1102 THE ORGANS OF VOICE AND RESPIRATION. 



The Arytenoid Cartilages, so called from dp'jraiva, a ladle, are two in number, 

 and each is situated at the end of the upper border of the lamina of the cricoid 

 cartilage. Each cartilage is pyramidal in form, and presents for examination three 

 surfaces, a base, and an apex. 



The posterior surface is triangular, smooth, concave, and gives attachment to 

 the Arytenoid muscle. 



The antero-external surface is convex and rough. It gives attachment to the 

 Thyro-arytenoid muscle ; and to the false vocal cord immediately above a depres- 

 sion, the fossa triangularis, situated at about its centre. 



The internal surface is narrow, smooth, and flattened, covered by mucous mem- 

 brane, and lies almost in apposition with the cartilage of the opposite side. 



The base of each cartilage is broad, and presents a concave (antero-posteriorly) 

 smooth surface for articulation with the cricoid cartilage. Projecting from the base 

 are two processes, one postero-externally and the other anteriorly. Between the two 

 is the base of the antero-external surface. The former, known as the muscu- 

 lar process, is short, rounded, and prominent, and receives the insertion of the 

 Posterior and Lateral crico-arytenoid muscles. The latter also prominent, but 

 more pointed and flattened, gives attachment to the true vocal cord. This is the 

 vocal process. 



The apex of each cartilage is pointed, curved backward and inward, and sur- 

 mounted by a small, cone-shaped, cartilaginous nodule, the corniculum laryngis. 



The cornicula laryngis (cartilages of Santorini) are two small, conical nodules, 

 consisting of yellow fibro-cartilage, which are attached to the summit of the ary- 

 tenoid cartilages and serve to prolong them backward and inward. To them are 

 attached the aryteno-epiglottic folds. They are sometimes united to the arytenoid 

 cartilages. 



The cuneiform cartilages (cartilages of Wrisberg) are two small, elongated, car- 

 tilaginous bodies, placed one on each side in the fold of mucous membrane, which 

 extends from the apex of the arytenoid cartilage to the side of the epiglottis (aryteno- 

 epiglottic fold) ; they give rise to small whitish elevations on the free edge of the 

 mucous fold, just in front of the cartilages of Santorini. 



The epiglottis is a thin lamella of fibro-cartilage, of a yellowish color, shaped 

 like a leaf, and placed behind the tongue, in front of the superior opening of the 

 larynx. During respiration its direction is vertically upward, its free extremity 

 curving forward toward the base of the tongue; but when the larynx is drawn up 

 beneath the base of the tongue during deglutition, it is carried downward and 

 backward so as to close, more or less completely, the opening of the larynx. Its 

 free extremity is broad and rounded; its attached end is long and narrow, and 

 connected to the receding angle between the two alse of the thyroid cartilage, just 

 below the median notch, by a ligamentous band, the thyro-epiglottic ligament. It 

 is also connected to the posterior surface of the body of the hyoid bone by an 

 elastic ligamentous band, the hyo-efriglottic ligament. 



Its anterior or lingual surface is curved forward toward the tongue, and covered 

 at its upper part by mucous membrane, which is reflected on to the sides and base 

 of the organ, forming a median and two lateral folds, the glosso-epiglottic folds. 



Its posterior or laryngeal surface is smooth, concave from side to side, concavo- 

 convex from above downward, and covered by mucous membrane ; when this is 

 removed the surface of the cartilage is seen, to be studded with a number of little 

 pits for the lodgment of mucous glands. To its sides the aryteno-epiglottic folds 

 are attached. It is somewhat prominent just below its centre (tubercle or cushion 

 of the epiglottis). 



Structure. The cornicula laryngis, cuneiform cartilages, and epiglottis are com- 

 posed of yellow fibro-cartilage which shows little tendency to calcification, but the 

 other cartilages are hyaline, becoming more or less calcified in old age. 



LIGAMENTS. The ligaments of the larynx connect the thyroid cartilage and 

 epiglottis with the hyoid bone, thg cricoid cartilage with the trachea, and the 

 several cartilages of the larynx to each other. 



