i85 



SCIATIC NEUROTOMY. 



40. SCIATIC NEUROTOMY. 

 Plates XXXl-XXXll. 



Objects. The destruction of sensation in the tarsus and 

 parts beyond for the relief of otherwise incurable spavin 

 lameness, diseases of the tendons, etc. 



Instruments. Same as in the preceding. 



Technic. Expert surgeons may operate on the standing 

 animal under local anaesthesia. Place the animal on the 

 operating table on the diseased side, extend the affected 

 limb and draw the upper leg forward or backward and 

 secure it out of the way. Produce complete general or local 

 anaesthesia. The posterior tibial or sciatic nerve, n, Plate 

 XXXI and NS, Plate XXXII, is then sought by grasping 

 the leg with the left hand from behind in such a manner 

 that the thumb rests above and the fingertips below it. 

 Reaching forward with the fingers to the deep flexor of the 

 foot grasp the leg with moderate firmness and draw the 

 hand slowly backward. Immediately behind the perforans 

 muscle and between this and the tendo- Achilles the nerve, 

 nearly i cm. in diameter, glides away forward from be- 

 tween the fingers with a distinct recoil. If the nerve can 

 not be recognized in this manner the hock should be more 

 strongly extended, by which means the nerve may be caused 

 to recede from the perforans muscle, so that it can more 

 readily be felt near the middle of the groove extending be- 

 tween it and the tendo- Achilles. 



At this point on the median side of the leg the skin is 

 shaved, disinfected and an incision made through it 5 cm. 

 long, parallel to the tendo-Achilles. The white rigidly- 

 stretched crural fascia is now divided in the same direction 

 after which it should be determined by palpation that the 

 nerve lies in the middle of the wound. Exci.se with the 

 scissors an elliptic or oval piece of the fascia or hold it 

 apart along with the lips of the cutaneous wound by means 



