390 VOICE AND SPEECH. 



plemented by the cavities above and below them, which act as 

 resonators. For the anatomy of the larynx the reader is referred 

 to page 354 ; in order to understand voice-production a knowl- 

 edge of the anatomy of this organ is absolutely essential. Especial 

 attention should be paid to the muscles and their action. 



I/aryng'OSCOpe. In order to observe the changes which take 

 place in the vocal bands, use is made of the laryngoscope. This 

 instrument also enables the physician to study the other structures 

 of the larynx and trachea, and to treat any diseases of these organs 

 which may be present. 



The laryngoscope consists of a concave head-mirror with an 

 aperture in its center, and one or more small hand-mirrors. The 



FIG. 214. The laryugoscopic image in easy breathing : 1, base of the tongue ; 2, 

 median glpsso-epiglottic ligament ; 3, vallecula ; 4, lateral glosso-epiglottic ligament ; 

 5, epiglottis ; 6. cushion of epiglottis ; 7, cornu major of hyoid bone ; 8, ventricular 

 band, or false vocal cord ; 9, true vocal cord ; opening of the ventricle of Morgagni 

 seen between 8 and 9; 10, folds of mucous membrane; 11, sinus pyriformis; 12, car- 

 tilage of Wrisberg ; 13, aryteno-epiglottic fold ; 14, rima glottidis ; 15, arytenoid 

 cartilage ; 16, cartilage of Santorini ; 17, posterior wall of pharynx (Stoerk). 



person whose larynx is to be inspected is seated at the side of a 

 lamp, gas, or electric light, and in front of him is seated the 

 observer, with the head-mirror so attached that he can look 

 through the aperture in its center. The observed now opens 

 his mouth, the head being thrown back, and with a napkin the 

 tongue is drawn out and its tip is held against the lower teeth, by 

 which act the epiglottis is drawn forward. One of the hand- 

 mirrors is then slightly heated and passed into the mouth, its back 

 elevating the uvula ; the head-mirror is then so directed as to re- 

 flect the light on the hand-mirror and illuminate the image formed 

 by it of the larynx and trachea. If the hand-mirror is not heated, 

 the vapor of the expired air will be condensed upon it, obscuring 

 the reflected image. To avoid overheating it and burning the 



