84 



CONFORMATION AND ITS DEFECTS 



speed, are less so in horses of power. The greater obliquity of the mov- 

 able segments of the limbs in the 

 latter enable the muscles to act at 

 much greater mechanical advan- 

 tage than they otherwise ^v•ould do. 

 The hind - limbs, although 

 assisting in supporting the body, 

 are pre-eminently organs of pro- 

 pulsion. United by solid union 

 to the pelvis above, and possessed 

 of muscles larger and more power- 

 ful tlian those of the fore-limbs, 

 they are in these and in other 

 respects admirably constructed to 

 exercise their power in the for- 

 ward movement of the trunk. The 

 manner in which this is effected 

 will be best understood by refer- 

 ence to Plate XII, where it is 

 seen that in commencing the fast 

 gallop the first act of the horse 

 is to bring the hind-limbs under 

 the body and raise the forehand. 

 The former at this time are short- 

 ened by the closing of the articu- 

 lar angles. Gradually these are 

 again opened, and one after the 

 other the legs are forcibly ex- 

 tended; and as they become more 

 and more backwardly inclined, 

 the body is forced foi'ward to a 

 point when the ground ceases to 

 offer further resistance, and they 

 leave it to take a fresh and more 

 forward j)osition in order that the 

 movement may be repeated. It 

 will be seen, therefore, that the 

 greater impulsive force which the 

 hind -leg is capable of transmit- 

 ting to the trunk is due to the column of bones of which it is made up 

 being directly and firmly connected with the trunk through the medium 



Fig. 66. — Posterior View of Pelvis and 

 Hind Liralis of Horse 



A, Pelvis. B, Femur or thigh-bone, c, Tibia or lower 

 thigh-bone. D, Fibula. E, Astragalus. P, Calcaneus, 

 forming point of hock. G, Cuboides. H, Large metatarsal 

 or canon-bone. I, I, Small metatarsal or splint-bones. 

 J, Sesamoid bones. K, Os suffraginis or large pastern. 

 L, Os coronffi or small pastern. M, Navicular bone. N, Os 

 pedis or Foot bone. 



