INNER ASPECT OF LIMB 21 



nerve and vessels pass beneath the latter head. The two heads unite, 

 forming a single muscular portion. This is succeeded by a powerful 

 tendon which is inserted into the upper border of the pisiform bone. 



Its action is similar to that of the preceding muscle, and it is supplied 

 by the ulnar nerve. 



The three flexors of the metacarpus clothe the flexors of the digit. 

 The muscular portions of the latter are consequently almost entirely 

 concealed from view. 



The Flexor Perforatus (48 and 62). — This muscle arises from the 

 lower extremity of the inner condyle of the humerus by a tendon which 

 is common to it and the humeral head of the flexor perforans. It runs 

 down the limb on the perforans, and receives a reinforcing band from the 

 roughened area on the back of the radius a little above the lower 

 extremity ot this bone. Its tendon then plays through the carpal sheath 

 and runs dow'n the limb to form at the fetlock a peculiar ring (62) through 

 which the tendon of the perforans passes. It is ultimately inserted into 

 the second phalanx. It is a flexor of the knee, fetlock, and pastern joints, 

 and is supplied by the ulnar nerve. 



The Flexor Perforans (36A, 54, and 64). — This is the deep flexor of 

 the digit, and it lies on the back of the radius. It has three heads of 

 origin, namely, the humeral, radial, and ulnar. The humeral and ulnar 

 (ulnar accessorius) heads have already been noticed. The radial head 

 arises from the back of the radius, and is consequently the most deeply 

 seated. 



The three divisions unite, and their common tendon plays through 

 the carpal sheath. 



In the plate it is seen as it emerges from the sheath, and on its edge 

 run the large metacarpal artery and the internal plantar nerve. 



It runs down the limb at first behind the check ligament, and after 

 receivino- the insertion of this ligament it is placed behind the suspensory. 

 Behind the tendon is that of the perforatus muscle. 



The tendon is next seen where it leaves the perforatus ring below the 



