462 



LARYNGOTOMY. 



membrane is then divided from the anterior upper border of the 

 arytenoid cartilage, care being taken to spare it as much as possible. 

 For this purpose the index finger of the left hand is introduced into 

 the sacculus laryngis, and the membrane cut through with scissors 

 close to the border of the cartilage. In this procedure one is specially 

 guided by the indications afforded by the left hand. The arytenoid 



L.R.U 

 L.R.E 



Fig. 367. Fig. 368.— Course of incision. 



Scalpel for Horse's larynx (seen from below). S.k., Thyroid carti- 



resection of lage ; R.S.B., cricothyroid ligament; S.b., vocal 



arytenoid. cord ; S.bf., vocal process of arytenoid ; R.k., cricoid 



cartilage; L.G.k., left arytenoid; L.R. (I., II., III.), 

 first, second, and third rings of the trachea. 



cartilage is now cut through with the scalpel, as near as possible 

 to its articular surface, so that only a thin fragment of cartilage 

 remains. This portion of the operation is the most difficult ; especially 

 in old horses, in which the articular process of the cartilage is often 

 ossified. The knife must be inserted within and below, and the 

 cut made upwards and outwards. As considerable force is often 

 necessary in dividing the cartilage, it requires care to prevent the 

 knife slipping off unexpectedly. As soon as the arytenoid cartilage 

 is divided it may be easily freed from the neighbouring soft parts, 

 and removed with the help of long and sharply-bent scissors. In 

 this case, also, it is necessary to follow carefully the borders of the 

 cartilage, holding the latter with a lion forceps (Fig. 370). Throughout 

 the operation the larynx is cleared of blood by using small pledgets 



