. An introduction to the study of mammals living and extinct. Mammals. EQUID^ 393 but the principal metatarsal is more laterally compressed at its upper end than is the corresponding metacarpal. The joint between the femur and tibia, corresponding to the knee of man, is called the "stifle joint"; while that between the tibia and tarsus, corresponding to the ankle of man, is termed the " ; The bones and joints of the foot have the same names as in the fore limb. The Horse is eminently " digitigrade," standing on the ex- tremity of the single digit of each foot
. An introduction to the study of mammals living and extinct. Mammals. EQUID^ 393 but the principal metatarsal is more laterally compressed at its upper end than is the corresponding metacarpal. The joint between the femur and tibia, corresponding to the knee of man, is called the "stifle joint"; while that between the tibia and tarsus, corresponding to the ankle of man, is termed the " ; The bones and joints of the foot have the same names as in the fore limb. The Horse is eminently " digitigrade," standing on the ex- tremity of the single digit of each foot, which is kept habitually in a position approaching to vertical. The muscles ^ of the limbs are modified from those of the ordi- nary mammalian type in accordance with the reduced condition of the bones and the simple re- quirements of flexion and ex- tension of the joints, no such actions as pro- nation and supination, or opposition of digits, being possible or needed. The muscles, there- fore, which per- form these functions in other mammals are absent or rudimentary. Below the carpal and tar- sal joints the fore and hind limbs corre- spond almost exactly in struc- ture as well as function. On the anterior or extensor surface of the limb a powerful tendon (7 in Fig. 164), that of the anterior extensor of the phalanges (corresponding to the extensw communis digitorum of the arm and extensor longus digiiorum of the foot of man) passes down over the metacarpal bone and phalanges, to be inserted mainly into the upper edge of the anterior surface of the last phalanx ^ Want of space and of the necessary illustrations rendered it impossible to give an account of mammalian myology in the earlier chapters of this Fig. 164.—Section of foot of Horse. 1, Metacarpal bone; 2, first phalanx (fts suffraginis); 3, second phalanx (os coronce); 4, third or ungual phalanx (os pedis, or coffin-bone); 5, one of the upper sesamoid bones; 6, lower sesamoid or "navicular" bone; 7,
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Keywords: ., bookauthorly, bookcentury1800, bookdecade1890, booksubjectmammals
