154 SURGICAL APPLIED ANATOMY. [Chap. ix. 



has been removed for carcinomatous disease, but the 

 operation, although not immediately fatal, has not 

 been followed by very satisfactory results. It is 

 removed through an incision in the middle line. In 

 this incision are divided the platysma, the fascia, and 

 the anterior jugular vein. The larynx is separated 

 from its connections, the following structures being 

 divided : sterno-thyroid, thyro-hyoid, stylo-pharyngeus, 

 palato-pharyngeus, and inferior constrictor muscles, 

 laryngeal branches of superior and inferior thyroid 

 arteries, superior and inferior laryngeal nerves, hyo- 

 epiglottic and glosso-epiglottic ligaments. The larynx 

 is then separated from the trachea, and is dissected off 

 from below up. In separating the gullet and pharynx 

 there is great risk of " button-holing " the former 

 tube. 



Tracheotomy and laryiigotomy. The trachea 

 is about four and a half inches in length, and from 

 three-quarters to one inch in its extreme width. 

 It is surrounded by an atmosphere of very lax con- 

 nective tissue, which allows a considerable degree 

 of mobility to the tube. The mobility of the 

 trachea is greater in children than in adults, and 

 adds much to the difficulties of tracheotomy. In 

 this procedure the windpipe is opened in the middle 

 line by cutting two or three of its rings above, 

 below, or through the isthmus of the thyroid gland. 

 Since the trachea, as it descends, lies farther from the 

 surface, and comes in relation with more and more 

 important structures, it is obvious that, other things 

 being equal, the higher in the neck the operation can 

 be done the better. The length of trachea in the 

 neck is not so considerable as may at first appear, 

 and, according to Holden, not more than some 7 or 8 

 of the tracheal rings (which number 16 to 20 in all) 

 are usually to be found above the sternum. The 

 distance between the cricoid cartilage and the sternal 



