96 TOPOGRAPHICAL ANATOMY OF THE 



The cavity of the larynx (Cavum laryngis). — If the interior of 

 the larynx be examined it will be observed that the lumen of the cavity 

 is constricted opposite two lateral folds of mucous membrane. These 

 are the vocal fohh (plicae vocales), and they form sharp and prominent 

 ridges running from the angle of convergence of the two thyroid lamime 

 to the vocal processes of the arytenoid cartilages. The folds are close 

 together at their ventral ends, but diverge dorsally; and it must be 

 noted that they are not disposed at right angles to the long axis of the 

 larynx, but run downwards and forwards. The interval between the 

 folds is the inter-membranous part (pars intermembranacea) of the 

 glottis {vim^ glottidis) ; its continuation between the arytenoid cartilages 

 being the intercartilaginous part (pars intercartilaginea) of this opening. 

 Anterior to the vocal folds the cavity of the larynx is relatively spacious 

 and is distinguished as the vestibule (vestibuhim laryngis). Its bound- 

 aries are formed mainly by the epiglottic and arytenoid cartilages and 

 the folds of raucous membrane that connect these with each other. 



Immediately lateral to each vocal fold there is a slitlike depression, 

 the lateral ventricle of the larynx (ventriculus laryngis lateralis), 

 bounded by two lips, one of which is formed by the vocal fold, the other 

 by a very inconspicuous ventricular fold (plica ventricularis). If the 

 depths of the ventricle be explored, it will be found that the cavity is 

 continued into a relatively spacious appendix of the ventricle (appendix 

 ventriculi), of which a complete examination will be more easily possible 

 after the removal of a lamina of the thyroid cartilage at a later stage of 

 the dissection. 



At the base of the epiglottis there is a small middle ventricle 

 (ventriculus laryngis medianus), trilocular in character. 



The oval entrance to the larynx (aditus laryngis) from the pharynx 

 should receive attention. The prominent epiglottis, which forms the 

 anterior boundary of the aditus, is connected with the tongue by the 

 thick and obvious glosso-epiglottic fold (plica glossoepiglottica) of 

 mucous membrane, to the side of which is the epiglottic vallecida 

 (vallecula epiglottica), a deep and somewhat triangular depression. 

 Joining the margins of the epiglottis to the apices of the arytenoid and 

 corniculate cartilages are the two aryepiglottic folds (plicae aryepiglot- 

 ticae). Between each aryepiglottic fold and the lamina of the thyroid 

 cartilage is the 'piriform recess ^ (recessus piriformis), the roof of which 

 is formed by the pharyngo-palatine arch. 



Beyond the vocal folds the cavity of the larynx is roomy and 

 directly continuous with the lumen of the trachea. 



The mucous membrane (tunica mucosa laryngis) lining the cavity of 

 1 Pirus [L.], a pear. 



