1222 



THE RESPIRATORY SYSTEM 



transversely in approaching the region of the glottis. Here the cavity has received 

 the special name, superior entrance to the glottis [aclitus glottidis superior]. The 

 parts of the framework of the larynx which enter into the walls of the vestibule are : 

 in front, the epiglottic and thyreoid cartilages with the thyreo-epiglottic ligament; 

 at the side, the quadrangular membrane, the cuneiform and corniculate cartilages, 

 and the medial surface of the arytsenoid cartilage; behind, the anterior surface of 

 the transverse arj^taenoid muscle. The vestibule communicates with the pharynx 

 by the laryngeal aperture [aditus laryngis] (figs. 970, 971, 972, 987), which 

 looks upward and backward. The form of the aperture is oval or triangular, 

 with the base in front; here it is bounded by the epiglottis; laterally by the ary- 

 epiglottic fold of the mucosa. Posteriorly the laryngeal aperture is prolonged as 

 a little notch between the corniculate cartilages and the apices of the arytsenoids 

 [incisura interarytaenoidea] limited behind by a commissure of the mucosa. 



The high anterior wall of the vestibule presents a marked convexity, the tubercle of the 

 epiglottis [tuberculum epiglotticum], over the thyreo-epiglottic ligament. The lateral walls, 



Fig. 987. — Median Section of the Larynx. (Merkel.) 



Median glosso-epiglottic fold 



Epiglottic cartilage 

 Cuneiform tubercle- 

 Corniculate tubercle a — ^^;'ll|li-Wt^'■»i&^' 



Arytaenoid muscles' 



Lamina of cricoid 



^' -^^ ^ — Appendix of the ventricle 

 Ventricular fold 



Ventricle 

 Vocal fold 

 Thyreoid cartilage 



Median crico-thyreoid ligament 



Arch of cricoid 

 Crico-tracheal ligament 

 First tracheal cartilage 



higher in front than behind, show two slight ridges, separated by a shallow groove, extending 

 downward from the cuneiform and corniculate tubercles. The posterior wall, very low, corre- 

 sponds to the commissure connecting the arytajnoid cartilages. 



On either side of the vestibule, toward its inferior end, is the sagittally running 

 ventricular fold [plica ventricularis] (false vocal cord) (figs. 970, 971, 987, 988). 

 This appears as an elevation of the mucous coat of the lateral wall, prominent in 

 its middle and anteriorly, fading away posteriorly. The ventricular fold contains 

 the inferior free edge of the quadrangular membrane, that is, the ventricular liga- 

 ment, and numerous glands. 



Wylie's experiments with the ventricular folds led him to conclude that the closure of the 

 glottis in defiKcation and vomiting is mainly effected by the apposition of these folds. (Quain.) 



The interval between the right and left ventricular folds, the vestibular slit 

 [rima vestibuli] leads downward to a space between the planes of the ventricular 

 and vocal folds, which extends on each side into the laryngeal ventricle [ventricu- 

 lus laryngis (Morgagni*)] (figs. 970, 971, 987, 988). The latter is a little antero- 

 posterior pocket of the mucosa reaching from the level of the arytaenoid nearly 

 to the angle of the thyreoid cartilage, and undermining the ventricular fold; 

 it opens into the cavity of the larynx by a narrow mouth limited above and below 

 by the ventricular and vocal folds. From its anterior part a small diverticulum, 



* Morgagni. Italian anatomist. B. 1682, D. 1771. 



