CAVITY OF LARYNX GLOTTIS VOCAL CORDS. 707 



membrane, inclosing ligamentous and muscular fibres, stretched between the sides 

 of the epiglottis and the apex of the arytenoid cartilage : these are the aryteno- 

 epiglottidean folds, on the margins of which the cuneiform cartilages form a more 

 or less distinct whitish prominence. 



The cavity of the larynx extends from the aperture behind the epiglottis to the 

 lower border of the cricoid cartilage. It is divided into two parts by the 

 projection inwards of the vocal cords and Thyro-arytenoid muscles; between 

 the two cords is a long and narrow triangular fissure or chink, the glottis or rima 

 glottidis. The portion of the cavity of the larynx above the glottis is broad and 

 triangular in shape above, and corresponds to the interval between the alae of the 

 thyroid cartilage ; the portion below the glottis is at first elliptical, and, lower 

 down, of a circular form. 



The glottis or rima glottidis is the interval between the inferior vocal cords. 

 The two superior or false vocal cords are placed above the latter, and are formed 

 almost entirely by a folding inwards of the mucous membrane ; whilst the two 

 inferior or true vocal cords are thick, strong, and formed partly by mucous mem- 

 brane, and partly by ligamentous fibres. Between the true and false vocal cords, 

 on each side, is an oval depression, the sinus or ventricle of the larynx, which 

 leads upwards, on the outer side of the superior vocal cord, into a cascal pouch of 

 variable size, the sacculus laryngis. 



The rima glottidis is the narrow fissure or chink between the inferior or truo 

 vocal cords. It is the narrowest part of the cavity of the larynx, and cor- 

 responds to the level of the arytenoid 

 cartilages. Its length, in the male, 

 measures rather less than an inch, its 

 breadth when dilated varying at its 

 widest part from a third to half an 

 inch. In the female, these measure- 

 ments are less by two or three lines. 

 The form of the glottis varies. In a 

 quiescent state, it is a narrow fissure, 

 a little enlarged and rounded behind. 

 In inspiration, it is widely open, some- 

 what triangular, the base of the triangle 

 directed backwards, and corresponding 

 to the space between the separated 

 arytenoid cartilages. In expiration, 



Fig. 358. Vertical Section of the Larynx 

 and upper part of the Trachea. 



\iyktiuil 

 curt? 



it is smaller than during inspiration. 

 When sound is produced, it is more 

 narrowed, the margins of the aryte- 

 noid cartilages being brought into 

 contact, and the edges of the vocal 

 cords approximated and made parallel ; 

 the degree of approximation and ten- 

 sion corresponding to the height of 

 the note produced. 



The superior or false vocal cords, so 

 called because they are not directly 

 concerned in the production of the 

 voice, are two folds of mucous mem- 

 brane, inclosing a delicate narrow 



fibrous band, the superior thyro-arytenoid ligament. This ligament consists of a 

 thin band of elastic tissue, attached in front to the angle of the thyroid cartilage 

 below the epiglottis, and behind to the anterior surface of the arytenoid cartilage. 

 The lower border of this ligament, inclosed in mucous membrane, forms a free 

 crescentic margin, which constitutes the upper boundary of the ventricle of the 

 larynx. 



