The skeleton of the horse : with key and explanatory notes

Wilkie, Henry C. (Henry Charles), Govt. Printer, Wellington, N.Z., 1904

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Title: The skeleton of the horse : with key and explanatory notes

Author: Wilkie, Henry C. (Henry Charles)

Published: Govt. Printer, Wellington, N.Z., 1904

THE NATIONAL LfBRARY OF NEW ZEALAND

THE SKELETON OF THE HORSE.

With Key and Explanatory Notes

BY

HEINRV O. WILKIE, F.R.0.V.5.,

VETERINARY DIVISION, DEPARTMENT OF AGRICULTURE, NEW ZEALAND

WELLINGTON.

AUTHORITY : JOHN MACKAY, GOVERNMENT PRINTER

1904.

THE SKELETON OF THE HORSE.

THE drawing of the skeleton of the horse has been made with J- the intention of giving as clear an idea of the general construction of the osseous framework of the animal as possible, omitting, however, such details as might tend to confuse those unacquainted with comparative anatomy.

The general outline or contour of the horse has been made in solid black, and shows to what extent this is determined by the bonv structure. In the head, for instance, it will be seen that the wellknown outlines are very largely governed by the shape of the skull, while in the contour of the neck the bones play but little part.

The bones of each side are symmetrically paired, and these pairs are in all essential particulars identical. Therefore, though a somewhat new departure in anatomical delineation, it has been considered of some possible advantage to omit structures which belong to the farther side such as the ribs, &c.

The skeleton is made up of an axial portion and its appendages, The axial portion (axis, or trunk) consists of the skull and vertebral column or backbone which supports the ribs and sternum. The appendages are the two pairs of limbs which are attached to the trunk by means of what are termed girdles—the fore limbs by the pectoral or shoulder girdle, and the hind limbs by the pelvic or hip girdle.

The vertebral column forms a bony tube for the lodgement and protection of the spinal cord, and is divisable by its special anatomical characteristics into five portions.

The whole column consists of fifty-four bones, but as five of them are fused together there are fifty separate bones, each movable upon its immediate neighbours. These bones are bound together bv powerful ligaments, and between the adjoining surfaces are thick cartilages which lessen the damaging effects of concussion.

The first or cervical portion of the vertebral column consists of seven bones, which are more or less cubical in form, and are so articulated as to allow of the greatest possible freedom of movement.

The second or dorsal portion is made up of eighteen bones which support the ribs, while the lumbar vertebrae arc six in number, and bv their extensive transverse processes form a kind of roof to that part of the abdomen.

The fourth portion of the vertebral column is the sacrum, which consists primarily of five bones fused into a single one, and which forms a kind of roof to the pelvis.

The coccygeal vertebra, with a varying number of from fifteen to eighteen bones, complete the column.

The neural canal, for the reception of the great nervous axis or spinal cord, exists from the first cervical vertebra throughout the whole column, until the first few bones of the coccygeal region are reached, where it terminates. The actual termination of the neural canal varies in different horses at from the third to the fifth coccygeal vertebra.

Both the fore and the hind limbs of the horse may be primarily divided into three segments a proximal [femur and humerus), a middle [tibia and radius), and a distal [metapodials, or, individually, metacarpals and metatarsals). Following the distal segments are the phalanges or digits, and it will be seen that the horse stands and moves upon the extremity of his third digit.

Being, therefore, an animal with a single toe, the horse belongs to the Perissodaetyle or odd-toed group, a classification which includes all equine animals, the tapir, and the rhinoceros.

A notable feature of the skeleton of the horse is the total absence of the clavicle or collar-hone. This fact is the more interesting because it is a special anatomical characteristic of the ungulates or hoofed animals. The clavicle is well developed in birds, reptiles, and amphibians, and also in many orders of mammals, such as the primates, marsupials, edentates, and insectivores, while in rodents and carnivores it exists as a distinct rudiment.

In some portions of the skeleton, where elasticity is specially needed, and where an unyielding material would he either inadmissible or liable to injury, hone is replaced by gristle or cartilage, or, it may be more correct to say, bones are continued hv cartilage. As an essential part of the skeleton these have been included in the d rawing.

The cartilaginous extension of the scapula is seen in the cartilage of elongation at No. 102.

The highly elastic cartilaginous extensions of the ribs are seen at No. 65, and form the extremity of every rib.

Tlie osteo-cartiiaginous mass called the sternum extends from No. 22 to No. 50, while the elastic wing-like extensions of the pedal hones are seen in the lateral fihro-cartilages at Nos. 34, 36, 53, 68.

the skeleton of the house. Entered at Stationed Hall, 1903.] [Drawn by H. C. Wilkie.

REFERENCES.

1. Parietal bone,

3. Zygomatic arch

3. Supra-orhital foramen of the frontal bone

4. Orbital cavity—a bony socket for reception of the eycba

5. Lachrymal bone

6. Nasal bone.

7. The infra-orbital foramen, or supermaxillo - dental canal ol the superior maxillary bone.

8. Zygomatic ridge of the superior maxillary bone

9. Nasal peak

10. Premaxillary bone. Immediately behind the termination of the pointer is seen the eanine tooth or tush, that of the lower law being seen below it.

11. The corner incisor tooth (upper

12. The foramen menti, or anterior maxillary foramen.

13. The molar teeth. The pointer here terminates on the upper third molar.

14. Malar bone

15. Inferior maxilla

16. Roughened surface of the bone for attachment of the massete muscle.

17. The shoulder-blade, or scapula. The pointer here terminates on the postea-spinatus fossa, which is separated from the anteaspinatus fossa by a ridge called the spine of the scapula.

18. The first rib. In the horse there are eighteen ribs on either side, of which eight articulate by means of their cartilages with the sternum, and are called true or sternal ribs. Ihe asternal or false ribs are prolonged by cartilages, each of which end in a point, and these cartilages are attached to each other by strong connective tissue. The head of every rib articulates with two vertebrae by means of an intervertebral articular cavity, while the tuberosity with which each rib is provided corresponds by its facet to a lacet on the transverse process of the posterior vertebra.

19. The coracoid process.

20. Inferior extremity of the scapula, which articulates with the head of the humerus by means of a glenoid cavity.

21. Head of the humerus,

22. Cariniform cartilage of the sternum

23. Shaft of the humerus, showing the twist on the body of the bone.

24. The first of the sternibrae.

25. The second „ „

26. The third „ „

27. Fossa for insertion of the external lateral ligament

28. The inner aspect of the radius.

29. The inferior extremity of radius articulating with the carpus,

30. Lunar or semilunar

31. Scaphoid.

32. The magnum, which articulates posteriorly with the trapezoid

33. The large metacarpal bone

34. The os pedis. The pointer here is on the basilar process of the bone.

35. The os pedis, or “coffin bone,” of the right foot —the third phalanx.

36. The lateral fibro-cartilage

37. The second phalanx, or os corome

38. The first phalanx

39. The external sesamoid bone

40. The cannon bone, or large metacarpal

41. The external small metacarpal, or splint bone

42. The unciform

43. The magnum

44. Lunar

45. Cuneiform

46. Trapezium

47. The shaft of the radius

48. The radio-ulnar arch

19. The ulna

50. The ensiform cartilage of the sternum

51. The retrossal process of the os pedis

52. The basilar process of the os pedis

53. The lateral fibro-cartilage

54. The second phalanx

55. The first phalanx

56. The external sesamoid bone

57. The inferior extremity of the large metatarsal bone

58. The large metatarsal bone

59. The external small metatarsal hone

60. Cuneiform magnum

61. Cuboid

62. Cuneiform medium or scaphoid

63. Astragalus,

64. The external malleolus of the tibia,

65. The costal or rib cartilages—the pointer being on the last of these.

66. The retrossal process of the os pedis

67. The os pedis, showing its numerous foramina for the passage of blood-vessels.

68. The lateral fibro-cartilage of the inner side of the foot

69. The second phalanx, or os coronse

70. The first phalanx

71. The internal sesamoid bone.

72. The inferior extremity of the large metatarsal bone

73. The shaft of the large metatarsal bone.

74. The internal small metatarsal bone

75. Cuneiform parvum

76. Cuneiform medium or scaphoid

77. The internal aspect of the astragalus

78. The calcis,

Inferior Maxilla. —Latin, inferior, lower ; maxilla, a jaw.

79. The inner aspect of the tibia

Masseter. —Greek, masseter, one that chews; massaomai , 1 chew.

80. The outer aspect of the tibia,

Sternum.—Greek, slernon, the breast.

Asternal. -Greek, a, without; sternal, of the sternum.

81. The fibula. The pointer terminates in the centre of the head of the bone.

.uiimumu. viv/v.., iv, , Vertebras. —Latin, vertebra:, joints ; from verto, I turn.

Intervertebral. —Latin, inter, between ; Eng., vertebral. from the

Coracoid.— Greek, koraks, a crow; korakos, of a crow ; eidos, a resemblance— trom me resemblance this process bears in human anatomy to a crow s beak.

82. Rough tuberosities for ligamentous insertion

83. The patella.

Humerus. —Latin, humerus, the shoulder.

Scapula.—Latin, scapula, the shoulder-blade.

84. The supra-condyloid fossa

Glenoid. —Greek, glene, a socket; eidos, a resemblance.

Cariniform.—Latin, carina, the keel of a ship.

85. The shaft of the femur

Radius.- Latin, radius, a spoke or ray.

86. Trochanter minor externus

Carpus.—Greek, karpos, the wrist.

Lunar. —Latin, luna, the moon.

87. The last coccygeal vertebra

Semilunar. —Latin, semi, half; luna, the moon.

88. Ischium

Scaphoid,—Greek, skaphe, a boat. m.. . - i. i :. ... „ ...-vttll fnKln • q. rnci>mhl;i.n

Trapezoid.—Greek, trapezion a small table ; eidos , a resemblance. XT /' 1. . I■ /• l/l fit a n/rief

89. Trochanter major.

Metacarpal.—Greek, meta, beyond; karpos , the wrist.

90. The external convexity of the trochanter major

Os. —Latin, os, a bone.

Pedis. —Latin, pes, a foot. n rtf Kofflrt TVin form is a.nnlien to the UlCltS. from

91. The head of the femur

Phalanx. —Greek, pkalangx, a line of battle. The term is applied to tne digits, iiom their regularity.

92. The first coccygeal vertebra

Sesamoid.—Greek, the grain sesame; eidos, a resemblance.

93. Ilium

Unciform. —Latin, uncinis, a hook.

Cuneiform. Latin, cuneus, a wedge.

94. Sacrum.

Trapezium.—Greek, trapezion, a small table.

95. Superior spine of the ilium

Ulna. —Latin, ulna, the elbow.

96. The last lumbar vertebra

Bnsiform. —Latin, ensis, a sword ; forma, a shape.

Retrossal.—Latin, retro, behind ; os, a bone.

97. Anterior spine of the ilium

Basilar.—Latin and Greek, basis, a foundation.

Metatarsal. —Greek, meta, beyond ; tarsos, the solo of the foot. The three metatarsal bones of the horse correspond to the five of the human foot, which, being situated between the tarsus, or ankle, and the toes, constitute the bones of the soles of the foot.

98. The first lumbar vertebra

99. Last dorsal vertebra

100. The spinal foramen

Astragalus.—Greek, astragalos, a die. Corresponding bones of the sheep and other animals being formerly used by the ancients as dice.

101. Transverse process of dorsal vertebra (13th).

Malleolus.—Latin, malleolus, a small hammer.

102. Cartilage of elongation of the scapula

Tibia.—Latin, a flute. The upper expanded end resembling the trumpet-liko extremity of an ancient flute, and the smaller portion the mouthpiece.

103. Second dorsal vertebra

Costal.—Latin, costa, a rib.

101. First dorsal vertebra

Cuboid.—Greek, kubos, a cube ; eidos, a resemblance.

'■. IVOR, .HVCWU, .V , wt.visu, IV ■- Foramina.—Latin, foramen, an aperture or opening; foramina , plural.

105. Seventh cervical vertebra, or prominens.

A. OlV.l Corona.—Latin, corona, a wreath.

106. Sixth cervical vertebra, or tricuspid

inruiii, uv/i r/ii*ui) w n luivvu. Galcis.—Latin, calx , the heel. This bone, in human anatomy, forms the osseous structure of the heel.

107. Fifth cervical vertebra

Fibula.—Latin, fibula, a buckle. So named in human anatomy from the head of the bone being opposite to the part the buckle of the knee of the breeches was placed.

108. Fourth cervical vertebra

109. Third cervical vertebra

Patella.—-Latin, patella, a small pan. The knee cap or pan. Supra-condyloid.—Latin, supra, on the upper side. Greek, kondulos, a knuckle or knob ; eidos, a resemblance.

110. Second cervical vertebra —the dentata, or axis.

Fossa.—Latin, a ditch or depression.

111. First cervical vertebra, or atlas,

Trochanter.—Greek, trochanter, a runner.

112. Condyle of the occiput.

Coccygeal.—Latin, coecygis, a cuckoo. Prom the supposed resemblance of the four terminal bones of the vertebral column in man to the bill of the cuckoo.

116. Styloid process of the occiput

Ischium.—Greek, ischion, the hip.

111*. Occipital bone.

Femur.— Latin, femur, the thigh.

Ilium.—Greek, eileo, I twist.

115. Petrous temporal bone, showing the external auditory meatus

Sacrum.—The sacred bone; from the Latin sacrum or saccr, sacred.

116. Occipital protuberance forming the crest of the poll

Lumbar.—Latin, lumbus, the loin.

Dorsal.—Latin, dorsum, the back.

Cervical.—Latin, cervix, the neck.

Prominens. —From the prominent spinous process of this bone.

Tricuspid.—Latin, Iris , three ; cuspis, a point

Axis. —Latin, axis, an axle-tree. This bone forming the pivot upon which the atlas and head rotate.

DERIVATIONS

Dentata.—Latin, dentalus, tooth bearing. So called from the tooth-like process this bone boars anteriorly.

Parietal. —Latin, paries, a side or wall; parielis, of a wall. Zygomatic.—Greek, zugoma, a bar ; from zugon, a yoke. Supra-orbital.—Latin, supra, on the upper side ; orbitum, the orbit. Foramen. —An opening for the passage of blood-vessels and nerves. Latin, foramen an opening ; foro, I boro.

Atlas.—Greek, atlas — a, intensive ; tlao, I sustain. In the mythology of ancient Greece, Atlas was the giant who sustained the earth upon his shoulders as the first bone of the neck sustains the head.

Condyle.—Greek, kondulos, a knuckle or knob.

Lachrymal.—Latin, lachryma, a tear. Infra-orbital.—Latin, infra, below ; orbis, a circle ; orbitum , the orbit Maxillary.—Pertaining to the jaw. Latin, maxilla, a jaw. Premaxillary.—Latin, pros, before ; maxilla, a jaw. Menti. —Latin, mentum, the chin. Malar. —Latin, mala, the cheek.

Occiput.—Latin, occiput, the back of the head.

Styloid.—Greek, stulos, a style or pen; eidos, a resemblance.

Petrous.—Latin, petrosus, hard like a rock ; from petra, a stone.

Temporal.—Latin, temporalis, for a limited time, mortal.

Auditory.—Latin, auditor, one who hoars ; from audio, I hear.

Meatus. —Latin, meatus, a passage.

[a.o-.0/7/1903-4995A

By Authority; John Mackay, Government Printer, Wellington.

NOTE.—A large wall chart (half life size) of the diagram of Horse shown in this work can be purchased from the Government Printer, Wellington, New Zealand.