THE LARYNX 



323 



(O.T. true vocal cords}. The vocal folds are the chief agents 

 in the production of the voice, and the larynx is so con- 

 structed that changes in their relative position, and in their 

 degree of tension, are brought about by the action of the 

 muscles and the recoil of the elastic ligaments. 



Vestibulum Laryngis. The vestibule is the upper sub- 

 division of the laryngeal cavity (Figs, in, 119); it extends 

 from the superior 

 aperture (aditus 

 laryngis) of the 

 larynx down to the 

 ventricular folds. 

 Its lower part 



Epiglottis 



Hyoid bone 



is 

 compressed from 



Side tO Side. ItS Ary-epiglottic fold 



width, therefore, 



diminishes from Tubercle of epiglottis 



above downwards, 

 whilst, owing to the 

 obliquity of the 

 aditus, the anterior 

 wall is longer than 

 the posterior. The 

 anterior wall is 

 formed by the pos- 

 terior surface of 

 the epiglottis and 

 the thyreo-epiglot- 

 tic ligament, both 

 covered with 

 mucous membrane. 

 It descends ob- 

 liquely from above 



downwards and slightly forward and becomes narrower as it 

 approaches the anterior ends of the ventricular folds. Each 

 side wall of the vestibule is formed by the medial surface of 

 a fold of mucous membrane called the ary-epiglottic fold. 

 For the most part it is smooth and slightly concave, but in its 

 posterior part the mucous membrane bulges medially, in the 

 form of two vertical elevations, placed one posterior to the 

 other. The anterior elevation is formed by the enclosed 

 cuneiform cartilage and a mass of glands associated with it ; 



Thyreoid cartilage 



Plica ventricularis 

 Ventricle of larynx 



Plica vocalis 



Musculus vocalis - 



Cricoid cartilage 



FIG. 1 1 8. Frontal section through the Larynx, 

 to show the Compartments. 



