CH. XXIV.] 



ORGANS OF RESPIRATION. 



339 



is to diminish, when required, the calibre of the trachea by 

 approximating the ends of the cartilages. Outside these are a few 



Fig. 308. Outline Knowing the general form 

 of the larynx, trachea, ana bronchi, u* 

 seen from the front. A, the great cornu of 

 the hyoid bone ; ', epiglottis ; (, xiiperior, 

 and f , inferior cornu of the thyroid carti- 

 lage ; f, middle of the cricoid cartilage ; 

 tr, the trachea, showing sixteen cartila- 

 ginous ring* : >>. the nVht . and b', the left 

 bronchus. (Allen Thomson.) 



Fig. 309. Outline showing the gener form of the 

 larynx, trachea, and bronchi, an seen from 

 behind, h, great cornu of the hyoid bone ; (, 

 superior, and ('. the inferior cornu of the 

 thyroid cartilage; -. epiglottis; a, points to 

 the back of both the arytenoid cartilages, which 

 are surmounted by the cornicula ; <. the middle 

 ridjre on the back !f tho oriroid cartilage ; tr, the 

 posterior membranous part of the trachea ; 6, 6', 

 right and left bronchi. (Allen Thomson.) 





longitudinal bundles of muscular tissue, which, like the preceding, 

 are attached both to the fibrous and cartilaginous framework. 

 The mucous membrane consists to a great extent of loose 



r. 2 



