182 VETERINARY SURGICAL OPERATIONS 



be depended upon so far as terminating the lameness is con- 

 cerned. 



In obstinate curb lameness tibial neurotomy cannot be 

 depended upon and should not be resorted to. The subject 

 is better off with the impediment than with the benumbed 

 leg. 



RESTRAINT. — The operation is performed in the re- 

 cumbent position with the affected leg undermost. The op- 

 erating table is par excellence the best apparatus to immobil- 

 ize the leg and bring it into an advantageous position. The 

 casting harness or hopples in lieu of a table will answer, 

 however. 



On the table the leg is secured some distance behind the 

 uppermost one, and in a slightly flexed position. When the 

 hock is slightly flexed the space between the tendo-Achilles 

 and the perforans muscle is widened and this brings the 

 nerve into a more available position. When the leg is 

 stretched in exterision the nerve is pressed against the 

 muscle anteriorly and is more difficult to find. 



When the casting harness is used the same flexed posi- 

 tion of the hock is desirable, but it is much more difficult to 

 maintain against the patient's struggles. About the best 

 method of overcoming this difficulty is to fix the leg in the 

 desired position to a plank, by means of several straps at dif- 

 ferent points encircling both the plank and the leg. Cocain- 

 ization of the seat completes the restraint. 



EQUIPMENT. — The instruments required are identical 

 to those for median neurotomy. Scalpel, dissecting forcep, 

 artery forcep, nerve elevator, probe-pointed bistoury, wound 

 retractors, needle and thread, needle holder, hypodermic 

 syringe, cocaine 5 per cent, mercuric chloride solution, razor 

 and scissors are the essential requirements. 



TECHNIQUE.— First Step.— Locating the Seat of Op- 

 eration. — The seat of operation is a hand's breadth above the 

 point of the os calcis, in the groove between the tendo- 

 Achilles and the perforans muscle, on the internal aspect of 

 the leg. 



It is made against the muscle rather than too near the 

 tendon, as the tibial nerve, when the hock is flexed, lies in 

 rather close apposition to the former. An incision made in 

 the depths of groove will answer, but the one made slightly 

 anterior to this point will more nearly parallel the nerve. 

 If made too near the tendo-Achilles some difficulty will be 

 encountered in locating the nerve, which will then be found 

 to lie somewhat anterior to it. 



