THE LARYNX 409 



The aditus laryngis has already been examined in the 

 dissection of the pharynx (p. 378). The parts which bound 

 it should again be carefully studied. 



The epiglottis projects upwards posterior to the root of the 

 tongue. Its lingual or anterior surface is free in the upper 

 part of its extent only, and is attached to the pharyngeal 

 part of the tongue by a prominent median fold of mucous 

 membrane, termed the glosso-epiglottic fold. Two lateral folds 

 are also present; they connect its margins with the lateral 

 walls of the pharynx at the side of the tongue and are 

 called the pharyngo-epi glottic folds. Between the two layers of 

 mucous membrane which constitute each of these three folds, 

 there is a small amount of elastic tissue. The depression on 

 each side between the tongue and the epiglottis which is 

 bounded by the glosso-epiglottic and the pharyngo-epiglottic 

 folds is termed the vallecula (Fig. 150). The posterior free 

 surface of the epiglottis forms the greater part of the anterior 

 boundary of the vestibule of the larynx. The upper part of 

 this surface is convex, owing to the manner in which the 

 upper margin is curved towards the tongue ; below this 

 convexity there is a slight concavity, and still lower a marked 

 bulging over the upper part of the thyreo-epiglottic ligament. 

 This last projection is called the tubercle of the epiglottis it 

 forms a conspicuous object in laryngoscopic examinations of 

 the larynx. 



The ary-epiglottic folds of mucous membrane enclose 

 between their two layers some connective tissue, the ary- 

 epiglottic muscles, and, posteriorly, the cuneiform and the 

 corniculate cartilages, which surmount the arytaenoid cartilages. 

 As already mentioned, these small nodules of cartilage raise 

 the posterior part of the ary-epiglottic fold in the form of 

 two rounded eminences or tubercles which are easily seen 

 when the larynx is examined by the laryngoscope. 



The Middle Subdivision of the Laryngeal Cavity (Fig. 157) 

 is the smallest of the three. Above it is bounded by the 

 ventricular folds, below by the vocal folds ; it communicates 

 with the vestibule above and the inferior compartment of the 

 larynx below. 



Plicce Ventriculares (O.T. false vocal cords}. The ventricular 

 folds are two prominent mucous folds which extend antero- 

 posteriorly on the lateral walls of the laryngeal cavity. They 

 are soft and somewhat flaccid, and their free borders are 



