^ THE HORSE
y nS'TRMTMENT'lN
«P*EAmi'®«niSEASI
^'
N»
s
/ 1
St
\
/ ..,
//
'J r\.
N
m^
">
J
QHtp i. B. Bill ^Itbrarg
i
1
Nnrtl) (EarDlina &tatp Iniopratta
* SF285
A8
V.5
M
The HORSEMAN'S BOOK Shop
Old-fixvui caxd Tbuo iBooki
122 NORTH CHICAGO AVE. FREEPORT, ILL.
This book is due on the date indicated
below and is subject to an overdue fine
as posted at the Circulation Desk.
NOV 1 4 iggil
MiR 0 7 !996 I
^.mNl9l97>2 51«« !
'/'??7/
THE HORSE
ITS TREATMENT IN HEALTH AND DISEASE
Digitized by tine Internet Arciiive
in 2009 witii funding from
NCSU Libraries
Iittp://www.arcliive.org/details/liorseitstreatm05axej
THE HORSE
ITS TREATMENT IN HEALTH AND DISEASE
WITH A COMPLETE GUIDE TO BREEDING
TRAINING AND MANAGEMENT
Edited by
PROF. J. WORTLEY AXE, M.R.C.v.s.
lix-Piesident of the Royal College of Veterinary Surgeons
Late Lecturer at the Royal Veterinary College, and at the Agricultural Colleges of Downton and Wye
Chief Veterinary Inspector to the Surrey County Council
Consulting Veterinary Surgeon to the British Dairy Farmers' Association
Author of ■' The Mare and Foal" " Abortion in Cattle" " Anthrax in Farm Slock "
■• Examination of Horses as to Soundness" " Glanders, its Spread and Suppression" " Swine Fever"
■■ Lithotomy or the Removal of Stone from the Bladder of the Horse"
DIVISIONAL VOLUME V
LONDON
THE GRESHAM PUBLISHING COMPANY
34 SOUTHAMPTON STREET, STRAND
CONTENTS
DIVISIONAL-VOLUME V
Page
Section IV.— HEALTH AND DISEASE (Continued)
13. Parasitic Diseases of the Horse {continued) —
Introductory (continued) —
Parasites derived from the Plant World — Classification - - - IGl
Parasites derived from the Animal Kingdom — Classification — Protozoa
— Helminths (Worms)- Arthropedes - - - - - IGl
Diseases which are induced by particular Parasites - - - 103
External Parasites of the Horse - - - - - - - - 163
Ringworm of the Horse - - - - - - - - - 1(13
Parasites of the Skin derived from the Animal Kingdom — Phthirinsis
(Lousine-ss) — Acariasis (Mange) - - - - - - - 166
Parasites of the Digestive System of the Horse 169
14. Organs of Locomotion — Ronks^
Composition of Bone --------- 175
Structure of Bone ---------- 176
Classification of Bones - - - - - - - - 177
Growth of Bonk; - - - 178
Skeleton - . - 178
Vertebral Column - 179
Tnie Vcrtebrte - 1 79
The Processes - - - - - 179
The Body - - - - 180
The Neural Arch 180
The False Vertebra- - 180
CONTENTS
Page
Particular Vertebr.e 1 80
The Atlas 180
The Axis - 181
The Dorsal Vertebrae - - - - - - - - -181
The Lumbar Vertel)i;v 181
The Sacrum - - - - - - - - - • -- 182
The Coccygeal Vertebra' --------- 183
Skui.l - 183
Cranium ------------ 183
Occiput - - - 184
Parietal- - - - - - 184
Temporal Bones - - - - - - - - - -184
Squamous Temporal - - - -184
Petrous Temporal - - - - -185
Sphenoid Bone - - - - - - - - - - 185
Ethmoid or Sieve Bone --------- 186
Frontal Bones - - - - - - - - - - 186
Bones of the Face - - - - - - • - - - 18G
Nasal Bones ----------- 186
Superior Maxillary Bones -------- 186
Anterior Maxillary Bones -------- 186
Lachrymal Bone - - - - - - - - - - 187
Malar Bone ----------- 187
Palatine Bones ---------- 187
Pterygoid Bones - - - - - - - - - -188
The Vomer ----------- 188
Turbinated Bones - - - - - - - - - -188
Inferior Maxillary Bone or Lower Jaw - - - - - - 188
Os Hj'oides or Tongue Bone - - - - - - - - 1 89
The Thorax or Chest - - - - - - - - - 189
Sternum or Breast-Bone - - - - - - - - - 190
TheEibs ------------ 191
Costal Cartilages - - - - - 191
The Pelvis - ----- 192
The Fore Lixiii ------- 193
Scapula ------------ 193
Humerus -.---. 194
Forearm — Radius — Ulna - - - 195
Carpus or Knee ----- 196
Metacarpal Bones — Os Metacai-pi JNlagnum — Os Sufl'raginis, Large
Pastern, or First Phalanx — Sesamoid Bones — Os Corona; — Os
Pedis — Os Naviculare or Shuttle Bone - - - - - 197
CONTENTS vi
Bones of the Hind Limb 201
Os Femoris or Thi^h-Bone -..---.. 201
Patella - - ^ 202
Tibia or Second Thigh 202
The Fibula - " - - - - 203
The Tarsus or Hock — The Calcis — Astragalus or Knuckle-Bone — The
Cuboid — The Cuneiform Magnum — The Cuneiform Medium —
The Cuneifoim Parvum , . . 203
Diseases ok Bones 205
Ring- Bone - 205
Splint - - 206
Ostitis — Inflammation of Bone -...---- 208
Periostitis - - - 208
Chronic Periostitis - 210
Acute Ostitis - - - - 210
Chronic Ostitis 211
Necrosis and Caries - - - - - - - - - - 212
Osteo-porosis — Big Head - - - - - - - - -214
Post-mortem Examination -....-.. 216
Spavin ...----.-.-. 216
Bone-Spavin .----....-- 217
Metacarpal Periostitis — Sore Shins ..----- 219
15. Fractii'.es —
Causes ....... 222
Predisposing Causes 222
Exciting Causes - - 224
Symptoms ............ 224
Treatment 227
Compound Fracture - - - 233
Particular Fractures - - 234
Fracture of the Bones of the Skull .--.... 234
Fracture of the Vertebrie ..--.---. 235
Fracture of the Dorsal and Lumbar Vertebra ..... 236
Fracture of the Bones of the Face — Fracture of the Frontal Bone - 238
Fracture of the Lower Jaw - 239
Fracture of the Anterior Maxillaiy Born - - 242
Fracture of the Bones of the Fore Extremity .... 243
Fracture of the Scapula or Blade-Bone ...... 243
Fracture of the Humerus .-...---. 244
Fracture of the Ulna 245
Fracture of the Radius - - - - 246
Fracture of the Knee-Bones ........ 247
Fracture of the Metacarpal Bones ....... 248
Fracture of the Os Suffraginis or Large Pastern ... - - 249
Fracture of the Sesamoid Bones 250
Fracture of the Navicular Bone .-.--..- 252
CONTENTS
Page
Pauticx'LAR Yertebk.'K 180
The Atlas - - IJ^O
The Axis - - - IKl
The Dorsal Vertebra? l'"*!
The liUnibar Veitebiw - - - - - - - - - 181
The Sacrum - --182
The Coccygeal Vertebiic - - - - 183
Skull 183
Cnmiuin ------ 183
Occiput - - - - - - - 184
Parietal- - - - 184
Temporal Bones 184
Squamous Temporal - - - -184
Petrous Temporal - - 185
Sphenoid Bone - 185
Ethmoid or Sieve Bone - . . 186
Frontal Bones - . . - 180
Bones of the Face - 1 86
Nasal Bones ----------- 186
Superior Maxillaiy Bones - - - - - - - - 186
Anterior Maxillary Bones - 186
Lachrymal Bone - - - - - - - - - - 187
Malar Bone ----------- 187
Palatine Bones 187
Pterygoid Bones 188
The Vomer - 188
Turbinated Bones - - - - - - - - - - 188
Inferior Maxillary Bone or Lower Jaw - - - - - - 188
Os Hyoides or Tongue Bone - - - - - - - - 1 89
The Thorax or Chest - - 189
Sternum or Breast-Bone - - - - - - - - - 1 90
The Ribs - - . - . lyi
Costal Cartilages - - - - 191
The Pelvis 192
The FoiiE Limp. ---------- 193
Scapula ----- 193
Humerus ------ 194
Forearm — K^idius — Ulna 195
Carpus or Knee - - ■ - - - - - - - 196
Metacarpal Bones — Os Melacarpi INIagnum — Os Sufl'ragiuis, Large
Pastern, or First Phalanx — Sesamoid Bones — Os Coromc — Os
Pedis — Os Naviculare or Shuttle Bone 197
CONTENTS X i
Bones of the Hinu Limi; 201
Os I'Vinoiis or Tliigh-Boiic 201
Patelln - - ^ - - - - 202
Tibia or Sccoml Thigh --------- 202
The Fibula - '^ 203
The Tarsus or Hock — The Calcis — Astragalus or Knuckle-Bone — The
Cuboid — The Cuneiform Magnum — The Cuneiform Medium —
The Cuneiform Parvuin 203
Diseases of Bones 205
Iving-Bone 205
Splint .------ 206
Ostitis — Inflammation of Bone -------- 208
Periostitis - - - - 208
Chronic Periostitis -.-....-- 210
Acute Ostitis ----------- 210
Chronic Ostitis - - - - 211
Necrosis and Caries - - - - - - - - -212
Osteo-porosis — Big Head - - - - - - - - -214
Post-mortem Examination -------- 216
Spavin ------------ 216
Bone-Spavin ----------- 217
Metacarpal Periostitis — Sore Shins 219
15. Fractiiies—
Causes ------------- 222
Predisposing Causes ---------- 222
Exciting Causes ----------- 224
Symptoms -.----- 224
Treatment .---...----- 227
Compound Fractcue .-.------- 233
Particular Fractures - - 234
Fracture of the Bones of the Skull - ----- - 234
Fracture of the VertebriB -------- - 235
Fracture of the Dorsal and Lumbar Vertebrte ----- 236
Fracture of the Bones of the Face — Fracture of the Frontal Bone - 238
Fracture of the Lower Jaw ---.--. 239
Fracture of the Anterior Maxillary Bone ------ 242
Fracture of the Bones of the Fore Extremity - - - - 243
Fracture of the Scapula or Blade- Bone ------ 243
Fracture of the Humerus - - - . 244
Fracture of the Ulna .--------- 245
Fracture of the Radius -.----.-. 246
Fracture of the Knee-Bones -------- 247
Fracture of the Metacarpal Bones ------- 248
Fracture of the Os SuflFraginis or Large Pastern ----- 249
Fracture of the Sesamoid Bones ------- 250
Fracture of the Navicular Bone - - ----- - 252
viii CONTENTS
Page
Fracture of the Ribs 254
Fracture of the Pelvis . - - 256
Fracture of the Bones of the Hind Extremity - - . . 2G0
Fracture of the Femur -----.-.. 260
Fracture of the Tibiii 261
Fracture of the Bones of the Hock 261
16. Articulations or Joints —
Diarthrodial or Free-moving Joints 262
Ball-and-Socket Joints 262
Hinge Joints 262
Arthrorlia or Gliding Joints -------- 263
Amphiarthrosis or Mixed Joints - - 263
Pivot Joints - - - - - 263
Synarthrosis or Immovable Joints ------- 263
Articulations of the Trunk - - 263
Intervertebral Articulations -------- 263
Union of the Processes --------- 263
Interspinous Ligaments - 265
Articulations of the Head ..-....- 265
Tempero-Maxillary Articulation -------- 265
Hyoidal Articulations— Joints of the Tongue - - - - 266
Articulations of the Ribs - - . 266
Costo- Vertebral Articulations - - - - - - - -267
Costo-Sternal Articulations -------- 267
Articulations of the Head with the Neck ----- 267
Occipito-Atloid ----- - 267
Atlo-Axoid ----------- 268
SCAPULO-HUMERAL OR SHOULDER-JoINT - 270
Humero-Rapial or Elbow-Joint- ------- 270
Articulations of the Carpus or Knee-Joint - - - - - 271
Riidio-carpal - - - - - - - - - - -271
Carpal _._. 271
Carpo-metacarpal - - - - - - - - - - 271
The Ligaments - - 272
The Metacakpo-Piialangial Articulation or Feti.ock-Ioint - - 272
First Inter-phalangial Articuationl or Coronet-Joint- - - 273
Second Inter-phalangial Articulation or Coffin-Joint - - 273
CONTENTS f
Page
Coxo-Femokal Auticulation or Hip-Joint 274
Capsular Ligament 274
Cotyloid Ligament - 275
Round Ligament - . . 275
Pubio-femoral Ligament 275
Femoro-Tibial AuTicrLATioN OR Stifle-Joint -
■^10
Patellar Ligaments 276
Femoro-tibial Ligaments ----..... 276
Crucial Ligaments 276
Posterior Ligament ------.... 276
Interarticular Fibro-cartilages ----.-.. 276
Tibio-Fibular Articulation 277
The Articulations of the Tarsus or HockJoint - - . . 277
External Deep Ligament 278
Internal Lateral Ligaments 278
Internal Middle Ligament 278
Internal Deep Ligament - - 278
Anterior Ligament ' 278
Posterior Ligament - 278
Diseases of the Joints - 279
The Local Origin of Joint Disease 280
Symptoms ------------ 281
Anchylosis ----.--.-.. 281
Synovitis — Inflammation of the Synovial Membrane - - - - 282
Acute Synovitis ---------- 282
Chronic Synovitis 283
Loose Cartilages in Joints 284
Rheumatic Arthritis -------... 285
Pywmic Arthritis - - 287
Sprains to Joints, Tendons, and Ligaments ----- 289
Bog-Spavin - - - - 290
Sprain or Strain - - 291
Sprain of the Flexor Brachii -------- 292
Sprain of the Radial or Supra-carpal Ligament ----- 294
Sprain of the Check Ligament -------- 294
Sprain of the Suspensorj' Ligament - ----- - 295
Sprain of the Perforans and Perforatus Tendons . - - - 296
Sprain of the Fetlock-Joint - 297
Sprained Back - 298
Sprain and Rupture of the Flexor Metatarsi ----- 299
Curb- - - - - 300
Bowed Knees - - 303
COxN TENTS
The MrscTLAK System —
Page
Muscles of the Face and Head 307
Masseter 309
Pterygoideus Iiiternus --------- 309
Pterygoideus Extcinus - - - - - - - - - 310
Temporalis ----..----- 310
Stylo-Maxillaiis .------.-. 310
Muscles of the Hxteunal Ear - - ----- - 310
Zj'gomatico-Auricularis - - - - - - - - - 311
Parieto-Auricularis Externiis - - - - - - - - 311
Scuto-Auriculaiis Externus - - - - - - - - 311
Cervico-Auricularis - - - - - - - - - -312
Parotide- Auricularis - - - - - - - - - - 312
Parieto-Auricularis Intcrnus - - - - - - - - 312
Scuto-Auricularis Internus - - - 312
Mastoido-Auricularis - - - - - - - - - -312
Muscles of the Hyoid Region -------- 312
Mylo-Hyoid - 312
Genio-Hyoideus - - - - - - - - - -313
Stylo-Hyoid 313
Hyoideus Transversus --------- 313
Kerato-Hyoid - - - - - - - - - - -313
The Disgastricus - - - - - - - - - -313
Occipito-Styloid 31-1:
Muscles of the Tongue - - 314
Stylo-Glossus - - - 314
Great Hyo-Glossus - - - - - 314
Genio Hyo-Glossus - - - - -314
Small Hyo-Glossus - - 314
Palato-Glossus - - - - - - - - - - -315
Muscles of the Pharyngeal Region - 315
Pterygo-Pharyngeus - - - - -315
Hyo-Pharyngeus - - - 315
Thyro-Pharyngcus - - - - -315
Crico-Pharyngeus - - - - - - - - - -316
Stylo-Pharyngeus - - - - - - - - - -316
Muscles of the Soit Palate 316
Palato-Pharyugeus - 316
Tensor Palati - - . - - . 3I6
Levator Palati ..--------- 316
CONTENTS y
PaKe
Muscles of the Larynx 31 G
Thy lo-Hyoid .Muscle - - - - - - ■• - - - .-JIG
Hyo-Epiglottidcus - - - - - - - - - - 316
Crico-Thyroid Muscle - 317
Posterior Crico- Arytenoid Muscle - - - - - - - 317
Lateral Crico-Ar^'tenoid Muscle - - - - - - - - 317
Thyro-Arytenoid Muscle - - - - - - - - -317
Arytenoideus Muscle - - - - 317
Muscles of the Neck - - - 318
Rhoraboideus -----------318
Levator Auguli Scapuhv --------- 318
^ Splenius -- _.- 318
The Complexus - - - - - - 318
Trachelo-Mastoideus ---------- 319
Spinalis Colli 319
Intertransversales Colli - -319
Obliquus Capitis Superioris 319
Obliquus Capitis Inferior - - - - - - - - -319
Rectus Capitis Posticus Major -------- 320
Rectus Capitis Posticus Minor --------_ 320
Cervical Panniculus ---------- 320
. Cervical Trapezius ---------- 320
Mastoido-Humeralis - 320
ILLUSTRATIONS
DIVISIONAL-VOLUME V
FULL-PAGE PLATES
Page
Yorkshire Coach-Horse Mischief (colour) Frontispiece
External Parasites of the House - - - 166
Skeletons of Horse and Man 177
Cervical and Dorsal Vertebr.^ - 181
Osteo-porosis — Fracture of the Sesamoid Bones 250
Well-Shaped Foal — Foal with Bowed Legs ------ 304
The Superficial Muscles Exposed (colour) 310
Second Layer of Muscles Exposed (colour) ------ 314
TEXT n.LUSTRATIONS
Pasje
Ringworm - - - - - - 164
Metamorphoses of the Bot-Fly - - 170
Ascaris - - - - - - 1 7 1
Oxj'urus of Horse - - - - 1 7 1
Tape-worms - - - - - 172
Taenia perfoliata - - - - 173
Tsenia plicata - - - - - 173
Ta?nia mamillana - - - - 173
Liver Fhike - - - 173
Transverse Section of Bone - - 176
Longitudinal Section of Bone - - 176
Cervical Vertebra - - - - 181
Dorsal Vertebra - - - - 181
Lumbar Vertebra - - - - 182
Sacrum - - - - - 182
Page
Skull (Front Aspect) - - - - 184
Skull (Posterior Surface) - - - 185
Skull (Side View) - - - - 187
Lower Jaw - - - - - 188
Hyoid Bone and Larynx - - - 189
Sternum - - - - - - 190
Sternum and Costal Cartilages - - 1 90
Pelvis ------ 191
Pelvis and Sacrum - - - - 192
Scapula (Outer Surface) - - - 193
Scapula (Inner Surface) - - - 194
Humerus (Front Aspect) - - - 194
Humerus (Outer Aspect) - - - 195
The Forearm 195
Carpus 196
ILLUSTRATIONS
Fore-Leg from the Radius - - - 197
Metacarpal Bones ... - 198
Os Suffraginis ----- 198
Os Coronifi and Os Naviculare - - 199
Os Pedis (Plantar Aspect) - - - 199
Os Pedis (Side View) - - - - 200
Os Femoris (Anterior Aspect) - - 201
Os Femoris (Posterior Aspect) - - 202
Patella 202
Tibia 203
Bones of the Hock separated - - 204
Ring-Bone ------ 205
" High " Ring-Bone - - - - 205
Splint ------ 206
Diagrammatic Transverse Section of
Tibia and Fibula - - - - 208
Acute Ostitis ----- 210
Rarefying Chronic Ostitis - - - 211
Chronic Ostitis - - - - - 212
Osteo-porosis — Bones of the Face - 215
Osteo-porosis — Lower Jaw - - - 215
Osteo-porosis — Metacarpals - - 216
Bone-Spavin - - - - - 217
Fractures— Simple, Comminuted - 221
Fractures — Transverse, Oblique, Longi-
tudinal ------ 222
Principal Tendons and Ligaments of
the Fore-Limb - . . 223
Impacted Fracture of Femur - - 226
An Example of Compound Fracture - 227
Fracture of First Rib of Horse - - 229
Bandaging a Fore-Leg - - - 231
Bandaging a Fore-Leg (completed) - 232
Walker's Face-Cradle - - - - 241
Tooth-Shears ----- 242
Tooth-Rasp 242
01)lique Fracture of the Radius - - 246
Iron Splint for Fractures of the Fore-
Limb ------ 247
Splint for Fracture of the Metacarpal
Bones 248
Page
Oblique Fracture of Suffraginis - - 249
Oblique and Transverse Fractures of
the Os Suffraginis - - - - 250
Fracture of the Sesamoid Bones - - 251
Fracture of Navicular Bone - - 253
Oblique Fracture of Rib - - - 254
Fracture of the Pelvis - - - 256
Ligaments of Spine - - - - 264
Ligamentum Nuchse - - - - 265
Temporo-Maxillary Articulation - - 266
Articulation of the Ribs and Spine - 267
Occipito-Atloid Articulation - - 268
The Occipito-Atloid and Atlo-Axoid
Articulations ----- 269
Capsular Ligament of Shoulder-Joint - 270
Humeroradial or Elbow-Joint - - 270
The Carpus or Knee-Joint - - - 271
Anterior View of Knee-Joint - - 271
Ligaments of the Fetlock-Joint - - 272
Ligaments of the Pastern and Foot - 274
Articulation of the Hip-Joint - - 275
Femoro-tibial Articulation or Stifle-
joint ------ 276
Posterior View of Stifle-Joint - - 277
External View of Hock-Joint - - 278
Loose Cartilages removed from the
Capsule of a Stifle-Joint - - - 285
Bog-Spavin ----- 290
Bog-spavin Truss or Compress - - 291
The Flexor Brachii - - - - 293
The Check Ligament - - - - 294
Sprain of the Perfoi'ans and Perforatus
Tendons ----- 296
Rupture of the Flexor Metatarsi - 299
Curb - - 301
Curb — Good hock with curb, Bad hock
without curb. Bad hock with curb - 302
Muscles of Horse's Head - - - 307
Muscles of the Ear - - - - 311
Muscles of the Tongue, Soft Palate,
and Larynx - - - - - 315
PARASITIC DISEASES OF THE HORSE 161
PARASITES DERIVED FROM THE PLANT W0RL13
Classification. — Parasitic plants lielong for the most part to the large
family of fungi. Their history is in many points obscure, and the various
attempts at classification have not been entirely satisfactory. For the
present purpose, however, it will be sufficient to refer to three divisions:
schizomycetes, saccharomycetes, and actinomycetes. The schizomycetes
include the fungi which multiply by division or fission, the saccharomycetes
or yeast fungi multiply liy budding and the formation of spore, actinomy-
cetes include the fungi the branches of which radiate from a ('entre-rayed
fungus. Individuals of the two first divisions are found on the surface of
the body and in the internal organs of the horse, but so far as is known
very few of them produce disease.
PARASITES DERIVED FROM THE ANIMAL KINGDOM
Classification, — Animal parasites are divided into three classes: —
1. Protozoa. 2. Helminths. 3. Arthropedes.
Protozoa include all organisms of the most simple form — the mere
beo-innings of life, in reality — from the small structureless mass of living
material (bioplasm) to the diflerent forms of cells consisting of a simple
investing membrane containing nuclei or sometimes only granular material.
Cells assume various forms — circular, oval, elliptical, and elongated.
Protozoa include amoebge, sporozoa, and infusoria. Amoe])8e have no
defined outline, but consist of small mas.ses of living material capable of
moving in any direction, and feeding upon ^^articles of food which they
find in the fluid in which they live. Those particles they appropriate by
enclosing them in the jelly-like material of which they are composed.
Sporozoa are divided into gregarines, coccidia, and psorosperms. They
have a more definite form than amoebae, as they are bounded by a
cell-wall and contain spores or nuclei. All of these primitive forms of
life inhabit stagnant pools, and are consequently taken in by animals
'which are feeding on the pastures. Their presence has frequently been
recognized in the digestive organs of animals, but it is only of late years
that the truly parasitic character which some of them assume has l^een
realized. Fatal outbreaks of disease among pheasants and poultry have
been traced to the invasion of coccidia, and the presence of the same
organism in the ducts of the liver of the rabbit has probably been respon-
sible for a considerable mortality among those animals. The true signifi-
cance of these lowest forms of parasitic life in the organs of warm-blooded
animals is not yet fully appreciated.
; Vol II. 45
162 HEALTH AND DISEASE
Helminths (Worms). — Between the highl)' organized parasites which
aie descril H'd a.s worms and the elementary forms which have just been
referred to there do not appear to be any connecting links; at least none
have been discovered. The word worm is popularly believed to indicate
creatures of which the earth-worm is an example, but the helminthologist
includes in the term animals which difter considerably from each other in
form, sufficiently, at least, to lead to their division into two sub-classes, the
characters of which are very easily distinguished.
In the first subdivision — round-worms or helminths — all the meml)ers
have the characteristic forms of the common earth-worm, that is to say,
they are round and elongated; but they differ in length from an eighth
of an inch to several feet, in other words, from very large to extremely
minute worms which can only be seen by the aid of the microscope.
Round-worms are found in various parts of the body of their host —
in the skin, the eye, stomach, intestines, in the kidneys, and occasionally
in the heart and blood-vessels.
The second subdivision includes all Hat-worms (flat helminths). There
are two varieties of them, which are known as tape- worms and fluke-
worms; the latter being entirely unlike the typical worm, as it resembles
a very minute sole, and when it is full}' gi'own it is little more than an
inch in length.
Both round- worms and flat- worms produce eggs in which embryos are
developed, but it is characteristic of all the division that the young worms
do not become mature in the organism of the animal which they infest;
in some cases the young worm is hatched out in the intestines or other
organs of the host, but before it is fully developed it appears to be
necessary that it should be expelled and find an intermediate host outside
-the animal in which it has lived. In the case of the round-worm this
phase in their life-history is still obscure; the intermediate host has not
been discovered. In the flat-worms, on the other hand, the changes have
been followed from the egg through the body of the intermediate host back
to the class of animal originally infested. In tlie fluke, for example, the
embryo bores its way into a small snail, in which it goes through certain
changes of form. In the case of the tape-worm the embryo in the body
of an intermediate host becomes a hydatid, which is really a small bladder
in which the tape - worm head is developed. The transference of the
hvdatid to the body of another host is followed by the development of
the tape-worm from the head or heads. The only mystery which exist.s
in reference to this parasite relates to the identification of the host, which
in a considerable number of tape-worms is not known, although, judging
from analogy, there can be no doubt of its existence. To make this mode
DISEASES WHICH ARE INDUCED 15V FAKTICULAR I'AliASITKS IG.J
of (lev(.'loi)nu'nt cleiir a .siin[)le illuwtnitioii will be .suffiuient. A certain
hydatid infesting the lirain of the sheep, which causes the disease kiidwn
as gid, will, if given to a dog, be developed into a tape -worm possessing
certain well-defined characters which mark its origin. The mature segments
of this variety of tape-worm, when given to sheejj or taken up li\- them
when feeding on pastures, will produce the hydatid in the brain.
Arthropedes. — In this division is included all animals with jointed
limbs, all kinds of insects wdiich, either in their mature or larval form,
become parasitic permanently or temporarily to any of the higher animals.
Horses are infested by the larval forms of certain Hies (diptera), ami
by some varieties of lice and acari or mange-mites, which produce diseases
of the skin of the animals which they infest.
DISEASES WHICH ARE INDUCED BY PARTICULAR
PARASITES
EXTERNAL PARASITES OF THE HORSE
Numerous parasites belonging both to the animal and plant kingdoms
take up their residence on or in the skin of the horse, and occasion consider-
able derangement. The common aflfection which is known as ringworm,
on account of the circular form which the eruption assumes, is due to a
fine hair-like fungus which is known as the Trichtyphyton tonsurans
or ringworm fungus. Other parasites of the skin are derived from the
animal kingdom, as lice, which, without producing any specific afiection,
cause a great deal of irritation and interfere with the animal's condition.
Acari or mites, wdiich cause different forms of mange; larvse (maggots) of
certain insects which take up a temporary residence on the skin, and bore
their way into it, or are thence transferred by the animal itself, in the act of
licking or biting, to its own stomach, where they undergo a certain amount
of development prior to quitting their hold and being expelled to complete
the necessary changes to form the perfect insect. Certain small thread-
worms, and a lower form of organic beings belonging to the protozoa,
known as psorosperms, also infest the skin.
RINGWORxM OF THE HORSE
It may be observed at the commencement that ringworm in the horse
is a comparatively rare affection. In cattle it is constantly found in
young animals; very rarely, how^ever, is it seen in an animal after the
age of one year. In the horse age does not appear to aflbrd any protection
from the disease.
164
HEALTH AND DISEASE
Symptoms. — lu consequence of the common occurrence of u form of
eczema, in which the eruption is distinctly circular, the term ringworm
is frequently applied to that disease, which is not associated with the
presence of a fungus and is not contagious in its character. In eczema
the round patch which characterizes the eruption is develojjed at once, but
in ringworm it commences as a
small pimple and spreads day by
day in widening circles until a
lounded patch is produced. True
ringworm is in all cases due to
the growth of the fungus {'T)-icho-
2'>hyton) in the hair follicles, and
frequently in the interior of the
hair, and the diagnosis of the
disease implies the detection of the
fungus under the microscope. For
this purpose a few hairs und a
certain small proportion of seal)
should be removed from one of
the spots of the skin, placed in
a little solution of potash, with
a few drops of glycerine added,
in order to render the opaque
scabs transparent. If the disease
is ringworm the appearance pre-
sented will be that which is indicated
in Plate XXXVI, figs. 9 and 10.
Another method of diagnosis
has been suggested, which, taken
in connection with the clinical
symptoms, i.e. itching and the
appearance of gray scabs along
the back, the sides of the withers,
and, in bad cases, on the neck and head, may lead to a correct conclusion;
but absolute proof of the nature of the disease can only be obtained by
microscopic inspection. The method jjroposed is as follows: — A few drops
of chloroform are allowed to drop on one of the suspected spots; if, after
the evaporation of the fluid, some of the hairs present a white or pale-
yellow colour, it is concluded that the disease is ringworm.
Two varieties of ringworm have been distinguished by writers — the
common kind, in which the scab is grav and the hairs are inclined to break
Fig. 272.-Ringwo
DISKASKS WHICH AKK INDUCED BV PAUTICULAK PAKASITES 165
otr short at the mouth ol' the foUiele, owiiiii,- to their brittle condition; and
another form, in which the scabs are yeUow, and the haii'S, instead of
breaking off, fall out and leave perfectly bare patches of skin. This variety
of the disease does not appear to have been recognized in England.
Treatment. — ft is a somewhat remarkable character of this disease
that while the eruption extends from the centre of the .scab by constant
distribution of the spores there is a well-defined limit to its progress,
anil at a certain point the disease undergoes a spontaneous cure. This
has been noted particularly in ringworm of calves, and there is no doubt
that the continuance of the affection in many cases is largely depen-
dent on the general weakness and poor condition of the subject. The
average duration of ringworm in the horse is said to be forty to fifty days,
but it must be understood to mean that in regard to a certain spot or
a certain number of .spots a cure will be evident by the growth of new and
healthy hair. Meanwhile, however, any advantage from this spontaneous
cessation of the afi'ection is often neutralized by the constant conveyance
of the spores (seeds) of the fungus to the other parts of the skin. Con-
secpiently it happens that as fast as the affection is cured in one place it
breaks out in another; hence the necessity for the prompt use of remedies
which will destroy the vitality of the fungus as cjuickly as possible.
Various agents are employed in the treatment of ringworm, and it may
be said of nearly all of them that they are perfectly successful, for, unlike
the ringworm of the human subject, ringworm in the lower animals is not
difficult to cure. Among the agents which are recommended are a solution
of corrosive sui)limate, 1 to 300 of water, to which a little spirit has been
added, or a mixture of 1 part carbolic acid with 10 parts of glycerine.
These preparations are to be applied by means of a brush to the spots
of ringworm wherever they are found. Of the ointments which are com-
monly eijiployed, blue mercurial ointment, and red biniodide of mercury,
each diluted with six times its bulk of lard or vaseline, are most effective.
The treatment in any case will have to be continued until a healthy state
of the skin is indicated by the growth of new hair in all parts of the
diseased skin.
Transmission of ringworm to other horses, probably also to other
animals, and certainly to human beings, is likely to take place unless
proper precautions are used. Care therefore .should be taken to cleanse
and disinfect thoroughly the stable and its fittings, destroy the litter, and
disinfect or destroy all the stable apparatus used about the diseased
animals.
For the protection of the helper who dresses the animal the shirt-sleeves
shouhl be kept down instead of being turned up, as is usually '(one,
166 HEALTH AND DISEASE
as experience proves that the arms are the parts most likely to be
attacked.
PARASITES OF THE SKIN DERIVED FROM THE ANIMAL
KIX(;D0M
The skin of the horse is infested by several varieties of parasites,
which occasion disease of the structures, attended with itching, and in
some cases with considerable eruption. The two most common affections
are known by the terms phthiriasis, when lice are present, and acariasis,
when different kinds of acari invade the skin. The latter are the cause of
several forms of mange.
Phthiriasis (Lousiness). — Lice which infest the skin of the horse are
of two kinds: one which, by its sharp-pointed mouth, is able to puncture
the skin and live on the blood, hence called Hrpmatojnnus, and another
the head and mouth of which are not adapted for puncturing the skin; this
variety feeds on the loosened cuticle and clings to the hair, hence the
name, Trichodectes, which is given to it. The two varieties are commonly
found together. In very young animals lice are frequently extremely
al)undant, and by the constant irritation which they produce they prevent
the animal from feeding or resting in any comfort. It is consequently
important to employ some dressing which will have the effect of killing the
parasites. Various agents are in favour for this purpose; the most simple
is any kind of fat oil which will destroy the lice by stopjaing their breath-
ing pores, as train-oil and linseed-oil. Mercurial ointment is a very effec-
tive remedv, l)ut it is also A'ery dangerous. Tobacco water, made by boiling
an ounce of tobacco in a quart of water, is also a very good dressing, or,
instead, a solution of carbolic acid 1 part to 50 parts of soft soap and
water may be used.
In consequence of the invarialjle presence of numerous eggs on the skin,
which will in all probability escape the action of the dressing, it is neces-
sary to repeat it in a week. Afterwards the animal must be examined
occasionally in order to ascertain if any more parasites are present. The
illustrations in Plate XXXVI, figs. 1 and 2 show the different varieties of
lice found on th(> skin of the horse.
Acariasis (-Mange). — The parasites which belong to this division are
the diti'crcnt \arieties of ticks and mange-mites. The presence of ticks on
the skin may be looked upon as an accidental circumstance, from which the
horse in its state of domestication is comparatively exempt. The same,
however, cannot be said of the invasion of the mange-mites, two varieties
of which are commoidy found in the horse, one (Psoroptcs) the cause of
PLATE XXXVI
EXTERNAL PARASITES OF THE HORSE— After Neumann
1. Haematopinus macrocephalus equi, female, X15.
2. Trichodectes pilosus equi, female, X 15.
3. Psoroptes communis equi, hexapod larva, x6o.
4. Psoroptescommunisequi. pubescent female, ventral surface, x6o.
5. Sarcoptes scabiei equi, ovigerous female, dorsal surface, x6o.
6. Same as 5. but ventral surface, x6o.
7. Symbiotes communis equi, male, ventral surface, x6o.
0. Symbi
9. H
i equi,
■igerous female, ventral surface.
60.
orse's tail invaded by tricophyton
mass of exterior spores; /', split ;
of epidermis of hair.
Tricophyton tonsurans, x 50.
, X 200. a, a^
of hair ; c, cells
DISEASES WHICH AKE INDUCED BY PARTICULAR PARASITES 1G7
common mange and the other a burrowing mite (Strrcoptes) the ravages of
which induce a more severe kind of skin disease, which is difficult to cure
owing to the mites burying themselves under the cuticle.
Symptoms. — In all forms of mange the prominent symptom in the
first instance is itching, which induces the animal to bite and rub itself,
sometimes so vigorously as to cause abrasion of the skin. The disease
is first apjjarent on the withers, the upper part of the neck, the root of the
mane. Ultimately it may reach the head, and indeed most parts of the
body excepting the extremities. An examination of the skin will lead
to the detection of small pimples, and elevations of the cuticle from the
exudation which goes on beneath it. The formation of scabs all over the
affected surface follows, and these become confluent as the disease advances.
Scabs, if violentlv removed, disclose a raw surface beneath.
A peculiar form of mange in the extremities, due to the presence of
a variety of mange-mite, which is known as the Symhiotes on account
of being found in clusters or colonies, occurs in the horse, but is only rarely
detected, as the itching which induces the animal to rub and bite its legs
is generally ascribed to other causes. The acarus usually locates itself in
the hind fetlocks, but occasionally it attacks all four limbs, and it is
commonly found in cases of grease. The symbiotes appear to be par-
ticularly active at night, and a knowledge of this fact is important, because
when a horse is found to kick at the stall-post or strike his hind- or fore-
feet constantly on the floor of the stable during the night, there is reason
to suspect the presence of this form of mange (symbiotic mange), and a
careful examination of the extremities should be made. The discovery of
the symbiotes in the loosened cuticle of the legs will furnish satisfactory
evidence of the nature of the disease.
The varieties of mange are to be distinguished with absolute certainty
only by microscopic examination of the hair and scabs taken from the parts
of the skin which are most affected. The examination is comparatively
easy. Scrapings from the diseased parts have to be placed in a drop of
water on the slide, teased out with dissecting needles, and covered in the
usual way with a thin covering glass, and examined with the half-inch
objective. The three varieties of mange-mites which have been mentioned
are illustrated in the accompanying plate (Plate XXXVI, figs. 5, 6, 7, 8),
and there will be no difticulty in distinguishing them by comparing them
under tlie microscope with the figures.
Treatment. — Under ordinary circumstances mange in the horse is
amenable to treatment, but when sarcoptic mange is allowed to run its
course, the rapid multiplication of the parasites, and the damage which
they do to the skin, and the consequent irritation which results, frequently
168 HEALTH AND DISEASE
lead to fatal consequences, and it has been found necessary, on several
occasions when the disease has assumed this virulent form, as it does
among ponies which are left to run wild in mountain districts, to apply the
stamping-out system in order to check the progress of the disease by the
slaughter of the "affected animals.
Mange frequently attacks horses in large working establishments, but
is comparatively unknown in well-managed stables, in which horses are
treated with particular care. In the present day it is never allowed to
spread, even where horses are congregated in very large numbers, but is at
once arrested by proper treatment.
It very commonly happens in large establishments, where animals are
under veterinary supervision by contract, that mange dressings are among
the remedies which are kept at hand, and as the veterinary surgeon
employed pays periodical visits of inspection, the first symptoms of
disease are noted, and the remedies are applied at once.
As a preliminary to any form of medical treatment it is essential that
all the affected parts of the skin should be thoroughly washed with hot
water and soft soap, applied by means of a hard brush, in order that all
the scabs may be removed, so that the agent used may reach the surface of
the skin. In instances where the scabs have become exceedingly thick and
hard it is recommended to use the curry-comb to remove them.
Preparations of mercury, carbolic acid, sulphur, turpentine, and tobacco
are commonly used as dressings, and perhaps it may be said that the
selection of the remedy is of less importance than the manner of its appli-
cation. One thorough dressing will prove more effective than any number
of partial and intermittent applications which leave certain diseased parts
untouched.
Dressings must of course be repeated, and in each case preceded b}- a
thorough washing, until the cessation of the disease is indicated by the
growth of new hair and the absence of itching. This can be ascertained
by rubbing the skin and watching for movements of the animal's mouth,
which certainly occur if any irritability remains.
Mange, like all parasitic diseases, is classed as a contagious afl'ection
simply l)ecause tlie acari may migrate from a diseased animal to others, or
some of the eggs may be transferred by the agency of clothing or stable
implements. It is therefore necessary to adopt precautions in all cases by
disinfecting or destroying such articles as soon as the disease is cured.
DISEASES WHICH ARE INDUCED BY PARTICULAR PARASITES IGS)
PARASITES OF THE DIGESTIVE SYSTEM OF THE HORSi:
Numerous organisms derived from the animal and also from the plant
world inhabit the digestive system of the horse. The majority of them
may be passed over with very slight notice, as it has not yet been proved
that they are responsible for any morbid conditions, although it is ex-
tremely probable that some of them do produce various forms of derange-
ment which are referred to other causes. Among the vegetable parasites
are numerous fungi, such as the common mould, and others which Itelong
to the same family. These fungi are found in the mouth, and thence (juite
through the digestive track.
The parasites which are derived from the animal world are extremely
numerous throughout the digestive system.
Beginning with the lowest forms of life, there are found many of the
sporozoa and infusoria, some families of which, the Coccidia, are met with
in the liver and the epithelial cells of the mucous membrane. But in the
horse it has not yet been demonstrated that any special disease attends
their presence.
Coming to the more important parasites, there are first to be considered
the worms which infest the stomach of the horse.
In this country the minute nematode discovered by Professor J. Wortley
Axe in the stomach of the ass, and two varieties described by Professor
Peuberthy in the horse, and the larvae of the (Estrus equi, or stomach bot
(fig. 273), are the only parasitic worms of the stomach of the equidre; but
two varieties of spiroptera, the megastoma and microstoma, are described
by Continental helminthologists. The spiroptera, like the Strongylns axel
(Cobbold), form small round tumours in the mucous membrane. No
special signs of illness appear to attend the presence of these worms in
the stomach. AVith regard to the larvje of the bot-fly, which are found in
clusters attached to the cuticular membrane of the stomach, opinions are
very much divided, some authorities contending that they produce irrita-
tion in the stomach, and sometimes even bore their way completely through
the coats of that organ. The rule, however, is that they simply penetrate
the mucous membrane sufficiently to enable them to retain their hold until
the time comes for them to quit their temporary habitation and assume the
pupa, or chrysalis stage, in which the perfect fly is developed.
The next illustration was taken from a portion of the stomach, showing
the small tumours of the spiroptera and a number of bots attached to the
membrane.
A .smaller variety of the bot, of a reddish colour, is .sometimes seen
clino-ino- to the anus; it is known as the Oestrus /uemon-Jwidalis.
170
HEALTH AND DISEASE
The eggs of the bot-fly are deposited on the hairs of the horse's legs in
the early summer, and they are soon hatched by the sun. The newly-
hatched larvse by their movements cause a certain amount of irritation
and are licked off l)y the horse, and in this way are quickly conveyed
to the stomach, to the mucous membrane of which they at once attach
themselves by means of the hooked mandibles with whicli tliey are
provided. The larvre remain attached to the cuticular membrane of the
Fig. 273.— irot.amoi-phoses of Uie Bot-Fly
A, Egg of Bot-Fly as it appears stuck on a hair. B, Egg of Bot-Fly, showing the Operculum or lid. C, Lid
pushed aside and the larva escaping. D, Larva fully developed after having been in the stomach of the horse.
E, Head of Larva, showing Hooklets by which it anchors on to the mucous membrane of the stoniacii. F, Bot-Fly
developed from D. G, Larva; of Bot-Fly anchored on to mucous membrane of the stomacii of the horse.
stomach for some months, probably the greater part of a year. When
sufficiently developed they relax their hold and are expelled. It may be
noted here, however, that treatment is of no avail; there are no safe
remedies which will cause the bots to abandon their position until the
proper time. But the fact of quitting their hold naturally calls attention
to their existence, and the use of any remedy at this period is sure to
be attended with an apparent success.
The .smaller red variety, the (Estrus hfemorrhoidalis, deposits its eggs
on the lips of the horse, whence the larvae are transferred to tlie stomach.
They are much less common than the larvse of the GEstrus equi.
Of the nematodes wliich infest the intestines of the horse a large white
or pale-yellow worm, the Ascaris megalocephala, is the mo.st common.
DISEASES WHICH ARE INDUCED BY PARTICULAR PARASITES 171
tl
Tlie worm varies in length from 3 or 4 inclies up to a foot or more, and
it is occasionally present in such enormous numbers in the small intestines
as to fill them completely, necessarily causing a good deal of disturl)ance.
Occasionally a worm passes up the pancreatic duct, and now and then one
is found in the duct leading to the liver. When in sufficient numl)ers to
cause obstruction in the intestinal canal they are said to cause symptoms of
colic, giddiness, epilepsy, and tetanus; but when only a few are present
do not seem to cause any inconvenience. The illustration repre-
sents the general form of these worms of small
dimensions (fig. 274).
Various remedies are used for the expulsion of
these worms, among them arsenic, calomel, tartar
emetic, carbolic acid, turpentine; and recently san-
tonine has been employed, and has proved to be
more reliable than any of the other agents. The
dose for a horse is 15 grains in a ball, with 3 or
4 drachms of aloes. The medicine should be re-
peated in a week.
Another of the nematode worms is the whip-
worm {Oxyurus curvida), which infests the large
intestines and occasionally excites irritation of the
anus, which is indicated by the horse constantly
rubbing the tail. A marked symptom of the
presence of oxyurides is the accumulation of
yellow dust -like matter around the anus. This
is made up of the eggs of the parasite.
The expulsion of these worms is much assisted by occasional
enemas of salt and water. An illustration of this worm is given
in fig. 275.
Two other nematode worms are found in the intestine of
the horse. Both of them deposit their eggs beneath the mucous
membrane, giving rise to small tumours. The two parasites are known as
{ 1 ) the Sti-ongi/his armatus and (2) the Strongylus tetracanthus. The latter
is the most common and the most destructive. The Strongylus armatus is
dist-inguished by its large mouth, which is armed with a row of cutting teeth
arranged close together. The St7-ongylus tetracanthus has, in addition
to the row of teeth like the Strongylus armatus, four large sjjines, from
which the name is derived, and also inside the mouth a row of sharjD
hooks. It will be evident, therefore, that the creature is well provided
with offensive weajions. The worm is constantly found accumulated in
the large bowel, frequently in company with the Strongylus armatus.
Fig. 275. — Oxy-
urus of Horse —
Female
(natural size)
r?f, Vulva.
a. Anus.
Fig. 274.
Ascaris {about
i nat. size)
172
HEALTH AND DISEASE
Tienia maraillana
(nat. size).
In young animals a serious mortality is often caused by the invasion
of this worm in large numbers, as both the parent worm and the young-
ones are true blood-suckers, and the eml)ryos begin their ravages as soon
as they escape from the cysts in which they are coiled up under the
mucous membrane, in the manner seen in the illustration l>elo\v, whicli
is taken from a portion of the caecum.
In the case of these two parasites, medical treatment has not hitherto
proved very successful. Turpentine, chinosol, perchloride of iron are
the most promising remedies. Colts, the animals which suffer most from
the invasion of the parasite, may receive san-
tonine in doses of 10 grains in a ball, or mixed
with the food every day for three or four days,
to be followed by a dose of linseed-oil.
Other nematodes have been described by
writers, but they are not of very frequent
occurrence, and it does not appear that they
have been found among horses in this country.
Information regarding them may be found in
Neumann On Parasites, from which work some
of the illustrations of the present chapter are
reproduced.
Very few of the parasites of the next class,
cystic worms or flat -worms (flat helminths),
inhabit the intestines of the horse.
The common name tajae-worm is given to
these parasites. In the horse the few tape-
worms which infest the intestines are remark-
able for their small size in comparison with
other varieties which are found in cattle, sheep,
and dogs.
The three varieties are: the 2'tritia per-
foliata, which is something under 2 inches long and f inch in width;
Tcenia plicata, about 3^ inches long and f inch in width: and T■
Ki -. ■:?.' I'-ni , in.iniUaiia,
CV'j'halic Kxticmily (enlarged
15 diameters)
are common in other A^arieties. Nothing is known of the hydatid stage,
which forms the intermediate condition between the tape-worm embryo
and the mature parasite.
There are no indications whatever of the existence of the worms
during the life of the horse which they infest, and consequently no treat-
ment has ever been attempted. A remark-
able case is recorded of the existence of
nearly all the parasites which have been
described in one horse which was examined
by Veterinary Surgeon Krause. There
were found 519 Ascan's megalocephala,
191 O.vyurus curvula, 214 Strongylus
armatus, many thousands of Strongylus
tetracantlms, 69 Tcenia j^^^'folictta, 287
Filnria papillosa, and 6 Cysticercus fas-
ciolaris.
To complete the history of the parasites
which infest the digestive organs of the
horse it is necessary to allude to some
which are found occasionally in the liver.
The fluke (Distoma hepaticum) (fig. 280)
sometimes effects an entrance into the liver
ducts of horses, especially colts, which
are feeding on wet pastures where the
embryos and larval forms of the parasite are abundant. Sheep, as is
well known, are destroyed in thousands in some localities by the invasion
of this parasite, which causes the disease known as rot. A few cases are
recorded of foals and colts having suftered from the accidental invasion
of the fluke, but the disease among horses must be looked ujoon as
Fig. 2S0.-
-Livei' Fluke {Distonta Itfpalit
Linn. )
A, Showing Anatomical details, B, Natural
size, c, Ciliated Embryo, or Young Distome.
174 HEALTH AND DISEASE
entirely exceptional. The fluke is not one of the worms which finds a
host in that animal under ordinary circumstances.
Another parasite which is found in the liver of the horse is the cystic
stage of an extremely small tape-worm found in the intestines of the
dog, the TcBuia echinococcus. The worm, when fully grown, is on an
average about \ inch in length, and never exceeds ^ inch, but in its cystic
(hydatid) stage it is one of the largest which exists.
The Cysticercus echinococcus is found frequently in the liver, and
occasionally the lungs, of cattle and sheep; the cysts varying in size from
that of a grape to that of an orange, as a rule, but now and then they
are found of an enormous bulk. Each cyst contains a fluid in which
are found floating a number of tape-worm heads, myriads of which are
observed growing on the interior of the cyst. In one form of the parasite
small cysts, or daughter-vesicles as they are called, are found abundantly
in the fluid. This peculiarity has given rise to a division of the parasite
into two classes: —
1. The Echinococcus altricipariens, in which the secondary vesicles
exist.
2. The Echinococcus scolicipariens, in which they are replaced by the
small spots on the membrane, and in tlie fluid the tape-worm heads
[Scolices).
The presence of these hydatids in the liver and other organs of animals
is often not attended with any indications of disease, even when the liver
is so filled with the cysts as apparently to replace the normal structure.
On the serous membrane of the chest and abdomen small wandering
echinococcus cysts are occasionally found. There is also a nematode worm
(Eilaria) which has been found in the peritoneal and pleural cavities
of the horse, ass, and mule. It does not appear to have been recorded,
however, among the parasites of the horse in this country.
In the circulatory system of the horse, parasites are occasionally en-
countered, as the Surra parasite, found in the blood of horses in India,
and the embryos of the Strongylus armatiis and Strongylus tetracanthus,
which locate themselves in the anterior mesenteric artery, and cause a
well-marked aneurism. It is comparatively common in the a.ss. Parasites
in the nerve-centres, or in the organs of special sense of the horse, are
extremely rare. There is one case recorded by Woodger of the presence
of a hydatid in the brain of a horse. In this case the animal suffered
from the same kind of giddiness and tendency to turn in one direction
as is known to be characteristic of a sheep similarly affected with
hydatid in the l)rain, and there are a few cases reported of the discovery
of the embryos of the armed Strongylus in the blood-vessels of the brain.
COMP(JSITIOX OF BONE 175
Cases liave also l)een reported of the presence of l)ots (larva; of the
CEstms c'(jiti) in the brain eavity of the horse, and also in the spinal eanal
of a pony.
Among the organs of special sense, the eye of the horse seems to
be the only one which is invaded by parasites. It is recorded that
Van Setten removed a pentastome from the right eye of a horse, and
in horses in India the presence of a nematode worm is extremely common.
The parasite is easily removed by puncturing the cornea and allowing
the aqueous humour to escape, carrying with it the worm.
A minute worm {Filcmia jJctJj^ehrati.is) is occasionally found under the
eyelids of the horse, causing irritation, with swelling of the eyelids and
an abundant secretion of tears.
14. ORGANS OF LOCOMOTIOK-BOMS
COMPOSITION OF BONE
All bones are made up of two parts: 1, an organic matrix; 2, mineral
matter or bone-ash. If the rib of a horse be macerated for a few days or
weeks in dilute hydrochloric acid, the mineral or earthy matter will be
dissolved out of it and the animal or organic matrix will remain behind.
In this condition it still retains its original form, but, having lost its
hai'dening constituents, it is now soft and flexible, and may be bent in
any direction like a piece of india-rubber, or even tied in a knot.
If a second rib be placed in a bright clear fire and burnt, all the animal
matter is destroyed and driven off, leaving the earthy substance behind as a
white brittle mass, and, as in the previous exjaeriment, still retaining the
shape of the bone.
The relative proportions of organic and inorganic matter entering into
the formation of bones vary at different periods of life. In young animals
the former makes up nearly one-half of the whole, while in the adult it is
reduced to nearly one-third, the remaining two-thirds comprising earthy
or mineral substance. It is on account of the larger quantity of soft
organic matter they contain that the bones of young animals are so
much more yielding, and therefore less liable to break, than those of
older ones. The earthy substance of a bone consists of phosphate and
carbonate of lime in the proportions of 56 per cent of the former and
about 13 of the latter. The animal matrix, which is a kind of gelatine,
makes up the rest.
176
HEALTH AND DISEASE
STRUCTURE OF BONE
When a long bone is cut tlirougli it is found to consist of a hard outer
shell of compact tiasue enclosing a looser portion made up of thin bony
plates, interlacing with each other to form a number of spaces, and called
spongy or cancellated tissue. In the centre of this is a cavity (medullary
cavity) containing a soft reddish-yellow substance, the medulla or mctrrow.
The compact substance is thick in the shaft of the bone, but thin towards
the extremities, which are chiefly made up of cancellated structure.
All bones are covered with a dense tough fibrous membrane termed
periosteinn. It serves as a matrix in which the blood-vessels ramify and
Fig. 281. — Transverse Section of Bone
A A, Haversian Canals. The small irreg-
ular black spots are the Lacunae ; the lines
radiating from them are the Canaliculi.
Fig. 282. — Longitudinal Section of Bone
A A, Haversian Canals.
break up into smaller and smaller branches, prior to entering into the bone
tissue through small ojjenings on its surface. A similar fibrous membrane,
though more delicate, also lines the interior of bones, and is known as
endostciim. This membrane is very thin, though rich in l)loo(l-vesscls,
and aflbrds nourishment to the inner portion of the bone and to the
marrow contained in it. Besides the vessels passing into tlie interior
from the periosteum, the long bones have also a nutrient artery, for which
a special opening is provided in the shaft of the bone called the mednllary
foramen, and others less considerable situated around tlie extremities
(articular foramen).
The intimate structure of bone can only be made out by microscopic
examination under a power of 300 to 400 diameters. Although lione looks
SKELETONS OF HORSE AND MAN
('The same figures indicate the corresponding parts in each)
1. SkiilL
2. Ailiis.
3. Dentata.
4-8. Cervical vertebrae.
9-27. Dorsal vertebrte.
28-33. Lumbar vertebra.
34-38. Sacral vertebrie.
39-52. Coccygeal vertebrae.
.")3. Ribs.
54. Sternum.
55. Scapula.
56. Humerus.
57. Elbow-joint.
.">3. Olecranon.
59. Ulna.
60. Radius.
61. Pisiform bone.
62. Lunar bone.
63. Cuneiform bone. ;• a. Carpus.
64. Os magnum.
65. Unciform bone.
66. Small metacarpal.')
'. 0. Metaca:
67. Lirge metacarpal. J
6S. Sesamoid bone.
rpus.
69. Fetlock-joint.
70. Os suti'raginis.
71. Os corona;.
72. Os pedis or pedal bone.
73. Navicular bone.
74. Inuominatiim.
75. Tuberosity of ischium.
76. Hip-joint.
77. Femur.
78. Patella.
79. Stirte-joiut (true kuee).
80. Fibula.
81. Tibia.
82. Os ealcis (true heel).
83. Astragalus.
84. Cuboid.
85. Os magnum
86. Os meiliiui].
87. Os parvum.
88. Large metatarsal."!
c. Phalanges.
d. Tarsus.
89. Small metatjii.<;al. j
90. Os suffraginis.
91. Os coronse.
92. O^ pedis or pedal bone,
e. Metatarsus.
[f. Phala
PLATE XXXVII
CLASSIFICATION OF BONES 177
the hard material tliat it is, we have already pointed out the provisions
which exist in it for an ample supply of blood to circulate in its interior,
and repair the waste of tissue that is here as elsewhere constantly taking
place. How this is eftected will presently be seen.
If a verv thin transverse section of bone (fig. 281) be made, and sul)-
jccted to the scrutiny of the microscope, it will be found to present a
definite order of arrangement of its several parts, conspicuous among which
are a number of openings -2-5^0 to -o^ inch in diameter. These are the
Haversian canals, so called from the name of the person (Havers) who first
detected tbem. The Haversian canals are each surrounded by a group
of bony rings arranged concentrically or one outside another. In and
between these rings will be noticed a number of small spider-like Ijodies
(lacuna?) from which fine dark lines (canaliculi) radiate in all directions.
If a similar section be made longitudinally, and inspected under a similar
power, what in the first appeared as openings will now come into view as
tubes traversing the bone tissue (fig. 282), and dividing and reuniting; the
same dark lacunse and canaliculi intervening iietween them.
The Haversian canals are so many channels for the accommodation of
blood-vessels, by which the circulation in the bone is carried on.
The lacunse are small corpuscles or spaces containing a mass of living-
protoplasm, and the fine lines proceeding from them are minute channels
which communicate with each other and with the Haversian canals, into
which some of them open. These channels serve the purpose of distribut-
ing nutritive matters for the su]3port of the bone tissue.
CLASSIFICATION OF BOXES
Bones are divided into three classes, distinguished as long hones, flat
hones, and irregular hones.
Long bones make up the extremities, where they give support to the
l)odv, and act as so many levers in the function of locomotion. Each long
bone is composed of a central jjortion or shaft and two extremities. The
former is the more compact and narrow, the latter is chiefly formed out of
spongy tissue, and is Inxiad, and yields an articular surface covered with
cartilage.
Flat bones, for the most part, enter into the formation of cavities con-
taining important organs, as the cranium, the chest, and the pelvis.
Irregular bones are distinguished by their many angles and depres-
sions, such as the vertebrae, and the bones of the knee and the hock-joint.
They are mainly composed of cancellated tissue enclosed in a dense outer
layer of compact structure.
178 h?:alth and disease
To whatever class a bone may belong it will have upon it eminences and
depressions. Some of these will be articular, and by uniting with other
bones form joints, while others will be non-articular, and give attachment
or lodgment to ligaments, muscles, or tendons.
GROWTH OF BONES
In the course of the growth of the foetus much of the skeleton is laid
down m a soft flexible substance termed cartilage or gristle, out of which
bone is ultimately developed by a succession of changes, including the
deposition of mineral matter into its structure. In long bones this process
of ossification is first commenced in the centre of the diaphysis or shaft,
from which it spreads to the extremities, where it is ultimately met by an
ossifying centre from each. The two ends are termed epiphyses, and
during the period when the animal is growing they may be, and sometimes
are, broken away from the shaft by muscular contraction and other forms
of violence. Where a considerable projection appears on a bone, as on
the upper end of the femur, they are produced from separate centres of
ossification and known as apophyses.
Growth in length takes place between the ossifying centre in the shaft
and those of the extremities; in thickness it proceeds from the inner surfece
of the periosteum, which lays down bony matter layer upon layer.
Flat bones, such as those which enter into the formation of the cranium,
the scapula or blade bone, &c., are developed l)etween two membranes and
not, as in long bones, from a pre-existing model of cartilage. The former
is termed intra-membranous ossification, the latter intra-cartilaginoiis.
SKELETON
The skeleton is the bony framework which gives attachment to muscles,
forms cavities for the safe lodgment of the organs essential to life, and gives
general support to the body. When the bones are united by their proper
ligaments the skeleton is said to be a nattiral one, but when they are
held together by wire, catgut, and other foreign materials, it is termed an
artificial skeleton.
The skeleton of the horse is made up of about 163 bones, which are
united in various ways to form joints movable or fixed, according to the
purpose of the part into which they enter.
The skeleton is divided into trunk and extremities. The trunk com-
prises the head and spinal column, the ribs, the sternum, and pelvis. The
extremities are distinguished as the fore and hind, or the thoracic and pelvic.
VEKTEmiAL ('(JLUMN 179
VERTEBRAL COLUMN
The vertebral column con.sist.s of a long series of irretiular-shapeil hones
termed vertel)r;t?, united together in various ways to form a long undulat-
ing column commonly known as the "spine".
Vertebrae are divisible into true and false. The former are cliaracter-
ized by the presence of a certain group of parts, some of which are absent
in the latter. Moreover, true vertebrte in health are always free and
separate from each other, while false ones may become joined together by
bony union. Examples of the latter are seen in the bones of the sacrum
and those of the coccyx or tail.
Each of the several vertebrae, from the head backward as far as the
commencement of the tail, forms a ring which, when the whole are brought
together, constitutes the spinal canal in which is enclosed the spinal cord.
The vertebral column contains from 50 to 54 pieces, which for con-
venience of description are divided into four sections, viz. : the cervical,
dorsal, lumbar, and sacro-coccygeal .
The first 7 bones are the cervical vertebrae or neck-bones; beyond
the.se are 18 dorsal vertebrae or back-bones, behind which are sometimes
5 but mostly 6 lumbar or loin bones, and beyond these are 5 sacral bones,
corresponding to the croup, and 14 to 18 coccygeal or tail bones.
For the most part the vertebrae composing these several regions bear
more or less resemblance to each other, but possess some special differ-
ences by which bones of one region may be distinguished from those of
another.
True Vertebrae are characterized by a numl)er of bony prominences
or processes, a central canal for the accommodation of the spinal cord, a
solid discoidal mass or body and an arch (neural arch). The anatomical
parts of a vertebra are shown in figs. 4 and 5, Plate XXXVIIL
A conspicuous exception to this formula is presented bv the first
cervical verteln-a, which is a simple ring of bone with two broad slop-
ing transverse processes and a small inferior spinous process (fig. 1, Plate
XXXVIII).
The Processes. — The superior spinous processes of the neck are verv
short, those of the back and loins are long, especially in the region of
the withers, where they increase in length from the fir.st to tlie fifth and
then diminish again backward (Plate XXXVII).
The inferior spinous processes are for the most part .small, and in some
of the bones only exist in a very rudimentary state.
The two transverse processes, right and left, consist of irregular liony
180 HEALTH AND DISEASE
prominences varying in form and size in different parts. In all they
serve for the attachment of muscles, in addition to which those of the
dorsal vertebrfe are also united to the ribs, with which they have a
synovial articulation. In the neck an opening passes through the trans-
verse processes of the first six vertebrae, while in the loins these processes
are very long and flat, and some of them behind have synovial articula-
tions by which they are joined together.
The oblic|ue processes are situated on the anterior and posterior parts
of the arch. They form joints with corresponding parts on the Itones in
front and behind them by broad synovial surfaces, the two anterior of
which look upward and inward, while the two posterior look downward
and outward.
The Body is the thick solid base on which the arch rests, and which
forms the floor of the spinal canal. Its anterior extremity is round or
convex, and fits into a corresponding hollow or concavity in the bone
before it. Its posterior extremity is concave, and receives the rounded
end of the vertebra which follows it. These convexities and concavities
are much greater in the cervical vertebrae than in other regions, on account
of which the neck is able to move with excejjtional freedom in all direc-
tions. On either side, in front and behind, a small depression exists on
the bodies of the dorsal vertebrae for the accommodation of the heads of
the ribs, which fit in between them to form a synovial articulation.
The NeUPal Arch is formed by two plates of bone which spring from
the upper surface of the body on either side, and unite above to form
the sjjinal canal. In the anterior and posterior borders of the neural
arch above the body of each vertebra are two notches which, with cor-
responding notches in the vertebrae before and behind it, form openings,
termed the intervertebral foramina, through which the spinal nerves leave
the spinal canal.
The False Vertebrae are those of the sacrum, the several pieces of
which arc firmly joined together by bony union, and the coccygeal bones,
from which some of the parts above described are wanting or exist only
in a rudimentary form.
PARTICULAR VERTEBRAE
The first vertebra or AtlaS (fig- 1, Plate XXXVIII), so described
because in the human family it supports the head, differs in a striking-
manner from the typical vertebra, being a mere ring of bone, having two
broad wings or transverse processes jutting out from the sides. In front
it presents two deep concave surfaces, which articulate with corresponding
PI.ATH XXXVIII
2. Supero-anterior foramen.
3. Postero -inferior foramen.
4. Surface for artJciilaiion w
Inferior iiibercle
spinons snrface.
Spinal canal.
Fig. 2. ATLAS Untero-inferi
Fig. 3. AXIS (side view)
1. Superior spinous process. 4. Odontoid process.
2. Intervertebral foramen. 5. Inferior spinous process.
3. Transverse process. 6. Posterior articular face of body.
7. Oblique process.
Fig. 4. DORSAL VERTEBRA (front vi
I. Superior spinous process. 2. Traiisve
process. 3. Articulation for tubercle of 1
4 Articulation for head of rib. 5. Antei
articular face of body. 6. Spinal c.inal.
Fig. 5. DORSAL VERTEBRA ^side view,
I. Superior spinous process. 2. Facet for
articulation of tubercle of rib. 3. Posterior
articular process. 4. Facet for articulation
of head of rib. 5. Intervertebral notch.
6. Body. 7. Posterior articular surface of
body. 8. Anterior articular surface of body.
CERVICAL AND DORSAL VERTEBRA
PARTICULAR VERTEHR.-E
181
Fig. 283.— Cervical Vertebra
' Articular Head. - Vertebral Foramen. 3 Transverse Pro-
cess. ■* Spinal Canal. ^ Anterior Articular Process. ^ In-
ferior Spin
Process.
convexities or condyles (occi-
pital condyles) at the back of
the head. It is by the peculiar
construction of this joint that
the free up-and-down move-
ment of the head upon the
neck is rendered possible.
Behind is a large single
articular surface with which it
is united to the second bone
or axis. The spinal opening in
this bone is of considerable size,
in order to permit the exten-
sive and varied movements of
the head upon the neck with-
out injury to the spinal cord.
The Axis (fig. 3, Plate XXXVIII) or second bone of the neck is so
called because it serves as a pivot on which the head is moved from
side to side. The pivot is provided by a pro-
cess of bone (odontoid process) which proceeds
from the anterior extremity of the body and
passes into the ring of the atlas which is in front
of it. This bone diti'ers from the other cervical
vertebrae, in the large size and strength of its
superior spinous process, the small size of the
transverse processes, and the presence of only
two oblique processes, which are behind.
The remaining five cervical vertebrae are dis-
tinguished numerically as the 3rd, 4th, 5th, 6th.
and 7th (fig. 283), and although each possesses
some minor distinctive feature, it is not neces-
sary to dwell upon them here.
The Dorsal Vertebrae (fig. 284) present
a good deal in common. Some of them, how-
ever, are readily distinguishable from the others
by the length of the superior spinous processes.
This is especially the case with regard to the
first eight bones. Of these the length in-
crea.ses to the fifth, and then gradually diminishes backward.
The Lumbar Vertebrae (fig. 285) are distinguished from those above
described in the much greater length and width of tlieir transverse pro-
Fig. 284.-
-Dorsal Vertebra ( Front
\'iew)
' Superior Spinous Process.
- Transverse Process. ' Articula-
tion for Tubercle of Rib. •■ Articu-
lation for Head of Rib. 5 ..\ntorior
Articular Face of Body. •* Spinal
Canal.
181'
HKALTH AM) DISEASE
cesses, which are directed horizontally outwards. The last two are much
thicker and somewhat shorter than the rest, and are united to each other
Fig. 285.— Lumbar Vertcl.r..
1 Superior Spinous Proce.ss. - Anterior Oblique Process. ' Transverse Process. •* Anterior
Articular Face of Body. ° Spinal Canal.
l)v the borders of their transverse processes, and to the transverse process
of the sacrum by synovial articulations.
The Sacrum (fig. 28G) or rump bone, as we have already pointed
Fig. iSe-^Sacniin (Si.K- Viow)
' ' Superior Spinous Processes. - Transverse Process. ^ Articulation for Last Lumbar Vertebra. < •'> 6 7 Superior
Sacral Foramina for the passatje of the Superior Sacral Nerves.
out, is a large single triangular bone in the adult, resulting from the
welding together of five vertebra^, which are separate in the foetus. It
CRANIUM 1S3
fonn.s tliat part of the Itody ti'iined the ciuup, and i.s fixed like a wedge
between tlie dorsal spines of the ossa innominata or hip bones.
The Coccygeal Vertebrae, or tail-bones, are from fourteen to
eighteen in number. The first tliree or four partake \"ery mueli of the
character of true vertebrae, being wanting only in the oblique proce.s.'^e.s.
In the remainder of the tail-bones the proper vertebral characters gradually
become more and more obscure until they altogether disappear.
]Most of the bones of the spine present some peculiarity of form by
wliich tliev may be distinguished one from another; but enough lias been
said to uive the reader a oeneral idea of their characters.
SKULL
The skull or bony framework of the head is situated at the anterior
extremity of the vertebral column, from which it is suspended by ligaments
and muscles, and on which it is capable of being freely moved in all
directions. It forms a number of cavities for the lodgment of important
organs, as the cranium, the orbit, and the mouth.
In the young animal it is made up of thirty-two pieces or separate
bones, all of which, excepting the lower jaw and the hyoid or tongue
bone, become united in the adult by ossification. Of the thirty-two bones,
the following six are single: —
Occipital Bone. Ethmoid Bone. Inferior Maxillary Bone or
Sphenoid Bone. Vomer. Lower Jaw.
Hyoid or Tongue Bone.
The rest are in pairs: —
Parietal Bones. Anterior Maxillary Bones.
Frontal Bones. Malar Bones.
Squamous Temporal Bones. Lachrymal Bones.
Petrous Temporal Bones. Palatine Bones.
Nasal Bones. Pterygoid Bones.
Superior Maxillary Bones. Tuibinated Bones (two pairs).
The head is divided into the cranium and the ^ace.
CRANIUM
As compared with the body, the cranium or brain-case of the hor.se
is remarkable for its .small size. Of the thirty-two bones forming the
skull, fourteen are engaged in enclosing the cranium, of which four are
single bones, and the re.st pairs.
184
HEALTH AND DISEASE
Occiput. — This bone is situated at the supeiior extremity of the
cranium, and, as we have already pointed out, furnishes two hirge con-
dyles, by which it articulates witli the atlas, or first bone of the neck
(15, fig. 289). Above, it forms
the crest or prominence between
the ears, while below it gives off
a process (basilar j^'i'oct'ss) which
passes forward to assist in form-
ing the base of the skull. Be-
hind, it forms the superior boun-
ilary of the cranium, where it
presents two rounded projections
or condyles. Between these is a
large opening {foramen magnwn),
through which the brain is con-
nected with the spinal cord. On
the outer side of the occipital con-
dyles a bony ^Drojection {styloid
process) is found. This, like other
parts of the bone, affords attach-
ment to important muscles.
Parietal. — The parietal bones
are two, situated immediately l)e-
neath the bone last described and
above the frontal bones. They are
united by the sagittal suture in the
middle line of the cranium, and
serve to form the roof of that cavity.
Temporal Bones. — These
are four in number, two pairs, dis-
tinguished from each other as the
squamous and the petrous tem-
poral bones, the former having a
shell-like structure, while the latter
are of great density and hardness.
The petrous temporal bones con-
tain the organs of hearing.
Squamous Temporal. — These are two flattened portions of bone
situated at, and forming the sides of, the brain cavity. From the outer
part, near the middle, a long bony eminence proceeds in a downward direc-
tion to unite with the orbital process of the frontal bone above, and the
Skull (Front Aspect)
^ Occipital Tuberosity. ^ Parietal Bone. ^ Squamous
Temporal Bone. ■* Superior Orbital Foramen. * Lach-
rymal Bone. * Malar Bone. '' Inferior Orbital Foramen.
' Foramen Incis,sivum. ^ Anterior Maxillary Bone. '" Nasal
Suture. '^ Superior Maxillary Bone. ^" Frontal Bone.
'' Frontal Suture. '■* Temporal Fossa. '* Sagittal Suture.
CRANIUM
185
nialai- or e-lieek-hoiie helow. Tl
surface of which will be seen a
of the lower jaw, the two to-
gether forming the inferior
maxillary articulation or joint.
Petrous Temporal.— Two
small hard irregular bones, but
of considerable importance ow-
ing to their having within them
the special organs of hearing.
They are interpo.sed between
the occipital bones above, and
the parietal and temporal bones
below, and assist in forming
the lateral walls of the cranium.
They are the hardest bones in
the skeleton, and fi-om them
project several bony processes.
One, the external auditory
canal, communicates with the
middle ear. Another, the sfi/-
loid 2^rocess, is a long thin piece
of bone projecting downward
and forward, and behind this is
a larger rounded protuberance,
the mastoid process, which is
hollowed out into a number of
small compartments connected
with the middle ear. Another
small process serves for attach-
ment of the tongue bone, and
is known as the hyoid process.
Sphenoid Bone. — This
bone assists in forming the base
of the cranium. It is situated
immediately below the occipital
bone, with which it articulates.
Its middle part or body is
somewhat thick, and from it
or wings, and downward two
{pterygoid processes).
lis is the zygomatic process, on the under
concavity for the reception of the condyle
Fis. 288.— Skull (Posterior Surface.
' Foramen Magnum. - Styloid Process of Occiput. ■• Ex-
ternal Auditory Process. •* Styloid Process of Petrous Tem-
poral Bone. ^ Sphenoid Bone. ^ Pterygoid Process. ^ Superior
Maxillary Bone. 8 Palatine Bone. ^ Molar Teeth. '<> Pala-
tine Process of Superior Maxillary Bone. " Premaxillary Bone.
^- Incisor Teeth. *■* Foramen Incissivum. '^ Palato-niaxillary
Foramen. '* Vomer. '^ Ethmoid Bone. " Temporal Con-
dyle. '® Foramen Lacerum Basis Cranii. '^ Basilar Process
of Occiput. ™ Petrous Temporal Bone. " Occipital Condyle.
proceed upward two flattened portions,
narrower and more slender projections
186 HEALTH AND DISEASE
Ethmoid or Sieve Bone. — The ethmoid bone is situated in front
of the sphenoid, and forms the lower part of the division separating tlie
cranium from the face. It consists of two lateral halves, separated by
a perpendicular plate (the lamina). Each half in front consists of a
number of thin fragile plates of bone, rolled up into small scrolls (ethmoidal
cells), and attached to the cribriform plates, i.e. two bony plates having
a number of small holes in them, by which the olfactory nerves escape
from the cranium into the nostrils. At the sides it throws up two wing-
like processes, which articulate with the frontal bones.
Frontal Bones. — These bones form a portion of the inferior wall
of the cranium, as well as that part of the face corresponding to the
forehead. Tliey are situated between the parietal bones above and the
nasal and lachrymal bones below, and have union with several other bones
of the cranium and face. Each of the frontal bones assists in forming
an irregular cavity of considerable extent {frontal sinus), which con-
tains air and communicates with the nostril. These frontal sinu.ses are
lined by mucous membrane. They give lightness to the head, and in
"nasal gleet" sometimes require to be opened in order to .give exit to
the pus which accumulates within them. They are very small in early
life, but enlarge as age advances, and are separated one from the other
by a bony partition.
BONES OF THE FACE
Nasal Bones. — These bones form the anterior part of the face below,
and are situated beneath the frontal bones, and between the lachrymal
and the superior and anterior maxillary bones. They are the slender
bones commencing above by a broad extremity and ending below in a
pointed process {nasal ji^eaX-). They form the front boundary wall of
the nasal cavities.
Superior Maxillary Bones. — The upper jaw - bones are situated
on the side of tiie face, and join together by means of a flattened plate
(palatine process) in the centre of the roof of the mouth, a large portion
of which they form. They also form the floor and sides of the nostrils,
and the sockets, or alveoli, into which the fangs of the upper grinders
or " molar" teeth are implanted. Like the frontal bones, they are hollowed
out into sinuses, which .sometimes become diseased as the result of direct
injury to the jaw, or to disease extending from the fangs of the teeth.
In these cases they become filled with matter to which exit has to be
given by an operation.
Anterior Maxillary Bones. — These bones are situated at the
HONKS OF THE FACE
187
lower purt of the face, and cany the upper incisor teeth. Tliey are joincil
together in front, and also by a thin flexible plate whicli forms the
anterior part of the roof of the mouth and the floor of the nostrils. In
the old animal they become in.separably bound together by ossific union.
Lachrymal Bone. — This is a small bone situated at the inner angle
of the orbit, which it assi.sts in forming. It has running through it a
funnel-shaped cavity {lachrymal fossa), which gives lodgment to a small
Sknll (Side View)
° Nasal Peali. ' X.isal Bone. - Inferior Orbital Foramen. ^ Lachrymal Bone. * Orbital Cavity. * Frontal Bone.
* Temporal Fossa. " Zygomatic Arch. * P.arietal Bone. ^ Supra-condyloid Process. i" Occipital Tuberosity.
" Petrous Temporal Bone. '^ External Auditory Hiatus. '^ Maxillary Condyle. ^* Styloid Process of Occipital
Bone. '' Occipital Condyle. "* Styloid Process of Petrous Temporal Bone. " Tcmporo-maxillary Articulation.
'^ Squamous Temporal Bone. " Malar Bone. ™ Superior Maxilla. -' Mental Foramen. '^° Anterior Maxilla.
sac (lacJin/maJ sac), and this is continuous with a long membranous canal
{/acJirt/iiial duct), which conveys the tears from the eye into the nostrils.
Malar Bone. — This is placed at the outer and inferior part of the
orbit, where it sends a branch backward and joins the temporal bone to
form the zygomatic arch, and the socket for the lodgment of the eye
and its muscles.
Palatine Bones. — The palatine bones are situated at the back part
of the roof of the mouth, and form a narrow border to the posterior nares
or opening between the nostrils and the throat.
188
HEALTH AND DISEASE
Pterygoid Bones. — These are two small slender bones placed imme-
diately above the palate bones.
On the outer side of each is a groove or pulley, through which a small
tendon plays, belonging to the muscle {tensor j^f^lati) that tightens up
the palate in the act of swallowing.
The Vomer. — A single bone running along the whole length of the
floor of the nasal cavities, wdiere it occupies a central position. Its anterior
border is deeply grooved, and gives lodgment to a Hat piece of cartilage
^ Coronoirl Process. - Condyle.
Fig. 290. — Lower Jaiv
^ Molar Teeth. ■* Mental Foramen,
attachment of Masseter Muscle.
Incisor Toeth.
{septum nasi) by which the nasal passages are divided one from the
other.
Turbinated Bones. — These are four in number, two situated in each
nasal passage, where they are attached to the outer walls one above the
other. They are long, thin, fragile plates of bone, folded upon themselves
into rolls, which extend nearly from one extremity of the iio.se to the
other. They are covered with mucous membrane, and afford a large
surface for the distribution of the nerves of smell {olfactonj nerves), and
for the secretion f)f mucus.
Inferior Maxillary Bone or Lower Jaw. — This is a single bone
composed of two flattened branches, which converge from above down-
ward, and unite in front to form the bodv. It is the largest bone of
THE TilUllAX V\l CHEST
189
the face. It eanies six molar teeth, or grinders, on each side, and six
incisor teeth in front. In addition, it also gives lodgment to two canine
teeth or tusks in the male. Above it forms a hinge joint on cither side,
where its rounded prominences or condyles are fitted to corresponding
depressions in the temporal bones by the interposition of a disc of cartilage.
In front of the condyles are two long, thin, and flattened bony pro-
minences, the " coronoid processes", which give attachment to muscles
of mastication. On the inner sides above, and on the outer sides below,
are two openings com-
municating with a long
canal, through which
pass an artery and a
nerve to supply the teeth
with blood and sensation.
Os Hyoides or
Tongue Bone. — This
bone is situated in the
region of the throat, and
is composed of five dis-
tinct pieces. One is
formed like a spur, hav-
ing a short, pointed pro-
cess projecting forward,
and embedded in the
root of the tongue, and
the heel - like branches
directed backwards to
be connected with the
larynx or upper part of
the windpipe. The others, two flat slender pieces on either side (svperior
and inferior cornua), are united together and attached above to the
petrous temporal bone at the base of the cranium by means of a short
rod of cartilage. The several parts composing the bone are joined to-
gether by articulations, some of which form free-moving joints, to which
the extreme mobility of the tongue is due.
Fig. 291.— The Hyoid Bone and the Larynx
A, Superior or Long Comu of Os Hyoides. B, Inferior or Short
Coniu. c, Thyroid or Heel -like Process. D, Spur Process.
E, Epiglottis. F, Cilottis. G, Cricoid Cartilage. H, Thyroid Cartilage.
I, First Ring of Trachea. J, Arytenoid Cartilage.
THE THORAX OR CHEST
The bony framework of this cavity is formed by the dorsal vertebrae
above, which we have already referred to, the sternum below, and the
ribs which form the sides and part of the roof.
190
HEALTH AND DISEASE
Sternum or Breast-Bone (fig. 292). — This is a long bone, suspended
from the dorsal spine by the ribs, the first eight of which articulate with
it. In early life it is made up of six distinct pieces, united by intervoning
Fig. 292.— Sternum
' Carinifoim Cartilage. ■ Ensiforni Cartilage or Xiphoid Appendage. ' Inferior Border. ■* ■* ■• Cavities for
articulation with lower extremities of Costiil Cartilages.
cartilage or gristle. In front it is like the keel of a vessel, owing to the
projection of a flattened piece of cartilage {cariniform cartilage) which
curves upward and presents a sharpened border to the front, and below
for about two-thirds of its length. The posterior extremity is continued
' Cariniform Cartilage.
,, .i.uMi and CosUd Cartilages
■ Ensiform Cartilage. '-'" Costal Cartilages.
backward by a Hat piece of cartilage, called the xijjhoid or ensiform
cartilage, and along the superior part of each side of this bone arc eight
depressions, which receive the inferior ends of the cartilages of the true
ribs to form so many .synovial articulations or joints.
TllH TIIOKAX oi; (_lJi:ST
The Ribs (Plate XXX\'ll).— Wo have already pointed out that there
are eighteen ribs on each side, distinguished numerically as the first,
second, third, and so on. The first eight are attached to the sternum and
designated true ribs. The remaining ten, having no such connection, are
called false ribs. Although they are thus distinguished, they all possess
certain common characteristics. They are long, Hat, more or less curved
or arched outward from the chest, and are, besides, somewhat twisted on
themselves. They are all connected with the vertebrte above ])y two free-
moving joints, and
below they are at-
tached to rods of car-
tilage (costal curti-
lages), through which
the first eight become
united by synovial
articulations to the
upper part of the
side of the sternum,
as already explained.
Each rib possesses a
head, a neck, and a
tubercle at the su-
perior extremity. The
head fits into a hollow
formed between the
bodies of two verte-
bne, where it is united
])y ligaments to form
a free -moving joint.
The tubercle forms
another svnovial articulation witli tlie transverse process of the vertebra
behind. The length of the ribs varies with the position they occupy.
From the first to the ninth they increase in length, and then progressivelv
they diminish to the last. Variation is also noticeable in the width, which
increases from the first to the sixth or seventh, and then diminishes to
the eighteenth.
The outward curve they make increases from the first to the last, and
gives rotundity to the body in proportion as it is great or otherwise.
Costal Cartilages. — These are cylindrical pieces of cartilage extend-
ing in a forward direction from the lower extremities of the ril)s, which
they .serve to elongate. The first eight are united with the sternum, and
Fig. 294. — Pelvis (Superior Aspect)
' Antero-inferior Spine of nium. ^ Siipero-posterior Spine of Ilium.
3 Obturator Foramen. * Lateral Ischiatic Notch. ^ Tuberosity of Ischium.
^ Ischiatic Arch. ' Symphysis Ischii. " Symphysis Pubis.
192
HEALTH AND DISEASE
are the thieker and stronger. They increase in lengtli from before ))aek-
ward to tlie eleventh, after which they become shorter.
The Pelvis (figs. 294, 295). — The bony pelvis or hip girdle consists
of two portions, termed coxse or ossa innominata, which, together with
the sacrum and the front segments of the tail-bones, form the cavity of
the pelvis.
The ossa innominata are flat, irregular bones, which, after forming the
sides of the pelvic cavity, join together below to form its floor. In the
foetus each innominate bone consists of three pieces, termed the ilnini, the
ischium, and the
pubis. The ilium,
the largest of the
three, is that portion
which unites with the
sacrum above, with
the acetabulum or
femoral joint l)elow,
and outwardly forms
tlie "point (if the
hip ". The ischium
is that portion which,
on leaving the hip-
joint, which it assists
in forming, passes
backward to the point
of the buttock, and
inward to join its
fellow on the opposite
side, thus contribut-
ing to the floor of the
pelvis, and to the for-
mation of a large opening there — the obturator foramen.
The pubis is the smallest of the three bones entering into the forma-
tion of the coxa. It is situated in front of the floor of the pelvis,
which, together with the foramen just referred to, it concurs in forming.
With the ilium and ischium it also joins in making up the acetabulum
or cup-like cavity into which the head of the femur fits to form the
nip-joint.
The two pubic bones unite on the floor of the pelvis to form a seam,
or, as it is termed, the symi:)hysis pubis.
The cavity of the pelvis is nuich larger at the front or inlet than at
Kin. 2y.5.- Pelvis and Saci'uni (Infui-ior Asjiect)
1 Anterior Articular Body of Sacrum. ^ Posterior Spinous Process of Ilium.
■^ Crista of Ilium. * Anterior Spinous Process of Ilium. ^ Neck of Ilium.
^ Acetabulum. ^ Obturator Foramen. ^ Lateral Ischiatic Notch. ® Ischiatit
Arch. 1" Tuberosity of I.'^chium. " Coccygeal Extremity of Sacrum. ^''Sub-
sacral Foramina. '^ Anterior Articvdar Process of Sacrum.
THE FOUH LIMB
193
the outlet behind. The pelvic ciivity of the mare is hirger than that of
the horse in every direction, but especially from side to side. The floor of
the female pelvis is distinctly wider than that of the male animal.
THE FORE LIMB
The fore extremity is made up of twenty bones: the scapula, humerus,
radius, and ulna above the knee; the scaphoid, lunar, cuneiform, pisiform,
trapezoid, os magnum, unciform in
the knee; and the large and two
small metacarpal bones, two sesa-
moid bones, the os suflraginis, os
coronse, os naviculare, and os pedis
below the knee.
Scapula (figs. 296, 297).— This
is tlie ujjpermost bone of the fore
limb, a flat triangular segment
placed on the side of the chest,
where it takes an oblique direction
downward and forward. Its base
is turned upward, and its apex con-
curs with the humerus to form the
shoulder-joint. A broad flat piece
of cartilage is attached to its ujjper
border, and gives increased length
to the bone, hence it is termed car-
tilage of pi-olongation, or scapular
cartilage. The scapula has three
angles: 1, cervical, nearest the
neck; 2, dorsal, nearest the back;
3, humeral, at the point of the
shoulder. The last presents a
shallow oval cavity, which receives
the rounded head of the humerus
to form the shoulder-joint. Im-
mediately above it, in front, is a large rough curved off'shoot of bone,
the coracoid process, which gives attachment to important muscles.
The outer surface of the bone is divided into two unequal parts Ijy
a bony ridge or spine. This bone is united with the trunk by muscles
only. It has no synovial articulation or joint connection as in the hind
limb.
Vol. II. 47
Fig. 296. — Scapula (Outer Surface)
1, 1 Spine of the Scapula. " Coracoid Process.
3 Glenoid Ca\nty for Articulation of Humerus. "* Dorsal
Angle. ' Cervical Angle. ^ Cartilage of Prolongation.
194
HEALTH AND DISEASE
Humerus (figs. 298, 299).
The humerus, or arm-bone, is a bone of
great thickness and density, and is
situated between the scapula or
bhide-bone al)ove and the radius
and the ulna below. Externally
the body of the bone is deeply
grooved by the furrow oj torsion,
and presents at about its upper
third a somewhat bold pointed pro-
jection, the external tuberosity. On
the internal surface it presents a
rounded prominence, the internal
Fig. 297. — Scapula (Inner Surface
• Coracoid Process. ' Glenoid Cavity,
of Prolongation.
3 Cartilage
important
luherositi/, into which
muscles gain in.sertion.
On the upper extremity are the
broad rounded head and several bony
prominences. The former, situated
behind, is coated with cartilage, and
articulates with the glenoid cavity of
the scapula or blade-bone to form the
shoulder-joint. The latter comprise a
double projection of bone on the outer
side, termed the great trochanter. On
the inner side is the small trochanter
or tubercle, and between them a prominence which divides the upper
front portion of the humerus into two grooves {bicipital groove). The
Fig. 298. —Humerus (Front Aspect)
' Bicipital Groove. ' Small Trochanter.
3 Great Trochanter. * External Tuberosity.
' Shaft with Furrow of Torsion. ^ Epitrochlea
or External Condyle. ' Supra-condyloid Fossa.
^ Epicondyle or Internal Condyle.
THE FORE LIMB
195
grooves and interveiiii
tubercle are covered witli fibro- cartilage, and
over them plays, pulley-like, the broad
tendon of the flexor brachii muscle,
l)etween which and the bone there is
a synovial membrane.
Fig. 299.— Humerus (Outer Aspect)
' Great Trochanter. " Deltoid Tuberosity.
3 External Tuberosity. ■* Epitrochlea. * Epi-
condyle. « Supra-condyloid Fossa. ' Shaft of
Bone with the Furrow of Torsion. 8. Articular
Surface or Head.
The lower extremity is smaller than the upper,
and in front jDresents two unequal rounded por-
tions separated by a superficial groove. These are
the internal and external condyles. Behind is a
deep pit {supra-condyloid fossa), which separates
two prominent ridges from each other, and re-
ceives into it a pointed jirocess (peak) on the
elbow when the joint is in extreme extension.
FOREARM
Fig. .300.— The Forearm: Radius
and Ulna
' Ulna. - Point of Ulna.
^ Beak of Ulna. ^ Radio-uluar
Arch. ° Radio-ulnar Articu-
lation. " Bicipital Tuberosity.
' Shaft or Body of Radius.
8 Radio-carpal Articulation.
Two bones, the radius and the ulna, which in early life are separate,
but in the adult are ossified together, constitute this region.
Radius (fig. 300). — This is the longest bone in the fore liml), and
196
HEALTH AND DISEASE
extends from the humerus above to tlie knee below. Its superior extremity
is divided into two concavities by a small ridge, and corresponds with the
two convexities and the dividing furrow observed on the lower extremity
of the humerus, with whicli it ar-
ticulates to form the ell.)OW-j(>int.
Behind, towards the outer side, it
presents a long roughened surface,
where it forms a bony union with
tlie ulna.
The lower extremity is some-
what irregular, and articulates with
tlie four bones comprising the upper
row of the knee. In front there are
three grooves over which three ten-
dons play in passing down the limb
to their points of insertion. Each
tendon is supplied with a synovial
membrane to facilitate its move-
ments over the bone during flexion
and extension of the knee.
Ulna (fig. 300).— The ulna is a
long tapering bone, united by ossi-
fication to the outer and posterior
surface of the radius. Its superior
extremity is of considerable length
and thickness, and projects from the
head of the radius in an upward
and backward direction. This is the
elbow or olecranon ^>?'oc'e*'.s'. In
fi'ont it presents a smooth surface,
which articulates with the groove
between the condyles of the humerus,
and also a hooked projection for-
ward termed the hcah.
CARPUS OR KNEE
Fig. 301. -Ca
' Radius. '^ Pisiform. ' Cuneiform. ■* Unciform.
** Outer Small Metacarpal BoiiC. ''Scaphoid. ^ Lunar.
* Trapezoid. ' Os Magnum. " Inner Small Meta-
carpal Bone. 11 Large Metacarpal Bone.
This (fig. 301) is the analogue of the wrist of man. It is made up of
seven, sometimes eight, small irregular bones arranged in two rows of
three each, one resting upon the other, with the seventh bone (pisiform)
situated at the posterior and outer part of the upper row.
THE FORK LLMB
197
The bones of tlie upper row,
enumerating them from within
outward, are the scaphoid, lunar,
cuneiform, and the pisiform be-
hind; those of the lower row
are the trapezoid, magnum, and
unciform. Sometimes a fourth,
termed the trapezium, is found
at the inner and posterior part
of the lower row.
All these bones are united
by short strong ligaments. At
their several points of contact
theyare covered with articular car-
tilage or gristle, and enclosed in
a synovial capsule. Altogether
the knee is admirably adapted,
by its many parts, to diffuse and
disperse concussion, and at the
same time for the performance
of that high and free action so
much admired by connoisseurs.
METACARPAL BONES
These are three in number,
and are distinguished as the large
metacarpal bone, which occupies
the centre, and two smaller ones
at the sides.
Os Metacarpi Magnum
(fig. 303), or large metacarpal,
or canon bone, extends from the
knee to the fetlock joint, which it
assists in forming. It is rounded
in front, flattened behind, and
very dense and strong through-
out. Its superior extremity ar-
ticulates with the lower row of
knee bones, and in front, below
the articulation, towards the inner
Fig. 302.— Fore Leg from the Radius
' Radius. ' Radio-carpal Joint. 3 Pisiform. * Cunei-
form. ' Lunar. * Unciform. ' Os Magnum. * Small
Metacarpal Bone. ' Large Metacarpal Bone. "> Sesamoid
Bone. " Fetlock Joint. " Suflraginis or First Phalanx.
'3 Superior Pastern Joint. '* Os Coronre or Second
Phalanx. "> Navicular Bone. '» Pedal Joint. '' Os
Pedis or Third Phalanx.
198
HEALTH AND DISEASE
side, is a roughened prominence into which the tendon of its extensor
muscle is inserted. At the back part of the upper end there is a roughened
patch for the attachment of the suspensory and check ligaments. The
lower extremity is rounded from before to behind, and divided by a
prominent ridge into two nearly equal parts or condyles. The whole of
this end is covered with cartilage, and
articulates with a corresponding surface
formed by the upper extremity of the os
suftVaginis, or large pastern bone, and the
two small sesamoid bones behind.
Os Suffraginis, Large Pastern, or
First Phalanx (fig. 304).— The large pas-
tern is a short stout bone placed between
the small pastern below and the fetlock
joint above. Its superior extremity is
larger than the inferior, and presents two
shallow depressions separated by a groove,
into which the central rids^e and two con-
Fig. 303.— Metacarpal Bones (Posterior
View)
' Outer Small Metacarpal Bone. -Inner
Small Metacarpal Bone. ^ Large Metacar-
pal Bone. ^ Nutritive Foramen. ^ Ar-
ticular Condyles. ^ Intervening Ridge.
Fig. 304. — Os Suff ragini.s or Large Pastern
Bone
dyles, already spoken of as existing on the lower end of the canon, are
fitted to form a joint of considerable extent of motion. The lower ex-
tremity is small, and divided by a superficial groove into two condyles.
Sesamoid Bones (lO, fig. 302). — These are two small floating bones
situated behind the inferior extremity of the canon. They are somewhat
triangular in form, with their bases directed downward, and are clo.'^ely
united one to the other. In front they are covered with cartilage, and
articulate with the condyles of the canon bone, thus forming part of the
THE FORE LIMB
199
fetlock joint. Behind they arc covered with fibro- cartilage, and by
apposition form a groove over which the great flexor tendon of the foot
plays like a rope over a pulley. On tlie outer
sides, from the apex downward, a roughened
groove gives attachment to the two branches
of the suspensory ligament. The under sur-
face of the base is also roughened, and from
it proceed short strong ligaments {inferior-
sesamoid), which attach the bones to the pos-
terior surface of the large and small pasterns.
Os Coronse (%. 305), small pastern, or
second phalanx, is a short bone placed be-
tween the large pastern and the os pedis, or
foot-bone. One-half of it is enclosed by the
hoof, and the rest forms the region of the
coronet. Its upper extremity presents two F'g- sos.-OsCoroiKcan.i OsNavicuiare
J^l _ . (Anterior Aspect)
shallow depressions, with which the two con-
dyles of the lower end of the large pastern articulate. The lower end,
like that of the sutfraginis, is divided by a shallow groove into two con-
dyles, Ijy which the bone
articulates with the os pedis.
The tendon of the extensor
pedis muscle is attached to
the anterior surface, and that
of the flexor pedis perforatus
to the inner and outer part
of the superior border behind.
At the upper and posterior
part it is flattened and
covered by fibro - cartilage,
thus forming a smooth sur-
face over which the tendon
of the flexor perforans freely
plays in its course towards
the foot-bone.
Os Pedis (figs, 306,
307), coflin-bone, or third
phalanx. The coflin-bone is
contained in the hoof, of the
shape of which it in a large measure partakes. It is a porous bone,
having a number of holes in its front and sides for the passage of blood-
Fig. 306.— Os Pedis (Plantar Aspect)
Inferior Border. B Semilunar Crest. c Plantar Foramina.
D, D Retrossal Processes.
200
HEALTH AND DISEASE
vessels, and is besides generally roughened for the attachment of the
sensitive laminse. A pointed process {coronal process) projects upward
from the superior border in front, which affords attachment for the tendon
of the extensor pedis muscle.
The under surface is concave, and presents (1) a crescentic ridge {semi-
liniar crest) to which the tendon of the flexor pedis is attached; (2) behind
tills two considerable openings {plantar foramina), through which pass
the plantar arteries and nerves; (3) still farther back a roughened surface,
to which the inferior ligament of the navicular bone is connected. The
upper surface is divided by a slight ridge into two shallow cavities, with
which the lower extremity of the coronet bone articulates. At the posterior
border of this surface a
narrow, smooth, transverse
space is provided for the
articulation of the navicular
l)one with the foot -bone.
Projecting backward from
the inferior border behind
are two bony processes, one
on either side, termed al(F,
or wings.
Os Naviculare or
Shuttle Bone (tig. 305).—
The navicular bone is a small
flattened bone, broad in the
middle and tapering towards
each extremity. It is situated
in the hoof, below the os
coronse and behind the os pedis, with both of which it articulates to form
the coflin-joint. The great flexor tendon passes over its under surface,
and between the two a synovial membrane exists to lubricate the surfaces
•of contact and facilitate movement. The anterior border articulates with
the foot-bone, as already explained, and is connected below with the
inferior navicular ligament. The posterior border affords attachment to
the posterior navicular ligament. To the pointed extremities are attached
lateral ligaments which unite the bone with the os pedis, the lateral car-
tilages, and the coronet bone.
The navicular bone is the seat of that very common ailment, navicular
disease.
Os Pedis (Side View)
A Coronal Process. E Superior Border. c, D Basilar and Re-
trossal Processes, forming one of the alie or wings. E Preplantar
Fissure. F Facet for Insertion of the Extensor Pedis.
BONES OF THE HIND LIMB
201
BONES OF THE HIND LIMB
The bones coiiipii.seil in this reoion are the femur or thiifh-boiie, the
pateUa or knee-cap, and the tibia and fibula. Tlien come the bones of the
hock, the astragalus, calcis, cuneiform
magnum, cuneiform medium, cunei-
form parvum, and cuboid. The bones
below the hock are the same as tho.se
already described in speaking of the
fore extremity — the three metatarsal,
suti'raginis, two sesamoid, coronte, pedis,
and naviculare.
Os Femoris or Thigh-Bone (figs.
308, 309). — This is a large, thick,
strong bone, extending obliquely down-
w-ard and forward from the hip-joint
above to the stifie-joint below\ The
.shaft presents a number of roughened
places for the attachment of muscles.
For the same purpose there are also
several bony prominences and ridges,
notably the trochanter minor extermis
on the upper third of the outer sur-
face, the trochanter minor internus
near the upper third of the inner sur-
face.
The superior extremity is formed
by the head, a rounded projection
which fits into the acetabulum or cup
in the innominate bone to form the
hip -joint, and on the outer side of
this a considerable eminence {tro-
chanter major) for the attachment of
some of the large muscles of the croup.
Behind and below the trochanter
major a somewhat deep cavity exists,
called the trochanteric fossa, into which some smaller muscles are inserted.
The lower extremity presents four large prominences — two behind, the
condyles, wdiich are separated by a deep notch {inter-condyloid fossa), and
two in front, the trochlea, with which the patella articulates. Above the
Fig. 308. — Os Femoris (Anterior Aspect)
^ Head. - Internal Trochanter. ^ 4 Tuberosities
for Ligamentous Insertion. ' Internal and Ex-
ternal Trochlea. ^ Trochanter Minor Externus.
' Great Trochanter.
202
HEALTH AND DISEASE
outer condyle behind is a deep depression termed the sujora-condyloid
fossa.
Patella (fig. 310). — This is a small irregular bone analogous to the
knee-cap of man, and in the horse fre-
(juently becomes displaced. Behind it
is covered with articular cartilage, and
comes into contact with the trochlea
of the femur, over which it plays in
pulley -like fashion as a part -of the
stifle-joint.
Tibia or Second Thigh (fig. 3ii).
— A long bone extending from the
femur to the hock joint. It is broad
above and narrow below. The sujjerior
extremity articulates with the condyles
of the femur, and is divided into two
lateral articular portions l)y a conical
projection [tibial sjjme). In front, and
extending for some distance down the
bone, is a projecting ridge, inclining
somewhat outward; this is known as
— Os Femoris (Posterior Aspect)
^ Great Trochanter. - Troclianteric Fossa.
3 Trochanter Minor Externns. * Supra-condyloid
Fossa. ° External Condyle. ^ Inter-condyloid
Fossa. ^ Internal Condyle. ** Internal Trochlea,
" Nutritive Foramen. '" Internal Trochanter.
" Fossa for attachment of Ligamentum Teres.
n Head of Femur.
Fifr. -310.-
- Patella (Superior and Posterior
Face)
■ Superior Face. ^ Articular Face.
' External Border.
the " tibial crest ". On the outer side of the head of this bone above,
a small smooth space is noticed for articulation with the fibula.
The lower extremity of the bone, smaller than the upper, jjresents two
deep grooves and three prominent ridges which are covered with cartilage
and articulate with the astragalus to form the " true hock joint ".
BONES OF THE HIND LUm
203
The inuer and outer ridge each bears a projection distinguished as the
internal and external malleolus of the tibia. The former is very prominent,
so much so, sometimes, as to give the inner and upper part of the hock
an abnormal appearance. These projections aftbrd attachment for strong
connecting ligaments uniting the bones of the hock joint.
The articular grooves, which they assist
in forming, take an oblique direction from
behind outward and forward.
The Fibula (3, fig. 31 1) is a long slender
bone connected with the outer side of the
tibia, with the head of which it unites by
a small synovial articulation. It is broad
above and tapers downwards to the lower
third of the femur, where it terminates in a
pointed extremity.
THE TARSUS OR HOCK
This joint (fig. 312) is composed of six
bones, viz., the calcis, astragalus, cuboid,
cuneiform magnum, cuneiform medium, and
cuneiform parvum.
The Calcis is situated at the posterior and
outer part of the hock, of which it forms the
" point ", and gives attachment to the tendons
of important muscles as well as to powerful
ligaments. It articulates in front with the
astragalus and below with the cuboid bone and
the cuneiform magnum, on which it rests.
Astragalus or Knuckle-Bone.— This
is the largest bone in the hock. It is placed
in front of the calcis, and from it project for-
ward two pulley -like ridges separated by a
deep groove. These ridges are received into
two corresponding grooves already referred to as existing on the inferior
extremity of the tibia, and the central ridge on the last-named part fits
into the groove separating those on the astragalus. Together these two
bones form the true hock joint, to which the movements of flexion and
extension of the limb are for the most part due. The astragalus rests
upon the cuneiform magnum, with which it forms a flattened gliding-joint
of verv limited movement. Behind, it articulates with the calcis.
Fig. 311.— Tibia (Posterior Aspect)
^ Spine of Tibia, ^ Articulation of
Fibula. 3 Fibula, •* External Malleolus.
^ Internal Malleolus. " Shaft showing
Bony Kidges for Muscular Attachment.
20-t
HEALTH AND DISEASE
The Cuboid is a small irregularly-shaped bone situated ou the outer
and back part of the hock, having the calcis above it and the large and
outer small metacarpal
bones below. Inwardly,
it articulates with the
cuneiform magnum and
the cuneiform medium.
The Cuneiform
Magnum is a Hat bone
covered on its two surfaces
with cartilage. It occupies
a position between the
astragalus above and the
cuneiform medium below,
and articulates besides
with the cuboid, the cal-
cis, and the cuneiform
parvum.
The Cuneiform
Medium is a triangular
bone, and, like the mag-
num, presents two flat-
tened surfaces for articu-
lation with the magnum
above, and the large
metacarpal or canon-bone
below. By smaller articu-
lations it is also connected
with the cuboid and the
cuneiform parvum.
The Cuneiform
Parvum, the smallest
bone in the hock, is situ-
ated at the inner and in-
ferior part of the joint, in-
clining backwards, where
it articulates with the
large and inner small
metatarsal bones below, the magnum above, and the medium in front.
The outer surface of this bone presents a smooth surface over which one of
the tendinous branches of the flexor metatarsi plays in a synovial sheath.
Fig. 312. — Bones of the Hock sejiar.iteii
'Tibia. 'OsCalcia. ^A.straKaliis. ^Cuneiform Mag^num. "Cuboid.
* Cuneiform Medium. 'Small Metatarsal Bone. * Large Metatarsal Bone,
DISEASES OF BONES
205
Except in very unimportant particulars the bones below the hock
resemble those below the knee, and do not, therefore, require special
description.
DISEASES OF BONES
RING-BONE
A ring-bone is an enlargement extending over the front, and sometimes
also over the back, of the pastern. It consists of a diffused bony excre-
scence growing out of or upon the large or small pastern bone, or both.
When affecting the former it is described as high ring-bone (fig. 314),
when the latter, as low ring-bone (fig. 313). It is common to all classes
of horses, but more especially prevalent in cart-horses and thoroughbreds.
A, Extensor Pedis Tendon. B, Os .Suffraginis or First Phalanx.
C, Os Coronse. D, Ring-bone. E, Os Pedis.
Fig. 314. — "High" Ring
Bone
Causes. — Horses with upright pasterns, and animals with pasterns of
undue length, are specially predispo.sed to it. The exciting causes are
chiefly blows, concussion, and sprains to the joints. Fracture of the
pastern is invariably followed by ring-bone in the form of a reiDarative
callus. It is also induced by the too early and severe work imposed
on young, undeveloped animals, and especially when attended with bad
shoeing, as where the heels are thrown up too high and an upright posi-
tion given to the limb.
Symptoms. ^ — A hard, unyielding enlargement, more or less promi-
nent and extensive, is the characteristic indication of the disease. It passes
across the front of one or the other of the pastern bones, and sometimes
206
HEALTH AND DISEASE
encroaches on the posterior surface. The degree and character of the
lameness will vary with the position of the growth. When situated on
the small pastern, within the hoof, the lameness is very considerable, and
the foot is brought to the ground with the bearing full on the heel. If
it be situated behind, the fetlock joint is partially flexed and the weight
is thrown on the toe. In other situations the action is not so conspicuously
altered, but in all there is more or less severe lameness, with swelling, heat,
and tenderness of the part.
Treatment. — To subdue existing inflammation should be our first aim.
In this connection a dose of physic, with perfect rest, and the application of
hot fomentations and bandaging, must be
resorted to; after which a rejjetition of
blisters, or the application of the actual
cautery to the pastern, will be required
to check further growth of the excre-
scence and to effect its reduction. A
long rest is often needed before pain
and lameness are removed, and in many
instances this desired result is never
attained.
SPLINT
Splint (fig. 315) is a bony excrescence
situated on or near the small splint
bones, and is often the means of per-
manently uniting the latter to the canon.
Not fewer than 90 per cent of our light
horses suffer from this ailment, but a
large proportion of this number acquire
it without sutfering any inconvenience.
Splints may be situated on the inner or
the outer part of the limb, but in the great majority of cases they occupy
the first-named position. Some are placed well forward, while others are
situated quite at the back of the leg. In the former position they are not
of much importance, but in the latter they usually prove troublesome, and
provoke most acute and lasting lameness by encroaching upon and irri-
tating the ligaments and tendons there situated. These growths assume
a variety of forms. Sometimes they are very prominent and project from
a narrow base, at others they are quite flat and diffused, and consequently
with difficulty recognized. There may be only one large one, or several
smaller ones may exist, placed one below another along the course of the
Fig. 315.— Spliiit
A, Exposed Splint. B, Splint covered by Skin.
DISEASES OF BONES 207
splint-bone. When involving the knee, splints inteifeie wilh the Hexion,
or bending, of the joint, and may occasion permanent disablement.
The degree of lameness is not always ^jroportionate to the size of the
growth. Splints sometimes develop to a large size without occasioning
trouble, while very small ones, when backwardly placed, may give rise to
the most acute and abiding lameness.
Causes. — Splints are hereditary in a very high degree — more so,
perhaps, than any other ati'ection of the limbs. They usually appear
between the ages of two and five years, but they are by no means rare in
yearlings, and may occasionally be seen in foals. Owing to the great pre-
disposition to them inherited by our horses, they are easily provoked to
growth by too early work, and the imposition of heavy weights on the backs
of the young and immature. Blows inflicted by one leg upon the other
occasionally cause splints, and many cases are referrible to the concussion
or jar induced by the high-beating action which some animals display.
How far conformation and indifierent shoeing may take part in the
production of splint it is difficult to say, but there are reasons for the belief
that they operate as inducing causes.
Symptoms. — Although, as a rule, splints are obvious enough either to
the sight or touch, this is by no means always the case. In some instances
the greatest care in the manipulation of the limb is required to detect
them, and occasionally they evade the most diligent search. This is
especially the case when they are small and placed on the posterior
aspect of the limb. In the early period of their formation, while the
pei-iosteum or covering of the bone is still inflamed, pressure applied to
the splint induces pain, and causes the animal to jerk away the leg forcibly.
Abnormal heat may or may not be discernible at this time.
Pain, however, in the splint itself is not always necessary to splint
lameness. In many instances the defective action remains after all inflam-
mation has subsided in the bone. In these cases impaired movement is
mainly due to mechanical irritation excited in the tendons and ligaments
on which the projecting splint encroaches. The lameness resulting from
this disease affects the action in various ways, according to the situation
of the growth.
When the splint is at the back of the shin the knee is imperfectly
fle.xed, and the movement of the limb is consequently stiff and short.
Wlien it encroaches on the knee the same imperfect action is observed,
with the addition that the limb is slightly abducted or thrown outward at
each step. Splint lameness is aggravated by the jar of hard ground.
Treatment. — On the first appearance of lameness from this cause the
horse should cease to work, and be placed in a well-littered box. A dose
208
HEALTH AND DISEASE
of physic and light diet should be promptly adopted as preliminaries to
more active treatment. After the efl'ects of the medicine have passed
away the leg should be irrigated with cold water for half an hour three
times a day, and in the intervals a cold wet bandage should be applied
to the affected limb. Should the lameness continue after four or five
days, a blister may be applied to the inner and outer side of the leg
between the knee and the fetlock, and repeated once or oftener according
to the requirements of the case. Should this not succeed, it may be
necessary to puncture the splint with the pointed iron, or to insert a seton
over it, or, as a last resort, to cut through the covering of the bone
(periosteotomy). It need hardly be said that the operations last referred
to can only be undertaken safely by the qualified veterinarian.
OSTITIS— INFLAMMATION OF BONE
A casual inspection of a bone shows it to consist of several structures.
Outwardly will be noticed a thin fibrous membrane (periosteum). This
not only covers the exterior of the bone, but serves as a bed in which
blood-vessels break up into small branches before entering it through the
minute openings provided
on the surfece. AVith these
small vessels fine fibres from
the periosteum itself also pass
into the tissue of the bone,
and become connected with
another membrane lining it
within termed the cndostcimi.
Tlie several structures
may separately sufter from
infiammation, but the in-
timate connection existing
between them renders it im-
possible for one to sufter with-
out the others being soon
involved in the disease.
Infiammation occurring in the periosteum is known as j^o'^ostitis, in
the bone as ostitis, and in the lining membrane of the bone as endostitis.
Periostitis. — This disease is mostly found to exist in the long bones
of the limbs of young animals when growth of the skeleton is most active,
and the vessels of the membrane are highly charged with blood for the
supply of its nutritive requirements.
Fig. ait). — Diagrammatic Transverse Section of Tibia and Fibula
A, The two layers of the periosteum with blood-vessels, &c.
B, Bone of the Tibia, c, Bone of the Fibula. D, Endosteum.
E, Marrow.
DISEASES OF BONES 209
It is especially frequent in the shin-bones of young raee-horses, where
it is commonly known among trainers and stablemen as " sore shins ".
Periostitis may be acute or subacute. In the former case it soon
spreads to the bone, and may cause portions to die and to slough. In
tiie latter, which is the more common form of the disease in the horse,
the action is of a more formative kind, and usually results in the thicken-
ing of the periosteum and the formation of new bone.
Two ffxctors are concerned in this destructive process: — 1. Exudation
is thrown out from the vessels within the bone into the miimte canals
which they traverse. This continuing, the vessels are pressed upon by
the exuded matter, and the circulation of blood being thereby interfered
with the nutrition of the bone sufiers accordingly.
2. Exudation also takes place from the vessels beneath the periosteum,
lifting the membrane away from the bone, with the result that a portion
of the latter dies, partly from want of the nourishment which the vessels
of the periosteum aflbrd to it, and partly also from pressure on the vessels
of the bone itself by the matter exuded around them.
Separation of the dead piece of bone from the living must in such
circumstances take place. During this process abscesses form over the
site of the injury, and pus (matter) is discharged by one or more openings
in the skin.
Symptoms. — Acute pain, great heat, and lameness are early symptoms
of the disease. Pressure over the part causes sudden withdrawal of the
limb. Swelling soon appears — at first firm, then less resisting, and ulti-
mately fluctuating. An abscess forms and breaks, and finally the dead
bone, if not removed by an operation, crumbles away and escapes in small
particles with the pus.
Treatment. — Perfect rest is the first requirement in these cases. An
incision should be made through the periosteum as soon as the disease is
found to exist. This will afford an opportunity for the escape of matter as
it is formed, and prevent any serious separation of the membrane from the
lione by its accumulation beneath it. Where this has already taken place
it is desirable to make a bold opening, and after irrigating the wound
freely with antiseptic solution continue the treatment on the principles
laid down for dealing with wounds on the antiseptic system. It should
not be overlooked to remove any dead piece of bone that may exist, as
soon as it is sufficiently detached to be taken away.
Acute periostitis is only of seldom occurrence, and perhaps the most
common examples are those which occur in the lower jaw as the result
of injury inflicted by the bit. Occasionally it is seen in the bones of
the extremities after severe blows.
Vol. n 48
210
HEALTH AND DISEASE
Chronic Periostitis. — Tliis form of the disease most commonly
presents itself in that affection of the limbs termed sore shins and splints.
It may, of course, attack any of
the bones of the skeleton, but those
of the legs are by far the most fre-
(juently involved. See Sore Shins
and Splints.
Acute Ostitis is comparatively
of seldom occurrence in the horse.
Why this should be so it is diffi-
cult to say precisely, but the absence
of those constitutional conditions
which favour its production in
man is no doubt in some measure
a safeguard against it in our equine
patients. The fact that amputation
is but seldom resorted to in the
horse may also contribute to render
him less frequently the victim of
this disease.
It is mostly observed in the
bones of the extremities, and es-
pecially those below the knees and
hocks.
Sometimes it is localized or
confined to a particular part, or it
may involve a large tract, or even
the entire bone. The writer has
seen the whole of the os suff'raginis
or large pastern bone destroyed,
and its remains enclosed in a per-
forated shell of bony matter, formed
around it by the periosteum (figs.
.317, 318). It sometimes occurs in
the upper and lower jaw-bones.
Causes. — Acute ostitis is the
result of injury infiicted on the bone
by external violence, the most severe cases being those in which the
bone is penetrated by some sharp instrument, as when the foot bone is
punctured by a nail. The example figured was caused by the foot of
the horse being brought violently to the ground when attempting to save
Fig. 317.— Acute Ostitis
1, Sequestrum or Slough. 2, 2, Cloacae or openings
for escape of pus and dead bone. 3, 3, New bone
enclosing the sequestrum.
1, Sequestn
3 IS. — Acute Ostitis
■ Slough. 2, New bone enclosing
sequestrum.
DISEASES OF BONES
211
himself in .slipping. The disease may also occur in connection with frac-
ture nf the lioiie when the result of extreme violence.
Symptoms. — When occurring in the bones of the extremities, it is
attended with acute lameness and suffering. The parts around the
bone are much swollen, hot and tender, and considerable difficulty may
be experienced in defining the precise stage and nature of the disease.
Sooner or later an abscess forms,
followed by another and another, from
which flows a blood-stained and offen-
sive matter.
Later the bone begins to crumble
away, and the debris escapes in
granular particles with the discharge.
The tendency in these cases is to
blood-poisoning, and the formation of
abscesses in one or another or several
of the internal organs. It is seldom
that the patient recovers from such
an attack so as to be again useful.
Chronic Ostitis. — Tliis is the
form in which ostitis most frequently
presents itself in the horse. Eing-
bones, some splints, and various other
excrescences on the bones of the limbs
and other parts of the skeleton are
frequently of this nature.
At first the affected bone becomes
porous and spongy (fig. 319), as the
result of the inflammatory exudation
pressing upon the vascular canals of
the bone and promoting their absorp-
tion and enlargement. As a result of
this the bone tissue becomes changed
from a close compact structure to a loose and spongy condition,
is what is known as rarefying ostitis.
As the inflammation abates, the material thrown out of the vessels into
the structure of the bone, by which the rarefaction was produced, is itself
converted into bone.
The effect of this is to change the part from a soft spongy condition
to a state of great density and hardness (fig. 320).
Fig. 319.— Rarefying Chronic Ostitis
This
212
HEAl.TH AND DISEASE
Fig. 320.— Chronic Ostitis
A, Lower portion of Radius of horse, showing results of Chronic Ostitis. B, Section of the same,
showing hard, dense condition of the bone.
NECROSIS AND CARIES
When bone is so far damaged by disease or accident as to cause it
to die, it is said to be affected with necrosis or caries, one or the other,
according to the mode of death. If a considerable quantity of the tissue
be destroyed at one time the term "necrosis" is used, but if the bone
gradually melts away or breaks down into minute particles during a
progressive ulceration it is spoken of as " caries ".
Necrosis. — Causes. The more common causes of necrosis as it affects
hor.ses are blows and bruises directly applied to the bone; hence it occurs
that those bones or parts of bones most superficially placed, and conse-
quently most exposed to injury, are especially liable to the disease. Bones
deeper seated and enveloped in thick layers of muscle are comparatively
DISEASES OF BONES 213
seldom affected. For the above reasons necrosis is found to implicate
the front of the shin or canon bones both in the fore and hind limbs,
and also the lower jaw-bone and the ribs. The shin-bones in the act
of jumping are not unfrequently brought into forcible contact with posts
and rails, gates and stone walls, or they ai'e injured by kicks from other
horses, &c. The most common seat of the disease is the lower jaw at
the resting-point of the bit, where the resistance to runaways, pullers,
and hard-mouthed horses is specially applied. In addition to external
violence necrosis may be induced by acute inflammation of bone in any
part of the skeleton.
Symptoms. — AVhei'e an injury is inflicted on bone sufliciently severe
to destroy its vitality the immediate efl'ects are more or less swelling,
heat, and tenderness of the part, and when involving the bones of the
extremities more or less lameness. In superficial bones the swelling
is not generally considerable and may soon altogether subside, leaving
behind, however, an abiding tenderness of the part. Sooner or later the
swelling reappears, or if still present becomes considerably increased,
while the heat and soreness return with greater severity than before. As
the inflammation becomes more and more severe an abscess is formed,
which may break, and heal, and break again and again, and finally
resolve itself into a chronic running sore. During this time the dead
piece of bone is being separated from the living. If a probe be passed
into the wound the harsh grating of its point on the dead bone will be
felt. These cases are always of a protracted nature, and when neglected
extend over months.
When the lower jaw is the seat of injury the animal jibs when ridden
or driven, or turns the head towards the side on wdiicli the disease exists.
The saliva is raised into foam by champing of the jaws, and may be stained
with blood. Feeding is rendered painful, and swelling appears on the outer
part of the injured bone and extends for some distance around it. If the
finger be applied to the spot a wound in the gum will be found correspond-
ing to the injured part, through which the dead fragment is readily felt,
and if completely detached may be brought away. The odour emitted in
these cases is usually very off'ensive. Although sloughing may have com-
pletely taken place, and the dead bone have been quite detached from the
living, it may still be retained unless means are adopted for its removal.
Treatment. — Here the aim and object of treatment should be to
remove the dead bone as speedily as possible, but no attempt should
be made in this direction until nature has defined its limits and well-
nigh completed its separation from the living. If after this it is allowed
to remain it becomes a source of irritation, and the wound continues to
214 HEALTH AND DISEASE
discliarge and refuses to heal. It becomes necessary, therefore, that a
periodical examination of the diseased part should be made, in order
that the earliest opportunity may be seized to extract the offending
matter. For this purpose it may be necessary to lay the wound open.
This done the finger should be introduced, and the necrosed mass will
be found probably grown over by granulations or "proud Hesh", or at
least united by them to the body of the bone. If detachment has not
been completely effected a little force, by means of a small lever placed
under the dead fragment, may be sufficient to disconnect it.
The dead bone having been removed the wound may be freely dressed
with a strong solution of chloride of zinc, and afterwards treated with
antiseptic applications until reparation is complete.
OSTEO-POROSIS— BIG HEAD
By this term is understood a swollen, soft, and porous state of the
bones. It is a constitutional disease usually involving the entire skeleton,
but manifesting itself with much greater severity in some parts than in
others. This is especially the case with regard to the head, from which
circumstance it has received the common appellation of "big head".
Not only is this difference observed in different regions of the
skeleton, but likewise in different parts of particular bones. In the
long bones of the legs, for example, it becomes much more pronounced
at the extremities where they unite to form joints, and where, as in the
bones of the face, the osseous tissue is naturally of a loose, spongy
character (cancellated).
Osteo - porosis is essentially a chronic and slowly progressive disease
affecting all classes of hoi'ses, both male and female, and at all periods of
life, but young animals seem to be more predisposed to it than those
advanced in years.
It has not been found to exist to any considerable extent in Great
Britain, l)ut in America, India, and Africa it is of more frecpient occurrence.
Origin.— Although much has been written both in this country and on
the Continent with regard to its origin, the writer is compelled to admit
that practically nothing is known as to the causes which give rise to it.
Captain Hayes, who refers to numerous cases as coming within his experi-
ence in Africa and India, believes that " feeding on unnutritious grasses
is one of the chief causes of the malady". This statement, however,
receives no support from experience in this country, where the cases
hitherto recorded have been stabled animals receiving a liberal supply of
good food. By others it has been attributed to damp and insanitary
DISKASES OF BONES
•215
stables, and Professor Variiell saw reason to regard it in one instance
as in some way connected with a too exclusive bran diet, and deficiency of
lime in the food. It is quite clear that the precise nature and conditions
of the origin of the disease still remain to be determined.
Symptoms. — The first noticeable indications of the aflection are slight
stiti'ncss and suljsequent lameness in one or more of the limbs, with tender-
ness over the region of the joints, winch sooner or later become enlarged.
The disease may attack all the limbs
more or less severely at once, or in
Fig. 321. — Osteo-porosis
Bones of the face enlarged, thickened, and
rendered soft and spongy.
Fig. 322. — Osteo-porosis
Lower Jaw affeoted by the disease.
succession at varying intervals of one to three weeks. At the same time
the head and face attract attention by the gradual obliteration of their
sharp angles, and the steady increase in size of the head as a whole. At
this time there is no perceptible constitutional disturbance. The animals
feed and rest and keep their condition. The swelling of the joints may
to some extent subside, only, however, to return again and add to the
permanent enlargement.
As the disease progresses the bones continue to increase in size and
216
HEALTH AND DISEASE
at the same time to become spongy and soft, so much so in some parts as to
yield to the pressure of the fingers from without. When in this condition
the animal has difficulty in rising, and the ligaments of the joints soon fail
to resist the weight imposed upon them, and break from their connections
with the soft and yielding bones.
In the early stages of the disorder the turning
movements are noticeably stiff, and pressure, if
applied to the spine, causes pain and shrinking.
The head continues to increase in size and
to present an unsightly appearance. The lower
jaw becomes thick and rounded, and as the bones
of the face enlarge, the teeth become loose in their
sockets and more or less displaced. At this time
mastication is imperfectly performed, nutrition is
impaired, and symptoms of constitutional derange-
ment appear and continue to become more and
more severe to the end. In fatal cases the dura-
tion of the disease extends from two to eight
months or longer.
Treatment. — Osteo- porosis is usually fiital.
It is w'orthy of note, however, that a case given
up to the writer was returned cured after under-
going three courses of iodide of potassium and
nux vomica at intervals of three or four weeks.
Post-mortem Examination. — After death
no special lesions are found to exist in the ab-
dominal or thoracic viscera. Many or all the
bones of the skeleton are enlarged (fig. 323),
spongy in texture, and soft in consistence.
The capsular membranes of the joints of the
extremities are much thickened, and the articular
ends of the bones are denuded of their cartilage, and present a worm-eaten
appearance.
SPAVIN
Fig. 323.— Osteo-porosis
Metacarpals of horse affected by
the disease.
The term spavin is applied to two distinct forms of enlargement of
the hock, one being a bony excrescence (bone-spavin), and the other a
distension of the joint capsule with fluid (bog-spavin). Spavin is also
spoken of as occult when the action declares the hock to be the seat of
mischief in the absence of any outward physical change. Bog-spavin is
dealt with in the section on Di-seases of Joints.
DISEASES OF BONES
217
BONE-SPAVIN
A bony outgrowth on the inner and lower part of the hock is termed
a bone-spavin (fig. 324).
The enhirgement usually appears towards the front, but it may occupy
a backward position, or extend from front to back. Spavins vary in size
as well as in position. Sometimes they are small and with difficulty
identified, at others they
reach a considerable size.
The same variation ap-
pears in respect to form.
They may present them-
selves as rounded, or more
or less pointed and ir-
regular swellings, or as a
projecting ridge, extend-
ing across the hock from
back to front. Usually
they appear on one hock
only, but frec|uently both
are affected either simul-
taneously or consecu-
tively. Hocks of every
variety of size and confor-
mation, from the biggest
and best to the smallest
and weakest, are liable
to become affected, but it goes without saying that the disease is most
frequently found in the latter.
Causes. — The predisposition to spavin is uncjuestionably hereditary.
Horses with straight quarters and upright pasterns seem especially liable
to it. SjDrain and concussion to the joint, acting se^iarately or together,
are the exciting causes, and there is reason to think that these accidents
are more e.specially likely to occur when animals are forced in their woi'k
under circumstances of fatigue and want of condition and development.
The outward enlargement is an evidence of the inflammation going on in
the articular surfaces of the bones.
The great variation found to exist in the conformation of the hocks
of different horses, and indeed sometimes in the two hocks of the same
horse, has ever been a stumbling-block to the veterinarian in the diagnosis
Fig. 324. — Bone-Spavin.
218 HEALTH AND DISEASE
of spavin, and a mine of wealth to lawyers and learned counsel. Coarse-
ness or lumpiness is a recognized condition of normal development in the
hocks of some horses, and to distinguish between the natural irregularities-
of coarseness and those resulting from disease is always difficult and some-
times impossible. If these facts were more generally recognized and
allowed by veterinary practitioners, much of the litigation which now
engages our law-courts would be avoided, and the veterinary profession
would be saved from those strange exhibitions of discrepancy which tend
to weaken public confidence in their opinion and advice, if they do not
engender distrust.
Symptoms. — The immediate effect of the jar or sprain giving rise to
spavin is to produce lameness, sometimes slight, sometimes severe. This
may or may not pass away, to return again when the enlargement of the
hock appears and encroaches upon the connecting ligaments of the joint.
The action of the spavined horse is marked by stiffness of the affected
limb. In movement the hock is imperfectly flexed and the leg has the
appearance of being carried.
Compared with the opposite limb the stride is short and limping, and
the quarter is noticed to drop when the foot is brought to the ground. If
continued in work the toe strikes the ground and in time becomes worn.
Spavin lameness is most severe after a rest, and particularly noticeable
when the horse first leaves the stable, but it improves as he goes on. Heat
may or may not be detectable in the joint, and as the patient stands the
limb is rested on the toe or front part of the foot.
Treatment.- — On the first appearance of the disease the animal should
cease to work and receive a dose of physic. At the same time fomentations-
or hot bandages should be applied to the hock until the existing inflam-
matory action is subdued.
Cold-water irrigation for a few days should follow, after which a
repetition of blisters at intervals of a fortnight or three weeks may suffice
to effect a cure. Should, however, the lameness still continue, choice must
be made between the operations of firing and setoning, in either of which
case a long rest at grass will be desirable.
Horses with spavins are frequently restored to service and continue to
work without interruption for the rest of their lives. Others, however, are
permanently crippled. The latter result is most fiequent when the spavin
occupies a forward position.
DISEASES OF BONES 219
METACARPAL PERIOSTITIS— SORE SHINS
This is an ailmeut of common occiiiTence in race-horses, but com-
paratively seldom seen in other varieties. The greater liability of the
one over the others is associated with early training, while the bones are
in active growth, and by their imperfect development specially susceptible
to injury and disease.
The term " sore shins" has been applied to it on account of the extreme
tenderness and pain found to exist in that part of the leg between the
knee and the' fetlock joint. The mischief, however, does not always
stop here, but may also involve the large, and sometimes the small pastern
bones, developing there the same soreness of the surface, and in some
instances provoking an outgrowth of bony matter in the form of ring-bone.
The fore-liml)s, for reasons presently to be stated, are more particularly
the seat of sore shins, although the hind ones are not wholly exempt.
Pathologically considered, " sore shins" at the outset consists in an
inflamed condition of the periosteum, or covering membrane of the bone;
but unless soon relieved from the operation of the cause, the shin-bone
itself soon shares in the disease. At this time the pain and lameness
become aggravated, the periosteum is much thickened, and a rough bony
growth appears on the surface beneath it.
Causes. — Youth, and want of development and power of resistance
in the bone is, as we have observed, the predisposing element to sore
shins, and this is materially intensified when, as sometimes occurs, there
is a hereditary predisposition to the morbid growth of bone.
The e.xciting cause is to be found in concussion, arising from the
forcible impact of the feet with the hard ground in the act of galloping,
when the "jar" is transmitted along the shaft of the bones, whose cover-
ing becomes irritated and inflamed. It will, therefore, be seen that in
proportion as the ground is hard, and the weight carried by these juveniles
is considerable, so will be the liability to injury. It is for this reason
that the disorder appears during seasons of drought, when the ground is
dry and resisting instead of being soft and spongy.
Symptoms. — The lad who habitually rides a horse in his daily w^ork
is often the first to detect the oncoming of this disease. He recognizes
a growing sense of discomfort arising out of a change in the animal's
action and spring. Then it soon becomes obvious that he is going short
in his stride, and some difiiculty is experienced in setting him going and
keeping up the pace. Examination of the legs at this time reveals more
or less heat and soreness along the course of the canons, and especially
220 HEALTH AND DISEASE
ill front. Later, the legs become somewhat enlarged from the knee
downward, and present a rounded appearance. The fetlocks are "filled",
and the swollen parts " pit ", when pressed upon, like soft dough. Lame-
ness now appears in all the paces, and the animal moves with a stiff, sore
gait, which becomes aggravated from day to day when work is continued.
Treatment. — In slight cases it may be sufficient to ease a horse in
his work, give him a mild dose of physic, transfer him for a time from
the hard turf to the tan, and irrigate the legs two or three times daily
with cold water. If, however, the patient has no pressing engagement
his work should be reduced to walking, with as little weight on his back
as possible. In more severe attacks it is better to throw the horse out
of work altogether, and apply hot bandages to the legs during a course
of physic.
When the infiammatory action has been subdued, then a mild blister
may be applied to the shins from the knee downwards, and repeated in
ten days or a fortnight, and again, after a similar period, if circumstances
appear to call for it. Iodide of potassium in 1 or 2 dram doses may
be given in the food morning and evening for a week, but not until the
physic has ceased to act. The medicine should then be discontinued for
two or three days, and renewed again for another week, and the same
course may be repeated if necessary. In all cases where horses evince
the slightest signs of sore shins the weight should be promjjtly reduced,
the pace let down to walking, and, as far as practicable, the work should
be done on tan, in cold wet bandages. Many a severe attack may be
warded off and horses kept in work by the early adoption of proper
measures.
In some instances, as the result of neglect, these cases assume a chronic
character. The shins become considerably enlarged and covered with a
rough bony growth, while the periosteum is much thickened, and continues
to lay down bone on the shaft of the canons. Here firing with the pointed
iron may prove serviceable after a run of two or three weeks at grass in
a damp meadow.
After an attack of this disease horses should not resume work too
early, and care should be taken that the ground is soft, and the pace
for a time slow. Cold wet bandages should be worn for a week or two
after work has been commenced, and occasional irrigation with cold water
will assist in imparting tone to the legs.
FRACTURES
221
15. FRACTURES
When a bone is broken into two or more parts it is said to be fractured.
Fractures assume a variety of forms, each of which presents some feature
requiring special consideration, either in regard to diagnosis or treatment.
They may be either pai-tial or com-
plete; simple or compound; commin-
uted or impacted.
When a bone is broken, but the
breach only extends through a portion
of its substance, the fracture is said
to be partial. If, however, the bone
is divided into two separate parts, it
is a complete fracture.
A sim,ple fracture is one in whicli
the broken bone is not connected with
an external wound; where such a
wound exists and communicates with
it the fracture becomes a compound
one (fig. 329).
If instead of the bone being broken
into two parts it is divided into three
or more — smashed — a corwrninuted
fracture results (fig. 325).
It sometimes happens that when
a bone is broken the broken end of
one piece is driven into that of the
other. Such a fracture is said to be
impacted (fig. 328).
Bones break in various directions;
hence fractures are spoken of as trans-
verse, longitudinal, or ohliipie (fig.
326).
A transverse fracture follows a line at a right angle with the shaft
of the bone. This is a comparatively rare form of breakage, but is some-
times seen in the scapula, the ilium, the olecranon or elbow, and the
calcaneus, or point of the hock.
Great importance attaches to the relations which the two or more
broken pieces maintain towards each other after the fracture has taken
place. In some instances they continue to remain in their natural position
Fig. 32.").— Fractures
1, Simple. 2, Comminuted.
222
HEALTH AND DISEASE
throughout the healing process, a couditiou favourable of course to re-
paration, and very much to be desired.
In others, however, the fracture is accompanied or followed by more
or less displacement of the divided parts, and all the bad consequences
which attach to it.
This separation of the broken pieces may result from the same cause,
and at the same time, as the fracture, or it may occur some time afterwards
by the weight of the body forcing the parts asunder; or by movement, or
as a result of the contraction of muscles which are attached to them.
The liability to displace-
ment is much greater in
some bones than in others.
In the canon it is almost
invariable, while in the pas-
tern it is comparatively rare.
This difference will be best
understood by reference to
fig. 327, where it will be seen
that nearly the whole of the
front and back of the pastern
bones, and to a less extent
the sides, have attached to
them strong ligaments and
tendons, so that when either
of them is broken the parts
are held firmly in their po-
sition, and unless the force
acting upon them is very considerable, displacement is prevented.
Displacement of the broken fragments may be immediate, i.e. may occur
at the time of the accident, or it may be deferred for a period varying
between a few hours and a few days, and during the interval between
the fracture and the separation of the broken pieces many animals have
been known to continue to perform ordinary work without showing in-
convenience.
Causes. — Two classes of causes are recognized as conducing to the
fracture of bones, viz., predispodng and excitmg.
Predisposing Causes. — For various reasons some bones are more
liable to fracture than others, and this represents their predisposition.
In looking over the body it is not difficult to see that certain bones
are much more exposed to collision and to external violence by virtue
of their position than others Of these the points of the hauncli proiect-
Fig, 326. — Fractures
1, Transverse. 2, Obli(iue. 3, Longitudinal.
FRACTURES
223
. lou^
^
ing from the quarters afford a striking example. They disphiy a special
liability to be brought into forcible contact with door-posts wliile horses are
passing into or out of
the stable, or through w
narrow passages, and ^
to receive the first
impact of the ground
where, as sometimes ^ i > i
occurs, their hind-legs c ' '^
slip from under them,
and they fall help-
lessly on their side.
The canons or
metacarpal bones, un-
protected by muscles,
are exposed to the full
force of any external
violence that may
be applied to them, E
besides which their
movements are sharp
and forcil)le, and
meet colliding objects q
with great resistance.
The large pastern
also, by virtue of its
position, is specially
liable to fracture, and
in a less degree also
the forearm and lower
, 1 • 1 1. Front View.
thigh.
' . . A, Extensor Metacarpi Obliquus.
Age nnpartS a ^^ Extensor Metacarpi Magnus.
State of brittleness to ^'^ ^"""'^'" Ljament.
D, Extensor Pedis.
bones which is not k, Extensor Suffraginis.
/. T . . , G, Outer Branch of Suspensory
found m the young Ligament.
and the adult; hence , ,
The hgaments of the pastern
old animals are more are more fully shown in fig. 356,
prone to fracture than ^^^ "'"
younger ones.
In early life, before the epiphyses or prominences which are connected
with the shafts of bones have become firmly united by ossific union, they
Fig. 327
ipal Tendons and Ligaments of the
Fore Limb
2. Outer Side View,
A, Extensor Metacarpi Obliquus.
B, Extensor Metacarpi Magnus.
C, Annular Ligament.
D, Extensor Pedis.
K, Exten.sor Suffr.aginis.
F, Outer Small Met-icarpal or Splint Bone.
G, Outer Branch of the Suspensory Liga-
ment.
H, Flexor Pedis Perforatus.
I, Subcarpal or Check Ligament.
J, Flexor Pedis Perforans.
K, Suspensory Ligament.
224 HEALTH AND DISEASE
are liable to be torn away by muscular contraction, or otherwise forcibly
displaced.
Structural alterations, the result of disease, by weakening the bone
tissue, lessen its power of resistance to ordinary forces, and thereby con-
duce to fracture.
The navicular bone, after a period of ulceration, breaks beneath the
weight thrown upon it in action.
The imperfectly - developed bones of the rickety foal, after bending
under the strain imposed upon them, may sooner or later present a partial
or complete fracture.
Various other morbid changes, such as cancer, osteo-porosis, melanosis,
&c., render bones specially amenable in this direction to causes which they
would otherwise resist.
Season of the year, and the nature of the surface over which horses
travel, tend to increase the liability or predispose to fracture.
In winter, when the roads are covered with ice, and in towns where
horses have to travel over wood pavement or other smooth surfaces made
slippery with water, legs, hips, and ribs are in consequence frequently
broken.
The exciting causes of fracture are: 1, external violence, such as kicks,
collisions, falls, blows, twists, &c. ; and 2, muscular contraction.
Violence may operate either directly or indirectly, i.e. it may break
the bone to which it is immediately applied, or some other at a distance
from it. It sometimes occurs that a horse falling upon the poll, and
striking the occipital bone, breaks the sphenoid bone at the base of the
brain. Horses fracture the os suffraginis, or long pastern, or even the
canon-bone by pitching on the toe while endeavouring to save themselves
from a fall, or in jumping or galloping.
Examples of fracture as the effect of muscular contraction are seen
in those common accidents which occur to horses while being cast, or in
the course of a surgical operation. The violent struggles to free them-
selves from restraint too commonly give rise to a broken back, or a broken
thigh, or the breaking away of one of the epiphyses or bony projections
from the sliaft of a bone.
Symptoms. — To determine the presence of a fracture in the hor.se is
sometimes a very difficult, and may be an impossible task. The parts to
be dealt with are large, heavy, and do not lend themselves to that thorough
and searching examination which is so capable of being made in the smaller
animals. Besides, the excitable and refractory character of the horse
greatly interferes with that full control .so necessary to a successful
diagnosis. Of course we can brine to our aid the restraining influence of
FRACTURES 225
chlorofoiTii, but even this is not an unmixed good. Wiietlier a horse
be cast before its administration, or be allowed to fall while under its
influence, there is in both cases the danger of displacing the broken bones
and converting a simple into a compound fracture, or causing a trouble-
some displacement of the broken parts.
Before any such step is taken it is desirable to exhaust all other means
at our disposal.
The symptoms exhibited as the result of fracture will vary according to
the situation and the purpose which the bone serves.
Fracture of the long bones of the extremities is not generally difficult
to diagnose. It may be at the time of its occurrence someone heard a
" snap ". If displacement result, this would be followed by sudden and
acute lameness and an inability to support weight on the broken limb.
The parts below the fracture would hang loosely, the toe would sway
involuntarily from side to .side, or might be directed backwards. Swelling
on the region of the fracture and parts below it soon appears, attended
with local inflammation and pain.
Of the many symptoms attending a fracture crepitus is the one which
should be specially sought for. It is the sensation or sound which results
from the rubbing of one broken piece against the other. In comminuted
fractures, where the bone is divided into several pieces, it is soon made
apparent; but in some cases of simple fracture it is difficult to develop, and
a good deal of care, guided by experience, may be needed to bring it about,
and especially in young and fi-actious animals.
AVhen it does not become at once apparent, the upper segment of the
broken bone should be firmly held by an assistant, and the lower one
gently rotated, and moved from side to side and from front to back by
another, while the operator is engaged in manipulating the seat of fracture.
By this method the broken ends may be made to rub against each other
and yield the rubbing sensation or sound which is the evidence required.
In some situations, as where a rib or the pelvis is broken, it is im-
po.ssible to carry out this method, for the reason that the parts are so
situated that they do not lend themselves to the kind of manipulation
prescribed.
In fracture of the ribs the part will show soreness to pressure, and some
irregularity may be felt in the line of the rib when accessible. By gently
pressing the rib inward, or making the animal cough while the fingers rest
firmly upon the part, crepitus may be felt.
Fracture of the front ribs is usually attended with more or less lameness
of the front limb on the side of the breakage. Fracture of the pelvis may
sometimes be felt by passing the hand up the rectum, or crepitus may be
226
HEALTH AND DISEASE
heard by applying the ear over the surface of the quarter while the leg is
moved about by an assistant.
The difficulty in question is particularly emphasized in fracture of the
neck of the femur, owing to our inability to restrict the movement of the
detached head and bring the body of the bone into contact with its broken
surface.
In fracture of the thigh or the pelvis or front ribs, where great masses
of muscle intervene between the ear and the fracture,
crepitus may not be recognized unless movement of
the broken parts one upon the other is of consider-
able extent.
For various reasons this most important and re-
liable symptom cannot always be made to reveal it-
self The broken pieces may be firmly held together
so as to preclude any movement one ujjon the other
such as would yield a rubbing sound. This is fre-
quently the case in fracture of the long pastern and
some other bones.
In impacted fractures (fig. 328), where one piece
of bone is driven into the other, and in incomplete
fractures where there is no movement of the imper-
fectly-divided bone, and in those instances already
referred to where the broken pieces are firmly held
together by strong ligaments, no crepitus or rubbing
is likely to be heard, and considerable difficulty is
experienced in bringing it about where a piece of torn
muscle or fascia has insinuated itself between the
broken ends of the bone, or where one piece has been
drawn some distance away from the other by the force
of muscular contraction, as where the point of the
elbow is raised from the body of the bone by the
great extensor of the arm, or a piece of the patella
is displaced upwards by the straight muscle of the thigh.
A sound simulating crepitus is sometimes heard where the tissues about
the seat of injury become infiltrated with air, or where infiamed tendons
rub against their investing sheaths.
This false crej^itus, however, does not emit that harsh grating sound
which is so characteristic of the rubbina; tooether of the rouoh surfaces of
a broken bone.
Care must be taken not to mistake a dislocation for a fracture. Where
the latter takes place in the middle of a long bone there is not much danger
Fig. 328. — Impacted Frac-
ture of Femur
FKACTL'KES
227
of such an error being committed, but when fractures occur near joints,
the case is altered. Here it should be borne in mind that where dislocation
exists the displaced bones are more or less fixed, and the movements of the
joints are very much restricted or altogether prevented; whereas in fracture
the broken bone exhibits excessive mobility, allowing the limb to be moved
in various directions to an abnormal extent.
Treatment. — The first consideration which will arise on the occurrence
of a fracture in relation to treatment will be the value of the animal, the
prospects of a speedy recovery, and to what extent, if at all, his future
usefulness will be compromised.
In this connection it will be safe to advise, no less from a sense of
humanity than from consideration' of economy,
that when the animal is of little value he should
be slaughtered at once. If, however, it is other-
wise decided, the sooner measures of treatment are
adopted the better. Owing to the restlessness and
unreasoning action of
the patient, delay in
this respect is fraught
with the greatest dan-
ger. Many a simple
fracture, which, if ad-
justed at once, would
have speedily reunited,
has been converted
into an incurable compound fracture by the unrestrained use which the
animal has been allowed to make of the injured limb after the occurrence
of the accident. A horse's highest intelligence fails to realize the advan-
tage of that perfect quiet upon which the surgeon sets so much store, in
guarding against an extension of the injury and in bringing about its
reparation.
The moment a fracture is suspected every means should be adopted at
once to restrain the animal's movements, and to provide as far as possible
against any undue use or disturbance of the injured limb.
If away from home, a splint should be extemporized, and the horse got
into the stable nearest to hand and allowed to remain there while under
treatment. If an ambulance cart can be procured without much delay, it
would be desirable to convey him at once wherever he may require to go;
l)ut it should be kept in mind that the success of treatment is greatly
facilitated by the speedy readjustment of the broken bone.
The prospect of treatment — as to whether it is likely to be successful or
Fig. 329. — An Example of Compound Fracture
228 HEALTH AND DISEASE
Otherwise — will depend upon a variety of circumstances, all of which should
be well considered before a decision is arrived at.
The position of the bone and the nature of the fracture will claim atten-
tion first. A simple fracture without displacement is not a serious matter,
unless it occurs in the immediate neighbourhood of a joint, to which the
reparative inflammation may extend and occasion some permanent inter-
ference with its movements.
Compound and comminuted fractures are always more serious than
simple ones, and in all the danger is greatly aggravated where the tissues
in the region of the breakage are much bruised or torn, especially where
large nerves and vessels are divided by the broken ends of the bone. All
these are matters which impart to a fracture in such an uncontrollable
subject as the horse a dangerous and discouraging outlook.
A young horse, with a sound constitution and a quiet generous tem-
perament, is much more amenable to treatment than an old, declining,
irritable subject.
In the treatment of fracture three important requirements must
be fulfilled. The broken fragments must first be brought together and
placed in their normal position; they then require to be retained there
until they have again become firmly united by the natural process of
repair.
The third requirement involves the care against complications, and
prompt measures of treatment when they arise.
If there is no displacement of the broken pieces, but by the history and
general symptoms of the case a fracture is denoted, the second and third
indications only will require to be met.
It is no rare occurrence for horses to break the bones of their legs and
to continue to work for hours, days, or weeks without any displacement
occurring. A case came to the notice of the writer where a horse in the
course of a day's hunting suffered a comminuted fracture of the canons of
both hind-limbs. He was noticed to be lame after striking them against a
stone wall, and was sent home in consequence. After being fed and dressed
and " set fair " he lay down, and when the groom returned to him and
caused him to rise, the broken fragments parted, and not till then was the
existence of a fracture made known.
The horse was destroyed, and a post-mortem examination showed both
bones to be broken into several pieces.
The means by which fractures are reduced or " set " will vary with the
seat and nature of the displacement. Some are altogether beyond rectifi-
cation. This is especially the case in the bones of the spine, and in some
bones to which large muscles are attached. By the latter the broken parts
FRACTURES
229
arc prevontcd from being brought together, or they are pulled away from
each other by forcible contraction when this has been effected.
This is very much the case in fracture of the thigh and the humerus.
It is more especially in bones below these, and others about the fece,
that success may be hoped for.
In the absence of a properly-constructed operating-table, by which a
horse can be taken otf the ground while in a standing posture and again
Fig. 330. —Fracture of First Rib of Horse (Inner Aspect)
1, Showing Fracture. 2, Repair of Fracture. 3, The same in section. A, Fracture. B, E, Callus.
replaced directly on his feet, the reduction of a fracture in so large and
uncontrollable an animal as the horse is in the last degree difficult.
AVithout some restraining influence the pain excited by the manipula-
tion of the parts is such as to provoke the most violent opposition. To
prevent this the animal must either be cast and placed under restraint, or
his resistance mu.st be overcome by the administration of a powerful seda-
tive, or of chloroform or some other ansesthetic. Whichever course is
adopted he will require to be brought to the ground, and after the fi-acture
has been adjusted, to rise again.
In the one act the damage may be seriously aggravated, and in the
other the work of setting may be completely undone.
In dealing with fracture of the pasterns, canons, and other long bones.
230 HEALTH AND DISEASE
a powerful oj^iate or a subcutaneous injectiou of morphia may in some cases
so far overcome the irritability of the animal as to allow of readjustment
of the broken parts and the application of retaining appliances. Where
this fails the horse should be lifted on to a proper operating - table
and placed under the influence of chloroform. By this means a more
careful examination of the divided bone may be made, and a correct idea
of the direction of the displacement and the extent of damage to neigh-
bouring structures is obtained. In this connection it may be desirable
to caution the operator against unnecessary manipulation, but when once
he has decided what is required to be done, he must not hesitate to apply
the necessary force to do it. How that force can best be obtained will be
a question for solution when all the ftxcts of the case are known. Hands
and apparatus are the means to be applied, and whether one or both are
brought into requisition, the direction in which they will be called upon to
act will be the same. Eopes and pulleys are in some cases indispensalile.
In proceeding to reduce the fracture of a long bone, force will require
to be exercised to a greater or less extent in two directions, extension and
counter-extension, and for this purpose one rope will need to be applied
below the fracture and the other above it. On each steady and continuous
traction is to be made by assistants, while the ojierator regulates the
position of the limb according to his requirements, and directs the
broken pieces into their normal position. Those to whom traction is con-
fided should be reminded that sudden and spasmodic or jerky action may
add to the difficulties of the operator by exciting the muscles to violent
contraction, or lacerating their fibres and with them other correlated struc-
tures. The pull in both directions should be as nearly as possible equal in
force and steadily maintained throughout in a line with the natural axis of
the limb. Those parts of the limb to which the rope or webbing is applied
.should be well padded with tow.
Where difficulty is experienced in bringing the displaced parts into
their proper position, the lower segment of the limb should be moved in
various directions by an assistant while the operator manipulates the frac-
ture. Slight rotation, first in one direction, then in another, and a little
manoeuvring of this kind will sometimes direct the fragments into their
normal position. If, however, exact coaptation cannot be effected, the best
that can be done must suffice.
We have already pointed out the desirability of early " setting " as
favourable to speedy and complete i-eparation. Where, however, delay has
been allowed to occur, some consideration must be given to the state of the
parts before readjustment is undertaken. Round and about the broken
bone the tissues will be swollen, inflamed, and painful, and more or less
FRACTURES
231
hard and rigid, and the broken pieces adherent to the neighbouring
muscles. These are ('onditions which seriously interfere with replacement,
and may altogether prevent it. In such circumstances no attempt should
be made at reduction until the inflammation has been subdued by appro-
priate means, and some discrimination will be required as to the desirability
of undertaking such a task in the horse at all.
When the parts have been returned to their proper position, or as
nearly so as can be ett'ected, the
next requirement to be fulfilled is
to secure them in such a manner
as to prevent their displacement
and favour the process of healing.
In man, whose intelligence is
always at the service of the sur-
geon, this is not a difficult matter,
but it is otherwise with the horse.
The one may be put to bed,
and all weight having been re-
moved from the broken limb, it
may be placed in the position
most favourable to reparation,
and retained there largely by the
will of the patient.
No such sense of self-govern-
ment is available to the veterin-
ary surgeon. His patient must
for the most part support his own
weight, and cannot be made to
obey the behests of his attendant.
His care of the limb is just so
much as is dictated by fear of the
pain which its movement excites, and the desire to use it, ever present, is
always being indulged more or less, with the result that reparation is
delayed, frequently imperfect, and not seldom altogether prevented. It
is this want of guiding intelligence, this excitability and restlessness, that
renders bone-" setting " in the horse so uncertain and unsatisfactory.
Among the various appliances employed for the purpose of retention,
splints and bandages are the main and the most reliable. In fracture of
the extremities the patient should always be placed in slings, and the
opportunity afforded him to relieve the injured part and rest during the
period of restraint.
Fig. 331. — Bandaging a Fore-leg
Showing the method of applying the bandage (
of cotton-wool.
. pad
232
HEALTH AM) DISKASE
Splints have for their object the restraining of movement !)}• fixing the
limb in such a way that the joints cannot be flexed. Anything which will
accomplish this without injuring the part to Avhich it is applied may be
employed for the purpose. Narrow strips of wood, thin sheet-iron or tin,
leather, gutta percha, strong cardboard, pitch or other adhesive plasters,
&c. To obtain the greatest possi])le l)enefit from a splint it should be
sufficiently long to extend over the joint above and the joint below the
fracture. Of course this is not always practicable, but it should always be
present to the mind of the
operator to adopt any means
in his power to restrict as
much as possible the action
of the joints of the aftected
limb.
^^ ^^ Movement of the fractured
j ^^fc.' "*^ iH^H bone is best controlled by Ijan-
dages soaked in some material
which will solidify and form
an unyielding splice over the
seat of the broken fragments.
These hardening substances
are variously compounded.
Nothing, perhaps, is better
than starch or flour mixed to
the consistence of treacle with
the white of egg. Dextrine,
'?S burnt alum, and alcohol is
"^ recommended by some; and
plaster of Paris, with or with-
°' out flour, and reduced to tlie
consistence of treacle with
water, is generally regarded as an excellent jjreparation.
These appliances will require to be supplemented with some soft com-
pressible substance, by which the irregularities of the limb may be filled
in and the pressure of the bandages equalized over the whole circumference
of the leg. Where this precaution is neglected there is danger of undue
compression of the more jjrominent parts, resulting in sloughing of the skin
and the production of troublesome sores with their attendant evils.
After " setting " has been completed, the limb should be kept under
close ol)servation for several days. It will sometimes be found to swell
in conse(|U(Micc of injury done to the soft tissues at the time of the fracture,
Fig. 332.— Bandaging a Fore-leg
Showing the bandage completed and tied,
bandage with tapes.
FRACTURES 233
or from excessive pressure applied to a part or the whole in the adjust-
ment of splints and bandages. In these circumstances relief must be
given to the strangulated limb either by cutting the bandages or otherwise
removing the pressure. If it is allowed to continue, more or less extensive
sloughing will result, and a complication will be added to an already serious
condition.
Compound Fracture. — Whether the fracture be simple or compound,
the method employed for the reposition of the broken fragments will be the
same; but the presence of a wound, and maybe also the protrusion of a
portion of the broken bone through the orifice, will give new and special
features to the case which will rec^uire to be taken into account.
Where a fragment of bone protrudes through the skin, a very material
difficulty is added to the operation of reducing the fracture, and serious
injury may have been infiicted on muscles, nerves, and vessels in its course
outward.
The protruding portion, which is usually the one uppermost, will
require to be withdrawn into its proper position, and this will call for
much force, great extension and counter-extension, and dexterous manipu-
lation of the limb. If the projecting bone is considerable, its re^iositiou
by this means may fail, and the operator will be called upon to decide
between two courses, viz., enlarging the opening, or sawing oft" a portion
of the exposed bone. If the former is decided upon, the enlargement
must be made in the direction of the axis of the bone, guarding as much
as pos.sible against the division of neighbouring vessels and nerves.
It may be that, notwithstanding this, complete return of the bone will
be found impossible, in which case the protruding portion, or some part of
it, must be removed by the saw^ In carrying out this latter operation care
must be taken to preserve the periosteum as far as pos.sible.
^\Tiere the fracture is a comminuted one, some splinters of bone may be
found to be completely torn away from the shaft and lying loose in the
tissues of the part. These must be removed, and at the same time any
shreds of broken fascia that may be met with. In the after treatment of
the wound the antiseptic method must be strictly carried out. The hair
for three or four inches round it .should be removed. The wound must be
freed from clotted blood by means of a sponge soaked in a five-per-cent
solution of carbolic acid, and freely irrigated with the .same solution.
A good pad of antiseptic gauze soaked in a three-per-cent carbolic
solution should be applied over the wound and parts around, and over this
a further succession of layers of dry antiseptic gauze, the whole being
surrounded by a covering of thin mackintosh or some other impermeable
material.
234 HEALTH AND DISEASE
The wound will require to be dressed again some time in the course
of twenty-four hours, according to the amount of exudation and satura-
tion of the gauze. Another dressing will be necessary in forty-eight
hours, after which the carbolic solution used should be reduced in strength
to 1 in 40. Subsequent dressing must be made according to the state
of the wound.
It will be understood that in the setting of the bone in compound
fracture the wound must be left accessible for the purpose of dressing.
PARTICULAE FRACTURES
FRACTURE OF THE BONES OF THE SKULL
Fracture in this region is comparatively rare, and serious in proportion
as the bone is depressed and the brain subjected to compression and trau-
matic injury.
Those bones forming the front of the cranium (the parietal) are most
frequently broken, but fracture of those at the base of the cavity {occipital
and sphenoid) is most uniformly fatal in its results.
The causes which produce the former are mainly concussion, especially
when the front of the head is brought into forcible contact with sharp
objects. The latter is invariably the result of striking the poll against
hard ground, or a wall, or other such resisting sui'ftice, when the horse
in rearing loses his balance and falls backwards.
In these cases unconsciousness and paralysis immediately follow the
accident, and death results from concussion and haemorrhage into and under
the base of the brain.
The writer once saw in the practice of the late ]\Ir. Gowing the base
of the cranium of a horse, which had at some time been fractured, but
recovered sufficiently to allow of the animal resuming work, and to
be afterwards sold without any evidence of the injury being detected.
He was, however, tlie subject of repeated attacks of brain disturbance,
which ultimately led to his destruction, and post-mortem examination of
the head revealed decided indications of an old fracture involving the
two bones referred to above — sphenoid and occipital.
Fracture of the parietal bone occurs with or without depression, and
it is frequently difficult in presence of swelling to determine to what
extent, if at all, the bone has been driven inwards. If, however, con-
sciousness remains undisturbed, and there is no defect in locomotion, it
may be inferred for the present that the brain is but little interfered
with. But it should not be too hastily concluded that no cercl)ral
PAKTICULAU FKACTUKES 235
disturbance will supervene later on. For several days after such an
accident the liability to brain trouble will continue.
Where the bone is simply split without depression, a dose of physic,
and cold cloths applied to the part, with perfect quiet, are all that is
required.
If a wound exists, it should be thoroughly cleansed and kept aseptic by
repeated dressing on antiseptic lines.
Depressed bone, if provoking brain disturbance, must be levered up,
but where no such disturbance exists it should be left alone, and the course
FRACTURE OF THE VERTEBRAE
Fracture of the vertebral column is an accident which is now and again
brought to the notice of most veterinarians in the course of their jjractice,
but it is by no means an event of common occurrence in this countrv.
Moller, a German authority, avers that he has "frequently seen riding-
horses, in violently bucking, or falling over backward, or in arching the
neck excessively, 'fracture a cervical vertebra". Such an experience of
one division of the vertebral column, added to that of the others, would
seem to warrant the statement that " it is not uncommon in horses"; but
the writer is of opinion that MoUer's experience is unique and exceptional,
and cannot be taken to represent that of the general practitioner.
Fracture of the cervical vertebrse, or neck-bones, is of less frequent
occurrence than fracture of the bones of the back and loins. It is seen
most frequently in steeple-chase horses and hunters which, having missed
their foothold in jumping, or after failing to clear a strong fence, pitch on
the face, and bring all the force of impact and weight to bear against the
incurved neck. In one case the writer found it to result from the
struggles of a horse whose head became fixed between the wall of his
stall and the post which supported the manger. It may, no doultt,
sometimes arise from a backward fall on the jioU.
Fracture of a vertebra may involve the body, or the arch of the
bone, or both, or one or more of its processes may be chipped off". When
the former are broken through, displacement invariably results, and the
spinal cord receives a fatal pressure — fatal, because breathing is arrested in
consequence of paralysis of the diaphragm, which receives its nervous supply
from the cervical spinal cord, which now fails to transmit it.
Symptoms. — Fracture of the vertebrae in the middle and lower part of
the neck is speedily fatal, and in any position the same result sooner or
later follows.
236 HEALTH AND DISEASE
FRACTURE OF THE DORSAL AND LUMBAR VERTEBRAE
It is here, in the back or loins, that fracture of the vertebrae most
frec[uently occurs. In this as in other fractures okl animals are much more
liable to the mishap than younger ones, owing to their bones containing
a larger amount of earthy matter, which adds materially to their brittleness.
When fracture occurs in these divisions of the spine it usually involves
one or both of the last two dorsal vertebrae, and the first or first and second
bone of the loins.
Various causes conduce to fracture here. Violent muscular contraction
at the time of being cast for a surgical operation, or during the course of its
performance, is one of the most common.
Some Continental veterinarians affirm that the accident happens in
the fall, while others regard it as occurring during the struggles which
follow. We are satisfied, however, that it occurs at both periods, but we
are unable to say to which of these causes it is most frequently due.
Fracture of the dorsal and lumbar vertebrae has resulted from violent
straining while being cast in the stable with the legs entangled in the tie-
rope, and from a heavy load falling on the spine of old horses when the
hind-legs suddenly slip from under them. To hunters and chasers it
sometimes occurs as the result of jumping short and alighting with the
hind-legs in a deep drain, or in the subsecpient struggle to reach the
bank.
Fracture of the vertebrae in the region of the withers or the loins may
result from falling over backwards, and it has been said to have occurred in
kicking, and also while galloping and in starting heavy loads.
Symptoms. — Pressure on the spinal cord from displacement of the
broken fragments usually occasions paraplegia or paralysis of the hind-
c[uarters. This result may come about at once, or it may be deferred for
some hours or, rarely, days. Where pressure exists, the animal sinks to
the ground and fails to rise. After it has done so, the hind-liml)s are
limp, and project straight out at right angles with the body. The muscles
quiver, and patchy sweat appears about the thighs. In the animal's
efforts to get up, the fore-end is raised, but the hind extremities are
helpless and the quarters incapable of movement.
When pricked with a pin there is usually no response, behind the
.seat of fracture sensation as well as motion being paralysed. AVhere
these symptoms are wholly present it may be reasonably concluded that
fracture exists, but it must be understood that paraplegia or paralysis of
the posterior part of the body may result from concussion of the spinal
PARTICULAR FRACTURES 237
cord, in which case there is a prospect of recovery. It is necessary, there-
fore, that a careful consideration be given not only to the symptoms, but
also to the history of the case, especially with regard to its origin.
There are two diseases with w^hich fracture of the vertebrae may be con-
founded by persons who have no practical experience of the subject.
These are " thrombosis ", or plugging of the iliac arteries, and a dis-
ordered state of the blood termed " htemoglobinuria ", both of which are
dealt with elsewhere.
Animals when sufiering from the former ailment lose the power of
motion behind after exertion, but it differs from fracture in the fact that
the disablement soon passes away, and the animal rises to his feet and
continues in apparent health until exertion is renewed, when the paralysis
returns, and this may be repeated again and again for weeks and months.
In the latter disease the affected horse is attacked with sudden and
acute lameness in one hind-limb, which sooner or later results in complete
disablement and inability to stand. The respiration is hurried, and accom-
panied by an outburst of profuse sweating. With this the urine becomes
dark or even black, like porter, and on being boiled shows the presence
of large quantities of albumen. The symptoms above described serve to
differentiate the two diseases from fracture of the vertebrae.
Treatment. — Where paralysis is due to concussion the injured animal
should be provided with a deep straw bed, and be allowed to lie c^uietly
for four or five days before any attempt is made to test his powers of
movement. A dose of physic should be given at once, and hot cloths
well wrung out applied over the spine. Returning innervation of the
affected muscles will be shown by slight voluntary movement of the
hind-limbs, which will increase day by day until an attempt is made
to rise. This, however, should not be hastened by any pressure or
encouragement to assume the upright posture, but everything should be
done to induce the animal to remain recumbent. To avoid the formation
of bed-sores, and minister to his general comfort, he must be carefully
turned over from time to time, and friction vigorously applied to the
region of the quarter will assist in bringing about restoration of power.
As this appears, the administration of small doses of strychnia may be
resorted to, and gradually increased as time goes on and the muscles
regain their strength.
Where the vertebrce are fractured there is little hope of any benefit
being derived from treatment, and the only alternative is slaughter.
2.38 HEALTH AND DISEASE
FRACTURE OF THE BONES OF THE FACE
Fracture of the facial bones is not as common as might be expected
considering the prominent and exposed position of the face. From time
to time, however, such cases are brought under the notice of the veterinary
practitioner as the consequence of external violence. The face is some-
times brought forcibly into contact with fixed objects, such as walls, trees,
or lamp-posts, when horses run away, or it is struck by other horses while
grazing, or brought into collision with various moving bodies. The jaw-
bones are sometimes broken by becoming fixed on hooks, in chains, or in
trappy positions.
FRACTURE OF THE FRONTAL BONE
This bone, forming a considerable area of the face, and arching over the
eye, is much exposed, and sometimes suffers fracture from one or another
of the causes referred to above.
The fracture may involve that portion of the face situated between
the eyes, or the orbital process which arches over them. The importance
of fracture of this bone, whether in the one part or the other, is centred
in the degree of displacement which attends it. Fracture without displace-
ment in either case does not give rise to any serious symptoms unless the
blow is high up and the brain suffers concussion.
A little swelling and drooping of the eyelid, and a blood-shot condition
of the mucous membrane of the eye with a discharge of tears, may be all
that is to be seen when the orbital process of the frontal bone is broken
without displacement. In these cases but little requires to be done. A
mild aperient, bran diet, and cold-water irrigation of the part will suffice
to keep down local inflammation and assist repair. Where, however, the
bone is depressed the eye will at the same time have suffered more or less
damage, and the sooner the displaced bone is lifted into its place again the
better. This may be effected by the employment of a bone lever and
gentle continuous upward pressure, after which irrigation with cold water
and a dose of physic are all that will be required.
Fracture of that part of the frontal bone between the eyes invariably
occasions more or less injury to the frontal sinuses whose walls they assist
in forming, and as these cavities communicate with the nostrils some
blood-stained discharge may flow from them. If the force producing the
fracture has been very considerable more or less depression of the broken
pieces will have taken place, and it may be that the bone has been broken
into several fragments. Any displacement should be remedied at once
PAirnCULAR FRACTURES 239
by levering up the depressed fragments. Tliis will require tluit a small
piece of bone shall be removed with a trephine from a suitable position
outside the fracture area, and a lever properly padded at the point intro-
duced into the opening and the depressed bone raised into its normal
position. If the bone should be broken into small pieces replacement
will be greatly assisted by manipulating them from the outside, while
they arc being raised by the lever from within. It may be that one
or more of them wall require to be removed. If so it should be done at
once under strict antiseptic precautions; but it must be pointed out that
since no muscles are attached here, and the bone is not exposed to any
moving force, or called upon to support weight, there is nothing to
occasion displacement when once adjustment of the broken parts has
been eftected.
Haemorrhage into the frontal sinuses is a common result of fracture
of this part of the frontal bone, and should the operation of trephining
be called for an opportunity will then be afforded for washing out the
blood, for which a tepid antiseptic solution should be employed.
Chronic disease of the bone is an occasional consequence of this accident,
and must be dealt with according to the indications of the case.
FRACTURE OF THE LOWER JAW
Fracture of the lower jaw may take place through the neck of the right
branch or the left, or both. It may proceed vertically through the body
and divide or separate the two branches from each other. It may pass
transversely through the body of the bone behind the incisor teeth, or it
may detach the styloid process, or sever the condyle from its branch, and
in various other ways the bone may be chipped or broken.
External violence in one or another of its many forms is accountable
for this mishap, to which in rare instances the bone is predisposed by
disease. Kicks from other horses, falls, and collisions are the more
common causes, but it sometimes results from the teeth becoming fixed
in narrow spaces, and from the careless use of the gag while performing-
dental and other operations on the mouth and throat. In young colts,
the parts of whose bones are not yet firmly united together, one branch
is sometimes partly or completely torn away from the other through
their connection at the body. At the same time the central incisor
teeth alone or together with others are loosened, and perhaps also more
or less displaced.
Symptoms. — In vertical fracture through the body of the bone there
is at first considerable flow of saliva from the mouth. The lower lip is
240 HEALTH AND DISEASE
constantly being moved sharply up and down, and in gathering his food
the animal breaks oft" abruptly. If there is much displacement mastication
is interfered with, and the food is dropjied from the mouth. The lips
remain somewhat separated from each other, and on ojDening the mouth
the mucous membrane will be found to be torn or placed on the stretch
by the parting pieces, or not, according to the presence or absence of dis-
placement and the extent to which it has proceeded.
AVlien the breakage occurs across the body of the bone behind the
incisor teeth, the chin is more or less depressed, the mouth remains open,
allowing a free escape of saliva and maybe more or less protrusion of the
tongue. Crepitation is perceived when the broken parts are moved one
upon the other. In consequence of the pendulous and disabled state of
the lower lip the patient fails to gather his food, or if he succeed it is
in a very small measure, and only accomplished with great difticulty
and at the expense of much suffering.
In fracture of the coronoid process the angle of the jaw on the side
of the injury will be found to be slightly lower than the opposite angle.
Mastication is seriously interfered with, and the movements of the jaw
lose their natural swing and become restricted and irregular. The animal
cannot masticate hard food, and will only take aliment of a soft and sloppy
character.
Fractures through the neck of the jaw between the molar teeth and the
tusk, without displacement, are sometimes difficult to identify at first, the
only symptoms observable being a marked shyness in feeding, in the act of
which the saliva becomes churned into foam.
Presently, however, a diftused swelling appears around the bone over
the seat of the fracture. This may encroach upon the " mental " nerve as
it escapes through the foramen on the outer side of the bone at this part,
and for a time partial paralysis of the lower lip is likely to result. If
the broken parts are displaced a crepitus or rubbing sensation may be
excited l)y moving one part upon the other.
Treatment. — Where displacement exists the parts should first be
brought into their natural position and retained there by suitable means.
If the body of the bone be split vertically through the centre and
the parts are displaced, they may be brought into position again by seizing
the corner incisor teeth between a pair of large pincers and steadily but
forcibly pressing them together. If they are raised one above the other,
they must first be brought into line by depressing one piece or raising the
other, as the case may be. If this cannot be effected by the hands, the
pincers properly padded must lie employed.
Should the teeth have undergone any displacement they must be
PARTICULAR FRACTURES
241
properly reiulju.stcd, after wliicli the broken bone may be fixed in position
by means of copper wire or whip-cord tied round the incisor teeth.
To guard against displacement the patient must be made to stand
in the pillar reins, and for two to three weeks his food should be soft and
slopj)y, such as scalded bran and chaff, boiled
roots, &c.
In fracture of the branches or the body of
the lower jaw the cradle designed by Mr.
Walker of Bradford, shown in fig. 333, may
be used, or a piece of gutta percha, first soaked
in hot water, should be moulded on to the
under surftice and sides of the lower jaw, and
made to fit into the hollow {intermaxillary
space) between its branches. By then punch-
ing four or five holes through the front border
on either side, and one or two into the upper
border, it may be made secure by strings or
straps passing in front of the face and behind
the ears.
Mr. Walker's cradle is composed of two
lateral portions, fitting to the sides of the face,
suspended from behind the ears by a padded
strap A, and kept in position by a brow-band
B, throat-strap c, and jaw-straps F F F F, with
a central portion of wood padded with leather
D, to fit between the branches of the jaw,
and two flanges E e to rest on the first molar
on each side of it, the side plates having an
arrangement for adjusting their length and
screws H H for clamping them when adjusted.
In order that the flanges should have a level
bearing and allow the animal to eat, the first
molars on which they rest must be short-
ened by tooth shears (fig. 334) or rasp (fig.
335). The apparatus should be so adjusted
as to lie evenly and without pressing more on one part than another.
In the absence of these appliances an adhesive compound of Burgundy
pitch, Venice turpentine, and a little bees'-wax may be plastered over and
round about the seat of fracture in a succession of layers until a thick
strong covering has been obtained. This when set will give considerable
support to the broken parts.
Fig. 333.— Walker's Face-Cradle
A, Padding to protect Poll, B, Brow
Band. c, Throat Lash. D, Pad for
submaxillary space. To be made of
wood and well padded with leather.
K, E, Flanges to rest on first molars.
P, F, K, F, Straps passing under lower
jaw. G, G, Supplementary Strap Slits.
H, H, Thumb-screws for lengthening
or shortening the plate : designed by
Mr. Broad, Bath.
242
HEALTH AND DISEASE
Where both branches of the jaw are fractured Fleming recommends
that the siDace between them be completely filled up by a large firm
pad of tow impregnated with an adhesive mixture, then one bandage
after another (covered with the resinous mixture) applied around the jaw,
Fig. 334.— Tooth-Shears
face, and nose. These, when the mixture has hardened, act as a cradle.
The animal may be allowed to drink thick, nutritious gruel out of a
wide shallow vessel, or the gruel may be injected into the mouth or
Tooth-Rasp
rectum or both. The standing position (for the horse) must be maintained,
and attention be given to the retaining apparatus that it be not dis-
placed nor cause abrasion.
FRACTURE OF THE ANTERIOR MAXILLARY BONE
The most common form of fracture of this bone is that in which it
becomes broken away from its fellow at their joining, and disjjlaced either
to one side or in an upward or downward direction. Fracture through
the body or the nasal process may occur, but these forms are compara-
tively rare.
Kicks, blows, and falls on the mouth are accountable for many cases
of this mishap, and in sevei'al instances the wiiter has seen the bone torn
from its fellow in the struggles to remove the incisor teeth from some con-
fined position, such as when fixed in an iron ring or between a hook and
the wall of the stable.
Symptoms. — Some distortion of the face on the side of the fracture,
in which the upper lip is either raised or depressed or drawn to one side,
is usually present when displacement takes place. There is some dis-
charge of saliva from the mouth for a while, and frequent movement of
the lips.
When the body is broken across, the fragment containing the incisor
FRACTrRE OF THE BOXES OF THE FOlii; EXTRE.NHTV 243
teeth is movable and emits a crepitus. AVhen the body of one bone is
broken away from the other the displaced portion may be firmly fixed
in an upward, downward, or outward direction. If, as sometimes occurs,
it is also broken across, then it will be freely movable.
Treatment. — The simplest form of fracture, and the one most amen-
able to treatment, is that in which one bone is torn away from the other.
In this case replacement may be eflected by means of a little pressure
and manoeuvring with the hand, or it may require the use of a pair of
large pincers, as already prescribed for the lower jaw, to bring the displaced
part into position.
Broken teeth must be removed, and any that may be found to be
pushed out of place should be properly restored to their natural position.
Any bits of bone that may be loose and detached must be taken away.
If allowed to remain, their presence will excite irritation and pus formation
in the surrounding tissues and retard reparation.
The broken fragments may be retained in position by copper wire
bound round the incisor teeth.
During the first forty-eight hours the patient should be kept exclu-
sively on thick gruel, and afterwards on slojjpy bran diet, other forms
of aliment being gradually added as the case progresses.
It is desirable to keep the horse in pillar reins for a short time after the
parts have been readjusted.
FEACTURE OF THE BONES OF THE FORE EXTREMITY
FRACTURE OF THE SCAPULA OR BLADE-BONE
Fracture of the scapula is fortunately of rare occurrence, partly because
it is covered with thick muscles and rests on others on the elastic chest
wall, partly also because its movements are of limited extent, and in some
degree also on account of its out-of-the-way position.
Sudden and violent blows are the chief cause by which fracture of this
bone is brought about. AYhen occurring at the upper angles there is some
prospect of recovery, but fracture of the body of the scapula, or the neck,
or the articular cavity can hardly be viewed otherwise than as a dangerous
condition. Splints and bandages cannot be applied with the same restrain-
ing influence on movement which they aflbrd when applied to those bones
which are below the elbow and away from the trunk.
The symptoms displayed in scapula fracture are very vague. Crepitus
is always difficult to develop and in most cases impossible. The bone does
not lend itself like the lower bones of the limb to the required manipulation
244 HEALTH AND DISEASE
of its broken parts, liut where the fracture occurs at the neck pressure
at the point of the shoulder, when the leg is raised from the ground, may
cause it to appear.
Some swelling will arise about the seat of the injury, and pain will be
evinced in response to deep pressure on the part. Forward movement
of the leg is effected with some difficulty, and weight imposed upon it
causes severe lameness.
Where displacement occurs it is most difficult to bring the broken
parts into position again, and when they are so adjusted it is practically
impossible by any bandage or splints or other means to maintain them
there. All that can be done is to suppoi't the patient in slings and leave
the rest to nature.
FRACTURE OF THE HUMERUS
The humerus or upper arm is seldom broken. The large muscles which
everywhere enclose it serve as a protection against external violence.
When this fracture does occur, and the breakage extends through the
body of the bone, but little difficulty is exjierienced in the diagnosis.
The limb below the fracture displays unusual mobility. It is incapable
of supporting weight, and when the animal is made to move, acute pain
and lameness are evinced. The part is much swollen, and by carefully
fixing the upper segment of the bone, and moving the lower one, crepitus
may be developed
Sometimes the external condyle is broken off, and the extensor muscles,
losing their fixed point of action, and being at the same time more or less
damaged, fail to antagonize the action of the flexors. As a consequence
the leg is drawn inwards and the foot and pastern are flexed on the canon
in such a way that the front of the hoof rests on the ground.
When the inner condyle is fractured and the attachment of the flexor
muscles becomes weakened, the action of the extensor muscles, overpowering
them, draws the foot forward, while the knee, losing its support from
behind, falls backward. When weight is imposed upon the damaged leg,
this backward inclination of the knee becomes more marked and the
concavity in front of the limb is increased.
Treatment. — When the shaft of the humerus is fractured there is
not much hope of restoring the animal to a state of usefulness for ordinary
physical labour. AVhere it is of special value for stud purposes an attempt
should be made to effect re-position and bring about reparation.
The arm is a difficult place on which to apply a splint, and equally so
to adjust a ])andage with any prospect of its being retained. We would
FRACTURE OF THE BONES OF THE FORE EXTREMITY 245
therefore advise that the patient be phieed in slings, and that the ground
be slightly hollowed out to receive the foot of the broken limb. A starch
bandage must be applied from below the knee to the middle of the arm,
and a thick pitch plaster round the humerus. AVith this, quietude must
be enjoined, and the reijuirements of the patient .supplied without
disturl)ance.
FRACTURE OF THE ULNA
The prominent position occupied by the ulna predisposes it to fracture
beyond that of some other bones of the extremities. The olecranon, which
forms the point of the elbow, is more especially the seat of fracture in the
horse. Here the breakage may occur deep down in the elbow-joint, or the
summit of the olecranon may be broken away, leaving the joint intact. In
whichever position the fracture may be, but little can be done to bring
about reunion of the parts, and should it by any chance be eflected in
those cases where the joint is involved, the animal will always • remain
a cripple.
The causes which give rise to fracture of this bone are mainly kicks
and blows, and on one occasion the writer has known it to occur in an
animal while pulling up suddenly to avoid a collision when going at
great speed.
Symptoms. — In these cases the limb is brought forward with the
knee in a semitlexed condition, and the elbow is depressed. Any attempt at
progression is marked by considerable downward inclination of the fore-
Cjuarter on the injured side. This attitude results from the great triceps
muscle having pulled the broken point of the elbow upward and ceased
to give support to the limb, while the biceps and the mastoido-humeralis,
having now nothing to antagonize their action behind, draw the limb
forward beyond its natural limits.
The pain and distress caused by this mishap are always considerable,
and progression is marked by great difficulty in bringing the leg into an
upright weight-bearing position. When the elbow-joint is involved, the
suffering is much increased, and general enlargement of the articulation
soon appears.
Immediately after the accident the detached piece of bone can be felt
to move, and the space dividing it from the other portion may be
recognized, but owing to the upward displacement it is seldom that crepi-
tation can be induced.
Treatment. — Nothing can be done to bring the broken pieces together
and maintain them in position, and there is little hope of any good
resultine from treatment.
246
HEALTH AND DISEASE
If it should be decided to do anything, we would advise the simple
course of slinging, after the whole limb has been straightened and put into
a starch bandage.
FRACTURE OF THE RADIUS
Fracture of the radius, or fore-arm, like most other fractures of the
bones of the limbs, is the result of kicks and blows, or false steps, or it
may arise in the struggles to recover the leg from some
fixed position. A blow on the inner side of the bone,
where it is least protected by muscles, is more likely to
occasion a fracture than one on the outer side or back
of the limb.
Symptoms. — An incomplete fracture of this bone,
without displacement, affords no other evidence of its
existence than local pain and swelling, with more or less
lameness, and in this form of injury recovery may be looked
forward to under proper treatment, and the same may be
said of complete fracture when the broken parts continue
to hold together.
It is when the broken fragments are separated that
the case reaches its more serious aspect.
Here the animal fails to bear any weight upon the
limb, and locomotion becomes impossible. The leg below
the fracture displays abnormal mobility, and when raised
from the ground swings forward and backward and bends
from side to side. Crepitation is readily detected, and the
part is swollen, hot, and painful to the touch.
Treatment. — If the animal is young and docile, and
the tissues in the region of the fracture have not been
seriously damaged, and the parts are promptly brought
together, reparation may possibly be effected. The chances,
however, are too often in favour of the contrary result;
and even in the majority of those cases in which a reunion is effected,
some deformity, or other equally serious defect, remains behind.
It is only, therefore, in animals of considerable value that treatment is
likely to be remunerative where successful. Since quietude is one of the
first requirements of treatment, the patient must, as soon as possible, be
placed in slings, and if a properly -constructed operating- table is not at
hand, whereon cliloroform may be given, a dose of morphia will have the
effect of rendering him more manageable during readjustment of the broken
Fig. 336.— oblique
Fracture of the
Radius
FEACTUKE OL^ THE BONES OF THE FORE EXTREMITY
247
bone. Before the bandages and splints are applied it is most essential
that the leg be brought into its natural position. The toe and the knee
should be in line, and there should be no deviation either to the right
or to the left in the course of the fractured bone.
A series of bandages soaked in a mixture
starch should be applied up the leg from the
coronet as far along the arm as it is possible,
and then the iron splint designed by Bour-
gelat (fig. 337) should be adjusted over them.
Of course the hollow of the heel and all
other depressions in the course of the limb
will be filled in with tow, so that the pressure
of the bandages may be equalized. Should no
such splint be accessible, then wooden splints
cut to the form and length of the limb must
be employed.
FRACTURE OF THE KNEE-BONES
This is comparatively rare. AVhen it does
■occur it is mostly associated with broken
knees, and assumes the form of a compound
fracture, complicated with inflammation of
the joint and damage to tendons which pass
over it.
Fractures here are attended with great pain
and sufiering and much constitutional dis-
turbance. There is free discharge of synovia
or '"joint oil", inability to support weight on
the affected limb, and considerable swelling.
In other than animals of considerable value
for stud purposes the result of treatment,
however successful it may be, will not be such
as to compensate for the time and trouble which these cases demand.
The knee invariably sufiers irreparable damage, and the animal remains a
cripple for the rest of his life.
Where treatment is resorted to, the horse must be placed in slings,
and splints and bandages employed to maintain the joint in a state of rest,
while at the same time provision should be made in the bandaging for the
free discharge of matter from the wound in the knee, which must be treated
on antiseptic principles.
Fig. 337. — Iron Splint for Fractures of
the Fore-limb
A, A, Screws for adjusting the length
of the Splint.
248
HEALTH AND DISEASE
FRACTURE OF THE METACARPAL BONES
In adult and aged horses the metacarpal bone.s are generally united
together by ossific union, and it results from this, when fracture occurs,
that all the bones are involved in it.
In colts, where they are united by
ligaments only, each one of them may
be broken independently of the others,
but such an occurrence is very occa-
sional.
Fracture of these bones (fig. 326,
p. 222) is mostly brought about by
kicks, jumping into deep hard roads,
l)lows against fences and walls, and
slijDS, &c.
The absence of muscles in this
region, and the opportunity thus
afforded of a clear view and thorough
manipulation of the part, renders diag-
nosis an easy matter when displace-
ment has occurred. The bone will be
seen to bend at the seat of fracture
when any attempt is made to put
weight upon it. In progression, that
part of the limb below the breach has
ceased to be under control, and swings
about as the body moves forward.
Crepitus can be readily produced, and
the existence of a fracture becomes at
once apparent.
Treatment. — Although these cases
are both difficult and uncertain, now
and again treatment has its reward
in restoration to a state of usefulness,
but it is seldom possible to avoid de-
preciation in the value of the animal.
To what extent this factor will assert itself will depend very much upon
the degree of displacement and the damage inflicted upon surrounding
tissues by the unrestrained movement of the broken fragments after the
accident.
Fractures without displacement, when they are diagnosed and promptly
Fig. 338.-
-Splint for Fracture of the Metacarpal
Bones
FKACTUKE OF THE BONP:s OF THE FORE EXTREMITY
249
treated l)y slinging and suitable splints, offer the best prospects of
success.
Where displacement occurs, the bone must be set, and in carrying
out this part of the work every care will require to be taken that the
fragments are brought into their proper position. Before splints and
bandages (fig. 338) are applied, the knee and the toe must
be brought into line, and the leg as a whole rendered
straight. Placed in slings, the patient must be disturbed as
little as possible, and careful watch kept over the limb, so
that prompt relief may be given by relaxing the bandages
where undue pressure provokes swelling.
Should this precaution fail to be observed, the case will
become complicated by dangerous sloughing, and the re-
union of the bone retarded or altogether prevented.
FRACTURE OF THE OS SUFFRAGINIS OR LARGE
PASTERN
Fractures of the large pastern are perhaps the most
common of all affecting the limbs of the horse.
They mostly take an oblique direction, extending from
above downwards towards the outer or the inner side (fig.
339), or pass vertically downwards from the upper to the
lower extremity. Less frequently the breakage is trans-
verse, in which case it mostly occurs towards the lower
extremity (fig. 340), and is very frequently comminuted.
In oblique fractures the division usually extends into
the fetlock joint, while in those taking a vertical course
it may also involve the joint formed with the small pastern.
In young horses they are most frequently partial, and take
the form which is commonly termed "split pastern". In
these cases there is no displacement, and treatment is thereby favoured.
Fracture of this bone is most commonly met with in race-horses,
hunters, and chasers. In the first it results more especially from slips,
false steps, twists, and striking the toe in the ground while going at
great speed. In hunters and chasers it also occurs as the result of jump-
ing into roads or travelling through deep holding-ground, or drojaping
the feet into holes.
Symptoms. — Following the mishap, there is sudden and severe lame-
ness. If the fracture is comminuted or attended with displacement the
leg is held in the air, and is incapable of bearing weight.
Fig. 339. -Oblique
Fracture of Suffra-
ginis
250 HEALTH AND DISEASE
If the foot be rotated or forcibly Hexed on the fetlock, crepitus or
rubbing of the broken pieces will be felt. Great sensibility to pressure
along the surface of the bone soon appears, accompanied by a firm diffused
swelling. In split pastern the lameness, although sometimes considerable,
is less severe, and there is usually no crepitus. The swelling may be
inconsiderable, and the existence of a fracture altogether overlooked.
Treatment. — No time should be lost in placing the animal in slings.
The shoe should be removed, and the stable littered with 3 or 4 inches
of saw-dust or peat-moss. If there is no displacement, which will be
readily determined by the undisturbed outline of the pastern, a starch
bandage should be applied at once. In making the application, the
hollow of the heel should first be filled in with a pad of tow, over which
the bandage should be rolled and carried
over the fetlock joint from the coronet,
nearly as high as the knee. In those cases
in which displacement occurs, the parts
should be readjusted and the bone sup-
ported by a starch bandage or some more
suitable splint.
A light, spare diet should be prescribed.
Fig. 340.-Obliaue and Transverse Fractures _^ ^ j^^^j^ linSecd-oll may be incorporated
of the Os Suffraginis •' ^
with it night and morning until the bowels
are gently acted upon. All that is now needed is to avoid any sudden
excitement, and to keep the animal perfectly quiet.
So soon as he begins to throw his weight upon the limb, and to con-
tinue it, the bandage may be removed. JNIore or less enlargement will
be found to have developed on the bone in the form of a reparative callus,
and subsequent treatment must be directed towards effecting its reduction.
For this purpose a repetition of blisters must be applied over the part
during a continuance of rest. In some cases a large ring-bone, with more
or less lameness, remains as a permanent result of the fracture, while in
others but little enlargement follows, and the action is in no respect
affected by it.
FRACTURE OF THE SESAMOID BONES
Fracture of the sesamoid bones is by no means of uncommon occurrence.
It happens most frequently in old hunters and chasers when carrying
heavy weights over deep ground, and mostly at the end of a long and
tiring run.
The line of the fracture is usually transverse. Sometimes the accident
is confined to one l)ono. but more frecjuently it involves both, and now
PLATE XXXIX.
OSTEOPOROSIS
Showing Diseasi.- .>.mi Descent uf the Sesailioiil T..
FRACTURE OF THE SESAMOID BONES
Border Lass, aged, broke down (fractured tlie sesainoid bones of both fore-legs) at
Ringnter Steeplechase, April lo. 1889. F^hotograph taken seven weeks later
FRACTURE OF THE BONES OF THE FORE EXTREMITY
251
and again it occurs to both fore-limbs at the same time. Tlie bone may
break through the middle, or a piece of the upper angle only may be
torn away from the rest. The fracture sometimes
follows upon repeated chronic sprain to the suspen-
sory ligament, and there is reason to think that
in these cases the cohesion of the bone has been
diminished by an extension of the inflammatory
action from the ligament to the bone to which it
is attached, for it fre(]^uently occurs that prior to
breakage the sesamoid bones have been for some
time more or less enlarged. Slipping and false
steps in making sharp turns are sometimes account-
able for this injury.
It has been said that " the accident is quite as
likely to happen while the horse is at rest in his
stall as under any circumstances"; but while grant-
ing the possibility of such an occurrence, we cannot
subscribe to a statement for which experience aftbrds
no sort of support. We have repeatedly known
horses which have been laid up for some time on
account of lameness in the fetlock joint, in which
perceptible enlargement of the sesamoid bones
•existed, to fracture their bones in the stable, or
very soon after renewing work, but we have always
xegarded such cases as having been predisposed to
fracture by a process of rarefaction of the bones
arising, out of inflammation extendino; from the
sprained ligament.
Many cases of what is called " breakdown", if
carefully examined after death, would be found to
result from a giving way of the bones in this
weakened condition, and the removal of a fragment
by the partially-separated ligament (Plate XXXIX).
These cases are attended with lameness more or
less severe, but in the slighter accidents there may
be but little distortion of the fetlock joint, and the
writer has found that in course of reparation the
ligament at its point of attachment with the sesamoid bone becomes
ossified.
Symptoms. — Fracture of the sesamoids results in sudden lameness,
but in degree varying with the nature of the fracture. When this is
Kig, 341. — Fracture of the
Sesamoid Bones
1, Carpal tendon cut away to
show suspensory ligament. 2,
Small metacarpal bone. .3, Sus-
pensory ligament. 4, Branch of
same. 5, Fractured sesamoid
bones. 6, Deep sesamoid liga-
ment. 7, Superficial sesamoid
ligament. 8, Intersesamoid
ligament.
252 HEALTH AND DISEASE
completely across the bone, the broken fragments are forced asunder l)y
the weight imposed upon them, and the fetlock joint, having lost the
support of the suspensory ligament, sinks towards the ground. The
weight, now felling more directly upon the heel, gives the toe an inclina-
tion upwards. This deformity may not occur immediately, and sometimes
only appears two or three days after the accident, at which time there
is much swelling, heat, and pain in the part. It may be that only one
sesamoid bone may be fractured, in which case the fetlock joint inclines
inward or outward, according as the one side or the other is affected.
Although the broken pieces may be much disjDlaced, crepitus may some-
times be induced by fixing the suspensory ligament above and forcibly
flexing the fetlock joint.
Treatment. — Very little can be done in these cases to fit the horse
for remunerative work, but when it is required to put it to the stud,
in some cases it may be made serviceable for the purpose.
The strain should be taken off the suspensory ligament by the appli-
cation of a high-heeled shoe. The joint should then be supported by a
starch bandage, carried from the coronet upwards to the middle of the
canon. This having been done, the animal should be jilaced in slings and
kept there eight or ten weeks, or longer if necessary, as quiet as possible.
In complete fracture, the fetlock joint is sure to remain deformed and
enlarged to a greater or less extent. A repetition of blisters after the
patient has been taken out of the slings will help to reduce the enlarge-
ment, and give further tone to the injured parts.
FRACTURE OF THE NAVICULAR BONE
Tlie frequent occurrence of navicular disease, as a result of which the
bone becomes weakened by ulceration and rarefaction of its tissue, renders
the bone in question 23eculiarly liable to fracture, and this predisjDosition
is still further increased by the position which it occupies, and the weight
and concussive force to which it is exposed during locomotion.
It is, however, more particularly in horses the nerves of whose feet
have been divided that the accident occurs. While the nerves are intact,
and sensation exists in the feet, the animal relieves himself from pain by
throwing the weight of the body on the front of the foot, but when
sensation has been removed by division of the nerves, pain disappears.
The heels are then brought to the ground, and the navicular bone,,
weakened by disease, is made to bear the full weight and impact of the
body.
At this time the perforans tendon has undergone more or less
FRACTURE OF THE BONES OF THE FORE EXTREMITY
253
excoriation and inflammatory softening, and failing in con.se(juence to give
the bone support, a fracture results. It is no uncommon thing for rupture
of the tendon to follow upon fracture of the bone.
Nails penetrating the frog have been noticed to cause fracture of this
bone, but such an occurrence is very rare indeed.
Symptoms. — Evidence of fracture of the navicular bone is difficult
to ditl'ercntiate from that severe inflammation of the navicular joint and
tissues of the foot which sooner or later follows upon neurectomy. A little
342. — Fracture of Na\ncular Bone
A, Crctification of Superior Navicular Ligament.
B, Diseased Bone.
Fig. 343. — Fracture of the Navicular Bone
fulne.ss in the hollow of the heel is first observed, which on pre.ssure is
somewhat yielding, and suggests the existence of deep-seated fluid. The
toe has a slight inclination upwards, and the fetlock joint is somewhat
depressed. Soon the coronet exhibits an abnormal fullness, and oozing
of serosity appears between hair and hoof. The coronal thin border of
the latter becomes white by saturation with serosity, and the horn com-
mences to separate from the skin, and soon the hoof sloughs, a result which
sooner or later follows upon fracture of the na\icular bone.
Of course nothing in these cases can be done with any prospect of
cure, and the better and more humane measure is to have the animal
destroyed.
251
HEALTH AND DISEASE
FRACTURE OF THE RIBS
Having regard to the large and exposed surfoce formed by tlie back
ribs, and the peculiar occupation and surroundings of the horse, fracture
of the ribs is much less common than might reasonal)ly be expected.
If the front ribs are j^i'oteuted against external
violence by tliick muscles, and also by the scapula or
shoulder-blade, those behind are possessed of great elas-
ticity, and, having no fixed attachment below, are much
more capable of yielding to external force without break-
ing than those in front. Both, however, are now and
again forced beyond their powers of resistance, and a
fracture follows. This may be transverse, as in fig. 337,
oblique (fig. 344), or vertical, with or without displace-
I 1 ment. The displaced fragment, if directed inwards, may
y puncture the pleura or the lung, thus inducing complica-
tions of pleurisy or pneumonia, or both, or it may pass,
through the skin and convert a simple into a compound
fracture.
Both these events add very materially to the danger
of the case, and too often give it a fatal turn.
Causes. — Fracture of the ribs is usually the result
of external violence. Sometimes a kick from another
horse, at otliers a collision with the shaft of a trap, or
the pole of a coach or brougham, will cause it; at others
it results from a fall on a harcl surface, where the legs
slip from under the body and the ribs strike the ground
first and without any break in the fall.
Symptoms. — Fractures of the ribs frecjuently occur
without displacement, and undergo repair without inter-
kind. In these cases there is nothing to be seen out-
wardly, and, excepting a slight thickening over the line of fracture, there
is nothing to be felt. The part is tender to touch, and deep jjressure
causes the patient to recede from it and to emit a subdued grunt. Ten-
derness may be found to exist on neighbouring ribs, and some stiff'ness
will be observed in turning.
Where the broken parts are displaced or contused, more or less swelling
appears over the site of fracture. By following the ribs downwards with
tlie fingers before this occurs, the breakage will be recognized as an irregu-
larity in its continuity, with more or less projection of one of the broken
Fig. 344. — 0hli,|i,e
Fracture of Rib (tliird
rib, right siJe, outer
aspect)
ference of anv
FRACTURE OF THE BONES OF THE FORE EXTREMITY 255
segments from the general surface. With this will be associated great
soreness at and about the seat of injury.
The fracture may be complicated with perforation of the chest or an
external wound. In the former case pleurisy of a local or general character
wall be excited, or should the lung be punctured or torn, as sometimes
occurs, signs of pneumonia will be present, or both may exist together.
In these cases the breathing will be more or less disturbed, accompanied
by cough, and the more serious symptoms incidental to disease of the
chest. An external wound connected with traumatic injury to the pleura
and lungs is a serious complication, and one which is invariably attended
with the greatest danger.
Where the broken ends of the bone are sharp and cutting, the inter-
costal blood-vessel may be divided and give rise to haemorrhage.
In fracture of the front ribs severe lameness of the fore-limb on the side
of the injury is of common occurrence. This would seem to result from the
movement of the broken bone by the serratus magnus muscle, which not
only enlarges the chest in the act of inspiration, but supports the trunk as
in a sling (fig. 44, Vol. I) between the fore extremities.
Treatment. — In cases of simple fracture, without displacement, it is
good practice to place the animal in slings for a fortnight or three weeks,
and then provide him with a good straw bed and keep him cpiiet.
Where displacement has occurred, by which the lung is interfered with,
it might be necessary to attempt re-position notwithstanding that the
operation is attended with considerable danger.
For this purpose an incision will require to be made over the seat of
fracture. The finger or a suitable lever must then be carefully introduced
and brought to bear on the inner side of the front edge of that portion
of the bone whose point is directed inwards, and when the chest expands
in the act of breathing an attempt should be made to bring the displaced
fragment into position by pressing it outwards.
Before proceeding with the 02Deration the hair should be closely clipped
off" the part, and the skin thoroughly washed with soap and water, and
then well irrigated with carliolic or some otlier antiseptic solution. Instru-
ments should also be disinfected, and the wound sul)se(|uently treated anti-
septically.
If the displacement does not interfere with the lung, it is not desirable
to interfere with it. Time and a period of rest in slings is all that can be
done to effect a union.
Where a wound is produced at the time of the fracture, advantage should
be taken to rectify displacement, if such exists, by the method above de-
scribed under antiseptic precautions.
256
HEALTH AND DISEASE
FRACTURE OF THE PELVIS
The large size of the pelvis, its projecting angles and position, render it
specially liable to fracture, and modern road-making in our large towns
contributes not a little to this result. Wood pavement, when the surface
is first moistened with water, is rendered difficult to travel over at any
time, but with heavy loads behind them, where the ground is on the
ascent, or slopes, as it usually does, from the centre towards the sides.
Fig. 345.— Fracture ot the Pelvis
A, Fracture through the Cotyloid Cavity. B, Fracture of the Symphysis Pubis. c, Transverse
Fracture of the Os Pubis. D, External Fracture of the Ischium. E, Fracture of the External Iliac
Angle. P, Fracture of the Internal Iliac Angle. G, Fracture of the Tuberosity of the Ischium.
heavy horses frequently fail to keep their legs, and sufler fracture of this
bone by a heavy and helpless fell. When the fall is on the side, and the
force is applied to the point of the haunch, a portion of the angle of the
ilium may be broken away from its body, or the fracture may take place in
some remote and deeply seated part. Draught-horses, when moving heavy
loads in two-wheeled carts, are sometimes brought to the ground by their
hind-limbs suddenly slipping away from them right and left, when the
pelvis is forced to the breaking-point by the weight of the load on the
one hand and the struggles of the animal on the other.
Blows on the hip while passing at high speed through doorways and
gates, or by collision with some other fast-moving body, are also account-
able for accidents of this kind, and in rare instances fracture has been
brought about by "casting", or in the course of a surgical operation. In
the hunting-field and the chase, horses have fractured their hips while
jumping, as well as by dropping the hind-f|uarters into a drain as the
result of failure to clear a bank.
From these and other causes fracture of the pelvis may take place in
one or another of its various parts. Breakage of the point of the haunch
(Jiip down) is the most frequent form which the accident assumes. Less
frequently the body or the neck of the ilium may break, or the pubis or
FRACTURE OF THE PELVIS 257
ischium which fonn the Hoor of the j^elvis, or the bony cup {acetabulum)
which is engaged in forming the hip-joint, or the breach may take place
through the tuberosity of the ischium where it forms the point of the
buttock. Of course more tlian one of these several parts may be rent at
the same time.
Symptoms. — Many and various phenomena result from fracture of the
pelvis, and veterinarians have attempted to assign to each particular frac-
ture its special set of symptoms, but it cannot be said that they have yet
established a reliable code. The physiological disturbance which results
from the fracture of any particular part of the pelvic girdle is sometimes
so masked and disturbed by injuries occasioned to neighbouring muscles
that the symptoms of no two cases of the same fracture sufficiently
resemble each other to ensure correct diagnosis unless the fracture can be
localized by the hand through the rectum.
Sudden lameness, more or less severe, according to the seat and nature
of the breakage and the extent of displacement, is the immediate effect of
the mishap; or the animal may be so far disabled at once as to be unable
to rise when down or to stand when up.
In some cases there is obvious deformity of the quarter. In fracture of
the neck or the inner angle of the ilium the croup becomes depressed, and
when compared with the sound side, while weight is on the leg, it is noticed
to be distinctly lower. Fracture of the outer angle of the ilium gives the
quarter a flat appearance on the side of the injury, owing to the broken
piece having been pulled downwards by the muscles attached to it. This
is soon recognized by inspecting the quarters first from before and then
from behind.
When the outer branch of the ischium is fractured, there may be
more or less swelling in the region of the hip-joint and about the inner
and back part of the thigh.
In fracture of the pubis, swelling of a diffused character appears sooner
or later between the thighs, about the sheath and scrotum in the horse
and the mammary gland in the mare. It may also extend in a forward
direction beneath the belly, or in a backward direction to the perineum in
the male or the vagina in the female.
Excepting in fracture of the outer angle of the bone {hip down) loco-
motion is very materially interfered with, and the power to bear weight is
either seriously impaired or altogether destroyed.
In progression the limb on the side of the fracture may be moved
unduly outward (abducted) or inward (adducted), or the animal experi-
ences difficulty in bringing it forward or in raising it from the ground.
The horse fails to walk straight but moves diagonally with the rump
258 HEAXTH AND DISEASE
inclined towards the sound side. In some fractures, especially those
involving the acetabulum or hip-joint, pain is expressed by a more or less
audible grunt, by spasmodic twitching of the muscles, and an expression of
anxiety and fear. Where the round ligament (fig. 358) is in part or wholly
detached from its connection with the cup, the limb ceases to be altogether
under muscular control. In any attempt to move it, either the foot goes
beyond or fells short of the point it is intended to reach. In one step
it is thrown outwards, while in the next it may incline inwards, and the
movement of the limb generally is limp.
The diagnostic symptom in this, as in all other fractures, is the presence
of a true crepitus or impression which rubbing of the broken pieces together
conveys to the hand or the ear.
This may be at once evident on manipulation, or auscultation, or only
detected after much careful manceuvring of the limb of the animal, or
it may be altogether absent. In order to bring it about, an assistant
should be instructed to move the leg carefully in various directions,
inwards, outwards, backwards, and forwards, and to rotate it gently first
in one direction and then in the other. During this time the hand or the
ear of the examiner should be ajjplied to the point of the ilium, and moved
backward from place to place to the point of the buttock, the mind being
at the same time concentrated upon it. The hand should then be passed
into the rectum and brought into contact with every available part of the
pelvis. Any crepitus occasioned by the movement will then be felt, and
any swelling or displacement of the broken pieces at once recognized.
Crepitus may sometimes be induced and recognized by pushing the animal
over from one side to the other, while still keeping the hand on the quarter
or in the rectum. The absence of crepitus and severe lameness does not
always indicate the absence of fracture, but may be the result of no
displacement of the broken bone having taken jjlace.
In these cases of doubt the examination should be repeated day by day
for several days, during which the patient inust be kept perfectly quiet.
Treatment.- — The broken pelvis does not lend itself to those measures
of mechanical restraint which are employed so successfully in dealing with
some of the bones of the extremities, and we are therefore restricted in our
■endeavours to effect reparation to the device of slinging and maintaining
as nearly as possible an upright posture, thereby avoiding those disturbing
efforts involved in lying down and rising again, movements which are
sometimes attended with most disastrous results.
AVhether treatment is likely to be attended with success or not is a
question which the examiner must answer for himself after having made a
searching examination.
FRACTURE OF THE PELVIS 259
Generally it may be said that, owing to the very imperfect control which
can be exercised over the movements of the horse, and the disturbing effect
of the weight of the body acting on the broken bones while in the upright
posture, but little can be hoped for from treatment.
In fracture of the acetabulum there is only a very remote prospect of a
reunion of the broken pieces being brought about, and much the same
may be said of a breach in the floor of the pelvis. We have seen instances
of repair in both these fractures, but they are very rare indeed, and in the
former case severe lameness continued throughout life.
The external angle of the ilium is frequently broken and displaced more
or less in a downward direction without materially affecting the patient's
usefulness. In these cases a replacement of the broken fragments cannot
be effected owing to the downward pull of the muscles attached to it, but
it continues to be connected to the part from which it was torn by a strong
band of connective tissue, and the patient suffers only a temporary incon-
venience from the accident. Here rest is all that is needed to bring about
a satisfactory result.
Less frequently, but in a large proportion of cases, the same good result
follows under the same simple course of treatment when the internal angle
is broken.
Some prospect of recovery offers, where the fracture involves only the
neck of the ilium, so long as there is no displacement, and the same remark
applies where the point of the ischium is ])roken; but it frequently occurs
that the parts break away in the course of repair, before it has sufficiently
advanced to keep them in position.
Except in those forms of fracture last referred to, unless some special
value be attached to the injured animal for stud purposes, the desirability
of prompt destruction should be well considered. Experience teaches that
in the most favourable cases, where reunion of the broken pieces is com-
plete, some deformity of the pelvis, some irreparable interference with
nerves or vessels, or wasting of muscles, is left behind to cripple the
patient after long and costly nursing.
Perfect quietude as fsir as it can be enforced is the one condition to
be aimed at, and this will be best secured by placing the animal in slings.
In doing so it should be observed that the ground is not slippery, and
that it is well covered with peat-moss or saw-dust, or, failing these, a
thick covering of sand. Peat-moss being the softest, most adhesive, and
least likely to jar the limb, is to be preferred. It may be that the patient
may experience some difficulty for a time in emptying the bladder, owing
to being unable to extend himself. In such cases the urine must be with-
drawn by means of the catheter with as little disturbance to the horse
260 HEALTH AND DISEASE
as possible. Brisk friction or rubbing with a brush over the legs and
quarter will tend to relieve stiffness and afford comfort while under
restraint.
A diet composed of bran and roots, with a moderate amount of hay,
chaff, and a few crushed oats, is the most suitable, and two table-spoonfuls
of linseed-oil incorporated with it three or four times a week will serve
to keep the bowels regular. Everything should be done to minister to
the comfort of the animal, and time must do the rest.
FRACTURE OF THE BONES OF THE HIND EXTREMITY
Fracture of the Femur. — Notwithstanding the large muscles which
everywhere surround and protect the femur, it is sometimes made to yield
to the violence which in one form or another is applied to it. The causes
which determine fracture of this bone are mostly kicks from other horses,
violent struggling while undergoing operations or in endeavouring to
escape from some difficult and confined position. It sometimes results
from a slip while attempting to start a heavy load.
The seat and nature of the fracture varies in different cases. Some-
times the head is broken off through the neck, at others the diaphysis
or shaft is divided in a transverse or oblique direction (fig. 328), or
one or both condyles may be separated from the inferior extremity of
the body, or the large trochanter broken away from the upper extremity
of the bone. The signs of fracture here are not usually difficult to read.
Sudden and acute lameness, with inability to bear weight, and difficulty
in advancing the limb, are at once manifest. When the animal is made
to move, the leg is advanced with an outward swing and displays unnatural
mobility. Crepitation is made apparent by passive movement of the broken
pieces, first in one direction and then in another. As the animal stands,
the quarter sinks into a resting position.
Reposition or reduction of the fracture is always difficult, mostly im-
possible; and when accomplished the size, form, and relations of the thigh
oppose the application of appliances to retain the broken fragments in
apposition. It will be seen, therefore, that unless great value is set upon
an animal for breeding purposes treatment is not likely to prove remu-
nerative, and should not be encouraged.
An unserviceable cripple is with very rare exceptions the only return
for much expense and trouble.
Slinging, pitch plasters over the part, and such quietude as can be
procured are the only available if doubtful means of effecting a reunion
of the parts.
FRACTURE OF THE BONES OF THE HIND EXTRE^HTY 261
Fracture of the Tibia. — Fracture of this bone is comparatively
frequent. Its greater length, more exposed position, and less ample pro-
tection by muscles than the femur render it more liable to succumb to
external violence.
The internal surface of the bone is quite superficial, having no other
covering than the skin. This is its most vulnerable point, and when sharp
forcible blows are applied to it, it not unfrequently splits or breaks.
Kicks, blows, false steps, collisions with cart-shafts, carriage-poles, and
stone walls, and violent struggling when cast either by accident or design-
edly for the purpose of an operation are the causes by which it is chieHy
produced.
Symptoms. — The outward manifestations resulting from the mishap
will depend upon the more or less completeness of the fracture. Some-
times the bone is only partially broken through, and, the parts being
maintained in their natural position, comparatively little pain or incon-
venience is suffered; so little, indeed, that in some cases the nfvture of
the injury remains undetected for days and weeks, until by the strain of
work the fracture is rendered complete by the parts being torn asunder, or
the fragments becoming displaced in the act of lying down or rising from
the recumbent posture. In such circumstances the evidence of fracture
becomes clear and decisive; the horse fails to support weight on the
injured limb, which, when raised from the gi'ound, hangs limp and pendu-
lous, and crepitus is readily detected in it.
Partial fracture may provoke more or less lameness, the seat of which
may or may not be indicated by swelling. But in the absence of swelling,
pressure applied over the surface of the bone will afford material evidence
of the existence of fracture.
Treatment. — Where the fracture is complete the prospect of restoring
the horse to a state of usefulness is very remote, indeed so much so that it
is only where high value is set upon the patient for breeding purposes that
the result would be likely to prove at all satisfactory. In this case the
limb should be enclosed in a strong pitch plaster, laid on in a succession of
layers from below the hock as high as the stifle.
Further support may be given to the broken fragments by strips of
thick cardboard let into the plaster over the region of the fracture. With
this should be conjoined the supjDort of slings and perfect rest.
Fracture of the Bones of the Hock. — This is an accident of
exceptionally rare occurrence, and mostly concerns the calcaneum (os
calcis) or bone forming the point of the hock. Occupying a prominent
position, and standing exposed to external violence, it is remarkable that
it so seldom suffers fracture.
262 HEALTH AND DISEASE
Kicks, blows, and violent struggling when cast are the most common
causes. In foals the point of the hock is sometimes torn off when rearing
and walking backwards on the hind-legs.
The symptoms resulting from this mishap are very striking and
characteristic.
There is a complete inability to support weight on the broken limb.
When an attempt is made to do so the hock joint sinks towards the
ground, and the point of the hock is drawn upwards by the pull of the
tendo achillis, the foot is advanced, and the quarter on the injured side
inclined downward. In progression the limb as a whole is raised as far
as possible, and then trailed forwards with the advancing body.
Treatment in these cases offers but little prospect of success. The
tendo achillis, acting upon the broken fragment, displaces it upward beyond
readjustment, and where it is practicable to bring the broken parts together
it is usually found impossible to maintain them in their natural position.
Fractures below the hock may be such as have been described as taking
place below the knee, and will require to be healed on the same lines.
16. ARTICULATIOI^S OR JOINTS
The bones of the skeleton are joined together in various ways to form
joints. The manner in which they are united will depend upon the
purpose they are intended to perform, hence joints are divided into three
classes according to their respective range of movement. 1. Dtarthrodial
joints, which enjoy the greatest freedom of action. 2. Ainphiarthrodidl
joints, whose powers of movement are much more i-estricted. 3. Sijn-
arthrodial, or those which are fixed and immovable.
Diarthrodial or Free-moving Joints are composed of two or more
bones whose articular surfaces are covered with a thin layer of cartilage
or gristle, and so formed as to permit one to play freely upon the other.
They are all enclosed in a sac lined by a delicate membrane for the
secretion of synovia or joint-oil, and for the most part the bones ai'e
held together by connecting ligaments.
Ball-and-Socket Joints. — Some diarthrodial joints are formed by
the rounded liead of one l)one fitting into a cup-like cavity or socket con-
tained in another bone. This is the case in the hip-joint (fig. 358), which
allows the leg to be moved in all directions — inward, outward, forward,
backward — and also to be rotated and circumducted or moved in a circle.
Hinge Joints. — Others assume the form of hinge joints, in which
ARTICULATIONS OR JOINTS 263
convexities or prominences on one bone fit into depressions or grooves
in its fellow. In this form of articulation the movement of the joint,
like that of a door, is only to and fro or in the direction of flexion and
extension. A good example of this class of articulation will be found in
the tibio-tarsal or true hock joint (fig. 361), the elbow-joint, &c.
Arthrodia or Gliding Joints. — This variety of diarthrodial joint is
found in the knee (fig. ;354) and the hock joints where the small flat bones
are closely united together, one upon the other, so as to allow simply a
limited gliding motion in various directions.
Amphiarthrosis or Mixed Joints. — In this variety the bones are
connected by a disc of fibro-cartilage, and possess just as much movement
as the flexibility and compressibility of the joining substance allows.
Mixed joints have no smooth surfaces or synovial capsules. Examples
of this description of joint are found in the union of the bodies of the
vertebrae (fig. 346), where a pad of elastic iibro-cartilage exists and gives
to the spine as a whole its flexibility and springiness without permitting
undue mobility between each pair of vertebrse.
Pivot Joints. — Here a pointed extremity of one bone furnishes a
pivot on wliieh another bone turns. This is the case with the odontoid
process of the dentata or second vertebra (fig. 350), which, as has been
previously explained, passes into the ring of the atlas or first neck-bone,
and permits a rotary movement of the latter upon the former.
Synarthrosis or Immovable Joints.— This form of articulation
prevails where fiat bones are united together by their borders to form
cavities, as in the case of the cranium and the cavities of the face. In
some of these a joining is effected by the overlapping of thin plates of
bone. In others, small tooth-like processes from one bone project into
the other, while a third is united by the dovetailing of small serrations, &c.
ARTICULATIONS OF THE TRUNK
Intervertebral Articulations. — All the vertebrae beyond the second
and as far backward as the first sacral are united together by their bodies
and processes. The bodies are connected one to another by circular discs
of fibro-cartilage which intervene between them, and by the superior and
inferior vertebral ligaments, the former running along the fioor of the
vertebral canal, to which it is attached in small festoons. The latter is
situated along the under part of the bodies from the sixth dorsal vertebra
to the sacrum.
Union of the Processes. — The superior processes are connected by
the supraspinous ligament and the inter-spinous ligament (fig. 346).
264
HEALTH AND DISEASE
The former runs along the tops of the superior spinous processes, to each of
which it becomes attached from the second cervical vertebra to the sacrum.
The anterior portion is represented by a broad yellow elastic structure,
termed the ligamentum nuchoe (fig. 347), which extends from the head
backwards as far as the sixth dorsal spine, where it becomes continuous
with the second portion or dorso-lumbar, which is continued to the sacrum
or haunch. The ligamentum nuchas consists of a superior rounded (funic-
ular) portion and an inferior broad fiat (lamellar) portion.
The former or funicular portion extends from the sixth dorsal spine
to the posterior part of the cranium, where it becomes inserted into the
tuberosity of the occipital
bone. This division of the
ligament is very strong,
and shows a groove run-
ning along its superior
surface. It is usually
covered with a dense
mass of fat and connective
tissue, which gives round-
ness to the superior border
of the neck.
The lamellar portion
is a broad sheet of yellow
elastic tissue attached to
the under surface of that
last described. It is com-
posed of two layers, one
placed closely in apposi-
tion with and connected to the other by a loose fibrous substance. The
fibres of these layers pass obliquely forward from the spines of the first
five or six dorsal vertebrae to those of the six posterior neck-bones. The
supra-spinous ligament gives support to the head and neck, and thereby
relieves the muscles from the weight which would otherwise be imposed
upon them at all times. Moreover, by its elasticity it allows of a certain
degree of stretching, and freedom of movement in all directions. Situated
in the middle line of the neck it separates the muscles of one side from
those of the other.
The dorso-lumhar portion of the supra-spinous ligament is attached
to the summits of all the lumbar and the twelve or thirteen posterior
dorsal spines. In front it becomes continuous with the cervical division
or " ligamentum nuchae ", behind with the sacro-iliac ligament.
Fig. 346. — Ligaments of Spine (Side View)
1. Supra-siiinous ligament. 2. Inter-spinous ligaments. 3. Bodies
of dorsal vertebrae divided longitudinally and vertically. 4. Inferior
common ligament. 5. Inter-vertebral discs. 6. Spinal canal.
ARTICULATIONS OF THE HEAD
265
Interspinous Ligaments (2, fig. 346). — In the dorso-lumbar region
there ia a series of short fiat layers of connective tissue passing in a
backward and downward direction from the posterior border of the superior
spinous process of one vertebra to the anterior border of the one succeeding
it. In the cervical region they are composed of elastic tissue to allow
of a more extensive and free movement of the neck.
Fig. 347. — Ligamentum Nuchie
A, Funicular or oordifonn portion. B, Lamellar or flat portion, c, Attachments to dorsal spines.
Nos. 1 to 7, Cervical Vertebrae.
The articular processes of the vertebrae throughout are connected by
means of a capsular ligament, and the same may be said of the articulations
on the transverse processes of the two last lumbar and first sacral vertebrae.
ARTICULATIONS OF THE HEAD
It has elsewhere been pointed out that these are for the most part
immovable, and the mode of formation has been described.
The Tempero-Maxillary Articulation (fig. 348) or joint formed
between the lower jaw and the temporal bone is an exception.
Here the condyles on the superior part of the inferior maxilla fit into
266 HEALTH AND DISEASE
shallow cavities provided by the squamous temporal bones. The condyles
and the cavities are not brought immediately into contact with each other,
but are separated by flat pieces of fibro-cartilage moulded on to the opposed
surfaces, and having a synovial membrane between them and each of the
bones forming the joints.
The bones and cartilages are enclosed in a capsular ligament which, as
Temporo- Maxillary Articulation
1. Section through maxillary condyle. 2. Inter-articular fibro-cartilage.
3. Posterior portion of capsular ligament. 4. Anterior portion of capsular ligament.
we have already observed, is lined by a synovial membrane and strength-
ened by a bundle of fibres on its outer surface.
IIYOIDAL ARTICULATIONS— JOINTS OF THE TONGUE
These are three in number, two cartilaginous and one synovial. The
cartilaginous or amphiarthrodial joints are formed by the union of the
superior extremity of the long horn of the hyoid bone with the petrous
temporal bone, and the inferior extremity of the same with the superior
extremity of the short horn. The synovial articulation exists between the
lower end of the short horn and the body of the bone. See fig. 291, j). 189.
ARTICULATIONS OF THE RIBS
All the ribs are connected with the vertebra above, and the first eight
true ribs are also united with the sternum below, by synovial articulations
ARTICULATIONS OF THE HEAD WITH THE NECK
267
or joints, by which means they are enabled to move freely in the required
directions during respiration or breathing.
Costo-Vertebral Articulations. — Each of these joints is formed by
the articulation of the head of a rib between the bodies of two vertebrae,
and by the union of the tubercle of the rib with the transverse process
of the vertebra behind it. Several small ligaments enter into each joint
1. Common inferior vertebral ligament.
articular costo-vertebral ligament.
2, 2. Inferior costo-vertebral ligaments, 3. Tnter-
4. Inter-vertebral iibro-cartilage in section.
and unite the rib firmly to the spine, while at the same time permitting
free play of one bone upon the others.
CostO-Sternal Articulations. — These are the joints formed b\- the
union of the inferior extremities of the cartilages of the eight true ribs
with the sternum or breast-bone. Each articulation has a capsular liga-
ment lined by a synovial membrane, and two other connecting ligaments
extending from the costal cartilage above and below to the sternum — -
superior and inferior costo-sternal ligaments.
ARTICULATIONS OF THE HEAD WITH THE NECK
OccipitO-Atloid. — The union of the head with the neck is effected by
the articulation of the two occipital condyles with corresponding concavities
268 HEALTH AND DISEASE
on the anterior face of the atlas. This joint is enclosed in a capsular liga-
ment (one to each condyle) and is further supported by small muscles
passing over it above and below (fig. 350).
Atlo-Axoid. — The atlo-axoid joint is formed by the projection of the
Fig. 350. — Occipito-Atloid Articulation
1, Occipital Bone. 2, Atlas (the upper wall removed to show the odontoid ligament). 3, Axis
or Dentata. 4, Third cervical vertebra. 5, Capsular ligament. 6, Odontoid ligament. 7, Fibrous
capsule (partly removed). 8, Interspinous ligament. 9, Fibrous capsule, uniting the articular
processes of the vertebree.
odontoid process of the axis into the ring of the atlas, where it is retained
by the odontoid ligament (fig. 351). Other ligaments, the superior and
inferior atlo-axoid and the capsular, also enter into the structure of the
articulation.
ARTICULATIONS OF THE HEAD WITH THE NECK 269
Fi^. 351. — The Occipito-Atloid and Atlo-Axoid Articulations
A A, Posterior portion of skull. BB, Atlas, cc, Axis or Dentata.
T. — Vertical section througfh the occiput, atlas, and axis. (The occiput is drawn apart from the atlas in order
io show the articular cavity of the latter bone.) 1, The occipital bone. 2, Its basilar process. 3, Occipital con-
dyle. 4, Superior arch of the atlas. 5, Its inferior tubercle. 6, Articular cavity (shown viewed in front at 3,
Vis- 2, Plate XXXVIII). 7, Spinal canal. 8, Odontoid process of the axis. 9, Its superior spinous process.
10, Its inferior spinous process. 11, Spinal canal.
II. —Vertical section through the same bones in their natural position, showing the ligaments. 12, Superior
occipito-atloid ligament. 13. Inferior occipito-atloid ligament. 1-i, Superior atlo-axoid ligament. 15, Inferior
atlo-axoid ligament. 16, Odontoid ligament. 17, Spinal canal, with the dura mater in position. (The spinal cord
has been removed.)
270
HEALTH AND DISEASE
SCAPULO-HUMERAL OR SHOULDER-JOINT
The shoulder-joint results from the union of the glenoid or shallow
cavity on the inferior extremity of the scapula or blade-bone, with the
much larger articular surface jDrovided
by the head of the humerus or upper
arm.
This joint, although so large, pos-
sesses only one ligament, the capsular
(fig. 352), but it receives the support of
a number of muscles which pa.ss over it
and are intimately connected with it.
The shoulder-joint is capable of de-
scribing a great variety and consider-
able range of movement. It allows of
tlexion, extension, abduction, adduction,
rotation, and circumduction.
Fig. 352. — Capsiilar Ligament of Shoulder-Joint
1, Scapula. '2, Humerus. 3, Capsular Ligament.
HUMERO-RADIAL OR ELBOW-
JOINT
Three bones are engaged in the for-
mation of this joint — the humerus above,
the radius below, and the ulna behind.
It lias two latei'al ligaments passing from
the humerus to the radius. The outer
one is the stronger and shorter of the
two; the inner, the longer and smaller.
It has also a capsular ligament of con-
siderable extent, lined by synovial mem-
brane. It is essentially hinge-like in its
action, and admits only of movements of flexion and extension (fig. 353).
353. — Humero-rarli.ll or Elbow-Joint
1, Humerus. 2, Radius. 3, Olecranon process
of ulna. 4, Arciform ligament. 5, External
lateral ligament. 6, Anterior ligament.
ARTICULATIONS OF THE CARPUS OR KNEE-JOINT
271
ARTICULATIONS OF THE CARPUS OR KNEE-JOINT
As we have elsewhere pointed out, tlie
knee is not one joint but several; the chief
of which are: 1 , the radio-carped ; 2, the ca?*-
pal; o, the carpo-metacai'pal. In addition,
other small articulations exist on the sides
of the bones forming the two rows (fig. 354).
The Radio - carpal articulation is
formed by the inferior extremity of the
radius or lower arm and the superior sur-
face of the upper row of carpal bones, the
two parts being suitably modelled to each
other. This joint enjoys and imparts to
the knee the greatest range of movement.
The Carpal joint is that between the
two rows of small bones, and its action.
Fig. 355.— Anterior View of Knee-joint
1, Radius. 2, Scaphoid. 3, Lunare. 4, Cunei-
form. 5, Os magnum. 6, Unciform. 7. Canon.
8, Transverse connecting ligaments. 9, Oblique
connecting ligaments.
Fig. 354. — Tlie Carpus or Knee-Joint
1, Radius. 2, Large metacarpal or canon
bone. 3, Small metacarpal or splint bone.
4, Pisiform bone. 5, Common external liga-
ment. 6. Radio-carpal ligament. 7, Carpo-
metacarpal ligament. 8, Anterior liga-
ments xmiting the two rows of carpal bones.
9, Anterior ligaments proper to the carpo-
metacarpal articulation.
although considerable, is less exten-
sive than that of the radio-carpal.
The Carpo-metacarpal articu-
lation is formed l)y the inferior sur-
face of the lower row of bones and
the superior extremities of the three
metacarpal bones. In the movement
of the knee this joint contributes
nothing to flexion and extension, but
allows a gliding movement favourable
to the action of the joints above.
The articulations by which the
bones composing each row are united
together laterally are small, and only
2i72
HEALTH AND DISEASE
allow of such a measure of gliding movement as will enable the larger
articulations to perform their more extensive and important functions.
The Ligaments. — The ligaments uniting the bones of the knee are
numerous, and comprise lateral ligaments, or
those passing from the sides of the lower end of
the radius — first to the upper row of bones, then
to the lower, and finally to the upper extremity
of the metacarpal bones (figs. 354 and 355);
inter-osseous ligannents, or those situated between
the small bones which they unite ; and a capsular
ligament.
The capsular ligament of the knee is, like
the joint, of considerable extent. Proceeding
from above, where it is attached around the
articular margin of the radius, it descends, to be
similarly connected with the superior extremity
of the large metacarpal bone. Behind, it is very
thick, and is attached to all the small bones of
the knee, and below it is continuous with the
check ligament which joins the tendon of the
flexor pedis perforans.
THE METACARPO-PHALANGIAL ARTICU-
LATION OR FETLOCK-JOINT
The bones which enter into the construction
of the fetlock-joint are four in number, the large
metacarpal or canon-bone, the os sufiraginis or
long pastern, and, behind these, two small sesa-
moid bones.
The lower extremity of the canon-bone rests
upon the superior extremity of the large pastern,
the convexities of the one fitting into correspond-
The two
Fig. 356.
-Ligaments of the Fetlock-
Joint
A, A, Suspensory ligament. B, B,
Outer and inner branches of same.
c, c, Outer and inner sesamoid bones.
D, Superficial or long sesamoid liga-
ment. E, E, Deep or short sesamoid
ligament. F, f, Lateral phaiangiai ing concavitics presented by the other.
ligament g. Crucial sesamoid liga- • -\ ^ ^ ^ •iij.i'Li
ment. H, intersesamoid ligament, scsamoid boncs are closcly United together liy a
I, I, Posterior inter-phaiangiai liga- thick, short, stroug ligament iintersesamoicl liqa-
ments. ' . . , ,
ment), and articulate with the back part of the
lower extremity of the canon-bone. The importance of this joint as a
spring and a means of breaking and dispersing jar or concussion has
rendered necessary a number of ligaments over and above those ordinarily
present in a diarthrodial or free-moving joint.
FIRST IXTEEPHALANGIAL ARTICULATION OK CORONKT-JOINT 273
111 additiou to a capsular ligament, common to all the bones, there are
also two lateral ligaments uniting the canon with the large pastern, and
two lateral sesamoid ligaments, each having two branches extending from
the bones of that name forward, one to the lower and outer part of the
large metacarpal bone, and the other to the upper and outer part of the
long pastern bone (fig. 357).
As the sesamoid bones have no support from below, it is necessary
they should have it from above, to prevent their undue descent. This is
provided by the suspensory ligament (fig. 356), the lower extremity of
which, after dividing into two thick strands, is inserted into these bones.
A similar provision is made to prevent too great upward displacement.
For this purpose three ligaments {infeiior sesamoid), distinguished respec-
tively as the long, short, and crucial, connect the sesamoid bones with the
posterior border of the os coroiue, and with the posterior surface of the
long pastern.
The movements of this joint are hinge-like and of great range both in
flexion and extension.
FIRST INTERPHALANGIAL ARTICULATION OR
CORONET-JOINT
This is a simple joint, of limited action, and formed by the union of the
lower extremity of the os suffraginis with the upper extremity of the small
pastern. The ligaments which unite these bones together are a capsular
ligament, two strong short lateral ligaments, some of the fibres of which
descend and ultimately become connected with the extremities of the
navicular bone, and two short posterior ligaments (fig. 357).
Its movements are those of flexion and extension.
SECOND INTERPHALANGIAL ARTICULATION OR
COFFIN-JOINT
The bones concerned in the construction of this joint are the os coronae
or coronet-bone, the os pedis or foot-bone, and the os naviculare or navi-
cular bone. The two last-named bones are united together in such a
manner as to form two concavities separated by a slight central ridge, to
which are applied the two convexities and central groove upon the lower
end of the coronet-bone.
The ligaments of this joint are : 1 , The capsular, common to the three
bones. 2. The lateral ligaments uniting the os coronae to the foot-bone.
3. The navicular ligaments: a, the broad or interosseous ligament extending
274
HEALTH AND DISEASE
Flo-. 3S7. — LiKament- nf the Pastern and Foot
A, Postei'ioi- aspect, outer layer. B, Inner layer. c, Side view.
1, Superior sesamoid or suspensory ligament, giving off a band, 2, to the extensor pedis. 3, Lateral
.sesamoid ligament. 4, Superficial inferior sesamoid ligament. 5, Deep sesamoid ligament. 6, Crucial
ligament. 7, Lateral ligament of the coronet -joint. 8, Posterior interphalangial ligament. 9, Inter-
sesamoidal substance over which tlie tendons pass. 10, Sesamoid bones. 11, Ligamentous substance common
to the coronal and navicular hones. 12, Navicular bone. 13, Intersesamoid ligament. 14, Lateral
navicular ligament. 15, Anterior lateral ligament of the coffin-joint.
from the anterior border of the navicular bone to the under surface of
the OS pedis or foot-bone; h. the hiteral navicular ligaments which proceed
from each extremity of the navicular bone (l) to the wing of the foot-bone,
(2) to the inner surface of the lateral cartilage, and (3) to the side of the
coronet-bone.
The movements of tlie coffin-joint are flexion and extension.
C'0X()-FE:\I()I!.\L articulation or HIP-JOINT
The hip-joint is formed l)y tlic union of the head of the femur or
thigh-bone with the cotyloid cavity of the coxa (flg. 358).
Four ligaments are engaged in connecting the two bones, viz. the
capsular, cctyloid, round, and puljio-femoral.
Tlie Capsular Ligament is attached around the articular margin of
the femur, to the margin of the cotyloid cavity, and to the cotyloid
ligament. Its inner surface is lined l)y a synovial membrane.
FK.MOKOTII^.IAI. ARTICULATION OR STIFLIvJOINT
The Cotyloid Ligament i« ;i rinu- of til)io-f;util;ige attached around
the margin of the cotyloid cavity. It serves to increase the depth of
the cup, and at the same time to give it a yielding margin for the protec-
tion of the head of the femur. This ligament bridges over the notch in
the inner part of the cup through which the pubio-femoral reaches the
head of the thioh-bone.
The Round Ligament {Uga- Vl*fl H
mentum tors) is a short, strong
fibrous cord extending from the
bottom of the acetabulum to the
inner side of the head of the femur.
The Pubio-femoral Liga-
ment, although short, is longer
and thicker than the round liga-
ment. It is derived from the ten-
dons of the abdominal muscles,
which, in front of the pubes, cross
from right to left and left to right,
and then proceed to the head of
the femur to be attached beside
the round ligament.
The hip-joint is capable of the most A'aried and extensive movements.
Net only is it freely flexed and extended, but as constructed it also permits
of abduction, adduction, circumduction, and rotation of the femur on the
acetabulum.
Fig. 358. — Articulation of the Hip-Joint
A, A, Capsular or enclosing ligament,
ment. c, Pubio-femoral ligament,
ment. E, Head of femur.
B, Round liga-
, Cotyloid liga-
FEMORO-TIBIAL ARTICULATION OR STIFLE-JOINT
This is the corre.sponding joint to the knee of man. It is formed bv
the union of the femur with the tibia on the one part, and with the patella
or knee-cap on the other. The femur raticulates with the upper extremity
of the tibia by its two condyles, and with the patella by its two ridges
or trochlea in front. Between the two condyles and the head of the
tibia there are two crescentic pieces of fibro-cartilage (semihinar cartilages)
vvhich serve to mould the rounded condyles of the thigh-bone upon the
flatter articular face of the tibia.
The three bones composing this joint are united by numerous strong
ligaments, so disposed as to jiermit the gz-eatest freedom of motion, while
at the same time oflfering adequate resistance to the great strain which
is thrown upon them.
The lioanients are divisilile into three sets, viz. those which connect
276
HEALTH AND DISEASE
the patella to the femur and tibia; those which unite the two last-named
bones together; and those which attach the semilunar cartilages to them.
Patellar Ligaments. — These are five in number — two lateral and
three straight. The lateral ligaments extend from the inner and outer
sides of the patella to corresponding parts of the lower extremity of the
femur.
The strau/ht ligaments, distinguished as the external, internal, and
middle, are attached above to the anterior
surface of the patella, and below to the
anterior tuberosity of the tibia.
The middle ligament plays over a
synovial bursa in the groove below which
it is attached, and is, besides, clothed in a
thick cushion of fat.
The Femoro-tibial Ligaments are five
in number, viz. two lateral, two crucial,
and a i^osterior. The lateral ligaments are
situated one on either side, and extend
from the inner and outer condyle of the
femur respectively, to the superior extremity
of the tibia on the inner side, and to the
fibula on the outer side.
The Crucial Ligaments. — These are
two thick short bands situated in the notch
which separates the two condyles, where
they cross each other like the lines of the
letter X. The anterior branch is attached
to the spine on the upper end of the tibia,
and to the intercondyloid notch and the
external condyle. The posterior branch is
united by its lower extremity to the superior
and posterior part of the tibia, and by its
upper end to the notch between the condyles and to the internal condyle.
The Posterior Ligament is practically the posterior section of the
capsular ligament of the femoro-tibial articulation. It is attached to the
femur, behind and above the condyles, and to the posterior part of the
head of the tibia, just below its articular margin. It joins the lateral
ligaments, uniting the femur and tibia on either side, and its inner face
is lined by synovial membrane.
The Interarticular Fibro-eartilages are the creseentic pieces of
dense fibro-cartilage upon which the condyles of the femur are made to
Fig. 359.-
-Femoro-tibial Artii
StiHe-.Ioint
1, Femur. 2, Patella. 3, Middle straitrht
ligament. 4, External .straight ligament.
5, External lateral ligament of patella. 6,
Outer condyle. 7, External lateral femoro-
tibial ligament. 8, Fibula. 9, Tibia. 10,
External inter-articular cartilage.
THE ARTICULATIONS OF THE TARSUS OR HOCK-JOINT
rest on the head of the tibia or second thigh. They are hollowed out
above for the reception of the condyles, for which they form a bed. The
outer cartilage is attached in front to the base of the spine on the head
of the tibia, and behind by two slips, one to the notch between the con-
dyles, and the other to the upper and posterior part of the tibia.
The inner cartilage is attached in front
and behind to the base of the spine on the
head of the tibia.
This joint possesses three synovial mem-
branes, one of considerable extent enclosing
the articular surfaces of the patella, and
the two ridges or trochlea in front of the
femur, and one to each condyle of the
femur and its corresponding half of the
articular face of the tibia.
The movements of this joint are essen-
tially those of flexion and extension, but it
also enjoys a limited power of rotation.
TIBIOFIBULAR AETICULATION
This joint, of very small dimensions
and of most limited action, is formed by
the union of the inner surface of the head
of the fibula with the upper and outer part
of the tibia. The two bones are connected
by short, strong fibres, which completely
surround the joint.
Fig. 360.— Posterior View of Stifle-.Joint
1, Femur. 2, Tibia. 3, Fibula. 4,
External condyle. 5, Internal condyle.
6, Internal lateral ligament. 7, Posterior
crucial lig.ament. 8, Internal inter-ar-
ticular cartilage. 9, Posterior ligament of
cartilage. 10, External lateral ligament.
THE ARTICULATIONS OF THE TARSUS OR HOCK-JOINT
The so-called hock-joint, like the knee, is formed of a number of articu-
lations, by which the various bones are enabled to move one upon the
other. The extent of movement between the different pieces varies from
a slight gliding action to a great range of flexion and extension.
In the tibio - tarsal articulation, or the "true hock -joint", seven
ligaments are engaged, viz., two external lateral, three internal lateral,
and an anterior and posterior.
Both external lateral ligaments are attached above to the tuberosity
{outer maleolus) on the lower and outer part of the tibia. The stiperjicud
one, the longer and stronger of the two, pa.s.ses down the outer side of
278
HEALTH AND DISEASE
the hock, and in its course becomes united with the astragalus, calcaneus,
cuboides. and finally with the large and outer small metatarsal bones.
The External Deep Ligament, on leaving the outer tuberosity of
the tibia, inclines backward, and becomes attached to the astragalus and
the calcaneus.
The Internal Lateral Ligaments are placed one within the other,
and are distinguished as tlie superjicial, the middle, and the deej). All
of them are attached above to the
tuberosity {internal maleolns) on the
inner part of the lower extremity of
the tibia. From thence the internal
superficial ligament passes downward
and becomes connected with (1) the
astragalus, (2) the scaphoid, (3) the
cuneiform, and (4) the large and in-
ternal small metatarsal bones.
The Internal Middle Ligament,
situated beneath that last described,
divides into two short strands, one of
which is implanted into the astragalus,
and the other into the calcaneus.
The Internal Deep Ligament
is a small batch of fibres which be-
comes attached to the astragalus.
The Anterior Ligament. — This
presents the form of a broad mem-
branous or capsular ligament stretch-
ing over the front of the true hock-
joint. It is lined by synovial mem-
brane, and is that portion of the ca^)-
sule which bulges in what is termed
"bog-spavin". The anterior ligament is united to the lower part of the
tibia above, it is attached below to the astragalus and the small
bones of the hock in front, and at the sides it blends with the lateral
ligaments.
The Posterior Ligament is situated behind the joint, and is much
thicker than the anterior, having in its centre a quantitv cf fibro-cartilage,
over which glides the perforans tendon in its course to th3 foot. On
either side its fibres mix with those of the superficial lateral ligament,
and in fioiit. whore it faces the joint, it is lined by synovial membrane.
Abo^■c it is attached to the tibia, and below to the astragalus and calcaneus.
External View of Hock-.Joint
1, Tibia. 2, Calcis. 3, Astragalus. 4, Os mag-
num. 5, Os medium. 6, Cuboid. 7, Calcaneo-
cuboid ligament. 8, Deep set of ligaments connect-
ing one bone with another. 9, Large metatarsal
bone. 10, Small metatarsal bone.
DISKASKS OF THE JOINTS 279
The joints below the hock are the sut
experience teaches us that these fears are, to a great extent, unfounded.
It is not to be understood, however, that we consider such a form of the
fore-legs as safe as those we term perfect. But let us endeavour to
ascertain what gives rise to this affection in the woi'king horse, since to
account for congenital deformity in the foal would be altogether beside
the purpose.
Various hypotheses have been advanced as to what parts are im])li-
cated which would cause this alteration in the form of the carpus. Some
persons consider it to dej^end on a relaxed and lengthened state of the
extensors, others on that of the ligamentous ti.ssue at the anterior part of
the knee; and again there are others who assert that it consists in an
inordinate contraction of the flexors, and to such an extent that the equi-
librium of the two sets of muscles (namely, the flexors and extensors) is
destroyed. Now, although the last hypothesis seems the most fea.sible, still
the results of my di.sseetions of the fore-legs of horses thus affected — and
which were purposely selected — certainly do not confirm any of those
opinions.
The only muscles likely to produce a curving forward of the knee are
the three which flex the metacarpus on the carpus, theii- attachments being
;304 HEALTH AND DISEASE
.siiperiorlv to the condyles of the humerus, inferiorly to the trapezius, antl
t\V(; small metacarpal bones; but in these the scalpel develops nothing
abnormal either in their muscular tissue or the tendinous structure by
which they are inserted and intersected, nor should we expect to find
anything, seeing their function is not interfered with.
At the posterior part of the carpus numerous ligaments are found, which
are so arranged as to admit of extension only in a forward direction, while
the bones present tuberous projections for the attachment of other liga-
ments, the direction of which is from above downwards, ol)liquely crossing
each other (crucial).
May it not be that these ligaments at the posterior part of the knee
l)ecome so deranged as to cause this affection? I am inclined to think such
is the case. I know of nothing, else that would so effectually prevent the
full extension of the liml). It may be asked. What is the primary cause?
Does the scalpel develop any lesion of this ligamentous tissue? In the
specimens I have examined, all have shown the same peculiarities. I have
carefully removed the muscles, both the flexors and extensors, taking care
not to divide the annular ligaments, or, in fact, an)' of those proper to the
carpus; after which I have endeavoured to straighten the leg, but invari-
ably have fiiiled. The abnormal position was persistent, and that to the
.same extent as before the muscles were removed. Further, to test the
share the ligaments took in the flexure, I have made as many as four
transverse sections through them, each of which was followed by an
altered position of the bones, thus allowing the limb to be easily placed
in a straight line, and of necessity leaving a considerable space between the
divided ends of each ligament. The question that now arises is. Can
anything be done to remedy this defect, either by the employment of the
knife, mechanical contrivance, or any other means?
It would seem that the ligaments at the posterior parts of the carpus
are in the first instance slightly sprained, giving rise to a disposition on
the part of the animal to refrain from putting them on the stretch, as this,
no doubt, would produce a certain amount of pain. To avoid this when
standing the extensors are a little relaxed, thus allowing the knee to come
somewhat forwards, thereby removing the tension of the ligaments pos-
teriorlv. This state of parts we observe only occasionally; for when the
animal is excited, or at work, the limbs resume their natural position. This
goes on for a time, but the cause alluded to being still in operation, the
al)normal position becomes permanent; and the burste wdiich are situated at
the lateral, inclining to the posterior, part of the limb, a little above the
knee, are now more than usually filled, which, if the animal be a valuable
one, iniluces the owner to seek advice. This being determined on, it is
PLATE XL
FOAL WITH BOWED LEGS
THE MUSCULAR SYSTEM 305
usually recommended that the horse be placed on a mash diet, and have a
dose of purgative medicine administered to him, and that afterwards he be
blistered once or twice and have a long rest — not less than two months.
The general result of such a course of procedure is that the animal comes
up much improved. He is put to work, which, if hard, in the course of
two or three months causes his legs again to become as bad as ever. Still
he is worked on, until finally he is permanently bowed at the knees, not
l)eing able, as when at first affected, to stand at times upright.
The impediment now consists in a slight thickening and consequent
shortening of the ligamentous tissue we have before referred to.
No treatment in this advanced stage would be of any avail, whether
medicinal, surgical, or mechanical. Such a horse must be considered as
unsound, if the affection exist in more than a slight degree; for although
we daily observe horses thus deformed doing their work well, still, on the
other hand, many of them show lilemished knees, the result of falls.
IT. THE MUSCULAR SYSTEM
There are two kinds of muscle, distinguished as striated or rohnitary
and non-striated or involimtary.
Striated muscle is red in colour, and forms nearly one-half of the
entire weight of the body. It clothes the bones of the .skeleton and
moves them in obedience to the will, hence the term " voluntary" muscle.
A voluntary muscle consists of an aggregation of bundles of fibres
united by connective tissue in which l)lood-vessels and nerves ramify
to nourish and innervate them.
A muscle fibre, as seen under the microscope, is a minute, pale, faintly
yellow filameut. It is composed of an outer sheath or sca-colernma , within
which is contained a coiUractile substance.
The sheath is a very thin, transparent, structureless membrane. It
possesses no power to contract, but, being elastic, is capable of accommo-
dating itself to the necessary changes which its contents undergo.
The contractile substance enclosed in the sarcolemma consists of a
number of delicate filaments placed side by side, termed JihrillcB. Each
fibrilla is composed of a chain of miimte bodies called sarcons elements.
These are united in such a way as to give the fibre a succession
of transverse markings, hence the term striated muscle; other but le.ss
distinct striations occur along its length, as a result of the contact of the
several fibrilte.
Vol, II. 54
306 HEALTH AND DISEASE
Non-striated muscle is of a pale grayisli hue, and enters into the
structure of hollow organs, such as the stomach and bowels, the uterus and
bladder, the l)lood- vessels, the bronchial tubes, &c. &c. It consists of a
number of minute spindle-shaped fibre-cells, about 45^ to 3-5750 of an
inch in breadth and g^jj to 3^^^ of an inch in length. Non-striated muscle
is not under the control of the will, its movements are therefore involuntary,
and carried on by reflex action.
Voluntary muscles are distinguished from one another by various names.
Of these some refer to their action. Those which bend a joint, for instance,
are termed flexors, while others which straighten it again are known as
extensors. There are also levators, depressors, abductors, adductors, con-
strictors, dilators, &c. &c.
Others are distinguished by their length, as the long muscle of the liack,
longissimuti dorsi, the short muscle of the tongue, hyo-glossus brevis. Size,
form, position, direction, and other qualities are also invoked as a means of
recognition.
Voluntary muscles, with few exceptions, exist in pairs — one on either
side of the body or organ in whose function they are engaged. They are
attached by their extremities to two or more bones, which they cause to
move at the instigation of the will.
When in action one extremity of the muscle is fixed, the other is
movable. The former is termed its origin, or the party7'om which it acts;
the latter is its insertioii, or the part upon which it acts and move.s. In
some instances the extremities are alternately fixed and mo\able; what is
at one time the origin is at another the insertion. This is the case with
the mastoido-humeralis, a long muscle running from the arm to the back of
the head. If when the arm is fixed the muscle contracts, the head is drawn
downwards and to one side; and conversely when the head is fixed, the
arm is raised.
Tendons. — Muscles are attached to Ijones either dii-ectly by their fleshy
fibres or by tendons which proceed from them. Tendons transmit the
action of muscles to the bones to be acted upon. They exist in the form
of dense rounded cords of various lengths, or as more or less broad, flat,
expanded sheets. In the latter condition they are spoken of as apoiinirotic
tendons, and are found in their highest development in connection with the
muscles of the belly, where they assist in forming the abdominal walls.
The long cord-like variety are met with in the extremities, where the more
important extend from above the knees and hocks downward to the feet
and pasterns.
Some tendons are partly or completely surrounded by a fibrous .sheath,
and this is lined by a synovial membrane, which, being also reflected on to
MUSCLES OF THE FACE AND HEAD
307
the tendon, enables the hxtter to nio\e freely through the former. This is
more especially the case in the vicinity of joints, as the knee, hock, and
fetlock, where movement is most active. Where tendons play over pro-
jecting points of bone or other prominences, a small, round .sac lined with
.synovial membrane is placed between them to facilitate the movement of
the one over the other. These are known as synovial l)ur.'<£e.
MUSCLES OF THE FACE AND HEAD
The muscles of the ftice comprise a number of longer or .shorter strips,
most of which are attached by one extremity to the bones above, and by
the other to parts about the lips and nostrils below. Those attached to the
Fig. 371. — Muscles of Horse's Head
A, Temporalis muscle. B, Levator palpebrae. c. Orbicularis palpebrarum. D, Supernaso-labialis or
Levator labii superioris alseque nasi. E, Supennaxilo-labialis or Levator labii sui>erions proprius.
F, Supermaxilo-nas.ilis or Dilator nans lateralis. G, Orbicularis oris. H, Mento-labialis. i, Maxilo-labialis
or Depressor labii inferioris. J, Zygomaticns. K, Buccinator. L, Parotid duct. M, Masseter muscle.
X, Parotid gland, o, .Jugular vein. P, JIa.stoido-huraeralis muscle.
former are for the most part muscles of prehension, and serve to gather up
the food and retain it in the mouth during mastication. With one or two
exceptions the muscles of the face are arranged in pairs, one lieing on one
side and the other on the other.
When in action some of them draw the lips upwards, others acting in
an opposite direction pull them downwards, hence they are called levators
and depressors respectively.
The orifice of the mouth is acted upon by a single mu.scle that
encircles the lips {orhicularis oris), and when in action diminishes
308
HEALTH AND DISEASE
the size of the opening, as may be seen in the act of drinking. A
similar muscle [orbicularis 2:)alpebrarum) surrounds the eyelids, which it
closes.
Besides these there are others much larger and stronger, one forming
the anterior part of the cheeks [buccinator and caninus). These are
attached to the upper and lower jaw, along the margins of the sockets
which contain the fangs of the molar teeth. When in action they throw
the food out of the channel of the cheek on to the grinding surfece of tlie
teetli.
Other muscles in this region are engaged in dilating the no.strils, and
thus ministering to the function of respiration.
Levator Palpebrse Superi-
oris E.xternus.
Orbicularis Palpebrarum.
Levator Palpebrse Superi
oris Internus.
Zygomaticus.
Levator Labii Superioris
Alseque Nasi.
Levator Labii Superioris.
Dilator Nan's Lateralis.
Dilator Naris Anterior.
Depressor Labii Inferioris.
From the e.xternal surface
of the frontal bone.
Surrounds the eyelids. Arises
from a small tubercle on
the lachrymal bone.
From the Ijottom of the
orbit behind the eye.
From the outer surface of
the masseter muscle.
From the frotita'
bone.
and nasal
From the malar and the
superior maxilla or upper
jaw-bone.
From the anterior part of
the superior ma.xilla or
upper jaw-bone.
A small, single muscle
attached to the front of
the nasal cai-tilages.
From the anterior border
of the lower jaw behind
the molar teeth.
Into the upper
eyelid.
Into the skin of
the eyelids.
Into the upper
eyelid.
Into the angle of
the mouth.
Into the outer
part of the nos-
tril and the angle
of the mouth.
Joining the ten-
don of its felloAV
on the opposite
side, it is in-
serted into the
upper lip.
Into the side of
the nostril and
upper lip.
To the skin of
the lower lip.
To raise the upper
eyelid.
To close the eye-
lids.
To raise the upper
lid.
To retract the
angle of the
mouth.
To dilate the nos-
tril and draw
the angle of the
mouth upwards.
To elevate the
upper lip and
draw it to one
side.
To dilate the nos-
tril and draw
the upper lip
liackward.
To dilate the nos-
trils.
To depress the
>uider lip.
MUSCLES OF THE FACE AND HEAD
309
Buccinator and Caninus.
Orbicularis Oris.
Dilator Xaris Superioris
Dilator Naris Inferioris.
Depressor Labii Superi
oris.
Levator Menti.
Attached to the tuberosity
of the superior maxilla,
to the anterior border of
the inferior maxilla be-
hind the last molar tooth,
and to the outer surface
of the sockets of the
molar teeth of the upper
and lower jaw. Below
it blends with the angle
of the mouth.
Has no bony attachment.
Encircles the lips.
From the side of the nasal Into the false
peak. j nostril and the
anterior turbin-
ated bone.
From the anterior and
superior maxillary bones.
From the anterior maxillary
bone above the upper in-
cisor teeth.
From the lower jaw beneath
the incisor teeth.
Into the cartilage
at the anterior
extremity of the
posterior tur-
binated bone.
Into the upper
lip.
Into the sub-
stance of the
chin.
To keep the food
between the
upper and lower
molar teeth
during mastica-
tion.
Closesthelipsand
assists in gather-
ing the food, in
drinking, and in
mastication.
To dilate the false
nostril. •
To dilate the false
nostril.
To depress the
upper lip.
To raise the lower
lip.
Masseter. — A broad, thick, square muscle situated on the outer face
of the lower jaw. It is largely intersected by tendinous layers and covered
by a strong fibrous membrane.
Origin. — From the zygomatic ridge of the upper jaw-bone by a strong
broad tendon.
Insertion. — Into the external surface of the upper broad portion of the
inferior maxilla or lower jaw.
Action. — It brings the teeth of the lower jaw forcibly into contact with
those of the upper in grinding the food. It is the most powerful of the
muscles engaged in mastication.
PterygoideuS Internus. — A broad, thick, flat mu.scle situated on the
internal aspect of the su]3erior broad portion of the lower jaw.
310 HEALTH AND DISEASE
Origiyi. — From the sphenoid and palatine liones.
Insertion. — Into the inner surface of the lower jaw opposite the
masseter.
Action. — To bring the lower jaw into contact with the upper, and to
move it from side to side in the process of mastication or grinding the food.
Pterygoideus Externus. — A short, thick, fleshy muscle situated
within and in front of the articulation of the lower jaw with the temporal
bone.
Oi-igin. — From the sphenoid bone at the base of the skull.
Insertion. — Into the inner part of the neck of the lower jaw below the
articular condyle.
Action. — To move the lower jaw forward and to one side in the act of
mastication.
Temporalis. — This muscle lies on the side and front of the cranium,
extending into the temporal fossa.
Origin. — From the outer surface of the parietal, squamous temporal,
and frontal bones, in the temporal fossa, and from the sphenoid bone.
Insertion. — Into the coronoid process of the lower jaw and the anterior
border of the same bone continuous with it.
Action. — To assist in masticating the food by bringing the lower jaw
into contact with the upper and moving it from side to side.
Stylo-Maxillaris. — This is a short, thick muscle situated in the region
of the throat.
Origin. — From tlie styloid process of the occipital bone above in
company with another small muscle — the digastricus.
Insertion. — Into the angle of the lower jaw.
Action. — By pulling the last-named bone away from the uj^per jaw it
opens the mouth.
MUSCLES OF THE EXTERNAL EAR
The external ear consists of a short bon\' tube jjrojecting from the
petrous temporal bone, termed the external auditory canal, together
with three pieces of cartilage, and a number of muscles, vessels, and
nerves, &c.
The Cartilages are distinguished as the conchal, the annular, and the
scutiform. The conchal cartilage forms the framework of all that portion
of the ear which stands erect. It presents a large vertical opening on one
side for the reception of sound, and is attached below to the annular
cartilage, a small ring of gristle connected with the auditory process of the
petrous temporal bone. The scutiform cartilage is a small, flat, somewhat
THE SUPERFICIAL MUSCLES EXPOSED
Orbicularis oris.
Dilatator naris lateralis.
Levator laliii superioris alseque nasi.
Levator labii superioris propiius.
Depressor labii iuferioris.
Zygoraaticus.
Buccinator.
Masseter.
Temporalis.
10. Mastoido-hmueralis.
Ehomboideus.
12. Spleuius.
Sterno-maxillaris.
14. Trapezius
(a) Cervical division.
(6) Dorsal division.
15. Supraspinatus.
16. Infraspinatus.
17. Deltoid.
18. Caput magnum.
19. Caput medium.
20. Extensor metacarpi magnvis.
21. Extensor pedis.
22. Flexor metacarpi externus.
23. Extensor suffraginis.
24. Extensor metacarpi obliquus.
25. Extensor metacai-pi magnns.
26. Flexor metacarpi iuternus.
27. Ulnaris accessor! us.
28. Flexor metacarpi medius.
29. Extensor metacarpi obliquus.
30. Latissimus dorsi.
31. 31. Serratus anticus.
32. 32. Serratus magnus.
33. Posterior deep pectoral.
34. 34. Intercostal mjiscles.
35. Gluteus medius.
36. Superficial gluteus.
37. Tensor vagina femoris.
38. Biceps femoris.
39. Semi-tendinosus.
40. Gastrocnemius.
41. Soleus.
42. Flexor pedis.
43. Peroneus.
44. Extensor pedis.
45. Flexor metatarsi.
iMUSCLES OF THE EXTERNAL EAR
311
triangular cartilaginous plate situated in the front of the base of the
concha, to which it is attached. The cartilages of the ear are for the
purpose of collecting and transmitting sound to the essential organ of
hearing within the temporal l)one, and to eftect this purpose they, and
especially the concha, rccpiirc to be mo\ed in various directions. This
is effected by means of the following muscles, which are connected with
them : —
Zygomatico-Auricularis. — This comprises two thin slips of muscle
ari.^iii;/ from the zygomatic process of the squamous temporal bone. They
Fig. 372.— Muscles of the Ear. Fig. .'SZS.— Muscles of the Ear. Fig. 374.— Muscles of the Ear.
(Anterior aspect ; outer and deep layers. ) i Lateral aspect. ) (Posterior aspect.)
1, Temporalis. 2, Parieto-auricularis intenius. 3, Parieto-auricularis externus. 4, Scuto-aurioilaris
intenius. 5, Zygomatico-auric\ilaris. 6, Scutiform Cartilage. 7, Scuto-auricularis externus. 8, Corru-
gator Supercilii. 9, Parotido-auricularis. 10, Splenius. 11, Tendon of Sterno-cleido-mastoideus. 12, Mas-
seter. 13, Cervico-auricularis externus. 14, C'ervico-auricularis medius. 15, Obliquns Capitis Superior.
become inserted into the scutiform cartilage, and into the outer and inferior
part of the concha.
Action. — To draw the ear forward.
ParietO-Auricularis Externus.— A broad, thin mu,scle spread over
the superior part of the forehead aud covering the temporalis muscle.
Origin. — From the parietal crest or bony ridge in the centre of the
forehead.
Insei'tion. — By two slips, one to the inner margin of the scutiform
cartilage and the other to the inner and anterior part of the conchal
cartilage.
Action. — To draw the ear inwards and direct the opening forward, as
when " pricked "
ScutO-Auricularis Externus.— This muscle attaches the scutiform
cartilage to the inner side of the concha. It assists in drawing the ear
inwards and directing the opening forward.
312 HEALTH AND DISEASE
Cervico-Auricularis. — Three muscles are included in this term — the
superficial, the middle, and the deep.
Origin. — All three arise from the ligamentum nuchte at tlie summit of
the head, where they are jjlat-'ed one upon another.
Insertion. — The superficial cervico-auricularis is inserted into the
middle of the inner surface of the concha, the middle one into the outer
side of the same cartilage, and the deep one into the posterior asjDect of its
base.
Action. — To turn the ear so that its opening shall be directed outward
or backward.
Parotido-AuriCUlaris. — A long, thin, ribbon-shaped muscle situated
on the external surface of the throat in contact with the parotid gland.
Origin. — From the outer surface of the parotid gland, from which it
ascends to be inserted into the outer part of the base of the concha,
immediately beneath the opening.
Action. — To abduct or move the ear outward.
ParietO-Auricularis Internus. — A triangular muscle placed beneath
the one last described.
Origin. — From the superior part of the parietal crest.
Insertion. — Into the inner side of the base of the conchal cartilage.
Action. — To draw the ear inward towards the centre of the poll.
ScutO-Auricularis Internus. — This muscle is composed of two small
divisions, which cross each other somewhat obliquely.
Origin. — From the inner surface of the scutiform cartilage.
Insertion. — Into the posterior part of the base of the concha.
Action. — A.ssists in directing the opening of the ear outwards, and also
backwards when recjuired.
MaStoido-Auricularis. — A very small muscle, situated at the inner
side of the root of the ear.
Origin. — From the margin of the auditory 2:)rocess of the petrous
temporal bone.
Insertion. — Into the base of the conchal cartilage.
Action. — Not definitely known.
The basement cartilages of the ear rest upon a cushion of fat, which
facilitates their rapid movement in various directions.
MUSCLES OF THE HYOID REGION
Mylo-Hyoid. — This muscle is situated beneath the tongue and between
the branches of the lower jaw. With its fellow they stretch across from
one branch to the other, and support the tongue as in a sling.
.MUSCLES OF THE HYOID REGION 313
Origin. — From the inner face of tlie lower jaw liehind the ninlar
teeth.
Insertion. — From the point of origin its fibres pass under the tongue
and meet those of thi; muscle from the opposite side in the centre, where
they blend together. Behind they are inserted into the si)ur-like projection
of the tongue bone.
Action. — This muscle lifts the tongue towards the palate, and assists in
mastication and swallowing.
Genio-Hyoideus. — This is a long, narrow muscle, with tapering ex-
tremities, situated beneath the tongue.
Origin. — From the lower jaw, near the symphysis or joining of the two
branches.
Insertion. — Into the spur-process of the hyoid or tongue bone.
Action. — To draw the hyoid bone forward and assist in protruding the
tongue.
Stylo-Hyoid. — Situated in the region of the throat.
Origin. — From the superior and posterior part of the long cornu of the
hyoid or tongue bone.
Insertion. — Into the outer part of the heel-like process of the same
Ijone, where its tendon divides to allow the middle tendon of the digastricus
to pass between its branches.
Action. — To draw the larynx and the tongue backwards and upwards.
Hyoideus Trans versus. — This is a small single muscle placed between
the two small cornua of the tongue bone. It is attached to the inner
surface of each, and crosses over from one side to the other.
Action. — To maintain the small cornu in position during the various
movements of the tongue.
KeratO-Hyoid. — A small, flat, triangular muscle situated at the root of
the tongue.
Origin. — From the posterior border of the lower end of the long cornu,
and from the posterior border of the small cornu.
Insertion. — Into the upper border of the heel process of the tongue
bone.
Action. — To raise the heel process and elevate the larynx.
The Digastricus. — This is compo.sed of two small muscular masses
unitr(l liy a short tendon; hence it is called digastric or a double-bellied
muscle.
Origin. — With the stylo-maxillaris from the styloid process of the
occipital bone. The tendon intervening between the two bellies plays
through a division above referred to in the tendon of another muscle (stylo-
hyoid) against the tongue bone.
314 HEALTH AND DISEASE
Insertion. — The second belly is inserted into the jjosteiior Ijorder of the
lower jaw behind the chin.
Action. — To raise the hyoid bone and assist in opening the mouth.
OccipitO-Styloid. — A very short, small, Hat muscle situated at the
posterior part of the base of the skull.
Origin. — From the anterior part of the st}'loid process of the occipital
bone.
Insertion. — Into the upper extremity of the long cornu of the hvoid
bone (bone of the tongue).
Action. — To draw the bone of the tongue upwards and backwards.
]\IUSCLES OF THE TONGUE
Stylo-GloSSUS. — A long, narrow, Hat muscle situated on the side of
the tongue.
Origin.- — ^From the outer part of the inferior extremity of the long
cornu of the tongue bone.
Insertion. — Into tlie tip of the tongue.
Action. — Acting with its fellow on the opposite side, it would pull
the tip of the tongue u]3wards. Acting alone, it would draw it to one
side.
Great HyO-GloSSUS. — Situated in the substance of the tongue.
Origin. — From the heel-like process and body of the tongue bone.
Insertion. — Into the front part of the mucous membrane of the tongue
along the greater portion of its length.
Action. — To draw the tongue backwards and upwards.
Genio-HyO-GloSSUS. — A broad, thin, fan-shaped muscle placed in the
centre of the tongue. Some of its fibres pass downwards to the tip, others
to the centre, and a third portion to the root of the tongue.
Origin. — From the inner surface of the lower jaw, near the symjjhysis,
or union of the two branches.
Insertion. — Into the under surface of the mucous membrane, along its
middle, from the tip to the root.
Action. — The lower portion of the muscle when contrat-ting would draw
the tongue into the mouth, the upper division would cause it to protrude.
The central part would pull it away from the roof.
Small Hyo-GlossuS. — A very small muscle surrounded l)y fat and
situated at the root of the tongue.
Origin. — From the inferior extremity of the small cornu and the body
of the tongue bone.
Insertion. — Into the posterior part of the sul)stance of the tongue.
SECOND LAYER OF MUSCLES EXPOSED
1. Temporalis.
2. Levator labii superioris aUcqu* na
3. Levator labii superioris.
4. Dilator iiaris lateralis.
5. Orbicularis oris.
6. Zygoniaticus.
7. Depressor labii iiiferioris.
8. Buccinator.
9. Masseter.
10. Trachea.
11. Jugular vein.
12. Steruo tliyro-hyoidens.
13. Scalenus.
14. Anterior deejj pectoral.
15. Supraspinatus.
16. Infraspinatus.
17. Teres minor.
18. Caput magnum.
19. Caput medium.
20. Extensur pedis.
21. Extensor metacarpi magnus.
22. Extensor metacarpi obliquus.
23. Extensor suft'raginis.
24. Flexor pedis perforatus.
25. Flexor metacarpi internus.
2fi. Ulnaris acces.sorius.
27. Flexor metacarpi externus.
28. Extensor metacarpi magnus.
29. Serratus magnus.
30. Olilicpius abdominis externus.
31. External intercostals.
32. Obliquus abdominis internus.
33. Peroueus.
34. Flexor metatarsi.
35. Flexor metatarsi in section.
30. Flexor accessorius.
37. Extensor pedis.
38. Flexor perforans.
39. Plautaris.
40. Gastrocnemius.
41. Semitendinosus in section.
42. Vastus externus.
43. Adductor magnus.
44. Semimembranosus.
45. Depressor coccygis.
46. Compressor coccygis.
47. Curvator coccygis.
48. Erector coccygis.
49. Middle gluteus.
50. Obliquus abdominis internus.
51. Retractor costie.
52. Serratus posticus.
53. Serratus anticus.
54. Khomboideus (doreal portion).
55. Ehomboideus (cervical portion).
56. Levator anguli scapula-.
57. Splenius.
58. Mastoido-luimeralis in section.
MUSCLES OF THE PHARYNGEAL REGION
315
In passing forward to its insertion it crosses over tlio ]i}'oideus trans-
versus.
Action. — To retraet the toniine.
rf^
Fiff 375. — Muscles of the Tongue, Soft Palate, and Laiynx
1, Tensor Palati. 2, Occipito-Styloid (riglitl. 3, Occipito-Styloid (left). 4, Palato-Glossus.
Hyoid Pharyngeus. 6, Thyro-Pharyngeus. 7, Crico-Pharyngeus. 8, Palato-Pharyngeus.
Thyroideus. 10, Sterno-Thyroideus. 11, Thyro-Hyoideus. 12, Stylo-Glossus. 13, Genio-Hyoideu:
14, Great Hyo-Glossus. 15, Genio-Hyo-Glossiis. 16, (Esophagus.
5, Stylo-
y, Crico-
PalatO-GloSSUS. — -A small collection of mu.scle fibres arising from the
side of the pharynx and becoming inserted into the root of the tongue.
Action. — To constrict the fauces.
MUSCLES OF THE PHARYNGEAL REGION
PterygO-PharyngeuS. — A thin, flat, triangular mu.scle lying above
the pharynx.
Origin. — From the pterygoid process, from which its fibres spread out
fan-like and become inserted into the upper and lateral aspect of the
pharynx. Some of its fibres intermix with those of the palato-pharyngeus.
Action. — To constrict the pharynx.
HyO-PharyngeUS. — A .small mu.scle .situated on the inferior and
lateral parts of the pharynx in front.
Origin. — From the heel process of the hyoid bone.
Insertion. — Into the roof of the pharynx, where its fibres interlace with
those of its fellow.
Thyro-Pharyngeus. — Situated behind the one last described.
Origin. — From the outer surface of the thyroid cartilage.
Insertion. — Into the roof of the pharynx, where its fibres interlace with
those of its fellow.
316 HEALTH AND DISEASE
Crico-Pharyngeus. — Placed liehind the thyio-pliaryiigeus.
Orujin. — From the outer surface of the cricoid cartilage.
Liscrtion. — Into the roof of the pharynx, where its fibres interlace with
those of its fellow.
Action. — The three muscles last described constrict the pharynx.
Stylo-Pharyngeus. — A triangular muscle situated above the pharynx.
Origin. — From the inner surface of the long cornu of the hyoid bone.
Insertion. — Below it spreads out its fibres and becomes inserted into
the outer edge of the pharynx.
Action. — To dilate the pharynx.
MUSCLES OF THE SOFT PALATE
PalatO-Pharyngeus. — This muscle lies in the posterior part of the
soft palate. It is attached to its fellow on the opposite side, to the outer
wall of the pharynx, and to the superior border of the thyroid cartilage.
Action. — To tighten the soft palate, and raise it during swallowing.
Tensor Palati. — A small. Hat, thin muscle placed above the pharynx.
Origiyi. — From the styloid process of the petrous temporal lione.
Insertion. — The tendon of this muscle plays over a pulley-like arrange-
ment on the free process of the pterygoid bone, and, after spreading out,
becomes inserted into the posterior wall of the pharynx.
Action. — To render the front portion of the palate tense.
Levator Palati. — A thin band of muscle situated above the pharynx.
Origin. — With the muscle last described from the styloid process of the
temporal bone.
hisertion. — Into the soft palate.
Action. — To raise the velum palati.
MUSCLES OF THE LARYNX
Thyro-Hyoid Muscle. — A Hat triangular muscle spread over the side
of the thyroid cartilage.
Origin. — From the entire length of the heel jjrocess of the hyoid or
tongue bone.
Insertion. — Into an oblique ridge on the outer side of the thyroid
cartilage.
Action. — To raise the larynx and draw it forward.
Hyo-Epiglottideus. — A short, small bundle of fibres situated at the
root of the tongue in a mass of fatty tissue.
Origin. — From the u])]ier surface of the body of the hyoid bone.
MUSCLES OF THE LARYNX 317
Insertion. — Into the front and lower part of the epiglottis.
Action. — To draw the epiglottis forward and downward after it has
been pushed over the glottis in the act of swallowing.
Crico-Thyroid Muscle. — A small, narrow muscle placed on the outer
side of the cricoid cartilage.
Origin. — From the upper and anterior part of the cricoid cartilage.
Insertion. — Into the inferior part of the thyroid cartilage.
Action. — To maintain the two cartilages in position during the nction
of the more movable parts, while at the same time permitting a certain
amount of liberty between themselves.
Posterior Crico-Arytenoid Muscle. — It occupies the upper and
Ijack part of the larynx, a great portion of which it covers. It is the
largest and most powerful of the intrinsic muscles connected with this
organ.
Origin. — From the posterior broad surface of the cricoid cartilage.
Insertion. — Into the outer angle of the arytenoid cartilage.
Action. — To draw the arytenoid cartilages apart and dilate the opening
into the larynx.
Lateral Crico-Arytenoid Muscle. — A small muscle situated on the
upper and posterior part of the larynx.
Origin. — From the upper part of the anterior border of the cricoid
cartilage.
Insertion. — Its fibres, passing upwards and backwards, become inserted
into the outer angle of the arytenoid cartilage with the posterior crico-
arytenoid muscle.
Action. — To constrict the laryngeal opening.
Thyro-Arytenoid Muscle. — This muscle is composed of two small
bundles of fibres situated on the inner side of the thyroid cartilage, where
they are separated from each other by the interposition of a pouch of
mucous membrane (ventricle of the larynx).
Origin. — From the inner surface of the body of the tliyroiil cartilage.
Insertion. — By some of its fibres into the outer border of the arytenoid
cartilage. Others mingle with those of the arytenoid muscle.
Action. — To constrict the larynx.
Arytenoideus Muscle. — A pair of small muscles .situated on the
up[)er and posterior surfac(> of the arytenoid cartilages. They are united
in the middle line by the intermixing of their fibres, and are inserted
into the posterior surface of the arytenoid cartilage.
By .some this muscle is said to constrict the laryngeal opening, and by
others to dilate or open it.
318 HEALTH AND DISEASE
MUSCLES OF THE NECK
Rhomboideus. — This is a long triangular muscle situated at the upper
border of the neck, where it commences at the second cervical vertebra and
extends backward to the fifth dorsal vertebra.
Origin. — From the superior border of the ligamentum nuchse and the
superior spinous processes of the 2nd, 3rd, 4th, and 5tli dorsal vertel)rfe.
Insertion. — Into the inner surface of the cartilage on the upper border
of the scapula.
Action. — To draw the scapula upwards and forwards. Acting when the
scapula is fi.\ed, it would incline the neck to one side.
Levator Anguli Scapulae. — A muscle of consideralde size spread
over the lower half of the side of the neck, from which its fibres converge
toward the cervical angle of the scapula.
Attachments. — To the transverse processes of the four or five posterior
cervical vertebrse, and to the internal surface of the upper extremity of the
scapula, just in front of the serratus magnus.
Action. — This muscle, like the one previously described, may act from
either extremity. AVhen the neck is made a fixed point it would pull
forward the upper end of the scapuhi and cause the shoulder point to
recede. AVhen the scapula is fixed, the muscle acting alone would draw
the neck to one side, or, acting with its fellow, the neck would be lifted up.
SpleniuS. — A broad, triangular, flat muscle, situated on the side of
the neck, and extending from the summit of the head backward to the
withers.
Origin. — From the superior spinous jn-ocesses of the 2nd, 3rd, and 4th
dorsal vertebrae and the upper border of the ligamentum nuchpe.
Insertion. — Into the mastoid crest of the temporal bone and the trans-
verse processes of the first five cervical vertebrae.
Action. — Acting alone, the sjolenius draws the head and neck towards
the side upon which it acts. When co-operating with its fellow on the
opposite side, they elevate the head and neck.
The Complexus. — This is a strong, fleshy muscle deeply seated on
the side of the neck, in close apposition with the ligamentum nuchse,
which divides the right from the left complexus. It extends from the back
behind to the head in front, becoming narrower as it passes upwards.
Origin. — From the spinous processes of the 1st, 2nd, 3rd, and 4th dorsal
vertebrae, from the transverse processes of the first six, and from the articular
tubercles of all the cervical vertebrae.
Insertion. — Into the posterior part of the occipital bone*
MUSCLES OF THE NECK 319
Action. — Contractiii;^ alone, it would bend the neck to one side.
Acting together with its fellow on the opposite side, it elevates and
extends the head.
Trachelo-Mastoideus. — Situated on the side of the neck heneath the
.splenius. It is u lung muscle, composed of two Heshy divisions which pass
from the head downwards to the anterior extremity of the back.
Origin. — It takes its origin from the transverse processes of the first
two dorsal vertebrje, and from the articular tubercles of the last six cervical
vertebrae.
Insertion. — Into the ma.stoid process of the temporal bone, and to the
wing of the atlas by a Hat tendon common to the splenius and mastoido-
humeralis.
Action. — When acting alone, the trachelo-mastoideus draws the head
and neck to one side. When acting with the corresponding muscle of the
other side, it raises the head.
Spinalis Colli. — Five thick, short strands of muscle deeply seated on
the side of the neck in proximity with the bones. They are in continuation
of similar short muscular fasciculi, presently to be noticed, in the regions of
the l)ack and loins.
Origin. — From the oblique processes of the five posterior cervical
vertebrte or neck bones.
Insertion. — Into the spinous processes of the 2nd, 3rd, 4th, 5th, and
6th of the same.
Action. — To extend the neck, and to fix the bones in accordance ^vitli
the action of other of the cervical muscles.
IntertransversaleS Colli. — These are six short muscles placed on the
side of the neck in apposition with the vertebra?. Each extends from the
oldic|ue process of one vertebra to the transverse process of the one preced-
ing it, except in the case of the two first.
Action. — To draw the neck to one side.
Obliquus Capitis Superior. — A short, thick, square muscle situated
on the side of the poll. It is largely intersected by strands of tendinous
ti.ssue, and covers over the articulation between the occiput and the first
cervical vertebra.
Origin. — From the ajiterior border and under surface of the wing of the
atlas.
Insertion. — Into tlie mastoid crest and the styloid process of the
occiput.
Action. — To incline the head to one side and to assist in extending it.
Obliquus Capitis Inferior is a thick, fleshy muscle, somewhat longer
than the last described, and situated immediately below it.
320 HEALTH AND DISEASE
Orirjin. — From the outer surface of the superior spinous rvocess of the
second cervical vertebi'a (axis or dentata).
Insertion. — Into the superior surface of the wing of the atlas.
Action. — To rotate the atlas on the dentata. Its action is shown in a
strikiu'j manner when tlie horse shakes his head.
Rectus Capitis Posticus Major. — A short, fleshy muscle placed
beneath that last described, and partly divisible into two portions.
Origin. — From the superior spinous process of the dentata or second
cervical vertebra.
Insertion. — Into the posterior part of the occipital bone.
Action. — Assists the complexus major in extending the head on the
neck.
Rectus Capitis Posticus Minor. —A small, wide, Mat muscle placed
beneath that last described, and extending over the articular capsule of the
joint formed by the occiput and the first cervical vertebra.
Origin. — From the superior surface of the atlas.
Insertion. — Into the posterior surface of the occiput.
Action. — It assists in extending the head on the neck.
Cervical Panniculus. — This is a thin layer of iiiuscular tissue spread
over the front of the neck, extending from the breast below, upward, to
behind the jaws, and on to the sides of the face.
Below, it is attaclied to the cariniform cartilage of the sternum, to which
it converges from either side. Above, it becomes closely adherent to the
muscles in front of the neck, which it braces and supports.
Cervical Trapezius. — See muscles of the back.
Mastoido-Humeralis. — This is a long, broad, fleshy muscle, extending
from the top of the head downward along the side of the neck over the
point of the shoulder to the humerus or upper arm bone.
Origin. — Above from the mastoid process and crest of the occipital
bone, and from the transverse processes of the first four cervical ver-
tebrae.
Insertion. — Into the upper third of the ridge on the outer part of the
humerus.
Action. — This is a muscle of considerable power and importance, being
specially instrumental in raising the linil) from the ground and carrying it
forward in progression. Upon it chiefly depends that grand shoulder action
.so much admired in our best harness horses.
It is capable of acting in two directions: when the head is fixed it
raises and advances the foredimb; w-hen the fore-limb is fixed, as in a
standing posture, it draws the head to one side, or, acting with its fellow
on the opposite side, it pulls it downward.
n^i':