354 VETERINARY SURGICAL OPERATIONS' 



cles until the underlying cartilaginous structures appear in 

 the foreground. The retractors are applied and the wound 

 widely opened, while the fascia covering the larynx is divided 

 to give a better view of the anatomical structures- exposed. 

 These, naming from before backward, are Adam's apple, 

 crico-thyroidean membrane (ligament), cricoid cartilage (a 

 narrow ring), the crico-trachealis ligament, and lastly the 

 first ring of the trachea. 



Third Step.— Laryngotomy.— The scalpel is pushed 

 through the crico-thyroidean membrane just behind Adam's 

 apple and drawn backward through the structures above 



Fig. 173 — Performing the Intra-Laryngeal Step. 



named. Although Williams has found it necessary to include 

 the first ring of the trachea in the incision its division may be 

 omitted since any intra-laryngeal surgery can be performed 

 through an incision extending to and not including any part 

 of the trachea. The bleeding from small vessels is now con- 

 trolled with the hsemosta.ts and then the retractors are moved 

 into the cavity of the larynx. 



Fourth Step. — Resecting the Mucous Membrane from the 

 Ventricle.— The mucous membrane of the- ventricle is picked 

 up with the forceps just below the edge of the arytenoid car- 

 tilage. Beginning between the forceps and the border of the 

 cartilage an incision is made through the mucous membrane 



