636 



THE HUMAN BODY. 



vocal cords are thick and rounded, and seem very unsuitable 

 for being readily set in vibration. They are also tolerably 

 widely separated behind, the arytenoid cartilages, to which 

 their posterior ends are attached, being separated. Air under 



11 



11 



FIG. 182. The larynx viewed from its pharyngeal opening. The back wall of 

 the pharynx has been divided and its edges (11) turned aside. 1, body of hyoid; 

 2, its small, and 3, its great, horns; 4, upper and lower horns of thyroid cartilage; 

 5, mucous membrane of front of pharynx, covering the back of the cricoid carti- 

 lage; 6. upper end of gullet; 7, windpipe, lying in front of the gullet; 8, eminence 

 caused by cartilage of Santorini; 9, eminence caused by cartilage of Wrisberg; 

 both lie in, 10, the aryteno-epiglottidean. fold of mucous membrane, surrounding 

 the opening (aditus larynyis) from pharynx to larynx, a, projecting tip of epi- 

 glottis; c, the glottis, the lines leading from the letter point to the free vibratory 

 edges of the vocal cords. 6', the ventricles of the larynx: their upper edges, mark- 

 ing them off from the eminences fe, are the false vocal cords. 



these conditions passes through without producing voice. If 

 they are watched with the laryngoscope during phonation, it 

 is seen that the cords approximate behind so as to narrow the 

 glottis; at the same time they become more tense, and their 

 inner edges project more sharply and form a better-defined 

 margin to the glottis, and their vibrations can be seen. 

 These changes are brought about by the delicately co- 



