638 



THE HUMAN BODY. 



breathing. Other muscles approximate the arytenoid carti- 

 lages after the cartilages have been separated. The most im- 

 portant is the transverse arytenoid (A, Fig. 183), which runs 

 across from one arytenoid cartilage to the other. Another is 

 the oblique arytenoid (Taep), which runs across the middle 

 line from the base of one arytenoid to the tip of the other; 



FIG. 183. The larynx seen from behind and dissected so as to display some of 

 its muscles. The mucous membrane of the front of the pharynx (5, Fig. 157) has 

 been dissected away, so as to display the laryngeal muscles beneath it. Part of 

 the left half of tne thyroid cartilage has been cut away, co, cartilage of San- 

 tor iui; c, cartilage of Wrisberg. 



thence certain fibres continue in the aryteno-epiglottidean 

 fold (10, Fig. 182) to the base of the epiglottis; this, with its 

 fellow, embraces the whole entry to the larynx; when they 

 contract they bend inwards the tips of the arytenoid car- 

 tilages, approximate the edges of the aryteno-epiglottidean 

 fold, and draw down the epiglottis, and so close the passage 

 from the pharynx to the larynx. When the epiglottis has 

 been removed, food and drink rarely enter the larynx in 

 swallowing, the folds of mucous membrane being so brought 

 together as to effectually close the aperture between them. 



Increased tension of the vocal cords is produced by the 

 crico-tliyroid muscles, one of which lies on each side of the 

 larynx, over the crico- thyroid membrane. Their action may 



