THE LIMBS 



101 



As all the joints of the limbs of the horse are 

 simply hinge-joints j acting only in one plane, the 

 muscles are almost all either simple c flexors/ bending 

 the distal segments backwards on the segment above, 

 or c extensors,' returning them to the straight position. 

 The structure of the joints prevents the segments being 

 bent forwards much beyond a straight line with the 

 segment above. The extensors are placed upon the 

 anterior or dorsal, and the flexors on the posterior or 

 ventral surface of the limb. 



In the human arm and hand there are muscles 

 having many other functions, such as turning the hand 

 round, spreading the fingers and bringing them in con- 

 tact again, which, of course, are not required in the horse. 

 In the limbs of all mammals having the typical number 

 of five digits completely developed, the muscles, as 

 might be supposed, are as numerous and arranged on 

 much the same general plan as in man. It is, however, 

 very remarkable that in the horse's limbs many more 

 muscles exist than would be thought necessary for the 

 very simple actions they have to perform. But it 

 appears that the reduction of bones to a rudimentary 

 condition, as in the case of the ulna and the fibula, or 

 their entire loss, as in the case of four of the toes, has 

 taken place more thoroughly than, and in advance of, 

 that of the muscles which were originally connected 

 with these bones, many of which linger, as it were, 



M 



