146 



THE STRUCTURE OF THE HORSE 



and fibula in the hind limb. The joint by which the 

 proximal segment is attached to the corresponding 

 girdle is called ' shoulder ' in the fore limb and c hip ' in the 

 hind limb ; that between the first and second segments 

 is called the c elbow ' in the fore limb and the ' knee ' (the 

 ' stifle ' in the horse) in the hind limb (see the skeleton 

 of the horse and man in Frontispiece). 



The distal or third segment is of more complex 

 character. It constitutes in the fore and hind limbs 

 respectively the ' hand ' and 4 foot ' of man, the fore and 

 hind c foot ' of quadrupeds, or, in more precise anatomi- 

 cal language, of general application to all animals, the 

 manus and the pes. Each of these consists of a group 

 of small bones at its proximal end, forming the carpus or 

 wrist in the fore limb and the tarsus or ankle in the 

 hind limb. Beyond these it always has a tendency to 

 divide up into a number of rays, called digits, fingers, 

 or toes (see fig. 1, p. 14). 



Leaving out of consideration certain vestigial 

 structures which are held by some anatomists to indi- 

 cate the possibility of the former existence of a larger 

 number of digits, no known mammal has more than 

 five digits in each limb. For the convenience of de- 

 scription the digits are distinguished by the numerals 

 I to V, counted from the radial to the ulnar side in the 

 fore limb, from the tibial to the fibular on the hind 

 limb. They are also sometimes named — (I) pollex or 



