64 TRACHEOTOMY 



the skin, which has very little sensation and the require- 

 ments for anaesthesia are small. After the skin muscle is 

 cut through, in order to avoid hemorrhage, separate the 

 two sterno-thyro-hyoidens muscles by means of tenacula 

 along the median raphe in the white strip of connective 

 tissue. The opening into the trachea may be made in a 

 variety of ways. The quickest and most crude method is 

 to slit it from above downward through two or three trach- 

 eal rings, and pressing the several ends apart, insert the 

 tube through the opening. Since the tracheal rings are in- 



FIG. 23 



Tracheotomy, .t, Sterno-thyro-hyoideus muscle ; t, trachea ; 



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



/, interannular ligament, 

 complete, being open on their dorsal surfaces, cutting 

 through the ventral portion divides each ring into two sepa- 

 rate parts and their being pushed apart distorts them and 

 tends to the causation of chondritis and collapse of the 

 trachea, a danger which increases with the duration of 

 time that the tube is maintained in position. The severing 

 of tracheal rings in tracheotomy is therefore most suitable 

 for hurried operations in impending suffocation where the 

 tube will probably be needed for a short time only. 



