TRACHEOTOMY. 



77 



ing the several ends apart insert the tube through the open- 

 ing. Since the tracheal rings are incomplete, being open 

 on their dorsal surfaces, cutting through the ventral portion 

 divides each ring into two separate parts and their being 

 pushed apart, distorts them and tends to the causation of 

 chondritis and collapse of the trachea, a danger which in- 

 creases with the duration of time that the tube is maintained 

 in position. It is therefore most suitable for hurried opera- 

 tion in impending suffocation where the tube will probably 

 be needed for a short time only. 



Tracheotomy, s, sterno-thyro-hyoideus muscle ; /, trachea ; 

 sch, mucous membrane of the posterior wall of the trachea ; 

 /, interannular ligament. 



A second method of operation, illustrated in Fig. 2, con- 

 sists in making a transverse incision through the inter-annu- 

 lar ligament between the two last exposed tracheal rings the 

 length of the diameter of the tube to be inserted. Make 

 a perpendicular incision upward from each end of this at a 

 point I to 1.5 cm. from the median line through one or two 

 tracheal rings, according to the size of the tube. With 

 forceps or tenaculum grasp the segments of partially de- 



