THE LARYNX 



1173 



straight margin of the true vocal cord ; externally, by the mucous membrane cover- 

 ing the corresponding Thyroarytenoideus muscle. The anterior part of the ven- 

 tricle leads up by a narrow opening into a cecal pouch of mucous membrane of 

 variable size, called the laryngeal saccule. 



The laryngeal saccule (appendix ventriculi) (Fig. 883), or laryngeal pouch, is 

 a membranous sac, placed between the superior vocal cord and the inner surface 

 of the thyroid cartilage, occasionally extending as far as its upper border or even 

 higher; it is conical in form, and curved slightly backward. On the surface 

 of its mucous membrane are the openings of sixty or seventy mucous glands, 

 which are lodged in the submucous areolar tissue. This sac is enclosed in a 

 fibrous capsule, continuous below with the superior thyroarytenoid ligament; 

 its laryngeal surface is covered by a few delicate muscle fasciculi which arise 

 from the apex of the arytenoid cartilages and become lost in the fold of mucous 

 membrane extending between the arytenoid cartilage and the side of the epiglottis 

 (they were named by Hilton the compressor sacculi laryngis); while its exterior 

 is covered by the Thyroarytenoideus and Thyroepiglottideus muscles. These 

 muscles compress the laryngeal saccule, and express the secretion it contains upon 

 the vocal cords to lubricate their surfaces. 



APEX OF SUP. HORN OF 

 THYROID CARTILAGE 



TRUE 

 VOCAL CORD 



CORNICULUM 

 LARYNGIS 



CUNEIFORM 



~ CARTILAGE 



AHYTENO-EPIGLOT- 

 TIDIAN FOLD 

 APEX OF GREAT 

 HORN OF HYOIO 



LATERAL GLOSSO- 

 EPIGLOTTIDIAN FOLD 



MIDDLE GLOSSO- 

 EPIGLOTTIDIAN FOLD 



FIG. 887. Larynx, viewed from above. (Testut.) 



The Rima Glottidis (Figs. 883 and 887) is the elongated fissure or chink between 

 the true vocal cords in front, and between the bases and vocal processes of the 

 arytenoid cartilages behind. It is therefore frequently subdivided into an anterior, 

 interligamentous or vocal portion, the glottis vocalis (pars intermembranacea), 

 and a posterior, intercartilaginous or respiratory portion, the glottis respiratoria 

 ( pars intercartilaginea). Posteriorly it is limited by the mucous membrane passing 

 between the arytenoid cartilages. The vocal portion averages about three- 

 fifths of the length of the entire aperture. It is the narrowest part of the cavity 

 of the larynx, and its level corresponds to the bases of the arytenoid cartilages. 

 Its length, in the male, measures rather less than an inch (23 mm.); in the female 

 it is shorter (16 to 20 mm.). The width and shape of the rima glottidis vary 

 with the movements of the vocal cords and arytenoid cartilages during respiration 

 and phonation. In the condition of rest?', e., when those structures are unin- 

 fluenced by muscular action, as in quiet respiration, the glottis vocalis is triangular, 

 with its apex in front and its base behind, the latter being represented by a line 



