LIGAMENT OF TEE LAEYXX. 253 



The cuneiform cartilages, or cartilages of Wrisberg, are two very 



small, soft, yellowish cartilaginous Ijodies, placed, one ou each side, in 

 the fold of the mucous membrane which extends from the summit of the 

 arytenoid cartilage to the epiglottis. They have a conical form, with 

 the base directed upwards. They occasion small elevations of the mu- 

 cous membrane, a little in advance of the cartilages of Santorini, with 

 which, however, they are not directly connected. 



The epiglottis (fig. 188,/; fig. 189, t) is a median lamella of yellow 

 cartilage, shaped somewhat like an ovate or obcordate leaf, and covered 

 by mucous membrane. It is placed in front of the superior opening 

 of the larynx, projecting, in the ordinary condition, upwards im- 

 mediately behind the base of the tongue ; but during the act of 

 swallowing it is carried downwards and backwards over the entrance 

 into the larynx, which it covers and protects. 



The cartilage of the epiglottis is broad and rounded at its upper free 

 margin, but inferiorly it becomes pointed, and is prolonged by means of 

 a long, narrow, fibrous band (the thyro-ephjloHic lujamcnt) to the deep 

 angular depression between the al* of the thyroid cartilage, to which it 

 is attached, behind and below the median notch. Its laieral borders, 

 which are convex and turned backwards, are only partly free, the lower 

 parts being enveloped in the aryteno-epiglottic folds of mucous mem- 

 brane. The anterior or linyual surface is free only in its upper part, 

 where it is covered by mucous membrane. Lower down, the membrane 

 is reflected from it forwards to the base of the tongue, forming three 

 folds or fi'a^nula, the middle and lateral giosso-epiglottidean folds. This 

 surface is also connected below with the posterior surface of the os 

 hyoides by means of a median elastic structure named the liyo-epiglottic 

 ligament. H^Ivq posterior or laryngeal surface, which is free in the whole 

 of its extent, is concavo-convex from above downwards, but concave 

 from side to side : the convexity projecting backwards into the larynx 

 is named the tubercle or cushion. The epiglottis is closely covered 

 by mucous membrane, on removing which, the yellow cartilaginous 

 lamella is seen to be pierced by numerous little pits and perforations, 

 in which are lodged small glands which open on the surface of the 

 mucous membrane. 



Structure of the cartilages of tlie larynx. — The epiglottis, 

 the cornicula laryngis and the cuneiform cartilages, are composed of 

 clastic or yellow fibro-cartilage (p. 78), and have little tendency to ossify. 

 The structure of all the other cartilages of the larynx resembles 

 generally that of the costal cartilages (p. 75), like which, they are very 

 prone to ossification as life advances. 



LIGAMENTS AND JOINTS OF THE LARYNX. 



The larynx is connected with the hyoid bone by a broad membrane 

 ending at the sides in two round lateral ligaments. The thyro-hyoid 

 membrane or middle thyro-hyoid ligament, is a broad, fibrous, 

 and somewhat elastic membrane, which passes up from the whole length 

 of the superior border of the thyroid cartilage to the hyoid bone, where 

 it is attached to the posterior and upper margin of the obliquely inclined 

 inferior surface. Owing to this arrangement, the top of the larynx, 

 when drawn upwards, is permitted to slip within the circumference of 

 the hyoid bone, between which and the upper part of the thyroid carti- 



