SC/A TIC NE URO TOMV. 1 7 3 



4t. SCIATIC NEUROTOMY. 

 Pi,ATES XXX AND XXXI. 



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 and secure it out of 

 the way. Produce complete anaesthesia. The posterior 

 tibial or sciatic nerve n, Plate XXX and NS, Plate XXXI, 

 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. Immediate- 

 ly behind the perforans muscle and between this and the 

 tendo- Achilles the nerve, nearly i cm. in diameter, glides 

 away forward from between the fingers with a distinct re- 

 coil. If the nerve can not be found in this manner the 

 hock should be stongly extended, by which means it is 

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

 more readily be felt near the middle of the groove extend- 

 ing between it and the tendo- Achilles. At this point 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. Excise 

 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 of the tenacula. In poor horses the contour of 

 the nerve, covered only by loose connective tissue, stands 



