88 



CONFORMATION AND ITS DEFECTS 



joint is least pronounced. It is this variety of conformation combined 

 with length of limb that gives the race-horse his immense stride, and 

 in turn enables him to extend the hind extremities to their farthest 

 limits, and to realize all the jjower of his propelling muscles. 



It matters not how strong the quarters may be, if the tibia or second 

 thigh slopes too much backward, or the canon too much forward, the 

 hock is no longer straight, and the power of extending the limb is 

 more or less curtailed, and the speed proportionately diminished. 



The importance of a straight hock and of a straight hind-limb generally, 

 so manifest in the race-horse, is not an essential point in the conformation 



of the draught-horse. 



The great power 

 which the latter puts 

 forth in the act of 

 draught is favoured by 

 a greater obliquity of 

 the bony segments, for 

 in this position the 

 muscles are able to act 

 in a direction more 

 at right anoles to 

 their levers, and con- 

 sequently at consider- 

 able mechanical ad- 

 vantage. In shifting 

 a heavy load the cart- 

 horse takes advantage of this l)y bending the joints (fig. 68) so as to 

 increase still further the obliquity of the bones and give more etfective 

 action to the muscles. 



Acting in this attitude the limbs are less considerably extended, 

 whereby the steps become short and the movements slow, but the power 

 is greatly augmented. 



In conformity with the anatomical disposition of the bones which 

 form the true hock-joint, the movements of the hock are restricted to 

 those of flexion and extension. In the former case the canon is carried 

 forward and upward, in the latter it is drawn downward and backward. 

 It is also noticeable that, viewed from behind, this joint is directed some- 

 what obliquely outward, so that its hinge-like formation is enal^led to 

 give the entire limb an outward inclination in its forward stroke, by 

 which the stifle is prevented from being brought into contact with the 

 belly, a provision of the highest importance to race-horses, chasers, and 



Copyright 1S97 hyEadweard Muyljridge. Redrawn from "Animals in Motion" (Chapman .ind Hall) 

 Fig. 68. — The Hind-Limbs bent in drawing a Load 



