124 THE SURGICAL ANATOMY OF THE HORSE 



meanwhile extend the knee as much as possible. When the tendon is 

 completely severed the leg becomes suddenly straightened. 



Another method is to pass the tenotome beneath the tendon and cut 

 from within outwards, but there is a danger in this method of exten- 

 sively lacerating the skin. 



It will be seen that in both methods the operator is very liable to 

 cut through the ulnar nerve or vessels in addition to the tendon. In 

 order to avoid this a small incision may be made at the seat of ulnar 

 neurectomy, just sufficiently large to admit of the introduction of a 

 probe with which the nerve and vessels may be pushed aside and kept 

 clear of the tenotome during the actual cutting of the tendon. 



In operating on the middle tendon the cutaneous incision is made 

 about two inches above the edge of the pisiform bone and in the 

 depression between the two tendons, as in the case of ulnar neurectomy. 

 The ulnar nerve, which, it will be remembered, is sometimes lodged on 

 the anterior face of the tendon, should be searched for, and then pushed 

 aside. The tenotome should then be introduced and the tendon cut 

 after the manner described in the preceding operation. 



THE TENDONS OF THE FLEXOR PERFORATUS AND 

 FLEXOR PERFORANS 



These tendons have already been noticed in our superficial examina- 

 tion, and in the longitudinal and transverse sections of the limb their 

 relationship was made evident. During the course of dissection of the 

 tendons it will be observed that they are intimately bound to one 

 another by a considerable amount of connective tissue. The perforatus 

 acts as a flexor of the knee, fetlock, and pastern joints, and the perforans 

 as a flexor of the corono-pedal joint also. 



Abnormal contraction of these tendons may arise from similar causes 

 to those described in connection with the metacarpal flexors. Retraction 



