338 THE ZVMAN 30DT. 



pushing out the mucous membrane, leave for the passage 

 of air only the narrow slit of the glottis, above mentioned. 



The largest cartilage of the larynx (t, Fig. 97) is the 

 thyroid. It is placed in front and consists of right and 

 left halves which meet at an angle in front, but separate 

 behind so as to enclose a V-shaped space. The front of 

 the thyroid cartilage causes the prominence in the neck 

 known as Adam's apple. The epiglottis, not represented 

 in the figure, is attached to the top of the thyroid cartilage 

 and overhangs the entry from pharynx to larynx. It may 

 be seen, covered by mucous membrane, projecting at the 

 root of the tongue, if that organ be pushed down, while 

 the mouth is held open before a mirror. It is represented 

 as seen from behind at a, Fig. 98. The cricoid cartilage 

 (x%, Fig. 97) has the form of a signet-ring, with its broad 

 part turned towards the back of the throat, and placed in 

 the lower part of the opening between the halves of the 

 thyroid. The two arytenoid cartilages ( f , Fig. 97) are 

 placed on the top of the wide posterior part of the cricoid; 

 each is pyramidal in form. The remaining laryngeal car- 

 tilages are of less importance. 



The Vocal Cords, which are rather projecting pads of 

 elastic tissue than cords in the ordinary sense of the word, 

 proceed, one from each arytenoid cartilage behind, to 

 the angle where the halves of the thyroid meet in front. 

 In quiet breathing the interval (glottis) between them (c, 



Describe the position and form of the thyroid cartilage. What 

 causes "Adam's apple"? What is the epiglottis? How may you see 

 it in your own throat? Describe th cricoid cartilage. What carti- 

 lages are set on top of the cricoid? What is their form? 



Between what points are the vocal cords stretched? Under what 

 circumstances does air driven through the glottis not set them vi- 

 brating? 



