VOICE AND SPEECH. 



565 



at an angle. This projection is popularly known as Adam's apple. 

 Each thyroid lamina terminates posteriorly in two horns: one su- 

 perior, the other inferior. 



The two cartilages which are alike are the arytenoids. Each 

 one is in the form of a triangular pyramid, whose base is movably 

 articulated at the back on the cricoid cartilage. The apex of each 

 arytenoid cartilage has attached to it, in the shape of a movable 

 point, a cartilage of Santorini. 



The true vocal cords are attached to the anterior angles, or 

 vocal processes, of the arytenoids; the crico-arytenoideus muscles 

 are inserted into the external angles. 



r 



Fig. 209. Action of the Muscles of the Larynx. (BEAUNIS.) 



The dotted line indicates the new positions assumed by the thyroid carti- 

 lage in the action of the crico-thyroid muscle. 1, Cricoid cartilage. 2, 

 Arytenoid cartilage. 3, Thyroid cartilage. 4, True vocal cord. 5, New posi- 

 tion of the thyroid cartilage. 6, New position of vocal cords. 



The cartilages of Wrisberg are found in the aryteno-epiglottic 

 folds. 



The epiglottis is attached to the inner surface of the anterior 

 >rtion of the thyroid cartilage. It projects upward behind the base 

 >f the tongue. The epiglottis is attached to the tongue by the three 

 ;los$o-epiglottic folds. 



The false vocal cords are two folds of the laryngeal mucous mem- 

 )rane which pass from the anterior surfaces of the arytenoids to the 

 thyroid cartilage. They are located above the true vocal cords. 



The true vocal cords extend from the anterior angles of the bases 

 )f the arytenoids to the thyroid cartilage. 



The glottis is the chink between the true vocal cords. 



The ventricle of the larynx is the pouch between the true and 

 false vocal cords. 



