. The anatomy of the domestic animals. Veterinary anatomy. BONES OF THE THORACIC LIMB 201 carpal bones. The carpal articular surface formed by them is concave from side to side, convex from before backward. The distal ends (Capitula) have articular surfaces of the nature of a head, but bear a sagittal ridge on the volar aspect, ex- cept the first, which is grooved. Ossification is complete at five or six months of age. The five digits have three phalanges each, except the first, which has two. The third and fourth digits are the longest; the first is very short and does not come in contact wit
. The anatomy of the domestic animals. Veterinary anatomy. BONES OF THE THORACIC LIMB 201 carpal bones. The carpal articular surface formed by them is concave from side to side, convex from before backward. The distal ends (Capitula) have articular surfaces of the nature of a head, but bear a sagittal ridge on the volar aspect, ex- cept the first, which is grooved. Ossification is complete at five or six months of age. The five digits have three phalanges each, except the first, which has two. The third and fourth digits are the longest; the first is very short and does not come in contact with the ground in walking. The first phalanges of the chief digits have four-sided shafts, which are slightly curved dorsally. The proximal end of each has a con- cave surface for articulation with the metacarpal bone and is deeply notched behind. The distal end has a trochlea for articulation with the second pha- lanx, and depressions on each side for ligamentous attachment. The second phalanges are about two-thirds of the length of the first phalanges. The proximal articular surface consists of two cavities separated by a sagittal ridge. The distal extremity is wider and flatter than that of the first. The third phalanges correspond in general to the form of the claws. The base has an [articular surface adapted to ! the second phalanx and is encircled by a collar of bone (Crista unguicularis). The volar surface bears a wing or tuber- osity, and on each side of this is a fora- men. The ungual part is a curved rod with a blunt-pointed free end. It is rough and porous. Its base forms with the collar previously mentioned a deep groove, into which the proximal border of the claw is received. The two pha- langes of the first digit resemble in ar- rangement the first and third phalanges of the other digits. Ossification is complete at five or six months. Nine volar sesamoids are usually present. Two are found at each meta- carpo-phalangeal joint of the chief digits. They are high and
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