THE NECK 157 



by the internal laryngeal nerve, and the lodgment of foreign 

 bodies in it at once sets up a fit of uncontrollable coughing. 

 They may be removed by the finger, which is passed backwards 

 into the mouth close to the dorsum of the tongue, until the epi- 

 glottis is felt. The recessus piriformis can be explored postero- 

 lateral to the epiglottis (Fig. 48). 



The uppermost part of the larynx is termed the vestibule. 

 Its cavity narrows from above downwards, and is limited below 

 by two inwardly projecting ridges on its lateral walls, the ven- 

 tricular folds (false vocal cords). 



The laryngeal ventricle is bounded above by the ventricular 

 folds, and below by the vocal folds (true vocal cords), which are 

 separated from one another by the rima glottidis, and lie on a 

 level with the fifth cervical vertebra. The vocal fold consists 

 of the ligamentum vocale (p. 155), to the lateral aspect of which 

 the vocalis muscle is closely applied. Its medial aspect is so 

 firmly bound down to the mucous membrane that it presents a 

 whitish colour on laryngoscopic examination. In front, the 

 vocal fold is attached to the thyreoid angle, and behind, to the 

 vocal process of the arytenoid cartilage. The intimate relation 

 of the mucous membrane to the vocal fold is of great importance 

 in connection with oedema glottidis. Elsewhere in the larynx 

 the submucous tissue is very lax and distensible. When oedema 

 occurs in this situation it cannot spread downwards beyond the 

 vocal folds. In consequence, the laryngeal ventricle may be so 

 encroached on by the swollen mucous membrane as to hinder 

 the in-take of air to a serious or even fatal extent. 



The-n'wwz glottidis is the narrowest part of the respiratory 

 tract, and measures i inch antero - posteriorly by J inch 

 transversely. It corresponds in level to the lower part of the 

 laryngeal prominence. 



On laryngoscopic examination the observer can see the ex- 

 panded upper end of the epiglottis and the ary-epiglottic folds. 

 In the posterior part of the latter two elevations can be made 

 out ; the posterior is produced by the corniculate cartilage (of 

 Santorini) and the anterior by the cuneiform cartilage (of Wris- 

 berg), which is a nodule of yellow elastic cartilage embedded in 

 the fold. Within the boundaries of the aperture both the 

 ventricular and vocal folds (false and true vocal cords) can be 

 examined (Fig. 49). The former, which are reddish in colour, 

 are more widely separated, as a rule, and have only a small range 

 of movement ; the latter are whitish in colour and move freely 



