908 THE LARYNX. 



The base of each arytenoid cartilage is slightly hollowed, having towards 

 its inner part a smooth surface for articulation with the cricoid cartilage. 

 Two of its angles are remarkably prominent, viz., one external, short, and 

 rounded, which projects backwards and outwards, and into which the pos- 

 terior and the lateral crico-arytenoid muscles are inserted ; the other ante- 

 rior, which is more pointed, and forms a horizontal projection forwards, to 

 which the corresponding true vocal cord is attached. 



The apex of each arytenoid cartilage curves backwards and a little in- 

 wards, and terminates in a blunt point, which is surmounted by a small 

 cartilaginous appendage named corniculum laryngis. 



The cornicula laryngis, or cartilages of Santorini, are two small yellowish 

 cartilaginous nodules of a somewhat conical shape, which are articulated 

 with the summits of the arytenoid cartilages, and serve as it were to pro- 

 long them backwards and inwards. They are sometimes continuous with 

 the arytenoid cartilages. 



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

 soft, yellowish cartilaginous bodies, placed one on each side of the larynx 

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

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

 or broader part being directed upwards. They occasion small conical eleva- 

 tions of the mucous membrane in the margin of the superior aperture of the 

 larynx, a little in advance of the cartilages of Santorini, with which, how- 

 ever, they are not directly connected. 



The epiglottis 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 immediately 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 somewhat rounded at its upper 

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

 a long, narrow, fibrous band (the thyro-epiglottic ligament) to the deep 

 angular depression between the alee of the thyroid cartilage, to which it is 

 attached, behind and below the median notch. Its lateral borders, which 

 are convex and turned backwards, are only partly free, being in part con- 

 cealed within the folds of mucous membrane, which pass back on each side 

 to the arytenoid cartilages. The anterior or lingual surface is free only in 

 the upper part of its extent, where it is covered by mucous membrane. 

 Lower down, the membrane is reflected from it forwards to the base of the 

 tongue, forming one median fold and two lateral fraenula, or glosso-epiglot- 

 tidean ligaments. The adherent portion of this surface is also connected 

 with the posterior surface of the os hyoides by means of a median elastic 

 tissue named the hyo-epiglottic ligament, and is moreover in contact with 

 some glands and fatty tissue. The posterior or laryngeal surface of the epi- 

 glottis, which is free in the whole of its extent, is concavo-convex from 

 above downwards, but concave from side to side : the lower convexity pro- 

 jecting 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. 



The structure of the cartilages of the larynx. The epiglottis, together 

 with the coruicula laryngis and cuneiform cartilages, are composed of what 



