CH. nv.] VOICE AND SPEECH. 727 



CHAPTER LIV. 



VOICE AND SPEECH. 



THE fundamental tones of the voice are produced by the 

 current of expired air causing the vibration of the vocal cords, 

 two elastic bands contained in a cartilaginous box placed at the 

 top of the wind-pipe or trachea. This box is called the larynx. 

 The sounds produced here are modified by other parts like the 

 tongue, teeth, and lips, as will be explained later on. 



Anatomy of the Larynx. 



The cartilages of the larynx are the thyroid, the cricoid, the two ary- 

 tenoids. These are the most important for voice production ; they are made 

 of hyaline cartilage. Then there are the epiglottis, two cornicular. and two 

 cuneiform cartilages. These are made of yellow fibro-cartilage. 



Coinu min. 



Cornu m&j.:^"~-^^^f^^^^^^ ie ..^0 St.-nio-hyoidew. 



""-TO. Thyro-hyoidens. 

 Cornu gup. ^ 



^^^^^^ .m. Rterno-hyoideuf. 



Lig. crico-thyr. med. - 



./ J^^^mm 



_J"n. Crico-thyroideu.*. 

 Cart, cricoidea 



Lig. crico-tracheae 



Cart, tracbeale <'-- 



Fig. 549. The larynx, as seen from the front, showing the cartilages and ligaments. The 

 muscles, with the exception of one crico-thyroid, are cut off short. (Stoerk. ) 



The thyroid cartilage (fig. 550. i to 4) does not form a complete ring 

 around the larynx, hut only covers the front portion. It forms the pro- 

 minence in front of the throat known as Adam's apple. () The erirnid 

 cartilage (fig. 550, 5, 6), on the other hand, is a complete ring ; the back 

 part of the ring is much broader than the front. On the top of this 



