1012 



DISEASES OF THE HOCK. 



which the tibial nerve is readily discovered. A fragment of this, 

 | of an inch to 1{ inch in length, is excised. The wound is closed 

 by a few cutaneous sutures, with or without providing for drainage. 

 The operation is easy. It is, however, always necessary to proceed 

 methodically and to take care not to injure the tibial vein. 



Neurectomy of the posterior tibial nerve is performed as follows : — 



The nerve is discovered on the inner side of the hind limb about 



4 inches above the point of the hock, where it passes downward just 



in front of the Achilles tendon. By grasping the tendon from behind 



and allowing the soft tissues gradually to slip between the fingers 



Fig. 543. — Neurectomy of the posterior tibial nerve. 



and thumb, the nerve can be felt as a firm cord. At this point it 

 lies about 1 to 1} inch in front of the Achilles tendon, and rather 

 nearer the inner side of the limb, from which the operation is 

 performed. 



The horse is cast with the affected limb undermost, and the upper 

 hind limb is fixed to the upper fore, so as to leave the field of operation 

 clear. To check bleeding a rubber cord may be tighty applied about 

 the middle of the lower thigh. A liberal space around the seat of 

 operation is shaved, washed and disinfected, and about 4 inches 

 above the top of the os calcis and 1 full inch in front of the Achilles 

 tendon an incision 2 to 2| inches long is made parallel to the tendon. 

 After ligaturing any bleeding vessels, two retractors are introduced 

 into the wound and the edges drawn back to allow the subcutaneous 



