HYOVEKTEBKOTOMY. 



Having cast the horse so as to 

 have the affected side uppermost, the 

 head is extended, and the anterior 

 margin of the wing of the atlas is 

 felt for. Over this the tendon of 

 the splenius is readily felt, and an 

 incision about an inch and a-half in Fig. i4 

 length, obliquely from above down- 

 wards and backwards, is made. The 

 fascia covering this region is then 

 cut through, and the index of the 

 left hand pushed downwards and 

 forwards on to the stylo-hyoideus 

 muscle. The margin of the superior 

 cornu of the os hyoides is felt, and, 

 with a sharp-pointed scalpel held in 

 the right hand, the stylo-hyoideus 

 muscle is divided. It is most im- 

 portant to attend to the position 

 and direction of the knife, to avoid 

 wounding the internal carotid artery. 

 For this purpose the sharp edge is 

 turned forwards, and the point is 

 directed in a line with the horse's 

 nose the head, as stated above, 

 being extended. The stylo-hyoideus 

 is thus punctured about its middle, 

 and obliquely from behind forwards. 

 An iron staff is then pushed through, 

 the opening, and turned downwards 

 and forwards to the antero-inferior 

 angle of the parotid gland. The Fig UL 



staff is readily felt behind the angle 



551 



