If the shoulder becomes the fixed point, it 
can act in the extension or lateral inclination of the neck. 

3. Splenius (Figs. 162, 4, 5 ; 163, 10). 

Synonyms. — Cervico-trachelian — Girard. 

Form — Situation. — A considerable muscle, flattened on both sides, triangular, 
and comprised between the cord of the cervical ligament, the inferior branch of 
the latissimus dorsi, and the transvei-se processes of the four first cervical ribs. 

Structure. — The splenius, aponeurotic only at its periphery, is composed of 
thick fleshy fasciculi which are all directed forwards and upwards, to reach the 
head and the first cervical vertebrae. 

Attachments. — It is fixed, by its posterior border, to the lip of the cei*vical 
ligament and the summits of the spinous processes of the first dorsal vertebrae, 
by means of an aponeurosis which is continuous behind with that of the 
serratus anticus, and confounded, by its inner surface, with that of the 
complexus. Its anterior border is cut into four or five digitations, which 
constitute the movable insertions of the muscle. The superior digitation is 
the widest and thinnest, and terminates in an aponeurosis (Fig. 162, 5), which 



MUSCLES OF THE TRUNK. 



247 



unites it to the mastoid tendon of the trachelo-mastoideus, and passes to the 
mastoid crest. The second joins a very strong tendon common to the splenius, 
the trachelo-mastoideus, and the mastoido-humeralis, which tendon is attached to 
the transverse process of the atlas (Fig. 162, 9). The two or three others 
are directly inserted into the transverse processes of the third, fourth, and fifth 
cervical vertebras. 

Relations.— ThQ splenius is related, outwardly, to the rhomboideus, the 



Fig. 159. 




StrPERFICIAL MUSCLES OF THE NECK AND SPINAL REGION OF THE BACK AND LCI 

1, Dorsal trapezius; 2, longissimus dorsi ; 3, cervical trapezius ; 4, angularis scapulae; 5, spleniu 
6, anterior, or superficial portion of the mastoido-humeralis; 7, its humeral iusertion ; 7', its 
mastoid insertion; 8, the thin aponeurosis uniting this insertion to the sterno-maxillaris ; 8' 
posterior portion of the mastoido-humeralis ; 9, its inferior aponeurosis inserted into the inter 
stice of the long abductor of the arm; 10, sterno-maxillaris; 11, subscapulo-hyoideus ; 12 
portion of the cervical panniculus; 13, portion of the great extensor of the forearm ; 14, posterior 
belly of the long abductor of the arm ; 15, great pectoral muscle. 



angularis scapulae, cervical trapezius, and mastoido-humeralis ; inwardly, to 
the complexus and the two oblique muscles of the head ; by its inferior border, 
to the superior margin of the inferior branch of the longissimus dorsi. 

Action.— It extends the head and neck in inclining them to one side. If the 
two act in concert, the extension is direct. 



248 THE MUSCLES. 

Third Layer. 
4. CoMPLEXUS (CoMPLEXUS Major) (Fig. 163, 6, 7). 

/Synoni/ms.— Durso-occipitalis — Ch'rard. 

/Situation — Direction — Form. — A powerful muscle, included between the internal 
surface of the splenius and the cervical ligament, the oblique direction of which, 
forwards and upwards, it follows ; it is triangular, flattened on both sides, 
elongated from before to behind, and divided longitudinally into two unequal 
portions — a posterior and anterior. 

Structure. — The posterior portion (Fig. 163, 6), the most considerable, is 
aponeurotic at its origin, intersected by linear fibrous bands which obliquely 
cross its direction, and is formed of fleshy fibres directed forwards. Those which 
compose the anterior portion (Fig. 164, 7), intennixed with some tendinous 

Fig. 160. 




LATERAL VIEW OF THE NECK (MIDDLE LAYER OF MUSCLES). 

1, Funicular portion of the cervical ligament; 2, complexus major; 3, complexus minor; 4, rectus 
capitis posticus major; 5, rectus capitis posticus minor; 6, stylo-maxillaris ; 7, carotid artery; 
8, pneumogastric nerve and branch of sympathetic; 9, longus colli; 10, recurrent nerve; 11, 
inferior scalenus; 12, intertransversalis colli; 13, incision through rhomboideus and trapezius; 
14, trachea. 

fasciculi, are directed upwards, and appear to be inserted into the preceding. 
It is this difference in the direction of the fibres of the two portions of the 
complexus which allows them to be distinguished from one another ; the two 
being only really separated by an interstice near their inferior extremity. 
Superiorly, the muscle is constricted to form the summit of the elongated triangle 
it represents, and terminates by a strong tendon. 

Fixed insertions. — The posterior portion derives its origin : 1. From the 
summit of the spinous processes of the first dorsal vertebrae, by a strong 
aponeurosis which is confounded with that of the splenius and the serratus 
anticus. 2. From the transverse processes of the four or five dorsal vertebrae 
which follow the second, by as many aponeurotic digitations united by their 
margins. The anterior portion is fixed : 1. To the transverse processes of the 
two first dorsal vertebras, by two tendinous digitations analogous to those of 



MUSCLES OF THE TRUNK. 249 

the posterior portion. 2. To the articular tubercles of the cervical vertebrae, 
by the inferior extremity of its fleshy fasciculi. 

Movable insertion.— The movable insertion of the great complexus is effected 
through its superior tendon, which is fixed to the posterior face of the occipital 
protuberance, beside the cervical tuberosity. 

Relations. — It is covered by the splenius and the trachelo-mastoideus. It 
covers the cervical ligament, the upper branch of the longissimus dorsi, the semi- 
spinalis colli, and the oblique and posterior straight muscles of the head. The 
aponeurotic digitations which attach it to the dorsal transverse processes, are 
comprised between the two branches of the longissimus dorsi. The interstice 
which separates, inferiorly, the two portions of the muscle affords a passage to 
the superior cervical artery. 

Action. — It is a powerful extensor of the head. 

5. Teachelo-Mastoideus (Complexus Minor) (Figs. 162, 6, 7 ; 163, 8, 9). 

iSf/nonj/TKS.— Dorso-mastoideus— GiVard. {Trachelo-mastoideus— Percivall.) 

Situation — Direction. — Situated at the internal face of the splenius, in an 
oblique direction upwards and forwards, this muscle lies along the anterior border 
of the complexus, and follows the inferior branch of the longissimus dorsi, wliich 
it appears to continue to the head. 

Form — Structure. — This is a long muscle, divided into two fleshy, fusiform, 
and parallel portions — anterior and posterior — wliich we might strictly consider 
as two distinct muscles. Both are composed of successive fasciculi, which become 
longer as they are superficial, and terminate by a tendon at their superior 
extremity. The tendon of the posterior muscle is flattened, and joins the 
mastoid aponeui'osis of the splenius. That of the anterior muscle is funicular, 
and receives, before its insertion, a digitation from the splenius (Fig. 163, 10), 
and another from the mastoido-humeralis (Fig. 163, 11). 

Fixed attachments. — The two fleshy portions have their fixed insertion in 
common with the anterior portion of the great complexus : 1. On the transverse 
processes of the two first dorsal vertebras, through the medium of aponeurotic 
digitations which serve as an origin to the last-named muscle. 2. On the 
articular tubercles of the cervical vertebrae, by the inferior extremity of their 
component fasciculi. 

Movable attachments. — The terminal tendon of the posterior muscle passes to 
the mastoid process of the temporal bone. The anterior passes to the transverse 
process of the atlas. 

Relations. — Outwardly, with the splenius ; inwardly, with the complexus and 
the oblique muscles of the head. The tendon of the posterior fleshy portion is 
covered by the mastoid aponeurosis of the mastoido-humeralis. 

Action. — The trachelo-mastoideus inclines to its side the head and upper part 
of the neck. It also acts as an extensor of the head.^ 

' Bourgelat has described, by the name of long transversal, the anterior portion of this 
muscle, and attached it to the posterior portion of the splenius. We do not know where to find 
one or other of these in the crude description of Lafosse and Vitet. Girard considered them, 
like ourselves, as a single muscle, which he designates the dorso-mastoideus. Rigot has united 
them with the anterior portion of the great complexus and the foremost fasciculi of the short 
transverse muscle (inferior branch of the longissimus dorsi), to make his long transversal; in 
doing so he has only complicated their description. These two muscular fasciculi being, to 
our view, exactly represented, the posterior, at least, by the complexus minor of authropotomists, 



250 TBE MUSCLES. 

Fourth Layer. 
6. Spinalis oe Semispinalis Colli (Fig. 161, 4). 

Synonyms.— ^hoxi spinous — Bourgelat. Dorso-spinalis— Gerard. (Spinalis colli— Percivall 
Transversali* colli of Man.) 

Situation. — Between the complexus and the cervical ligament, on the laminae 
of the last five vertebrae of the neck. 

Form — Structure — Attachments. — This muscle, a continuation in the cervical 
region of that of the back and loins, is generally formed of five thick and short 
fasciculi, strongly aponeurotic, directed forwards, upwards, and inwards. 

These fasciculi, attached by their posterior extremities^^icff/ insertion — to 
the five last articular tubercles of the cervical region, are fixed by their anterior 
or superior extremities — movable insertion — into the sixth, fifth, fourth, third, 
and second spinous processes of that region. 

Relations. — Outwards, with the complexus ; inwards, with the superior branch 
of the longissimus dorsi and the cervical ligament. By its anterior face, with 
the laminae of the cervical vertebrae and the interlamellar ligaments. 

Action. — An extensor and flexor of the cervical spine. 

7. Intertransversales Colli (Fig. 162,. 9). 

Synonyms. — Intercervicals — Girard. (The intertransversales of Man- Not mentioned by 
Percivall.) 

These are six small, short, and very tendinous fasciculi, each of which is 
doubled into two secondary fasciculi, a superior and inferior. They are lodged 
in the lateral excavations comprised within the transverse and articular processes 
of the cervical vertebrse, and are carried from one vertebra to another, except 
from the first to the second. Covered by the cervical attachments of the 
majority of the muscles of the neck, they cover the vertebrae to which they 
are attached, -as well as the vertebral arteries and veins, and the intervertebral 
foramina. They incline the neck to the side. 

8. Obliquus Capitis Anticus or Inferioris (Fig. 161, 7). 

Synonym, — Axoido-atloideus — Girard, 

Form — Direction — Situation. — A short, thick, and broad muscle, oblique 
forwards and outwardly, and applied to the superior face of the two first vertebrae 
of the neck. 

Structure and Attachments. — Its fibres are nearly all fleshy, parallel to each 
other, and longer as they become superficial ; they are attached by their posterior 
extremityr-^cce^ insertion — to the external face of the spinous process of the axis, 
and by their anterior extremity — movable insertion — to the superior surface of the 
transverse process of the atlas. 

Relatiotis. — Outwards, with the splenius, the complexus and trachelo-mas- 
toideus ; inwards, with the atlas, the axis, and the atlo-axoid articulation ; above, 
with the posterior straight muscles of the head ; below, with the anterior great 
straight muscle. 

we have thought it proper to give it that name. With regard to the muscle generally termed 
the complexus minor by veterinary anatomists, following the example of Meckel we will describe 
it as a portion of the rectus capitis anticus major. 

(Percivall names Girard's axnido-occipitalis longus the " complexus minor," and his dorso- 
mastvideus the " ti achelo-mastoideus." Leyh, following Girard, designates the latter muscle 
the dorso-mastoideus.) 



MUSCLES OF THE TRUNK. 



251 



j^ction. — It pivots the atlas on the odontoid process of the axis ; it is, there- 
fore, the special rotator of the head. 

9. Small Oblique, Obliquus Capitis Posticus oe Supekioris (Fig. 161, 8). 

Synonyms. — Atloido-mastoideus — Girard. (Obliquus capitis superior — Percivall. Lateral 
atloido-occipitalis of Leyh. Obliquus superior of Man.) 

A short, thick, quadrilateral, and strongly aponeurotic muscle. Its fibres are 
fixed posteriorly — origin — to the lip bordering the transverse process of the atlas ; 

Fig. 161. 




CERVICAL LIGAMENT AND DEEP MUSCLES OF THE NECK. 
1, Lamellar portion of the cervical ligament; 2, funicular portion; 3, 3, semispinales muscles 
of the back and loins ; 4, 4, spinales colli ; 5, rectus capitis posticus major ; 6, small ditto ; 
7, great or inferior oblique muscle of the head ; 8, small ditto ; 9, 9, intertransversales colli ; 10, 
anterior great straight muscle of the head ; 11, inferior portion of scalenus muscle; 12, superior 
ditto. 

they are carried from thence forward, upward, and inward, to be attached — 
termination — 1. To the styloid process of the occipital bones. 2. To the external 
surface of that bone, on the imprints which border the mastoid crest posteriorly. 
3. To the mastoid crest itself. This muscle is covered by the mastoid tendon of 
the trachelo-mastoideus, by the superior aponeurosis of the splenius, and that of the 



252 THE MUSCLES. 

mastoido-humeralis. It covers the occipito-atloid articulation, the occipital inser 
tion of the posterior straight muscles of the head, and the origin of the occipito- 
styloid and digastric muscles. It inclines the head on the atlas, and shghtlj 
extends it. 

10. Posterior Great Straight Muscle of the Head (Rectus Capitis 
Posticus Major) (Fig. 161, 5). 

Synonyms.— SmaU complexus and great posterior straight axuscle—Bourgelat. Long and 
short axoido-occi pi talis— Gerard. (^Complexus minor and rectus capitis posticus major. — 
Perdvall. Leyh gives this muscle the same designation as Girard. It is the rectus capitis 
posticus major and medius of Man.) 

Form — Structure — Situation. — Elongated, prismatic, easily divisible into two 
fasciculi — one superficial, the complexus minor of Bourgelat (and Percivall) ; the 
other deep, th.Q great posterior straight muscle of Bourgelat (and the rectus capitis 
posticus major of Percivall) — entirely fleshy, and formed of parallel fibres, this 
muscle is lodged, with the small posterior straight muscle, in a triangular space 
circumscribed by the cord of the cervical ligament and the internal border of the 
obUque muscles. 

Attachments. — It is attached, by its superior extremity, to the whole extent of 
the uneven lip which terminates the spinous process of the 2ix\s,-^fixed insertion. 
Its anterior extremity is insinuated beneath the small oblique muscle, and is fixed 
to the occipital bone, behind the superior insertion of the gi'eat complexus, the 
tendon of which receives some of the fibres of the superficial fasciculus — movable 
insertion. 

Relations. — Above, with the complexus ; below, with the small straight 
muscle ; inwards, with the cord of the cervical ligament and the analogous muscle 
of the opposite side ; outwards, with the oblique muscles. 

Action. — This muscle, a congener of the complexus, aids in extending the 
head. 

11. Posterior Small Straight Muscle (Rectus Capitis Posticus 
Minor) (Fig. 161, 6). 

Synonyms. — Atloido-occipitalis — Girard. {Rectus capitis posticus minor — Percivall. The 
Atloido-occipitalis superior of Leyh. The rectus capitis posticus minor of Man.) 

A very small, wide, and triangular muscle, flat above and below, and lying 
immediately upon the fibrous capsule of the occipito-atloid articulation. It is 
attached, posteriorly, to the superior face of the atlas — origin ; in front, to the 
external surface of the occipital bone, below the preceding muscle, the action of 
which it #iares. 

Differential Characteus in the Muscles of the Cervical Region in the other 

Animals. 

1. Ruminants. — In the Ox, the angularis scapulas arises by six digitations from all the 
cervical vertebr£e except the first ; the splenius is little developed, and is not attached to either 
the tliird or fourth cervical vertebra. 

In the Carnal, the angularis scaiiulae is very small, and does not go beyond the fifth cervical 
vertebra in front. All the other muscles in this region are very much reduced in size. " If 
the splenius exists in the Camel, it is so small that it often escapes dissection" (Cuvier). 

2. Pig.— The muscles of tlie superior cervical region in this animal are generally very 
developed. The rhomboideus is divided into two flesliy bodies, one of which proceeds to the 
occipital protuberance, and the other to the rudimentary cervical ligament and the first dorsal 
vertebrae. The angularis is attached, as in Ruminants, to the six oerviral vertebrae ; sometimes 
it even shows a digitation that descends to the atlas. The splenius only terminates anteriorly 



MUSCLES OF THE TRUNK. 253 

by three fleshy portions ; but they are voluminous, and are inserted, one into the atlas, another 
into the mastoid crest, and tlie third into the occipital protuberance. In the complexus, the 
two portions are completely separated from each other, except at their upper extremity, by 
the interspace lodging the superior cervical artery. The aponeurosis attaching the muscle to 
the spinous processes of the first dorsal vertebrae is not confounded with that of the spleniua 
or the serratus anticus respiratory muscle. The atloidean fleshy body of the trachelo- 
mastoideus is scarcely distinct from the superior branch of the iongissimmo dorsi and the 
intertransversales. Lastly, it is difficult to distinguish the small posterior straight muscle from 
the deep fasciculus of tlie great straight muscle. 

3. Camivora. — In these animals the muscles of the superior cervical region are nearly all 
voluminous, as in the Pig. The rhomboidem is bifid at its origin, and its anterior branch arises 
from the mastoid crest. The angularis is also attached to the last six cervical vertebrse. Very 
thick and broad, the splenius only passes to the atlas and mastoid crest. The oblique and 
$traight posterior muscles of the head are also remarkably thick. 

B. Inferioe Cervical or Trachelian Region. 
The muscles composing this region are situated in front of the cervical 
vertebrae, and are, for the most part, grouped around the trachea, which they 
envelop as in a kind of sheath. They are eleven in number, and are : the cervical 
panniculus, mastoido-humeralis, sterno-maxillaris, sterno-thyro-hyoideus, suisca- 
pulo-hyoideus, rectus capitis anticus major, rectus capitis anticus minor, rectus 
capitis lateralis, scalenus, and the longus colli. 

Preparation. — 1. Place the animal in the first position. 2. Remove the skin of this region- 
in order to expose and study tiie cervical panniculus. 3. Remove that muscle and the parotid 
gland to prepare the mastoido-humeralis,' the stylo-maxillaris, and sterno-thyro-hyoideus. 4. 
Transversely cut through the mastoido-humeralis near the angle of the shoulder, and isolate it 
from the subscapulo-hyoideua to expose this muscle ; taking care to preserve the jugular vein 
and parotid gland, in order to study their relations with it. 5. Remove the fore limbs ; open 
the thoracic cavity by sawing through the eight first ribs near their superior extremity'; take 
out the viscera contained in tliis cavity, as well as the trachea, oesophagus, pharynx, and 
larynx, to expose the longus colli, the scalenus, and the straight muscles of the head. 

1. Subcutaneous Muscle of the Neck (Cervical Panniculus) 
(Figs. 159, 12 ; 174, 1). 

Synonyms.— It has been described by Bourgelat, and the majority of veterinary anatomists 
who have followed him, as two muscles : the cuticularis of the neck and the face. (Percivall 
includes this muscle in his description of tlie panniculus carnosus. It is the platysma myoide» 
of Man.) 

This is a membraniform expansion, partly fleshy, partly aponeurotic, which 
covers the muscles of the neck, the submaxillary space, and the face. 

The fleshy fibres form, in front of the neck, a thin band, which is united, 
through the medium of a fibrous raphe, to that of the opposite side. This band 
is in contact with the sterno-maxillaris, sterno-thyro-hyoideus, and subscapulo- 
hyoideus, as well as the jugular vein — enveloping them all as in a sort of furrow. 
It gradually becomes thinner from below upwards, in such a manner that around 
the upper part of the throat it is only composed of some scattered fibres. In the 
submaxillary space, and on the expanding borders of the inferior maxilla, the fleshy 
fibres appear again of a certain thickness, but only to become attenuated on the 
external surface of the cheeks. 

• These fleshy fibres leave the carinif orm cartilage of the sternum ^ and inter- 

' The mastoido-humeralis may be dissected at the same time as the trapezius, the subject 
being placed in the second position. This conveniently permits the superior insertions of the 
muscle to be studied (see Fig. 159). 

* It will be seen, on referring to Fig. 159 and its legend, that we restore to the cervical 

19 



254 THE MUSCLES. 

mediate middle raphe of the two muscles, and, directing their course outwards and 
upwards, soon become confounded with the aponeurosis. The latter, extremely 
thin, is spread over the mastoido-humeralis, the superior cervical muscles, the 
parotid region, and the cheeks, and is finally attached to the zygomatic crest. On 
an'iving near the commissure of the Ups, it is united to the buccinator muscle by 
a fleshy fasciculus named, in Man, the risorius Santorini (Fig. 163).. 

The cervical panniculus braces the muscles it covers, during their contraction, 
and pulls backwards the commissures of the lips. We doubt very much whether 
it has — in the cervical region at least — any action on the skin, for it adheres but 
very slightly to its inner surface. 

2. Mastoido-humeralis (Levator Humeri) (Figs. 158, 160, 162, 163). 

Synonyms. — The muscle common to the arm, neck, and head — Bourgelat. Representing 
the cleido-mastoid, and the clavicular portions of the trapezius and deltoid of Man, and the 
trachelo-acromialis peculiar to quadruped Mammals ' — G. Cuvier, Lemons d'Anatomie Com- 
par^e, 2iid edition. (This is the muscle which Percivall namts the levator humeri. The 
above is the designation given to it by Girard and Chauveau. Leyh gives it the same designa- 
tion as Bourgelat.) 

Extent — Sitication — Direction — (Joynposition. — This muscle extends from the 
summit of the head to the inferior part of the arm, and is applied to the scapulo- 
humeral angle at the side of the neck, in an oblique direction downwards and 
backwards. It is composed of two portions lying longitudinally, and somewhat 
intimately united, and distinguished into anterior and posterior. 

Form — Structure — Attachments. — A. The anterior or superficial portion (Fig. 
159, 6) constitutes a long fleshy band, which appears to be united, by its anterior 
border, to the cuticular muscle of the neck. Its superior extremity, thin and Avide, 
is attached to the mastoid process and crest by an aponeurosis (Fig. 159, 71), which 
is united, in front, to the tendon of the sterno-maxillaris by a very thin cellulo- 
aponeurotic fascia. Its inferior extremity, thicker than the superior, is inserted 
by means of a very short aponeurosis into the humerus, on the salient border 
descending from the deltoid imprint, and which limits, in front, the musculo- 
spiral groove on the body of that bone (Fig. 159, 7). 

panniculus the sternal band attributed until now to the mastoido-humeralis. These are the 
considerations which induce us to make this modification : 1. This band is not distinct from 
the cervical panniculus ; a separation between the two muscles can only be artificially obtained. 
2. In dissecting this band with care, we can see that its fibres, like those of the panniculus, are 
not mixed with those of the mastoido-humeralis (superficial portion) ; they pass along the 
external surface of that muscle, to which they intimately adhere, it is true, but they can easily 
be separated, and are continuous with the aponeurosis of the first. 

> At first sight, we might hesitate to admit that this muscle is formed of such varied and 
complicated elements as are enumerated above. Nevertheless, it is a scientific fact ; and we 
will give a demonstration, as simple as it is clear, that such is the case — the idea we owe to 
J. F. Meckel. If we take the Dog, for example, and suppose it to be possessed of a clavicle 
extending from the anterior extremity of the sternum to the acromion, this clavicle would bisect, 
transversely, the inferior portion of the mastoido-humeralis, which would thus be divided into 
two portions— a superior and an inferior. Tlie first, extending from the clavicle to the mastoid 
process, on this side, and on the other to the mastoid crest, as well as to the cervical ligament, 
where it is confounded with the trapeziiis, would exactly represent the clavicular portion of the 
latter muscle, and the cJeido-mastoideus. With respect to the inferior portion, it perfectly 
resembles, by its attachments, the clavicular portion of the deltoid. But, on the contrary, if 
we suppose Man deprived of a clavicle, the three muscular fasciculi indicated, in becoming 
confounded with each other, would form the mastoido-humeralis of the Dog, minus the posterior 
portion, or the trachelo-acromialis, which is not represented in Man. 



MUSCLES OF THE TBUNK. 255 

B. The posterior or deep portion (Fig. 159, 9) is a second muscular band, 
shorter and stronger than the preceding. It is attached, above, to the transverse 
processes of the first four cervical vertebrae by as many fleshy bands (Fig. 159, 8), 
which cover the superficial portion. The upper digitation, given off to the atlas, 
is united to the tendon common to the trachelo-mastoideus and splenius (Figs. 
162, 9 ; 163, 9, 10, 11). The inferior extremity of this portion of the muscle 
widens on the scapulo-humeral angle, which it envelops in becoming closely united 
to the anterior portion, terminating with it on the humerus. An aponeurosis, 
which is confounded with that of the trapezius, and sends off a septum into the 
interstice between the two portions of the long abductor of the arm, concurs to 
fix this extremity by spreading over the muscles of the arm. 

Relations. — It is covered, near its mastoid insertion, by the parotid gland and 
the cervico-auricularis muscles ; for the remainder of its extent, by the aponeu- 
rosis of the cervical panniculus, from which it is separated by a thin fascia con- 
tinuous with that which extends over the trapezius. It covers the splenius, 
trachelo-mastoideus, oblique muscles of the head, subscapulo-hyoideus (to which 
it adheres intimately), the digastricus, long flexor of the head, the angularis, 
scalenus, small pectoral, supra- and infra-spinatus muscles, the long abductor of 
the arm, and the coraco-radialis. 

Action. — When the superior is the fixed point, it carries the entire anterior 
limb forward. This muscle, therefore, plays a very important part in locomotion, 
as it is called into action when the animal raises the fore limb in getting over the 
ground. If the fixed point of the muscle is the limb, it inclines the head and 
neck to one side. 

3. Steeno-maxillaeis (Figs. 159, 10 ; 174, 4). 
Synonym. — The sterno-mastoideus of IVfon. 

Form — Structure — Situation — Direction — Attachments. — ^A long narrow muscle, 
almost entirely fleshy, and terminated at its upper extremity by a flattened tendon ; 
situated in front of the neck, beneath the panniculus, and parallel to the anterior 
border of the supei'ficial portion of the mastoido-humeralis, from which it is 
separated by a space that lodges the jugular vein ; attached, inferiorly, to the 
cariniform cartilage of the &ternnm—fix£d insertion; and superiorly — movable 
insertion — to the curved portion of the posterior border of the maxiUaiy bone by 
its terminal tendon. 

Relations. — The muscle is covered by the panniculus, and the parotid gland. 
It covers the trachea, the subscapulo-hyoideus, sterno-thyro-hyoideus, and the 
maxillary gland. Its external border, parallel to the anterior border of the 
mastoido-humeralis, forms with it a longitudinal depression termed the jugular 
furroiv, because it lodges the vein of that name. Its inner border is intimately 
united, in its lower third, to that of the opposite muscle. 

Action. — It directly flexes the head, when acting in concert with its congener ; 
but alone it turns it to one side. Lafosse and Rigot have wrongly considered 
this muscle as a depressor of the lower jaw, Bourgelat has correctly stated that 
it cannot move this jaw independently. (Percivall says that the pair will assist 
in opening the mouth ; and Leyh asserts that when the mouth is closed, each 
muscle will act as a flexor to the head.) 

4. Steeno-thyeo-htoideus (Fig. 174, 6, 7). 
Form — Structure — Situation — Attachments. — Small, ribbon-shaped, long, and 



256 THE MUSCLES. 

slender muscle in two portions ; digastric ; situated in front of the trachea ; con- 
founded at their inferior extremity and united to those of the opposite side, so as 
to form a single fasciculus which is attached to the cariniform cartilage of the 
steTimm—flxed insertion ; isolated from each other above the tendon which makes 
them digastric, and terminating by their superior extremity — movable insertion : 
the first, on the inferior surface of the body of the hyoid bone in common with 
the subscapulo-hyoideus ; the second, on the posterior border of the thyroid 
cartilage. 

Relations. — Covered by the sterno-maxillaris and the panniculus muscle, they 
cover the anterior face of the trachea. 

Action. — Depressors of the hyoid bone and larynx. 

5. Subscapulo-hyoideus (Figs. 159, 11 ; 174, 5). 

Synonyms. — Hyoideus — Bourgelat. (Subscapulo-hyoideiis — Percivall.) 

Form — Structure — Situation — Direction. — This muscle forms a thin and wide 
band, almost entirely fleshy, oblique forwards and upwards, extending from the 
scapulo-humeral angle to the submaxillary space, and applied to the side of the 
trachea, which it slightly crosses. 

Attachments. — It derives its fixed insertion from the inner surface of the 
subscapularis, by an aponeurosis which is detached from that covering the latter 
muscle. Its movable insertion is into the body of the hyoid bone, in becoming 
confounded with the sterno-thyro-hyoideus, and in being intimately united to the 
muscles of the opposite side. 

Relations. — Outwardly, with the subscapularis, supra-spinatus, small pectoral, 
mastoido-humeralis — which closely adheres to it, the jugular vein, the sterno- 
maxillaris, and the panniculus. Inwardly, with the scalenus, the large anterior 
straight muscle of the head, the main trunk of the carotid artery and the nei^ves 
accompanying it, the trachea, thyroid gland, and the inferior face of the larynx. 
The jugular vein is entirely separated from the carotid artery by this muscle in 
the upper half of the neck. 

Action. — It is a depressor of the hyoid bone and its appendages. 

6. Great Anterior Straight Muscle of the Head (Rectus Capitis 
Anticus Major) (Figs. 161 and 162, 10 ; 163, 13). 

Synonyms. — Long flexor of the head — Bourgelat. Trachelo-suboccipitalis — Girard. (Rectus 
capitis anticus major — Percivall. Trachelo-occipitalis — Leyh.) 

Form — Structure — Situation — Direction. — A long, flat muscle, fasciculated in 
its posterior half, terminated in a tendinous cone at its anterior extremity, and 
passing along the first cervical vertebrae in front. 

Attachments. — Behind, to the transverse processes of the third, fourth, and 
fifth cervical vertebrae by as many fleshy digitations, the most inferior of which 
are the \oTige?,t— fixed insertion. In front, into the imprints on the body of the 
sphenoid bone and the basilar process, by its terminal tendon — movable insertion. 

Relations. — Outwardly, with the mastoido-humeralis, the subscapulo-hyoideus, 
and the small anterior straight muscle. Inwardly, with the longus colH and 
the muscle of the opposite side. In front, with the common carotid, the nerves 
accompanying this arteiy, and the guttural pouch, which lines it near its movable 
insertion. Behind, with the great oblique muscle of the head and the occipito' 
atloid articulation. 



MUSCLES OF THE TRUNK 267 

Action. — It either directly flexes the head or carries it to one side, according 
as it acts alone or with its fellow of the opposite side. 

7. Small Anterior Straight Muscle of the Head (Rectus Capitis 
Anticus Minor). 

Synonyms. — Flexor capitis brevis — Bourgelat. Atloido-suboccipitalis— Girard. (Rectiis 
capitis anticus minor — Fercivall. Atloido-oocipitalia inferior — Leyh.) 

A small, entirely fleshy, prismatic fasciculus, lying to the external side of the 
preceding muscle ; attached, posteriorly, to the inferior face of the body of the 
atlas ; in front, to the body of the sphenoid bone and the basilar process, beside 
the great anterior straight muscle. It is covered by the guttural pouch, and 
covers the occipito-atloid articulation. It concurs in flexing the head. 

8. Small Lateral Straight Muscle (Rectus Capitis Lateralis). 

Synonyms. — Flexor capitis parvus — Bourgelat. Atloido-styloideus — Girard. (Obliqum 
capitis anticus — Percivall. The rectus capitis lateralis of Man.) 

Smaller than the preceding, and prismatic and entirely fleshy, like it, this 
muscle lies on the side of the occipito-atloid articulation ; it is attached to the 
atlas, outside the small anterior straight mu&cle— fixed insertion ; and to the inner 
face of the styloid process of the occipital bone — movable insertion. It is the 
congener of the two anterior straight muscles of the head. 

9. Scalenus (Figs. 161, 162, 163). 

Synonyms. — Costo-tracheleus — Girard. (Scalenus anticus and posticus of Man.) 

Sitimtion — Direction — Composition. — Deeply situated at the inferior part of 
the neck, in an oblique direction downwards and backwards, this muscle com- 
prises two portions of unequal dimensions, placed one above another. 

Form — Structure — Attachments. — A The superior portion {scalenus posticus 
of Man), the smallest, is composed of three or four fleshy fasciculi, attached by 
their extremities to the transverse processes of the last thi-ee or four cervical 
vertebras. The last terminates at the superior extremity of the first rib. 

B. The inferior {scalenus anticus of Man), the most considerable, is flattened 
on both sides, thick and wide posteriorly, thin and naiTOw anteriorly, and is 
composed almost entirely of fleshy fibres which are longest as they are inferior. 
It is attached : 1. To the transverse processes of the last four cervical vertebrae 
by short fasciculi scarcely distinct from one another, the first of which is crossed 
by the last digitation of the great anterior straight muscle. 2. To the anterior 
border and external face of the first rib, where all its fibres end. 

Relations. — The scalenus responds : by its external face, to the subscapulo- 
hyoideus, mastoido-humeralis, and the deep pectoral ; by its internal face, 
to the longus colli, trachea, common carotid artery and its accompanying nerves, 
and — on the left side only — to the oesophagus ; by its inferior border, to the 
jugular vein. The two portions of the scalenus are separated from each other, in 
front of the first rib, by an interspace traversed by the nei-ves of the brachial plexus. 

Action. — When the first rib is the fixed point, this muscle either directly 
flexes the neck or inclines it to one side. When the neck is the fixed point, it 
draws forward the first rib and fixes it in this position dm'ing the dilatation of 
the chest, in order to aid the inspiratory action of the external intercostal muscles. 



THE MUSCLES. 



10. Long Muscle of the Neck (Longus Colli). 

Synonyms. — Flexor longus colli — Bourgelat. Subilorso-atloideus — Girard. {Longus colli 
— Percivcdl. Dorso-atloideus — Leyh.) 

Situation — Composition. — A single and considerable muscle, immediately 
covering the inferior aspect of all the cervical and the first six dorsal vertebrae, 
and composed of two lateral portions which are united on the median line, and 
constitute, in certain animals, two distinct muscles. 

Structure — Attachments. — Each lateral portion of the longus colli is composed 
of a succession of veiy tendinous fasciculi. The most posterior of these is 
attached to the inferior face of the bodies of the first six dorsal vertebrae, and 
proceeds directly forward to reach the inferior tubercle of the sixth cervical 
vertebra, into which it is inserted by a strong tendon. The other fasciculi, less 
considerable, and confounded outwardly with the intertransversales of the neck, 
are carried from one cervical vertebra to another, and are directed forwards, 
upwards, and inwards, converging towards those of the opposite side. They are 
attached successively : outwardly, to the transverse processes of the last six 
cervical vertebrae ; inwardly, to the inferior ridge on the bodies of the first six. 
The most anterior fasciculus passes to the inferior tubercle of the atlas, into 
which it is inserted by a tendon common to it and the fasciculus of the opposite 
side, and which receives the most superficial fibres of the tlii-ee or four preceding 
fasciculi. 

Relations. — Above and behind, with the vertebrae which it covere, as well as 
their intervertebral discs ; below and in front, with the trachea and oesophagus, 
and the vessels and nerves accompanying these two tubes ; on the sides, with the 
great anterior straight and the scalenus muscles in its cervical portion ; and in 
its intra-thoracic portion, with the pleurge, and important vessels and nei-ves. 

Action. — It' flexes the whole neck, and the cervical vertebrae on one another. 

Differential Characters in the Muscles of the Inferior Cervical Eegion in the 
OTHER Animals. 

A. Ruminants.— In the Ox and Sheep, the arrangement of the cervical pannicului< oflFers 
a very considerable ditference from tliat observed in Solipeda. The fleshy portion is absent, 
or appears to be absent, in the cervical region; tl:e anterior mnscles of the neck are only 
covered by a thin fascia developed on the sides of tlie neck. When this fascia reaches tlie 
face, it becomes continuous with the fleshy fibres ; a fasciculus of these fibres comporis itself 
as in the Horse, and joins the buccinator: another is intercrossed in the maxillary space by 
the analogous fasciculus of the opposite side. 

The cervical panniculus in the Ox is also distinguished by an extremely remarkable 
peculiarity, which it is necessary to allude to here: — The fleshy cervical band, altogether 
absent in the Sheep, is not so in the Ox; wc have found it forming, beneath the above- 
mentioned aponeurotic fascia, the hmg, thick strip which has been described by veterinary 
anatomists as the analogue of the sterno-maxillaris in the Horse. This strip is attached, like 
the muscular band which represents it in Solipeda, to the anterior point of the sternum. But 
Us fibres, instead of being spread outwards over the mastoido-humeralis, ascend, perfectly 
isolated from that muscle, to the posterior border of the inferior maxilla. There it terminates 
(Fig. 172, 18) by a flattened tendon, which, after reaching the anterior border of the masseter, 
is confounded with the aponeurosis of that muscle, and sends some fibrous bands over the 
muscles of the face. 

The two portions of the mastoido-humeralis of Ruminants are better defined, and more 
oblique on one another, than in the Horse. The superficial partion receives, on its inner face, 
a small, bright- red, funicular fasciculus, which proceeds from the cartilage of the first rib, and 
which Meckel is inclined to consider as the vestige of the subclavius. It is divided, superiorly, 
into two branches: one, the clavicular portion of the trapezius, very wide, passes to the mastoid 



MUSCLES OF THE TRUNK. 259 

process, the curved line of the occipital bone, and to the cervical ligament, in becoming con- 
founded with the trapezium (Fig. 172, 22); the other, the cleido-mastoideus, terminates in a 
tendon that joins the sterno-maxillaris, and is inserted into the basilar process, after 
receiving the fibres of the long flexor of the head (Fig. 172, 21). The upper extremity of the 
deep portion of the mastoido-humeralis is inserted into the atlas by a flattened tendon alone, 
which is quite distinct from the atloid insertions of the splenius and the trachelo-mastoideus. 

In the Sheep and Goat, the costal band that joins the superficial portion is absent. The 
latter is divided at its inferior extremity into two branches, between which pass the biceps. 
The upper branch passes to the epitrnchlea. 

The sterno-maxillaris muscle, instead of being inserted into the inferior maxilla, is united 
to the suboccipital branch of the mastoido-humeralis, to be attached to the basilar process. At 
another time we will discuss" the determination of this muscle, and that of the fleshy band here 
considered as belonging to the first (see Spinal Nerve). 

The sterno-thyro-hyoid muscle is thicker than in the Horse, and not digastric. 

The subscapulo-hyoideus of Ruminants is but slightly developed, and might be termed the 
trachelo-hyoideus, as it proceeds to the transverse process of the tiiird or fourth cervical 
vertebra. In its passage beneath the basilar branch of the mastoido-humeralis and sterno- 
maxillaris, it contracts adhesions with the fibres of these two muscles. 

The great anterior straight muscle of the head descends to the sixth cervical vertebra. Its 
cervical insertions are covered by a very strong muscular fasciculus, which is annexed to it. 
Like it, this fasciculus leaves the sixth cervical vertebra, and is attached to the transverse 
processes of the four vertebrae preceding the last, by becoming confounded with the inter- 
transversales, and finally terminating at the tracheal process of the atlas by fleshy and 
aponeurotic fibres. This muscular fasciculus singularly strengthens the neck when it is 
inclined to one side. In consequence of its attachments, it might be named the trachelo- 
atloideus (Fig. 172, 24). 

Lastly, in Ruminants the superior scalenus is very developed, being a flattened band which, 
gradually expanding, is prolonged to tlie surface of the serratus magnus. 

B. Pig. — In this animal, tlie cervical panniculus is in two portions : an inferior, which 
comes from tiie point of tlie sternum ; and a superior, from the external capsular region. They 
unite in front, and are prolonged in common on the muscles of the face, contracting adhesions 
with the outer surface of the body and branebes of the inferior maxilla. 

The other muscles of the inferior cervical region are not unlike those of Ruminants. 

Of the two portions of the mastoido-humeralis, the superficial is bifid at its superior 
extremity. The posterior branch, the clavicular portion of the trapezius, is attached to the 
side of the occipital protuberance ; the anterior branch, the cleido-mastoideus, goes beneath 
the external auditory hiatus, to the crest that replaces the mastoid process ; the deep portion 
is attached above to the atlas only. 

In the Pig, the fterno-maxillaris exactly represents that muscle in the Horse, as its tendon 
passes directly to the mastoid process. 

The sterno-thyro-hyoideus is double ; the supplementary branch going to the inferior face 
of the thyroideus. 

The subscapulo-hyoideus and great anterior straight muscle of the head, resemble those of 
the Ox. The small straight lateral muscle is scarcely distinct from the small oblique. The 
superior scalenus extends to the third rib. The two lateral portions of the longus colli are 
separate, and form two distinct muscles. 

C. Camivora. — In the Dog, each cervical panniculus is in two portions, as in the Pig. 
The fibres from tbe breast are directed in a diveiging manner over the face, the submaxillary 
space, and the parotid gland, where they form the parotido-auricularis muscle. The portion 
coming from the external scapular region is thicker and wider; it covers the lateral parts of 
the neck, the parotid gland, the parotido-auricularis, passes above the preceding, and termi- 
nates on the face and in the submaxillary space, where its fibres join those of the opposite side. 

The mastoido-humeralis comports itself somewhat as in Ruminants and the Pig. The 
superficial portion is bifid superiorly ; one of its branches is fixed into the mastoid process — 
the cleido-mastoideus ; the other into the mastoid crest and cervical ligament, in uniting by 
aponeurosis with the trapezius— the clavicular portii.n of the trapezius. The deep portion 
passes from the atlas to the scapular spine. 

The tendon of the sterno-maxillaris goes to the mastoid process. The sterno-thyro-hyoideus 
Is thick and not digastric, and commences from the cartilage of the first rib. 

The Camivora have no subscapulo-hyoideus ; but they possess a very long scalenus, which 
passes to the eighth rib, and a longus colli, which tends to become divided into two lateral 
portions. 



260 THE MUSCLES. 

Spinal Region of the Back and Loins. 

This offers for study seven pairs of muscles, nearly all of which have their 
insertions extended over the dorso-lumbar spine, and are disposed in four layers 
on each side of this long multifidious crest. These muscles are — 

In the Fikst Layer. 

Trapezim. Latissimm Dorsi. 

In the Second Layee. 

Serratus Anticus. Serratus Posticus. 

In the Third Layer. 
Longissimus Dorsi. Transversalis Costarum. 

In the Fourth Layer. 
lis of Back mid Loins. 



Preparation. — 1. Place the animal in the second position. 2. Remove the skin with the 
panniculus and the mass of olecranian muscles, to show, in a first operation, the trapezius and 
latissimus dorsi (Fig. 159). 3. In a second operation, remove the entire fore limb, with 
the latissimus dorsi muscle, the mode of termination of which may then be studied ; then pre- 
pare the two smiiU serrated muscles. 4. Remove these two muscles, as well as the angularis 
of the scapula and tlie splenius, to expose the transversalis costarum and longissimus dorsi 
(Fig. 163). The superior branch of the latter remaining covered by the great complexus, 
excise tliis muscle, leaving only its insertions into the transverse processes of the dorsal 
vertebrae, to show how they are fixed between the two branches of the longissimus dorsi. 5. 
Dissect the semispinalis by removing the longissimus dorsi and the internal angle of the ilium. 

First Layer. 

1. Trapezius (Fig. 159, 1, 3). 

Synonym. — Dorso- and cervico-acromialis — Girard. 

Situation — Form — Structure. — This is a superficial membraneous muscle, 
situated on the sides of the neck and withers. Its shape is that of a triangle 
base upwards. It is aponeurotic at its upper border and in its centre, which 
allows it to be distinguished, especially in emaciated subjects, into a cervical and 
a dorsal portion. The fleshy fibres of the first are directed downwards and back- 
wards ; those of the second are oblique forwards. 

Attachments. — By its superior aponeurosis, it is fixed to the cord of the cer- 
vical ligament and to the summits of the transverse processes of the first dorsal 
vertebrae, where it adheres to the external face of the latissimus dorsi. By its 
central aponeurosis and that of its summit, it is attached to the tuberosity of the 
olecranian spine and the external scapular aponeurosis. 

Relations. — This muscle is covered by two aponeurotic planes, the fibres of 
which cross its owti at a right angle. Inwardly, it responds to the rhom- 
boideus, splenius, angularis, deep pectoral, the supra- and infra-spinatus, and 
the latissimus dorsi. 

Action. — It raises the shoulder, and carries it forward or backward, according 
as one or other of its muscular portions contract. 

2. Great Dorsal (Latissimus Dorsi) (Fig. 159, 2). 

Synonyms. — Dorso-humeralis — Girard. (Latissimus dorsi — PercivaU.) 
Form — Situation — Structure — Attachments. — A very broad triangular muscle^ 



MUSCLES OF THE TBUNK. 



261 



extended over the loins, back, and side of the thorax, and formed of an aponeu- 
rotic and a muscular portion. 

The aponeurosis is attached, by its superior border, to the summits of the 
spinous processes of all the lumbar, and the last fourteen or fifteen dorsal 
xeTtehrss—Jixed insertion of the muscle. 

The fibres of the fleshy portion are detached from the inferior border of the 
aponeurosis, at the twelfth or thirteenth ribs, to the cartilage of the scapula. 
They are directed forwards and downwards, and all converge into a flat tendon 
which is inserted into the internal tuberosity on the body of the humerus — 
movable insertion. This tendon is remarkable, at its termination, for being 

Fig. 162. 




JBUSCLES OF THE SPINAL REGION OF THE NECK, BACK, AND LOINS (MIDDLE LAYER) ; AND OF THE 
COSTAL AND ABDOMINAL REGION (SUPERFICIAL LAYER). 

1, 2, Rhomboideus ; 3, annularis muscle of the scapula ; 4, splenius ; 5, its mastoid aponeurosis ; 
6, mastoid portion of the trachelo-mastoideus ; 7, its tendon ; 8, cervical insertions of the 
mastoido-humeralis ; 9, atloidean tendon common to the mastoido-humeralis, splenius, and 
trachelo-mastoideus; 10, great anterior straight muscle of the head; 11, inferior scalenus; 
12, superior scalenus ; 13, small anterior serratus ; 14, posterior ditto ; 15, serratus magnus ; 

16, anterior fibres of the rectus abdominis, sometimes described as the traiisversalis costarum; 

17, one of the external intercostals ; 18, great oblique ; 20, rectus abdominis; 21, stylo-maxillaris 
portion of the digastric muscle. 

placed at the external face of the teres magnus or adductor of the arm, from 
which it receives fibres, and between it and the long extensor of the forearm ; 
it then turns inwards, on the inferior extremity of the first, in such a manner 
that this extremity is comprised within a duplicature of the membranous tendon 
of the latissimus dorsi. 

Relations. — This muscle is covered by the skin, panniculus carnosus, dorsal 
portion of the trapezius, and the mass of olecranian muscles. It covers the 
infra-spinatus ; the cartilage of the scapula ; the rhomboideus ; the anterior 
and posterior serrated muscles, the aponeurosis of which is directly joined to its 
own ; the longissimus dorsi ; the principal gluteal ; a portion of the external 
surface of the last ribs, to which its aponeurosis strongly adheres ; as well as to 
the corresponding external intercostals, and the serratus magnus. Between 
the last rib and the external angle of the ilium, the aponeurosis unites with the 



262 THE MUSCLES. 

small oblique, but more particularly with the great oblique, muscle of the 
abdomen : it is prolonged, posteriorly, on the muscles of the croup to constitute 
the gluteal aponeurosis. 

Action. — It carries the arm backwards and upwards ; and it may, according 
to a great number of authors, serve as an auxiliary in inspiration when its fixed 
point is the humerus. According to others, but in whose opinion we do not 
share, it is an expiratory muscle. 

Second Layer. 

3. Small Anterior Serrated Muscle (Serratus Anticus) (Fig. 162, 13). 

Synonyms. — Dorso-costalis — Girard. Anterior portion of the long serrated muscle — 
Bourgelat. (Superficialis costarum — Percivall, Anterior serrated muscle of Leylj. Serratus 
posticus superior of Man.) 

Form — Situation. — This is a flat, thin, quadrilateral muscle, situated beneath 
the rhomboideus and the latissimus dorsi. 

Structure. — It is composed of an aponeurotic and a fleshy portion. The first 
is confounded, in front, with the aponeurosis of the splenius, and is insinuated, 
behind, underneath that of the posterior small serratus, with which it soon 
becomes united. Its inferior border gives origin to the muscular portion, a little 
above the interval which separates the transversalis costarum and the longissimus 
dorsi. Narrow and elongated antero-posteriorly, the muscular portion is com- 
posed of bright-red fibres directed obliquely backwards and downwards, which 
form at the inferior border irregular, and sometimes but faintly marked, festoons. 

Attachments. — It takes its fixed insertion, by the superior border of its 
aponeurosis, from the summits of the anterior dorsal spines, with the exception 
of the first, to the thirteenth inclusive. The movable insertion takes place on 
the external surface and anterior border of the nine ribs succeeding the fourth, 
by means of the digitations of the fleshy portion. This muscle is also attached 
to the external surface of these ribs by a short fibrous band, which is detached 
from the internal face of the aponeurosis, near its inferior border, and penetrates 
the space between the longissimus dorsi and the transversalis costarum. 

Relations. — Outwards, with the rhomboideus, serratus magnus, latissimus dorsi, 
and the posterior small serratus, which covers its three last festoons ; inwards, 
with the longissimus dorsi, the transversalis costarum, and the external 
intercostals. 

Action. — This is an inspiratory muscle, and it also serves as a check to the 
deep spinal muscles. 

4. Small Posterior Serrated Muscle (Serratus Posticus) (Fig. 162, 14). 

Synonyms.— Jjumho-coHtalis— Girard. Posterior portion of the long serrated muscle — 
Bou/gelat. (Superficialis costarum — Percivall. The posterior serrated muscle of Leyh. The 
serratus posticus inferior of Man.) 

Situation. — Situated behind the preceding, which it follows, and presenting 
the same form and arrangement, this muscle also offers the following particular 
features for study : — 

1. Structure. — Its muscular portion, which is thicker and of a deep-red colour, 
is cut into nine well-defined digitations.^ The fibres which compose it run in an 
almost vertical direction. 

' It frequently happens that only eight diiritations are found in each muscle. 



MUSCLES OF THE TRUNK. 263 

2. Attachmmts. — Its aponeurosis, closely united to that of the latissimus 
dorsi, which covers it, is attached to the spinous processes of the dorsal vertebrse 
succeeding the tenth, and to some lumbar vertebrae. Its digitations are fixed to 
the posterior border and external face of the nine last ribs. 

3. Relations. — Outwards, with the latissimus dorsi ; inwards, with the small 
anterior serratus, the longissimus dorsi, transversalis costarum, and the external 
intercostals. Some of its posterior digitations are partly concealed by those of 
the great oblique muscle of the abdomen ; the last, indeed, is entirely covered by 
that muscle. 

4. Action. — This is an expiratory muscle, in consequence of its drawing the 
ribs backwards and upwards. 

Third Layer. 
5. The Ilio-8pinalis Muscle (Longissimus Doesi) (Fig. 163). 

Synonyms. — It represents the loug dorsal, short transversal, and long spinous of Bourgelat. 
Cuvier and others have described it as consisting generally, in Mammalia, of five particular 
muscles, designated as longissimus dorsi, transversalis cervicis, semispinalis dorsi, and semi- 
spinalis colli. It corresponds to the longissimus dorsi, and transversalis cervicis of Man. 

(Percivall designates this important muscle the longissimus dorsi — the name given to its 
analogue in Man, By Girard, Leyh, and Oliauveau, it is styled the ilio-spinalis.) 

Extent — Situation. — This, the most powerful and complex of all the muscles 
in the body, extends along the dorso-lumbar spine, above the costal arches, from 
the anterior border of the ilium to the middle of the cervical spine. 

Form. — It is elongated from before to behind, and flattened above and below 
in its posterior half, which represents the common mass in Man ; this mass is 
prismatic in form, thick inwards, and thin outwards. Anteriorly, it is flat on 
both sides, and bifurcates into two vohmiinous branches, a superior and inferior, 
between which pass the insertions of the complexus to be fixed into the transverse 
processes of the first dorsal vertebrae. 

Attachments. — 1. Upon the lumbar border, the external angle and internal 
smface of the ilium, the sacro-iliac ligament, and the sacrum. 2. To the spinous 
processes of all the lumbar and dorsal, and last four cervical vertebrae. 3. To 
the articular tubercles of the lumbar vertebrae and the transverse processes of all 
the dorsal, and the last fom* cervical vertebrae. 4. To the costiform processes 
of the lumbar vertebrae, and the external surface of the fifteen or sixteen last ribs. 

Structure. — If this muscle is examined posteriorly, in the part which forms 
the common mass, it wiU be found to be composed of very compact fleshy fibres, 
covered in common by a thick aponeurosis. These fibres commence at the 
posterior extremity of the muscle, and all proceed forward, stopping to make 
successive insertions on the various bony eminences in its track, and forming 
three diflferent orders of fasciculi, which are more or less tendinous at their 
anterior or terminal extremity. These fasciculi are internal and superficial, 
internal and deep, and external. 

The internal and superficial, or spinal fasciculi, pass to the summits of the 
spinous processes already noticed when speaking of the attachments. These 
fasciculi are little, if at all distinct posteriorly ; but they become more so 
anteriorly. About the sixth dorsal vertebras, they separate from the other 
fascicuU to form the superior branch of the muscle (Fig. 163, 3). 

The internal and deep, or transverse fasciculi, are those which attach the 
muscle to the articular tubercles of the lumbar vertebrae and transverse processes 



264 



THE MUSCLES. 



of the back and neck. They are well detached from each other, even posteriorly, 
and are very tendinous. Anteriorly, they pass into the inferior branch of the 




fongissimus dorsi, which they, in common with the external fasciculi, go to form. 
From profound, they now become superficial ; and they are seen springing up be- 
tween the others, which appear to separate to allow them to pass (Fig. 163, 4, 4). 



MUSCLES OF THE TRUNK. 265 

The external, or costal fasciculi, turn a little outwards to reach the ribs and 
costiform processes of the lumbar region ; they are not very apparent in this 
direction (%. 163, 2, 2). 

It win be easily understood that all these fasciculi do not come from the 
common mass, which would be expended long before its termination at the neck, 
in consequence of the successive emissions of the fasciculi composing it. To 
prevent this exhaustion, there are continually added to it numerous bimdles of 
fibres, which arise either from its aponeurotic envelope, or from the bones on 
which the primary fasciculi terminate, and comport themselves absolutely like 
these, which they are charged to continue to the neck. 

Relations. — It is covered by the pyramidal point of the principal gluteal 
muscle, which it receives in a particular excavation, and by the aponeurosis of 
the latissimus dorsi and the small serrated muscles. It covers the inter- 
transversales of the lumbar region, the semispinalis of the back and loins, the 
levatores costarum, and the external intercostals. Outwards, it is bordered by 
the transversalis costarum. 

The superior branch is covered by the complexus and the semispinaHs colli. 
Inwardly, it responds to the cervical ligament and the analogous branch of the 
opposite muscle. 

The inferior branch responds, outwardly, to the angularis of the scapula ; it 
covers some intertransversales colli, and the aponeurotic digitations which attach 
the complexus to the transverse processes of the first dorsal vertebrse. From 
these digitations it even detaches a number of muscular fasciculi, which go to 
strengthen this branch of the longissimus dorsi. 

Action. — It is a powerful extensor of the vertebral column, which, when it 
acts singly, it inclines to one side. It may also take part in expiration. 

6. Common Inteecostal Muscle (Teansversalis Costaeum (Fig. 163, 5). 

Synonyms. — Trachelo-coatalis — Girard. The sacro-lumhalis of Man. 

Form — Situation. — A long, narrow, and thin muscle — particularly at its 
extremities — situated along the external border of the preceding muscle, with 
which it is confounded behind the last rib. 

Structure — Attachments. — This muscle, the structure of which has been 
complicated by so many anatomists, is yet extremely simple. It is formed of 
a series of fasciculi, directed obliquely forwards, downwards, and outwards, 
tendinous at their extremities, and originating and terminating successively on 
the external surface of the ribs. The most posterior leave the external border 
and inferior face of the common mass. The tendinous digitation of the anterior 
fasciculus is inserted into the transverse process of the last cervical vertebra, in 
common with the inferior branch of the longissimus dorsi. 

Relations. — Outwards, with the great and small serratus ; inwards, with the 
external intercostals. 

Action. — It depresses the ribs, and may extend the dorsal portion of the spine. 

Fourth Layer. 

Transverse Spinous Muscle of the Back and Loins (Semispinalis 

OF THE Back and Loins) (Fig. 161, 3). 

Synonyms. — Transverso-spinous — Girard. Dorso-lumbar portion of the semispinalis of Maa 
(The spinalis and semispinalis dorsi — Percivall.) 

Situation — Extent. — This is a very long muscle, directly applied to the super- 



266 THE MUSCLES. 

sacral and dorso-lumbar spine, and continuous, in front, with the semispinalis 
colli ; these two muscles, therefore, measure nearly the whole length of the spine. 

Structure. — It is formed by an assemblage of short fasciculi, which are 
flattened on both sides, tendinous at their extremities, directed obliquely forwards 
and downwards, and a little inwards, thus crossing at a right angle the spinous 
processes they cover. 

Attachments. — These fasciculi are attached, below, to the lateral lip of the 
sacrum, the articular tubercles of the lumbar vertebrae, and the transverse 
processes of the dorsal vertebrae — origin. They are fixed, above, to the spinous 
processes of the sacral, lumbar, and dorsal vertebrae, and into that of the last 
cervical vertebra — termination. It is to be remarked that they do not attain the 
summits of these spinous processes in the first half of the dorsal region. 

i^e/a^wws.— Outwards, with the lateral sacro-coccygeal and longissimus dorsi 
muscles, which are confounded with it near its posterior extremity ; inwards, 
with the sacral spine and the spines of the lumbar and dorsal vertebrae, and with 
the interspinous ligaments of these three regions. 

Action. — It is an extensor of the spine. 

Differential Characters in the Muscles of the Spinal Region of the Back and 
Loins in the other Animals. 

A. Ruminants. — In the Ox, Slieep, and Goat, the trapezius is thick and very broad. 

In the Sheep, only the posterior fasciculus of the muscle annexed to the latissimus dorsi is 
seen. Some of its fibres are prolonged to the anterior border and external face of the latissimus 
dorsi. In the Camel, the dorsal portion of the trapezius is remarkable for its size. The 
latissimus dorsi has a thicker and wider body than that of the Hortse ; it descends low on the 
ribs ; the aponeurotic portion passes beyond the boss or hump. In the longissimus dorsi, the 
fasciculi are very distinct, even in the midst of the common mass, where the external fasciculi 
can be clearly seen to become attached separately to the extremities of the transverse processes 
of the lumbar vertebrae. 

The anterior small serrated muscle is inserted, by its last digitation, into the ninth rib. 
The posterior serrated is fixed into the four last ribs. 

B. Pig.— Its trapezius is well developed. The latissimus dorsi is voluminous, and is attached 
to the surface of the ribs, which it covers by digitations from its flesliy portion. It is fixed 
near the small trochanter to the lip of the bicipital groove. The inferior branch of the 
hngissimus dorsi of tbis animal is easily divided into two portions, traces of which are found 
in the Horse : one is formed by the costal fasciculi, the other by the transversal fasciculi. The 
latter constitutes the muscle to which Bourgelat has given the name of short transversal. 

C. Camivora. — Several of the spinal muscles in tbe Bog resemble those of the Pig ; such 
are the trapezium, the latissimus dorsi, and the longissimus dorsi. In animals of this group, it 
is remarked that the anterior serrated is very tiiick and very developed, and that it is attached 
to the eight ribs succeeding the second by as many well-marked festoons. The posterior has 
only three digitations, which are attached to tbe three last ribs. The transversalis costarum 
exactly resembles the sacro-lumbalis of Man ; behind the last rib, it constitutes a thick fleshy 
body, separated by a fissure from the longissimus dorsi, with which it is attached to the coxa. 
Lastly, the semispinalis of the back and loins is very strong in the lumbar region, and is 
prolonged on the coccygeal vertebrae. 

(According to Leyh, the semispinalis muscles are absent in the Horse and Ruminants; 
they are found in the Pig between tlie spinous processes of the dorsal and lumbar vertebrae, 
and in Camivora between the spinous processes of the cervical vertebrae.) 

Comparison of the Mdscles of the Back and Neck in Man with the analogous 
Muscles in the domesticated Animals (Fig. 164). 

It is usual, in human anatomy, to describe by the name of muscles of the back and neck 
those which correspond to the superior cervical region, and those of the spinal region of the 
back and loins of the domesticated animals. The muscles of the inferior cervical region are 
described in Man as muscles of the neck, with the hyoid muscles and the scalenus. 



MUSCLES OF THE TRUNK. 



267 



1. Muscles of the Back and Cervix. 
In the trapezius of Man, a cervical and a dorsal portion can no longer be distinguished. 
Abo\ie, it is attached to the superior occipital curved line ; below, it is fixed to the external 
third of the upper border of the clavicle, and to the acromion and scapular spine. The fibres 
of the trapezius, which are fixed into the clavicle, represent a portion of the mastoido-humeralia 
, of quadrupeds. 

The latissimus dorsi resembles that of the Dog and Pig, its fleshy portion being very 

Fig. 164. 




FIRST, SECOND, AND PART OF THIRD LAYER OF MUSCLES OF THE BACK OF MAN; THE FIE8T 
LAYER OCCUPIES THE RIGHT, THE SECOND THE LEFT SIDE. 

Trapezius ; 2, tendinous portion, forming, with a corresponding part of the opposite muscle, the 
tendinous ellipse on the back of the neck ; 3, acromion process and spine of scapula ; 4, latissimus 
dorsi ; 5, deltoid; 6, muscles of dorsum of the scapula (infra-spinatus, teres minor, and teres 
major; 7, obliquus externus; 8, gluteus medius ; 9, glutei maximi ; 10, levator anguli scapulae; 
11, rhomboideus minor; 12, rhomboideus major; 13, splenius capitis, overlying the splenius, 
above; 14, splenius colli, partially seen (the common origin of the splenius is attached to the 
spinous processes below the origin of the rhomboideus major) ; 15, vertebral aponeurosis ; 16, 
serratus posticus inferior; 17, supra-spinatus ; 18. infra-spinatus; 19, teres minor; 20, teres 
major; 21, long head of triceps, passing between teres minor and major to the arm; 22, serratus 
magnus, proceeding forwards from its origin at the base of the scapula ; 23, obliquus internus 
abdominis. 



developed ; it is attached to the external face of the four last ribs by muscular digitations, and 
terminates on the border of the bicipital groove. 

The rhomboideus is bifid, as in the smaller Quadrupeds. Less developed than in these 
animals, the levator anguli scapulx is only fi.xed iu front to the four first cervical vertebrae. 

In Man, the splenius is large, but by its insertions it resembles that of Solipeds. The 
complexus, thick and broad above, is incompletely divided into two fleshy bodies, which are 



268 THE MUSCLES. 

attacher], superiorly, to the sides of tlie external occipital crest. The trachelo-mastoideus 
is not fixed into the axis and atlas, its superior extremity passing directly to the mastoid 
process. 

There is nothing particular to note regarding the straight posterior and oblique muscles of 
the head ; the differences they offer in their form are allied to the conformation of the bones in 
this region. 

Of the two small serrated muscles, that which corresponds to the anterior serrated or 
animals rises very high ; for it is attached by an aponeurosis to the spinous processes of the 
three first dorsal vertebrae, the seventh cervical, and the cervical ligament. 

There are found in Man, lying along the vertebral furrows, several muscles which represent 
the longissimus dorsi and the transversalis costarum of Solipeds. Thus tlie common mass 
covering the lumbar vertebrae behind, is prolonged by two series of fleshy and tendinous 
fasciculi ; one forms the sacro-lumhaiis, which resembles the transversalis costarum of animals ; 
the other, the long dorsal, represents the inferior branch of the longissimus dorsi. The 
superior branch of the latter is found in the semispinalis colli. 

Lastly, there are also seen in Man semispinalis and intertransversalis muscles, which 
correspond : the first, to the semispinalis of the back and loins and semispinalis colli ; the 
second, to the intertransversales of the loins of the domesticated species. 

2. Muscles of the Neck. 

The mastoido-humeraUs is not present in Man, being peculiar to Quadrupeds; but we 
should see a portion of its fasciculi in the cleido-mastoideus muscle, and in the clavicular 
portions of the trapezius and deltoid. 

The sterno-mastoideus corresponds to the sterno-maxillaris of animals; as in the Dog, it 
is inserted into the external face of the mastoid process and the external two-thirds of the 
superior occipital curved line. Below, it commences by two fasciculi — one from the sternum, 
the other from the clavicle. We have already alluded to this clavicular fasciculus. 

The sterno-lhyro-hyoideus is large and well developed, resembling in its disposition that of 
the smaller animals. It is to be noted that the sterno-hyoideus portion leaves the sternum, tlie 
first costal cartilage, and the internal extremity of the clavicle. The subscapulo-hyoideus is 
digastric. The anterior great straight muscle of the head is attached to four cervical vertebrae, 
as in Ruminants and the Pig. The anterior small straight, the lateral small straight, and the 
longus colli, comport themselves as in the smaller animals. The anterior scalenus is very 
developed, for it is attached to the six last cervical vertebrae. 

Sublumbar, or Inferior Lumbar Region. 

The muscles of this region are deeply situated at the inferior face of the 
lumbar vertebrae and the ilium, concurring to form the roof of the abdominal 
cavity, and are in more or less direct contact with the viscera contained in that 
cavity. They are nine pairs. Three of these have received the generic name of 
psoas, and are of large volume ; they are bound by a strong aponeurosis — the 
iliac fascia, and are distinguished as the great psoas, iliac psoas (or iliacus), 
and small psoas. A fourth is named the square muscle of the loins {quadratus 
lumhorum). The other five, placed between the transverse processes of the 
lumbar vertebrae, represent, in consequence of their connection with these kind 
of fixed ribs, veritable intercostal muscles ; these are the intertransversales muscles 
of the loins. 

Preparation.— 1. Place the subject in the first position : open the abdominal cavity by 
completely removing its inferior walls ; empty the cavity of the viscera it contains, and excise 
the diaphragm, as that muscle prevents the anterior extremity of the great and small psoas 
muscles being seen. 2. First study the iliac fascia, its form, relations with the long abductor 
of the leg, its attachments, its continuity with the tendon of the small psoas, and the expansion 
reflected from the aponeurosis of the ^reat abdominal oblique muscle. 3. Expose the three 
psoas muscles by removing the iliac fascia, the two adductors of the leg, and the three 
adductors of the thigh. 4. Remove the psoas muscles for the dissection of the quadratus and 
intertransversales. 



MUSCLES OF THE TRUNK. 269 

1. Iliac Fascia, oe Lumbo-iliac Aponeurosis (Fig. 165, a). 

This is a very resisting fibrous expansion, covering the great psoas and iliacus 
muscles. Attached, inwardly, to the tendon of the small psoas, outwardly to 
the angle and external border of the ilium, this aponeurosis, as it extends for- 
•wards over the great psoas, degenerates into connective tissue. Behind, it also 
becomes attenuated in accompanymg the two muscles it covers, until near their 
insertion into the internal trochanter of the femur. Its external or inferior face 
receives, posteriorly, the insertion of the crural arch, and gives attachment to 
the long adductor of the leg ; for the remainder of its extent, it is covered by 
the peritoneum. 

2. Great Psoas Muscle (Psoas Magnus) (Fig. 165, 1). 

i&j/nonj/ms.— Sublumbo-troclian t : n eus— Gi'rard. Psoas — Bourgelat. {Lumho-femoral — Leyh.) 

Form — Situation. — This is a loug muscle, flattened above and below at its 
anterior extremity, prismatic in its middle, and terminated in a cone at its 
posterior extremity. It lies beneath the transverse processes of the lumbar 
vertebrae. 

Structure. — Almost entirely fleshy, this muscle is formed of very delicate 
fasciculi, which are directed backwards, and long in proportion to their super- 
ficial and deep situation. They all converge to a tendon which is enveloped by 
the iliacus, and is confounded with it. 

Attachments. — It is attached : 1. By the anterior extremity of its fleshy 
fasciculi to the bodies of the last two dorsal and the lumbar vertebrae, except the 
hindermost, and to the inferior face of the two last ribs and the transverse 
processes of the lumbar vertebrae. 2. By its posterior tendon to the internal 
trochanter, in common with the iliacus. 

Relations. — Below, with the pleura, the superior border of the diaphragm, 
and the lumbo-iliac aponeurosis, which separates it from the peritoneum and the 
abdominal viscera situated in the sublumbar region ; above, with the two last 
internal intercostals, the quadratus lumborum, and the intertransversales muscles ; 
inwardly with the small psoas and the internal branch of the iliacus ; outwardly, 
for its posterior third, with the principal branch of the latter muscle. 

Action. — A flexor and rotator of the thigh outwards when its fixed point is 
the loins, this muscle also flexes the lumbar region when the thigh is a fixed 
point. It is, therefore, one of the agents which determine the arching of the 
loins, and which operate, during exaggerated rearing or prancing, in bringing 
the animal into a quadrupedal position again. 

3. Iliac Psoas Muscle (Iliacus) (Fig. 165, 3). 

Synonyms.— T\\o-irochaxiixnevii&—Girard. (Leyh divides this muscle into two portions, 
which he describes as the great and middle ilio-femoralis. 

Form — Situation — Direction. — This is a very strong, thick, and prismatic 
muscle, incompletely divided into two unequal portions by the groove for the 
reception of the tendon of the great psoas : an external portion, somewhat con- 
siderable in size ; and an internal, small. These two muscular portions lie at 
the entrance to the pelvis, on the inner face of the ilium, in an oblique direction 
downwards, backwards, and inwards. 

Structure. — It is almost entirely fleshy. The fasciculi forming it are spread 



270 



THE MUSCLES. 



out in front, and collected behind, where they become slightly fibrous, and unite 
with the tendon of the great psoas. 

Attachments. — It has its fixed insertion on the whole of the iliac surface, on 
the external angle of the ilium, the sacro-iUac hgament, and the ilio-pectineal 

Fig. 165. I 




MUSCLES OF THE SUBLUMBAR, PATELLAR, AND INTERNAL CRORAL REGIONS. 

1, Psoas magnus ; 1', its terminal tendon ; 2, psoas parvus ; 3, iliacus ; 4, its small internal portion ; 
5. muscle of the fascia lata ; 6, rectus femoris of the thigh ; 7, vastus internus ; 8, long adductor 
of the leg ; 9, short adductor of the leg; 11, pectineus ; 12, great adductor of the thigh ; 12', 
small adductor of the thigh; 13, semimembranosus; 14, semitendinosus. A, Portion of the 
fascia i/iaca ; B, portion of the membrane reflected from the aponeurosis of the abdominal great 
oblique muscle, forming the crural arch (Poupart's ligament) ; C, pubic tendon of the abdominal 
muscles ; D, origin of the pubio-femoral ligament. 

crest. Its movable insertion is into the small internal trochanter, in common 
with the great psoas. 

Relations. — Above, with the ilium ; below, with the iliac fascia and the long 
adductor of the leg ; outwardly, with the muscle of the fascia lata and the origin 
of the rectus femoris, from which it is separated by a space filled with fat ; 
inwardly, with the crural vessels. It passes between the vastus internus and the 
pectineus, to reach the trochanter. 

Actions. — It is a flexor and rotator outwards of the thigh. 



MUSCLES OF THE TRUNK. 



271 



4. Small Psoas Muscle (Psoas Parvus) (Fig. 165, 2). 



according to Girard. 



of the loins — 1 
(^Psoaa parvus — Percivall. 



Sublumbo-pubia 
The lombo-iliacus 



3, or sublumbo-iliacua, 
Leyh.) 



Situation — Form — Structure. Placed at the inner side of the psoas magnus, 
very much elongated, and semipenniform in shape, this muscle is terminated 
behind by a flattened tendon, and is composed of fleshy fibres, the longest of 
which are anterior. These fasciculi are all directed backwards and outwards to 
gain the tendon. 



Attachments.— 1. To the bodies 
of the three or four last dorsal, and 
to all the lumbar vertebrse, by the 
anterior extremity of its fleshy fibres. 
2. To the ilio-pectineal line and the 
lumbo-iliac aponeurosis, by the pos- 
terior extremity of its tendon. 

Relations. — By its inferior face 
with the pleura, the superior border 
of the diaphragm, the aorta or pos- 
terior vena cava, and the great 
sympathetic nerve ; by its upper face, 
with the psoas magnus. It is tra- 
versed, near its vertebral insertions, 
by numerous vascular and nervous 
branches. 

Actions. — It flexes the pelvis on 
the spine, when the loins are the 
fixed point ; but should the pelvis be 
fixed, it arches or laterally inclines 
the lumbar region. It is also the 
tensor muscle of the lumbo-iUac 
aponeurosis. 



Fig. 166. 




DEEP MUSCLES OF THE SUBLITMBAR REGION. 

1, Quadratus lumborum ; 2, 2, intertransversales ; 
3, small retractor muscle of the last rib — a de- 
pendent of the small oblique of the abdomen. 



5. Square Muscle of the Loins (Quadratus Lumborum) (Fig. 166, 1). 

Synonyms. — Sacro-costalis — Girard. (Sacro-lumbalis — Percivall. Quadratus lumborum of 
Man.) 

Situation — Form — Structure — Attachments. — This muscle is comprised between 
the transverse processes of the lumbar region and the psoas magnus, is elongated 
from before to behind, flattened above and below, and divided into several very 
tendinous fasciculi. The principal fasciculus, situated outwardly, takes its origin 
from the sacro-iliac ligament, near the angle of the sacrum, and extends directly 
forward to gain the posterior border of the last rib, after being attached by its 
upper face to the summits of the transverse processes of the lumbar vertebrse. 
The other fasciculi are longer as they are anterior ; they leave the internal border 
of the first, and are directed obliquely foi-ward and inward, to be fixed into the 
transverse processes of the majority of the lumbar vertebrae, and the inner face 
of the two or three last ribs. 

Relations. — By its upper face, with the intertransversales, the small retractor 



E72 THE MUSCLES. 

of the last rib, and the fibrous fascia which unites that muscle to the small 
oblique of the abdomen. By its inferior face, to the psoas magnus. 

Actions. — It draws the last ribs backwards, and inchnes the lumbar spine to 
one side. 

6. Intertransveesales of the Loins (Fig. 166, 2, 2). 

(^Synonym. — Litertransversales lumborum — Percivall. ) 

These are very small flat muscles which fill the intervals between the trans- 
verse processes of the lumbar vertebrae. Their muscular fibres are mixed with 
tendinous fibres, and are carried from the anterior border of one transverse 
process to the posterior border of the other. 

They respond, by their superior face, to the longissimus dorsi, and by their 
inferior face to the quadratus, as well as the psoas magnus. They act by inclin- 
ing the lumbar region to one side. 

drpfebential characters in the muscles of the sublttmbar region in the otheb 

Animals. 

In Ruminants and the Pig, the muscles of this region so closely resemble those of 
Solipeds, that a special description is unnecessary. It may be remarked, however, that the 
quadratus lumborum in the Sheep is very developed, and throws fibres as far forward as tlie 
four last ribs. 

In the Dog, the psoas magnus is little developed, and only commences at the third, or even 
the fourth lumbar vertebra ; the iliacus is very slender, particularly in its external portion ; 
otherwise it is scarcely distinct from the psoas magnus, with which it may be said to form one 
muscle ; the psoas parvus is relatively larger than the great ; it is not prolonged into tlie 
pectoral cavity, and its anterior extremity is confounded with the quadratus lumborum, which 
is longer and stronger than in all the other animals. 

Comparison of the Subltjmbab Muscles of Man with those of Animals. 

In human anatomy, by the names of psoas and iliacus are described the psoas magnum and 
iliacus of animals. The psoas magnus of Man is distinguished from that of Solipeds by its 
superior insertions, whicii do not go beyond the last dorsal vertebrae. 

The psoas parvus is often absent : when present, it is attached, above, to the bodies of the 
twelve dorsal vertebrae ; below, to the ilio-pectineal crest. 

The intertransversales have been studied with the muscles of the back. The quadratus 
lumborum, classed by anthropotomi.sts with the abdominal muscles, is distinctly divided into 
three series of fasciculi : ilio-costal fasciculi, which pass from the upper border of the ilium to 
the twelfth rib; lumbo-costal fasciculi, passing from the transverse processes of the three or four 
last lumbar vertebrae to the twelfth rib ; and ilio-lumbar fasciculi, going from the iliac crest to 
the posterior face of the transverse processes of all the lumbar vertebrae. 

Coccygeal Region. 
This region is composed of four pairs of muscles destined for the movementg 
of the tail ; three, named the sacro-cocajgeal, are disposed longitudinally around 
the coccygeal vertebrae, which they completely envelop ; the fourth is designated 
the ischio-coccygeus {compressor coccygeus). 

1. Sacro-coccygeal Muscles (Fig. 167, 1, 2, 3). 

These three muscles are enclosed, with those of the opposite side, in a strong, 
common aponeurotic sheath, which is continuous with the inferior ilio-sacral 
and sacro-sciatic ligaments. They commence on the sacrum, are directed back- 
wards and parallel with the coccyx, gradually diminishing in thickness, and are 
formed by several successive fasciculi terminating in small tendons, which are 



MUSCLES OF THE TRUNK. 



273 



inserted into each of the coccygeal bones. With regard to their situation, these 
muscles are distinguished as sacro-coccygeus superior, sacro-coccygeus inferior, and 
sacro-coccygeus lateralis. 

A. Sacro-coccygeus Superior (Erector Coccygis). — The fasciculi which 
form this muscle have their fixed insertion either in the summits and sides of the 
three or four last processes of the supra-sacral spine, or from the coccygeal vertebrse 
themselves. The tendons for their movable insertion into these vertebrae are 
always very short. 

This muscle, covered by the coccygeal aponeurosis, in turn covers the vertebrae 
it moves. It responds : inwardly, to the analogous muscle of the opposite side ; 
outwardly, to the lateral sacro-coccygeus, and, near its anterior extremity, to a 
very strong aponeurotic expansion which separates it from the semispinahs 
muscle. It directly elevates the tail, or pulls it to one side, according as it acts 
in concert with its fellow or singly. 

B. Sacro-coccygeus Inferior (Depressor Coccygis). — This muscle is 
thicker than the precedmg ; its constituent fasciculi take their origin from the 

Fi?. 167. 




SACRO-ILIAC AND COXO-FEMORAL ARTICULATIONS, WITH THEIR SURROUNDING MUSCLES. 

1, Sacro-coccygeus superior ; 2, sacro-coccygeus lateralis ; 3, sacro-coccygeus inferior ; 4, ischio- 
coccygeus ; 5, deep gluteus; 6, crureus. 

inferior surface of the sacrum, towards the third vertebra, and from the internal 
face of the sacro-sciatic ligament and the coccygeal bones. It readily divides into 
two parallel portions, which Bourgelat has described as two separate muscles. 
The fasciculi of the internal portion are inserted, by their posterior extremity, into 
the inferior face of the first coccygeal vertebrae. Those of the external portion 
are furnished with strong superficial tendons, nearly all of which are for the 
bones of the tail. 

This muscle responds : outwardly, to the sciatic ligament, the ischio-coccygeus 
{compressor coccygeus) and coccygeal aponeurosis ; inwardly, to the muscle of the 
opposite side, and to the coccygeal attachment of the rectum ; above, to the 
sacrum, the bones of the tail, and the lateral muscle ; below, to the rectum and 
the coccygeal aponeurosis. 

It either directly depresses the tail or inclines it to one side. 

C. Sacro-coccygeus Lateralis (Curvator Coccygis). — This muscle may 



274 THE MUSCLES. 

be considered as the semispinalis of the coccygeal region ; indeed, it is confounded 
with that muscle of the back and loins by its anterior extremity, and appears to 
continue it to the inferior extremity of the tail. 

The fasciculi composing it arise from the spinous processes of the last lumbar 
vertebrfe, through the medium of the semispinahs, and from the coccygeal bones. 
The tendons terminating these fasciculi are deep and not very distinct. 

It responds : outwardly, at the posterior extremity of the longissimus dorsi, 
to the inferior ilio-sacral ligament and the coccygeal aponeurosis ; inwardly, to 
the semispinalis and the coccygeal vertebrae ; above, to the superior muscle ; 
below, to the inferior muscle, from which it is nevertheless separated by several 
small independent muscular fasciculi, which are carried from one coccygeal 
vertebra to another. (Leyh designates these the intertransversales of the tail.) 

It inchnes the tail to one side. 

2. ISCHIO-COCCYGEUS (COMPRESSOR COCCYGIS) (Fig. 167, 4). 

A small, thin, wide, and triangular muscle, situated against the lateral wall of 
the pelvis, at the internal face of the sacro-sciatic Ugament. 

It is attached, by an aponeurosis, to that Ugament and to the ischiatic ridge ; 
it is then directed upwards to be fixed, by its muscular fibres, to the side of the 
last sacral vertebra and the first two coccygeal bones. 

It is related, outwardly, with the sacro-sciatic Ugament. and inwardly to the 
lateral sacro-coccygeus and the rectum. 

It depresses the entire caudal appendage. 

Region of the Head. 

The head has a large number of muscles disposed around the mouth, nostrils, 
eyelids, the external ear, inferior maxilla, and os hyoides. They will be divided 
into five secondary regions. 

A. Facial Eegion, 

This region includes those muscles of the head which form a part of the 
framework of the lips, cheeks, and nostrils. Authors are far from being 
unanimous with regard to the nomenclature and description of these muscles. 
"We recognise eleven, which are enumerated below, chiefly according to the 
nomenclature of Girard. They are : the labial {orbicularis oris) ; zygomaticus ; 
supermaxillo-labialis (nasalis longus, or levator labii superioris proprius) ; maxillo- 
labialis {depressor labii inferioris) ; mento-labialis, suspensor of the chin (levator 
menti), which act on the lips ; alveolo-labialis {buccinator), which moves the 
jaw ; super naso-labial is {levator labii superioris alcequi nasi), which moves lips 
and nostrils ; great supermaxillo-nasalis {dilatator naris lateralis), small super- 
maxillo-nasalis {dilatator naris superior), naso-transversalis {dilatator naris 
transversalis), which dilate the nostrils and false nostrils only. 

1. Labialis, or Orbicularis of the Lips (Orbicularis Oris) (Fig. 167, 27). 

Preparation.— Remove with scissors the skin covering the two portions of this muscle ; 
afterwards the buccal mucous membrane and subjacent glands within the lips, to expose its 
internal face. 

The orbicularis, disposed as a sphincter around the anterior opening of the 
mouth, is regarded as the intrinsic muscle of the lips, and is composed of two 
portions or fasciculi — one for the upper, the other for the lower lip. United to 



MUSCLES OF THE TRUNK. 



27$ 



each other at the commissures of the mouth, and confounded with the superficial 
layer of the buccinator, which they appear to continue, these two muscular por- 
tions also receive a large portion of the fibres belonging to the majority of the 
extrinsic muscles, such as the dilatator naris lateralis and levator labii superioris 
alfequi nasi. 

The orbicularis is not attached to the neighbouring bone ; its component 
fibres, affecting a circular form, have, consequently, neither beginning nor ending, 
except in being continuous with other fibres. 

The internal face of the superior fasciculus responds to a layer of salivary 
glands, which in part separate it from the buccal mucous membrane. The external, 
covered by the skin, adheres to it in the most intimate manner, and is found 
isolated from it only on the median line, at first by the aponeurotic expansion of 

Fig. 168. 




SUPERFICIAL MDSCLES OF THE FACE AND HEAD. 

1, Temporo-auricularis externus, or attollens maximus ; 2, levator palpebrae, or corrugator super- 
cilii; 3, temporo-auricularis internus, or attollens posticus; 4, 5, zygomatico-auricularis, or 
attollens anticus ; 6, orbicularis palpebrarum; 7, abducens, or deprimens aurem ; 8, parotid 
gland; 9, temporal, or subzygomatic vein; 10, ditto, artery; 11, 12. superior and inferior 
maxillary nerves- 13, fascia of the masseter muscle; 14, nasal bones; 15, supernasol-abialis, or 
levator labii superioris alseque nasi; 16, supermaxillo-labialis, or nasalis longus labii superioris; 
17, external maxillary or facial artery; 18, facial vein; 19, supermaxillo-nasalis magnus, or 
dilatator naris lateralis ; 20, superior maxillary nerve ; 21, zygomatico-labialis, or zygomaticus ; 
22, parotid, or Steno's duct ; 23, masseter ; 24, alveolo-labialis, or buccinator ; 25, super- 
maxillo-nasalis parvus, or nasalis brevis labii superioris ; 27, labialis, or orbicularis oris ; 28, 
maxillo-labialis, or depressor labii inferioris ; 29, mento-labialis, or levator menti. 

the nasalis longus, then by a musculo-fibrous layer analogous to that which forms 
the levator menti. 

By its internal face, the inferior fasciculus likewise responds to the buccal 
mucous membrane, and to some salivary glands. By its external face, it forms 
an intimate union with the cutaneous integument, like the superior fasciculus. 

This muscle plays the part of a constrictor of the anterior opening of the 
mouth, and has complex functions to perform in suction, the prehension of food, 
and in mastication. 

2. Zygomatico-labialis (Zygomaticus) (Fig. 168, 21). 

Synonyms. — Portion of the cuticularis of Bourgelat. The zygomaticus major of Man. 

A very small, pale, and thin ribbon-like muscle, arising from the surface of 
the masseter, near the maxillary spine, by an aponeurosis which is confounded 
with the panniculus ; it terminates on the surface of the buccinator, at a short 



276 THE MUSCLES. 

distance from the commissure of the lips. Covered by the skin, it covers the 
buccinator, and some of the superior molar glands, vessels, and nerves. 

When this muscle contracts, it pulls back the commissure of the lips. 

In SoJipeds there is also sometimes found a muscle resembling the zygomaticus 
ininoi' of Man. It is a very small fasciculus situated under the preceding muscle, 
near its superior extremity. It appears that this fasciculus is continued, above, 
by the fibres of the lachrymal muscle, and is lost, below, on the buccinator sur- 
face, a little beneath the carotid canal. 

3. SUPERMAXILLO-LABIALIS (LEVATOR LaBII SuPERIORIS PrOPRIUS, OR NaSALIS 

LONGUS) (Fig. 168, 16). 

Synonyms. — Levator labii superioris of Bourgelat. The levator labii superioris proprii of 
Man. {Nasalis longus labii superioris — Percivall.) 

Situation — Direction— Form — Structure. — Lying vertically on the side of the 
face, below the levator labii superioris alseque nasi, this muscle is a thick and 
conical fleshy mass, terminated inferiorly by a tendon. 

Attachments. — It is attached, by the upper extremity of its fleshy body, to the 
external surface of the supermaxillary and zygomatic bones — origin. Its terminal 
tendon passes over the transverse muscle of the nose, to unite with that of the 
opposite side, and with it to form a single aponeurotic expansion, which dips by 
small fibres into the subcutaneous musculo-fibrous tissue of the upper lip. 

Relations. — Covered by the lachrymal and levator superioris alfequi muscles, 
this muscle in turn covers the supermaxiUary bone, the bottom of the false nostril, 
the dilatator naris inferioris, and the transversalis nasi. 

Actions. — It raises the upper lip, either directly or to one side, as it acts singly 
or in concert with its congener on the opposite side. 

4. Maxillo-labialis (Depressor Labii Inferioris) (Fig. 168, 28). 

Synonyms. — Depressor labii inferioris — Bigot. A dependency of the buccinator of Man. 
(Depressor labii inferioris — Percivall. Inferior maxillo-labialis — Leyh. Depressor anguli oris 
of Man.) 

Situation — Direction — Form — Structure. — Situated along the inferior border 
of the buccinator, and following its direction, this muscle forms a long narrow 
fasciculus, terminating inferiorly by an expanded tendon. 

Attachments. — 1. By its superior extremity, to the anterior border of the 
lower jaw, in common with the deep plane of the buccinator— ^a;^c? origin. 2. 
By its terminal tendon, to the skin of the lower lip — movat)le insertion. 

Relations. — Outwardly, with the masseter and the facial portion of the cervical 
panniculus ; inwardly, with the maxillary bone ; in front, with the buccinator, 
with which it is directly united in its upper two-thirds. 

Actions. — It separates the lower from the upper lip, and pulls it to the side 
if one alone acts. 

5. Mento-labialis, or Muscle of the Chin (Levator Menti) (Fig. 168, 29). 

[Synonyms. — Percivall appears to describe this and the next muscle as one, the levator menti. 
It is the quadratus menti of Man.) 

This name is given to a musculo-fibrous nucleus, forming the base of the 
rounded protuberance beneath the lower hp in front of the beard. This single 
nucleus is confounded, in front, with the orbicularis of the lips, and receives into 
its upper face the insertion of the two posterior middle muscles (levatores menti). 



MUSCLES OF THE TRUNK. 277 

6. Intermediate Posterior Muscle. 

Synonyms.— M-eAins posterior — Bourgelat. (Levator menti — Percivall. Incisive muscle of 
the lower lip — Leyh.) 

Bourgelat describes, by this name, a small muscular fasciculus, analogous in 
every respect to the medius anterior. This little muscle takes its origin from the 
external surface of the body of the lower jaw, beneath the intermediate and 
corner incisors ; from thence it descends into the texture of the lip, to unite with 
that of the opposite side on the upper face of the mento-labialis. Several authors 
have described it as a dependent of the last muscle. 

7. Alveolo-labialis (Buccinator) (Fig. 168, 24). 

Synonyms. — Molaris externus et internus — Bourgelat. {Buccinator — Percivall. Leyh 
divides this muscle into two portions ; its superficial plane he designates the Buccinator, and 
the deep plane the Molaris.) 

Preparation. — Proceed to the ablation of the masseter ; dissect the external surface of the 
muscle, taking care of the risorius Santorini and zygomaticus, which are confounded with it. 
Then divide it in the middle, as far as the commissure of the lips ; turn down each strip on 
the jaws, and remove the mucous membrane, in order to study the inner face of the muscle and 
the attachments of the superficial plane to the maxillary bones. 

Situation — Form. — Situated on the sides of the face, partly concealed by the 
masseter muscle, and applied to the mucous membrane of the cheeks, the bucci- 
nator is a flat, thin muscle, elongated in the direction of the head, and formed 
of two superposed planes. 

Extent — Structure — Attachments. — The deep plane, the longest and least wide, 
is narrower at its extremities than its middle, and is formed of strongly aponeu- 
rotic muscular fasciculi, which are attached, posteriorly : 1. To the alveolar 
tuberosity. 2. To the external surface of the superior maxillary bone, above 
the last three molar teeth. 3. To the anterior border of the inferior maxillary 
bone, behind the sixth molar, in common with the depressor labii inferioris. 
On reaching the commissure of the lips, this muscular layer appears to be 
continued by small tendon's with the fibres of the orbicularis. 

The superficial plane only begins about the middle of the deep one, the 
anterior half of which it entirely covers. Its fibres, less tendinous than those of 
the latter, extend from a median raphe which also divides the deep layer in its 
length, and are directed, some forwards, some backwards, to terminate in the 
following manner : the first are inserted into the external face of the super- 
maxillary bone, above the first molar tooth and the superior interdental space ; 
the second are attached to the inferior interdental space alone. 

Relations. — Externally, with the masseter, zygomaticus, panniculus, dilator 
naris lateraUs, levator labii superioris, the parotid duct, which crosses it to enter 
the mouth, and the facial artery and veins ; internally, with the buccal mucous 
membrane. The deep plane is accompanied and covered at its anterior border 
by the upper molar glands ; its posterior border is margined by the inferior molar 
teeth, which it partially covers. The superficial layer is distinctly separated from 
the deep one in its anterior part, which is attached to the supermaxillary bone. 
Behind, these two planes adhere more intimately to one another, though they 
are found completely isolated by an interstice in which one or two large veins pass. 

Actions. — The function of the buccinator is particularly related to mastication : 
this muscle, in fact, pushes between the molar teeth the portions of food which 
fall outside the alveolar arches : but it cannot aid in bringing the two jaws 
together, as Lecoq has correctly observed. 



278 THE MUSCLES. 

8. SUPERNASO-LABIALIS (LEVATOR LaBII SuPERIORIS Al^QUI NaSI) 

(Fig. 168, 15). 

Synonyms. — The maxillaris of Bourgelat. The levator labii superioris alxque nasi of Man. 
(Levator labii superioris alxque nasi — Percivall. Fronto-lahialis — Leyh.) 

Situation — Direction — Form — Structure. — Situated on the side of the face, in 
an obUque direction downwards and backwards, this is a wide muscle, flattened 
on both sides, elongated from below to above, aponeurotic at its superior 
extremity, and divided inf eriorly into two unequal branches, between which passes 
the dilatator naris lateralis. 

Attachments.— It has its origin, by its superior aponeurosis, from the frontal 
and nasal bones, and unites on the median line with the muscle of the opposite 
side. Its anterior branch, the widest and thickest, goes to the external ala of the 
nostril and to the upper lip, where its fibres are confounded with those of the 
orbicularis. The posterior branch terminates at the commissure of the lips. 

Relations. — Outwards, with the skin ; inwards, with the levator labii superioris, 
the posterior portion of the dilatator naris superioris, and vessels and nerves. Its 
posterior branch covers the dilatator naris lateralis, and the anterior is covered 
by that muscle. 

Actions. — It elevates the external ala of the nose, the upper lip, and the com- 
missure of the lips. 

9. Great Supermaxillo-nasalis (Dilatator Naris Lateralis) (Fig. 168, 19). 

Synonyms. — The pyramidalis-nasi of Bourgelat. The caninus of Man. (Dilatator naris 
lateralis — Percivall.) 

Situation — Direction — Form — Structure. — This muscle, situated on the side 
of the face, between the two branches of the levator labii superioris, in an almost 
vertical direction, is triangular in form, and slightly tendinous at its summit. 

Attachments. — It has its origin, by the aponeurotic fibres of its summit, from 
the external face of the supermaxillary bone, below its ridge. It terminates, by 
its base, on the skin covering the external wing of the nostril, its most posterior 
fibres being confounded with those of the orbicularis of the hps. 

Relations. — Outwardly, with the skin and the inferior branch of the levator 
labii superioris ; inwardly, with the anterior branch of that muscle, and with 
vessels and nerves. 

Actions. — It dilates the external orifice of the nasal cavity, by pulling out- 
wards the external wing of the nostril. 

10. Small Supermaxillo-nasalis (Dilatator Naris Superioris) 
(Fig. 168, 25). 

Synonyms.—The nasalis brevis, and portion of the subcutaneous muscle of Bourgelat. 
(Nasalis hrevis labii superioris — Percivall.) 

Girard has described, by the above name, a small, thick, and short muscular 
fasciculus which covers the external process of the premaxillary bone, the fibres 
of which, either originating from that, the supermaxillary bone, or the internal 
face of the levator superioris muscle, terminate in the skin of the false nostril, 
and the appendix of the inferior turbinated bone. 

Rigot has attached to this muscle that described by Bourgelat as the short 
muscle. The latter is composed of short, transverse fibres, applied to the 



MUSCLES OF THE TRUNK. 279 

expansion of the cartilaginous septum of the nose which projects laterally beyond 
the nasal spine. These fibres abut, by their most eccentric extremities, against 
the skin of the false nostril and the appendix of the inferior turbinated bone. 

To this muscle we may attach the small muscular fasciculus which Bourgelat 
has described as the anterior intermediate. To study it, it is necessary to raise 
the upper lip and remove the mucous membrane lining it. It is then seen that 
its fibres, attached to the inner side of the premaxilla, above the incisor teeth, 
ascend to meet those of the dilatator naris superior, and to terminate with them 
on the anterior appendix of the inferior turbinated bone ; some fibres become 
lost in the lips. 

The dilatator naris superior acts as an external dilator of the nostril and false 
nostril. (Percivall names it the depressor labii superioris.) 

11. Transversalis Nasi (Dilatator Naris Transversalis). 

{Synonym. — Dilatator naris anterior — Percivall). 

This muscle is in two parts : one, inferior, single, short, and quadrilateral, 
flattened on both sides, lies on the wide part of the nasal cartilages, forming 
transverse fibres ; the other, superior, pair muscle, formed of pale short fibres 
passing from the thin portion of the septum nasi which is laterally bordered by 
the nasal prolongation, to the skin of the false nostril and appendix of the upper 
turbinated bone. Covered by the skin and the aponeurotic expansion of the two 
elevator muscles of the upper lip, the transverse muscle of the nose covers the 
cartilages to Avhich it is attached, and is confounded below with the orbicularis 
of the lips. 

Designed to bring together the two internal alte of the nose, this muscle 
ought to be considered more particularly as the dilator of the nostrils ; and, in 
addition, as an internal dilator of the false nostril. 

B. Palpebral Region. 

This region includes three muscles which act upon the eyelids or the sldn 
in proxindty to the orbit ; these are the Orbicularis Palpebrarum, Fronto- 
palpebral {Corrugator Supercilii), Lachrymalis. 

1. Orbicularis of the Eyelids (Orbicularis Palpebrarum) (Fig. 168, 6). 

This muscle is a thin wide sphincter common to the two eyelids, and lying 
on the palpebral fibrous plate and the bones forming the margin of the orbit. 
Its external surface is covered by the skin, to which it adheres very closely. A 
small tendon wliich extends from the lachrymal tubercle to the nasal angle of the 
eye, is considered as the origin of the fibres of this muscle ; some of these — 
the most numerous— pass upwards and are distributed in a circular manner in 
the upper eyelid ; the others reach the lower eyelid and rejoin the numerous ones 
towards the temporal angle of the eye. 

The contraction of this muscle determines the occlusion of the palpebral opening. 

2. Fronto-Palpebral, or Corrugator Supercilii (Fig. 168, 2). 

This is a short flat muscle, arising from the external surface of the frontal 
bone, and passing downwards and outwards to mix its fibres with those of the 
orbicularis at the supra-orbital foramen, which it covers, and the skin of the eye- 
brow. It has been erroneously considered as an elevator of the upper eyelid. When 



280 



THE MUSCLES. 



it contracts, it is limited to wrinkling the skin of the eyebrow in drawing it slightly 
to the nasal angle — which it can do whether the eyelids are in contact or apart. 



3. Lacheymalis Muscle. 

((Synonym.— Not mentioned by Percivall. It is the inferior palpebral muscle of Leyh.) 

A wide and very thin muscle, situated superficially below the eye. It is con- 
tinuous, in front, with the panniculus ; behind, with the levator labii superioris ; 
above, with the orbicularis of the eyelids. Its fibres, partly muscular and partly 
aponeurotic, leave the external surface of the lachrymal and malar bones, are 

directed do«Ti wards, and become 
Fig- 169. lost in a connective tissue fascia 

which covere the buccinator ; 
some pass beneath the zygo- 
maticus and form the zygoma- 
ticus minor, when this is present. 
This muscle is supposed to 
corrugate and twitch the skin 
below the eye. 

c. aueicular, or conchal 
Region. 

The muscles of this region 
move the concha, or pavilion 
of the ear {concha auris). The 
largest arise from the surface 
of the cranial bones or cord of 
the cervical ligament, and 
terminate on the cartilages of 
the external ear ; the medium- 
sized pass from one cartilage to 
another ; and the smallest are 
found on the surface of the 
concha, inside and out. The 
latter are really intrinsic 
muscles, but they are of so little 
importance that we will not 
describe them. The others are 
ten in number. 

In the first plane we find 
the zijgomatico-auricularis {atto- 
Ims anticus), temper o-auricu- 
laris externus (attolens maxi- 
mus), scuto-auricularis externus, 
three cervico-auriculares (re- 
trahens externum, medius, inter- 
nus), and parotido-auricularis 
(abducens) ; the second plane, the temporo-auricularis internus {attolens posticus), 
scuto-auricularis internus, tympano-auricularis {mastoido-auricularis). 

Before studying these muscles, it is indispensable to examine the pieces of 




MUSCLES OF THE EXTERNAL EAR OF THE MULE. 
1, 1, AttoUens maximus; 2, attoUens posticus; 3,. scuti- 
form cartilage ; 4, scuto-auricularis externus. A, auri- 
cular branches of the first cervical nerve ; B, anterior 
auricular nerve (from the facial) ; C, terminal branches 
of the superciliary nerve ; D, superficial or temporal 
branch of the lachrymal nerve. 



MUSCLES OF THE TRUNK. 281 

cartilage which form the concha. These are three in number : 1. Conchal 
cartilage. 2. Annular cartilage. 3. Scutiform cartilage. 

1. Conceal Cartilage. — The principal portion of the pavilion, this cartilage 
determines its general configuration. In shape it resembles a trumpet with a 
wide opening on one side. Its entrance is elliptical, and elongated vertically, 
being circumscribed by two thin borders which unite above at a point that 
constitutes the summit (apex) of the organ. Its base, bulging in a cul-de-sac, 
terminates in front by a constricted infundibulum ; it is attached to the margin 
of the auditory hiatus by means of the annular cartilage, to the surface of 
the guttural pouch by a pointed prolongation that descends outside this annular 
cartilage, beneath the parotid gland, and terminates by several fibrous filaments. 
This portion of the framework of the concha is a cartilaginous plate, rolled on 
itself in such a manner as to circumscribe, between its borders, the entrance to 
the ear, and to form, inferiorly, the complete infundibuliform canal just men- 
tioned. (Externally, the integument of the ear is covered by ordinary hair, but 
internally there are long fine hairs, especially near the entrance ; these prevent 
the intrusion of foreign substances.) 

In Ruminants, this cartilage is thin, inclined outwards, and largely open. In the Fig, 
it differs slightly according to breed, but it is always much developed, sometimes erect, and 
more frequently drooping forward. It is always short, pointed, erect, and open towards the front 
in the Cat. In the Dog, it is sometimes short and straight ; in others broad and pendant. 

2. AjraruLAR Cartilage. — By this name is known a little ring-shaped plate, 
placed at the lower part of the conchal cartilage, intermediate between it and the 
auditory canal. The internal integumentary membrane, with some yellow elastic 
fasciculi, unites this cartilage to the other two portions between which it is situ- 
ated. Its relations with these are such, that it receives within its lower border 
the bony circular prominence forming the margin of the auditory hiatus, while it 
may itself be received into the infundibuliform canal of the conchal cartilage — 
an arrangement resembling the tubes of a telescope. 

3. Scutiform Cartilage. — This is a small cartilaginous plate, situated in 
front of the base of the concha, at the surface of the temporal muscle ; it is 
irregularly triangular, is attached to the conchal cartilage by some muscular 
fasciculi, and transmits to that cartilage the action of some other muscles which 
are fixed on the cranial bones. 

(The arteries of the concha proceed from branches of the external carotid, 
and the veins pass to a trunk of the same name ; the nerves are divisions of the 
facial and the first cervical pair.) 

An adipose cushion, placed at the base of the ear, facilitates the movements of 
the cartilages when they are acted upon by these muscles. 

1. Zygomaticus-auricularis (Attollens Anticus) (Figs. 168, 4, 5 ; 170, 19). 

This muscle is generally composed of two fleshy bands joined by connective 
tissue, and rising from the zygomatic process of the temporal bone by means of an 
aponeurosis common to it and the orbicularis palpebrae. The inferior of these 
two bands is inserted into the outside of the base of the concha, its fibres mixing 
with those of the abducens ; the superior band terminates on the outer border 
of the scutiform cartilage. 

Placed immediately beneath the skin, this muscle partly covers the superior 
extremity of the parotid gland, and the zygomatic process. 

It draws the ear forward. 



282 TEE MUSCLES. 

2. Temporo-auricularis Externus (Attolens Maximus) (Figs. 168, 1 ; 
169, 1, 1 ; 170, 3, 4). 

A very thin, wide muscle, covered by the skin, lying on the temporal muscle, 
united posteriorly to the retrahens externus, in front and outwardly to the 
attollens maximus. It arises from the whole of the parietal crest or ridge,^ 
mixing in its upper half or third with the muscle of the opposite side ; it termi- 
nates, by one portion, on the inner margin of the scutiform cartilage, and by 
another, on the inner side of the conchal cartilage, by means of a thin fascia that 
covers part of the former cartilage and the external scuto-auricularis. 

It acts as an adductor of the concha, drawing it inwards ; it also carries it 

Fig. 170. 




MUSCLES OF THE EAR. 

1, Retrahens externus; 2, attollens posticus; 3, 4, attollens maximus; 5, scutiform cartilage; 
6, scuto-auricularis externus; 7, posterior auricular artery; 8, portion of the zygomaticus-auii- 
cularis; 9, orbital process; 10, temporo-auricularis internus ; 11, temporal muscle; 12, scutiform 
cartila£;e ; 13, ditto ; 14, concha of the ear ; 15, scuto-auricularis externus ; 16, internal scuto- 
auricularis; 17, abducens; 18, corrugator supercilii ; 19, zygomaticus-auricularis. 



forwards, and concurs in making it pivot on itself, 
the ear forward. 



as to bring the opening of 



3. Scuto-Auricularis Externus (Figs. 169, 4 ; 170, 6). 

This muscle may be said to be a dependency of the preceding, the action of 
which it transmits to the conchal cartilage, and renders it more complete. 

Extending from the external face of the scutiform cartilage to the inner side 

' Owing to this crest bordering the temporal fossa, Girard has thought proper to give to 
the two muscles of the ear attached thereto, the name of temporo-auriculares ; but it would be 
more appropriate to designate them the parieto auricularea. 



MUSCLES OF THE TRUNK. 283 

of the concha, and generally composed of two fasciculi, it is covered by the skin 
and the conchal band of the attollens maximus, while it covers part of the internal 
scuto-auricularis muscle. 

When this muscle contracts, it principally participates in producing the 
rotatory movement that carries the opening of the concha outwards. 

4. Cekvico-auriculares (Retrahentes Aurem) Muscles (Fig. 168). 

Three in number, and situated behind the ear, these muscles are broad, thin 
bands, extending from the cervical ligament to the conchal cartilage. With 
regard to their position at their origin, they may be distinguished as external^ 
middle, and internal ; the situation of their point of insertion in the concha also 
permits their being classed as superior, middle, and inferior. 

The retrahens externus, or superior or superficial cervico-auricularis, closely 
united to the attollens maximus, and covered by the skin, covers the medius and 
internus muscles. Attached by iis terminal extremity to the middle of the 
posterior face of the concha, it draws that cartilage backwards and downwards. 

The retrahens medius, or middle cervico-auricularis, comprised at its origin 
between the other two, and intimately attached to them, especially the deep one, 
is in relation with the skin for the greater part of its superficies. Its terminal 
extremity is very wide and thin, and passes over the upper end of the parotid 
gland, to be inserted outwardly into the base of the concha, after being slightly 
insinuated beneath the abducens. This is a rotator muscle, turning the opening 
of the ear outwards and backwards. 

The retrahens internus, or inferior or deep cervico-auricularis, concealed beneath 
the upper extremity of the parotid, to which it adheres closely, is inserted at the 
base of the concha. Its action is similar to that of the middle muscle. 

5. Parotido-auricularis (Abducens, or Deprimens Aurem) 
(Figs. 168, 7 ; 170, 17). 

Lying on the external face of the parotid gland, this is a long, thin, ribbon- 
like band, narrower and thicker at its upper than its lower extremity. It arises 
on the tissue of the gland, and terminates outside the base of the concha, below 
the inferior commissure formed by the two borders of that cartilage. 

Covered externally by a very thin portion of the cervico-facial panniculus, 
the abducens is an abductor of the ear, inclining it outwards. 

6. Temporo-auricularis Internus (Attollens Posticus) (Fig. 170, 2). 

Situated beneath the superficial muscle of this name, and partly covered by 
the retrahens externus, this muscle is long and triangular in shape, bright-red in 
colour, and extending transversely on the surface of the temporalis ; it is attached, 
inwardly, to the sagittal or spur-like ridge of the parietal bones, and outwardly, 
by means of a small tendon, to the inner side of the concha, within the terminal 
insertion of the retrahens externus auricularis. It is an adductor of the ear. 

7. Scuto-auricularis Internus (Fig. 170, 16). 

This is a muscle composed of two short, pale fasciculi, which cross each other 
very obliquely, are concealed beneath the scutiform cartilage and the scuto- 
auricularis externus, and lie directly on the adipose cushion of the ear. They 



284 TEE MUSCLES. 

arise from the inner face of the scutiform plate, pass backwards, and termi- 
nate at the base of the concha, behind the infundibuhform cavity which that 
cartilage forms at its root. This muscle is antagonistic to the external muscle 
of this name, as it turns the opening of the ear outwards, and even backwards. 

8. Mastoido-auricularis. 

This name is given to a very thin fasciculus lying vertically on the inner 
side of the cartilage, at the entrance to the ear. Arising from the margin of 
the auditory external hiatus, and attached to the base of the concha, this little 
muscle, in contracting, constricts the cartilaginous tube with which it is in contact. 

D. Masseteric, or Temporo-maxillary Region. 

This region comprises five pair-muscles for the movement of the lower jaw. 
These are : the masseter, temporalis, pterygoidms internus, pterygoideus externuSy 
and digastricus. 

Preparation.— \. First study the digastricus and its stylo-maxillary portion, with the 
internal pterygoid, in preparing the hyoid muscles as they are represented in Fig. 171. 2. 
Expose the pterygoideus extemus, by removing in this preparation the hyoid bone and its 
dependencies, as well as the two preceding muscles. 3. To dissect the temporalis, excise the 
external pterygoideus from its inferior border, an operation which exposes the orbital fasciculus 
of the temporalis ; then turn over the piece, saw oflF the orbital process at each end, and remove 
the eye and auricular muscles. 4. Dissect the masseter, in clearing away from its external 
surface the cuticularis and the vessels and nerves which cover it. 

1. Masseter (Fig. 168, 23). 

Synonyms. — Zygomatico-maxillaris — Girard. 

Situation — Form — Structure. — Applied against the external face of the branch 
of the lower jaw, the masseter is a short, wide, and very thick muscle, flattened 
on both sides, irregularly quadrilateral, and formed of several superposed planes, 
two of which are perfectly distinct towards the temporo-maxillary articulation, 
by the somewhat different direction of their fibres. These are divided by a 
considerable number of intersections, and are covered by a strong aponeurotic 
layer, which becomes gradually thinner backwards and downwards. 

Attachments. — The fasciculi of the masseter have their fixed insertion on the 
zygomatic crest. Their movable insertion is on the imprints which cover the 
upper half of the ramus of the inferior maxilla. 

Relations. — It responds, by its superficial face, to the facial portion of the 
cervical panniculus, to the nerves of the zygomatic plexus, and several venous and 
arterial vessels ; by its deep face, to the inferior maxillary bone, the buccinator 
and depressor labii inferioris muscles, the superior molar glands, and two large 
venous branches ; by its inferior border, with the parotid duct, and the glosso- 
facial artery and vein ; by its superior and posterior border, to the parotic gland. 
Its deep plane responds, anteriorly, with the temporo-maxillary articulation, and 
is so intimately confounded with the temporalis, that it is impossible to define 
the respective limits of the two muscles. 

Action. — This muscle, the special elevator of the lower jaw, plays an important 
part in mastication. It always acts as a lever of the third class — the middle 
Une, which represents the resultant of all its constituent fibres, passing behind 
the last molar. 



MUSCLES OF THE TRUNK. 285 

2. Temporalis. 

Synonyms. — Temporo-maxillaria — Girard. 

Situation — Form — Structure. — Situated in the temporal fossa, to which it is 
moulded, and which it fills, this muscle is flattened from above to below, divided 
by strong tendinous intersections, and covered by a nacrous aponeurotic layer. 

Attachments. — It takes its origin : 1. In the temporal fossa and on the bony 
crests which margin it. 2. By a wide fasciculus, paler than the other portion of 
the muscle, but not unconnected with it, from the imprints situated behind the 
crest surmounting the orbital hiatus. It terminates on the coronoid process and 
the anterior border of the branch of the lower jaw. 

Relations. — This muscle covers the temporal fossa, and is covered by the 
attoUens muscles, scutiform cartilage, internal scuto-auricularis, the fatty cushion 
at the base of the ear, and by another adipose mass which separates it from the 
ocular sheath. Its deep fasciculus responds, by its internal face, to the two 
pterygoid muscles. 

Action. — It brings the lower jaw in contact with the upper, by acting as a 
lever of the first kind ; but the orbital portion of the muscle elevates the inferior 
maxilla and moves it laterally by a lever of the third kindo 

3. Pterygoideus Internus. 
Synonyms. — Portion of the spheno-maxillaris of Bourgelat. 

Sitimtion — Form — Structure.— Sit\ia.ted in the intermaxillary space, opposite 
the masseter, the pterygoideus internus, although not so strong as that muscle, 
yet so closely resembles it in form and structure as to be named by "Winslow the 
internal masseter. 

Attachments. — 1. To the palatine crest and subsphenoidal process— ;/?a;e^ 
insertion. 2. In the hollow excavated on the inner face of the branch of the 
lower jaw — movable insertion. 

Relations. — Outwardly, with the pterygoideus-externus, the orbital fasciculus 
of the temporal, the maxillo-dental nerves, mylo-hyoideal, and lingual muscles, 
arteries and veins, and the inner surface of the bone which receives its movable 
insertion. Inwardly, with the tensors palati— external and internal, the 
guttural pouch, the hyoideus magnus, hyoid bone, digastricus, the hypoglossal 
and glosso-pharyngeal nerves, glosso-facial artery and vein, the hyoglossus longus 
and brevis muscles, the laryngo-pharyngeal apparatus, the Stenonian duct, and 
the submaxillary glands. 

Action. — It is an elevator of the lower jaw, and also gives it a very marked 
lateral or diductive motion. If the left muscle acts, this movement carries the 
inferior extremity of the lower jaw to the right ; if it be the right muscle, then 
in the contrary direction. 

4. Pterygoideus Externus. 

(Synoraj/w.— Portion of the spheno-maxillaris of Bourgelat. 

Form — Situation — Strmture — Attachments. — A small, short, and very thick 
muscle, situated within and in front of the temporo-maxillary articulation, 
formed of shghtly tendinous fasciculi which leave the inferior face of the 
21 



286 THE MUSCLES. 

sphenoid bone and the suhsphenoidal process, and are directed backwards and 
upwards to be fixed to the neck of the inferior maxillary condyle. 

Relations. — Outwardly, with the orbital fasciculus of the temporalis muscle 
and the temporo-maxillary articulation. Inwardly, with the numerous nerves 
emanating from the inferior maxillary branch, and with the internal pterygoid 
and tensors palati. 

Action. — When the two external pterygoids act in concert, the inferior 
maxilla is pulled forward ; but if only one contract, the propulsion is accompanied 
by a lateral movement, during which the extremity of the jaw is carried to the 
opposite side. 

5. DiGASTRICUS (StYLO-MAXILLARIS). 

Synonyms. — Bourgelat has made two distinct muscles of this — the digastricus and stylo- 
maxillaris. Girard lias described it as the stylo-maxillaris. (Percivall has evidently followed 
Bourgelat's example, and divided the muscle into digastricus and stylo-maxillaris. Leyh 
adopts the same course.) 

Form — Structure — Situation — Direction. — Composed of two fleshy bodies 
more or less divided by intersections, and united at their extremities by a median 
tendon, this muscle is situated in the intermaxillary space, and extends from the 
occiput to near the symphysis of the chin, describing a curve upwards. 

Attachments. — It takes its origin from the styloid process of the occipital 
bone, by its superior fleshy body. It terminates : 1. On the curved portion of 
the posterior border of the lower jaw by a considerable fasciculus, which is 
detached from the superior fleshy body.^ 2. On the internal face of the same 
bone and the straight portion of its posterior border, by aponeurotic digitations 
which succeed the muscular fibres of the inferior fleshy body. 

Relations.— The superior belly of the muscle responds, superficially, to the 
parotid gland and the tendon of insertion of the sterno-maxillaris ; deeply, to 
the guttural pouch, the submaxillary gland, and the larynx and pharynx. The 
median tendon passes through the ring of the hyoideus magnus. The lower 
belly is in contact, outwards, with the ramus of the inferior maxilla ; inwards, 
with the mylo-hyoideus muscle. 

Action. — When this muscle contracts, it acts at the same time on the hyoid 
bone, which it raises in becoming straight, and on the lower jaw, which it pulk 
backwards and depresses at the same time. 

E. Hyoideal Region. 

This region includes six muscles grouped around the os hyoides, which they 
move. Five of these are pairs : the mylo-hyoideus, genio-hyoideus, stylo-hyoideus, 
kerato-hyoideus {hyoideus parvus), and the occipito-styloideus. The single one is 
the hyoideus transversus. 

Prepara(/on.— Separate the head from the trunk, and remove the muscles of the cheeks on 
one side, with the parutid gland. 2. The branch of the inferior maxilla being thus exposed, it 
is sawn through in two places; at first beliind the last molar, then in front of the first. 3. 
After having separated the pterygoids and the stylo-maxillaris from the upper fragment or 
condyle, and the coronoid process, it is torn off by pulling it backwards ; then the pterygoids 
and digastricus are excised. 4. The inferior fragment of the jaw bearing the molar teeth is 



1 This is the fasciculus which Bourgelat has described as a distinct muscle, and named the 
ttylo-maxillaris. 



MUSCLES OF THE TRUNK. 287 

turned down by isolating the mylo-hyoideus from the mucous membrane. 5. Carefully remove 
the tongue by separating its extrinsic muscles from the genio-hyoideus, the anterior appendix 
of the hyoid bone, the transverse muscle, and the small hyoideus. 

The dissection having been performed in this manner, the large hyoideal branch may Ijp 
separated from the small, by sawing through the head longitudinally, leaving the symphysis 
menti intact, and turning down the corresponding half to the side already dissected, as well as 
the great hyoid branch, the pharynx, larynx, and soft palate. 

1. Mylo-hyoideus. 

jPorm — Situation — Structure. — A membranous muscle situated in the inter- 
maxillary space, flattened from side to side, elongated in the direction of the 
head, thinner and narrower below than above, and formed entirely of fleshy fibres 
which extend transversely from its anterior to its posterior border. Inferiorly, 
it is composed of a small fasciculus, which is distinguished from the principal 

Fig. 171. 




HYOIDEAL AND PHARYNGEAL REGIONS. 

1, Neck of inferior maxilla ; 2, hard palate ; 3, molar teeth ; 4, buccal membrane ; 5, submaxillary 
glands ; 6, soft palate ; 7, tendon of hyoideus magnus through which the tendon, 8, of the 
digastricus passes; 9, lower portion of digastricus ; 10, stylo-hyoideus ; 11, buccal nerve; 12, 
zygomatic arch; 13, orbital branch of fifth pair of nerves; 14, articular process of temporal 
bone; 15, right cornu of hyoid bone; 16, hyo-glossus longus, or Kerato-glossus ; 17, lingual 
nerve; 18, 18, tongue; 19, angle of left branch of inferior maxilla; 20, submaxillary gland, 
left side ; 21, subscapulo-hyoideus ; 22, great hypoglossal nerve ; 23, hyo-thyroideus ; 24, sterno- 
hyoideus ; 25, sterno-thyroideus ; 26, subscapulo hyoideus ; 27, thyroid gland ; 28, external 
carotid artery ; 29, pneumogastric nerve ; 30, stylo-hyoideus ; 31, genio-hyoideus. 

portion by the slightly different direction of its fibres, and which covers in part 
the external surface of the muscle. 

Attachments. — It originates from the mylo-hyoid line by the anterior 
extremities of its fibres. Its movable insertion takes place on the inferior face 
of the hyoid body, on its anterior appendix, and on a fibrous raph6 which extends 
from the free extremity of this appendix to near the genial surface, and which 
unites, on the median line, the two mylo-hyoidean muscles. 

Relations. — By its external face, with the inferior maxilla, the digastricus, 
and the submaxillary lymphatic glands. By its internal face, with the sublingual 
gland, the Whartonian duct, the hypoglossal and lingual nerves, the genio-glossus, 
hyo-glossus longus and brevis, and genio-hyoideus. Its superior border responds 
to the internal pterygoid. 

Action. — In uniting on the median line with that of the opposite side, this 



288 THE MUSCLES. 

muscle fonns a kind of wide band or brace on which the tongue rests. "When it 
contracts, it elevates this organ, or rather applies it against the palate. 

2. Genio-hyoideus. 

Form — Strmture — Situation. — ^A fleshy, elongated, and fusiform body, tendinous 
at its extremities, but especially at the inferior one, and applied, with its fellow 
of the opposite side, to the mylo-hyoidean brace. 

Attachments. — By its inferior extremity it is fixed to the genial surface — 
origin ,- by its superior, it reaches the free extremity of the anterior appendix of 
the hyoid body — termination. 

Relations. — Outwards and downwards, with the mylo-hyoideus ; inwards, with 
its fellow, which is parallel to it ; above, with the genio-glossus. 

Action. — It draws the hyoid bone towards the anterior and inferior part of 
the intermaxillary space. 

3. Stylo-hyoideus. 

Synonyms. — The hyoideus magnus of Percivall. The kerato-hyoidetis magnus of Leyh. 

Form — Structure — Situation — Direction. — Thin and fusiform, this muscle, 
smaller than the preceding, and, like it, tendinous at both its extremities, is 
situated on the side of the laryngo-phaiyngeal apparatus and the guttural pouch, 
behind the large branch of the hyoid bone, the direction of which it follows. 

Attachments. — Above, to the superior and posterior angle of the styloid bone — 
Hxed insertion ; below, to the base of the comu of the os hyoides — movable insertion. 

Relations. — Outwards, with the pterygoideus intemus ; inwards, with the 
gattural pouch, the pharynx, and hypoglossal nerve. Its anterior border is 
separated from the posterior border of the styloid bone by the glosso-facial artery 
and glosso-phaiyngeal nerve ; along the posterior border lies the upper belly of 
the digastricus. Its inferior tendon is perforated by a ling for the passage of the 
cord intermediate to the two portions of the latter muscle. 

Action. — It is antagonistic to the preceding muscle, drawing the body of the 
hyoid bone backwards and upwards. 

4. Kerato-hyoideus (Hyoideus Paevus). 

(Synonyms. — This is the hyoideus parvus of Percivall, and the small kerato-hyoideus of 
Leyh.) 

A very small fasciculus, triangular in shape, and flattened on both sides. In- 
serted, on one side, into the posterior border of the styloid comu and the inferior 
extremity of the styloid bone ; and on the other, to the superior border of the 
thyi'oid cornu. It responds, outwardly, to the hyo-glossus brevis and the lingual 
artery ; inwardly, to the buccal mucous membrane. 

It approximates the cornua of the os hyoides to each other. 

5. OCCIPITO-STYLOIDEUS. 

Synonyms.— This is the muscle which, up to the present time, has been described by 
veterinary anatomists as the stylo-hyoideus. This name has been given to the muscle named 
by Girard the kerato-hyoideus magnus. 

A small, flat, and triangular muscle hke the preceding, yet thicker and more 
spread, filling the space comprised between the styloid process of the occipital 



MUSCLES OF THE TRUNK, 289 

and the horizontal portion of the posterior border of the styloid bone. Its 
fasciculi become longer as they are situated posteriorly, are rather tendinous, and 
are earned from one of these bones to the other. Outwardly, it responds to the 
parotid gland ; inwardly, to the guttural pouch, which it covers for its whole 
extent ; its posterior border is largely confounded with the superior insertion of 
the digastricus. When this muscle acts, it causes the os hyoides to swing, caiTy- 
ing its inferior extremity backwards and downwards. 

6. Hyoideus Transversus. 

By this name Bourgelat has described a short riband of parallel muscular 
fibres, which unites the superior extremities of the styloid cornua, and approxi- 
mates them to each other. 

Differential Characters of the Muscles of the Head ik the other Animals. 
1. Facial Region. 

Ruminants. — There are found in the Ox : 

1. An orbicular muscle of the lips, analogous to that in the Horse. 

2. A buccinator of the same kind (Fig. 172, 5). 

3. A zygomaticus, stronger and redder than in Solipeds. Its aponeurosis of origin, covered 
by the panniculus, extends upon the surface of the masseter muscle as far back as the zygo- 
matic arch, to which it is attached (Fig. 172, 7). 

4. A levator labii superioris alsequi nasi, continued, above, with the inferior border of the 
frontal or fronto-cuticularis muscle ; and divided, inferiorly, into two branches, which comprise 
between them the levator labii superioris and the dilator naris lateralis. These two branches, 
however, are not disposed as in Solipeds, the anterior covering the preceding muscles, and the 
posterior, of but little importance, passing beneath them to lose itself in the substance of the 
upper lip (Fig. 172, 3). 

5. A levator labii superioris proprius, which gains the middle of the muzzle by passing 
along the inner side of the nostrils (Fig. 172, 1). 

6. Two additional levator labii superioris muscles to the above, considered as accessories to 
the first, and which originate with it. Each terminates by a ramifying tendon that passes 
under the nostril to mix in the tissue of the upper lip (Fig. 172, 1', 1'). 

7. A dilator naris lateralis, situated between the supermaxillo-labialis and its two accessory 
muscles, and deriving its origin, in common with these three muscles, in front of the maxillary 
spine (Fig. 172, 2). 

8. A depressor labii inferioris, confounded with the buccinator, and having no terminal 
tendon. 

9. A levator menti, attached to the body of the inferior maxillary bone, as in the Horse, 
by two middle posterior muscles. No anterior middle muscle has been found by us; and it is 
certain that there is no dilator naris transversalis or dilator naris superioris present. 

In the Sheep, the levator labii superioris does not exist ; apart from this peculiarity, there 
is DO difference between the facial mu»cles of this animal and the Ox. 

Pig. — This animal has no levator labii superioris, or dilator naris transversales muscles. The 
dilator naris superior is present ; it is short, very thick, and situated near the margin of the 
nostrils. The levator labii superioris proprius and the dilator naris lateralis are replaced by 
three fleshy bodies, nearly parallel, lying on tiie side of the face. The superior originates in 
the lachrymal fossa, and terminates by a tendon in the middle of the snout. The inferior, with 
the middle, leaves the imprints in front of the zygomatic ridge, and is continued at its inferior 
extremity by a tendon divided into several fibrillse, which pass below the nostril to be united 
to the tendon of the superior portion : this is done in such a manner that the external opening 
of the nose is encircled on the inner side by a kind of fibrous cravat, which, when these two 
muscles contract, carries this opening outwards. It will also be understood that the superior 
fleshy body, acting alone, ought to elevate the snout, while the inferior depresses it in drawing 
it to one side. With regard to the intermediate fleshy mass, it is the representative of the 
dilator naris lateralis of the Ox, and terminates in a great quantity of tendinous fibrillae at 
the internal ala of the nose. 

Camivora. — In the Dog and Cat the following peculiarities are found : — 

The orbicularis oris is quite rudimentary. 



290 THE MUSCLES. 

The buccinator is very thin, and formed of only one muscular plane. 

The zyijomaticus is continued, superiorly, with the attollens anticus. 

The levator lahii superioris represents a wide, undivided, muscular expansion, united 
superiorly to the panniculus of the forehead, and terminating inferiorly on the upper lip. 

The levator lahii superioris and dilator naris lateralis constitute a single fleshy body formed 
of several parallel fasciculi, which take their origin above the supra-orbital foramen, and 
terminate together at the external wing of the nose and in the upper lip. 

There is no dilator naris superioris, or dilator naris transversalis. 

The middle anterior (depressor alx nasi) is perfectly developed. 

The mento-labialis and its suspensory muscle, the middle posterior, are scarcely apparent. 

2. Palpebral Region. 
The lachrymalis in the Ox is more developed and thicker than in the Horse. Its most 
anterior fibres glide under the zygomaticus, and are lost on the surface of the buccinator ; while 

Fig. 172. 




SUPERFICIAL MUSCLES OF THE OX'S HEAD. 

1, Dilator naris superioris ; 1, 1', accessory fasciculi of the same ; 2, dilator naris lateralis ; levator 
labii superioris ; 4, lachrymalis; 5, depressor labii inferioris ; 6, buccinator confounded with the 
preceding; 7, zygomatico-labialis; 8, frontal, or cuticularis muscle of the forehead ; 9, orbicular 
muscle of the eyelids; 10, zygomaticus; 11, attollens maximus; 12, scutiform cartilage; 
13, external scuto-auricularis ; 14, mastoid process; 15, masseter ; 16, stylo-hyoideus ; 17, 
digastricus ; 18, sterno-maxillary fasciculus belonging to the cervical panniculus; 19, subscapulo- 
hyoideus; 20, sterno-maxillaris, or mastoideus; 21, anterior branch of the superficial portion of 
the mastoido-humeralis ; 22, superior branch of ditto ; 23, deep portion of same muscle ; 24, 
trachelo-atloideus, peculiar to Ruminants and Pachyderms ; 25, great anterior straight muscle 
of the head. 



the most posterior pass above the aponeurotic tendon of the zygomaticus and become confounded 
with tiie panniculus. This muscle unites, above, with the orbicularis palpebrarum in a more 
intimate manner than in the Horse, so that it is almost impossible to define the limits of the 
two (Fig. 172, 4). The lachrymalis is absent in the Pig. 

3. Masseteric or Temporo-maxillary Region. 
In Ruminants, the masseter and temporalis are not so large as in Solipeds. In the 
Camivora, however, they offer a remarkable development. The origin of the pterygoideus 



MUSCLES OF THE TRUNK. 



291 



internus in Ruminants is nearer the middle line than in the Horse. Its obliquity is also 
greater, and the movements of diduction it gives the lower jaw are more extensive. In all the 
animals, other than Solipeds, the stylo-maxillaris fasciculus of the digastricus is entirely absent, 
and the muscle has only a single belly extending directly from the occipital to the maxillary 
bone. In the Ox is found a siball square muscle, formed of transverse fibres, which unites the 
two digastric muscles by passing beneath the base of the tongue. This muscle, in contracting, 
may raise the hyoideal apparatus, and in this way supplement the tendon of the digastricua 
and the inferior ring of the stylo-hyoideus. 

4. Hyoideal Region. 

The two flesliy planes composing the mylo-hyoideus are more distinct in Ruminants than 
in the Horse. The stylo-hyoideus of these animals commences by a long thin tendon. The 
muscle has no ring for the passage of the digastricus. 
a feature observed in all the domesticated animals 
except Solipeds. 

In the Carnivora, the stylo-hyoideus, formed by 
a narrow, very thin, and pale fleshy band, commences 
on the mastoid portion of the temporal bone by a 
small tendon; the lerato-hyoideus is remarkable for 
its relatively considerable volume; the occipito- 
styloideus and the hyoideus transversus are absent. 

COMPAEISON OF THE MOSCLES OF THE HuMAN HeAD 
■WITH THOSE OF THE DOMESTICATED AnIMALS. 

In Man, there are described as muscles of the 
head, the epicranial muscles, muscles of the face, and 
those of the lower jaw. The hyoid and digastric 
muscles are reckoned in the region of the neck. Here 
tliey will be placed in the region of the head. 

1. Epicranial Muscles. 
The middle portion of the human cranium is 
covered by an aponeurosis that adheres closely to the 
hairy scalp, but glides easily on the surface of the 
bones. To the circumference of this epicranial 
aponeurosis are attached four muscles, which move 
it. One of them, attached behind to the superior 
occipital curved line, is named the occipital muscle; 
another, fixed in front of the forehead, is called the 
frontal muscle ; the other two, double and lateral, are 
inserted on the face of the temporal bone (ir the ex- 
ternal ear, and are designated auricular muscles. 
These epicranial muscles move the scalp forwards, 
backwards, and sideways. 

2. Muscles of the Face. 
These are fourteen in number, ten of which are 
found in the domesticated animals. We commence 
by describing these common muscles (Fig. 170). 

1. The orbicularis oris, which has a fasciculus that 
passes to the skin from the columna of the nose; this 
fasciculus is termed the depressor of the columna, or 
moustache muscle (naso lahialis). 

2. The buccinator, corresponding to the buccinator 
of animals. Besides its oflSce in mastication, it takes 
an important part in the blowing of wind instruments. 

3. The superficial elevator of the wing of the nose and the upper Up. It resembles the 
levator labii superioris, descends from the orbital margin of the supermaxilla, passes along the 
wing of the nose, and is lost in the upper lip. 

4. The deep elevator of the wing of the nose and the upper lip, the analogue of which is 
found in the dilator naris lateralis. 




muscles of the human head 
(superficial layer). 
, Frontal portion of the occipito-fron- 
talis ; 2, its occipital portion ; 3, its 
aponeurosis ; 4, orbicularis palpebra- 
rum ; 5, pyramidalis nasi ; 6, com- 
pressor nasi; 7, orbicularis oris; 8, 
levator labii superioris alasque nasi ; 

9, levator labii superioris proprius ; 

10, zygomaticus minor; 11, zygo- 
maticus major ; 12, depressor labii 
inferioris ; 13, depressor anguli oris ; 
14, levator labii inferioris ; 15, super- 
ficial portion of masseter ; 16, its deep 
portion ; 17, attrahens aurem ; 18, 
buccinator; 19, attollens aurem; 20, 
temporal fascia covering temporal 
muscle ; 21, retrahens aurem ; 22, 
anterior belly of the digastricus, with 
tendon passing through pulley ; 23, 
stylo-hyoid muscle ; 24, mylo-hyoi- 
deus ; 25, upper part of sterno-mas- 
toid ; 26, upper part of trapezius — 
the muscle between 25 and 26 is the 
splenius. 



292 TEE MUSCLES. 

5. The zygomaticus, the presence of which is constant in all species. 

6. The small zygomaticus, represented in the Horse by only the small oblique fasciculus 
sometimes found beueath the zygomaticus. 

The small zygomaticus and the two elevators of the lips are lachrymal muscles; by their 
simultaneous contraction they express discontent and melancholy. The zygomaticus, on the 
contrary, is the muscle of laughter ; it draws the commissures of the lips outwards. 

7. The caninus, or dilator naris lateralis of animals, is attached beneath the infra-orbital 
foramen, and terminates in the skin of the upper lip. 

8. The risorius of Santorini. 

9. The muscle of the chin (jnento-lahialis). 

10. The myrtiformis, or middle anterior of Bourgelat. 

The other facial muscles of Man, whose analogues it is difBcult or impossible to find in 
animals, are : — 

11. The triangularis of the lips, which is inserted into the anterior face of the inferior 
maxilla, and is carried upwards to the commissure of the lips. By its contraction it gives the 
face an expression of melancholy or contempt. 

12. The quadratus menti, which, after been attached to the maxilla within the mental 
foramen, passes upwards on the skin of the lower lip, which it depresses, and thus contributes 
to the expression of fear or dismay. 

13. The transversalis nasi {comprei<sor nasi), a muscle which is fixed into the supermaxilla 
and on the bridge of the nose, where it is confounded with the opposite muscle. 

14. The dilator of the ala of the nostril, a very small triangular fasciculus applied to the 
external part of the nostril, whicli, by contracting, it elevates. 

3. Muscles of the Lower Jaw. 
There is nothing remarkable to be noted in tlie masseter, temporal, or pterygoid muscles. 
The upper belly of the digastricus is not attached directly to the inferior maxilla, as it is in 
Solipeds. 

4. Hyoideal Muscles, 

These are only three in number : — 

1. The mylo-hyoideus. 

2. The stylo-hyoideus, which commences at the styloid process of the temporal bone, and 
shows a ring for the tendon of the digastricus. 

3. The genio-hyoideus. 

We do not find in Man the occipito-styloideus, kerato-hyoideus, or the hyoideus-transversus. 

Axillary Region. 

This comprises two muscles, pairs, placed beneath the sternum, in the axilla 
which terminate on the anterior limb. These are the superficial and deep 
pectorals} 

Preparation. — 1. Place the animal in the first position. 2. Unfasten one of the forelimbs, 
and allow it to hang, so as to separate it from the opposite one. 3. Eemove the skin with 
care, and dissect, on the side corresponding to the detached limb, the two muscles which form 
the superficial pectoral. 4. Prepare the deep pectoral on the opposite side. To do this, 
remove the panniculus cautiously, so as not to injure the muscle about to be examined ; divide 
the superficial pectoral transversely, and turn back the cut portions to the right and left ; divide 
also the mastoido-humeralis and cervical trapezius near their insertion into the limb, and 
reflect them upon the neck. 

1. Superficial Pectoral (Pectoralis Anticus and Transversus) 
(Figs. 174, 9, 10 ; 175, 3). 

Synonyms. — Muscle common to the arm and {orearm— Bourgelat. Pectoralis magnus of 
Man. (Percivall and Leyh describe three pectorals, others four ; but, as will be seen in this 
work,