ANATOMY OF LARYNX. 597 



from the pharynx to the larynx (e, Fig. 89);* it may be 

 seen, covered by mucous membrane, projecting at the base 

 of the tongue, if the latter be pushed down while the 

 mouth is held open in front of a mirror; and is, similarly 

 covered, represented, as seen from behind, at a in Fig. 157. 

 The cricoid, the last of the unpaired cartilages, is the shape 

 of a signet-ring; its broad part (*., Fig. 156) is on the pos- 

 terior side and lies at the lower part of the opening between 

 the halves of the thyroid; in front and on the sides it is 

 narrow, and a space, occupied by the crico-thyroid mem- 

 brane, intervenes between its upper border and the lower 

 edge of the thyroid cartilage. The angles of the latter 

 are produced above and below into projecting horns 

 (Cs and Ci, Fig. 156), and the lower horn on each side 

 forms a joint with the cricoid. The thyroid can be ro- 

 tated on an axis, passing through the joints on each side, and 

 rolled down so that its lower front edge shall come nearer 

 the cricoid cartilage, the membrane there intervening being 

 folded. The arytenoids (f, Fig. 156) are the largest of the 

 paired cartilages; they are seated on the upper edge of the 

 posterior wide portion of the cricoid, and form true joints 

 with it. Each is pyramidal with a triangular base, and has 

 on its tip a small nodule (co, Fig. 156), the cartilage of 

 Santorini. From the tip of each arytenoid cartilage the 

 aryteno-epiglottidean fold of mucous membrane (10, Fig. 

 157) extends to the epiglottis; the cartilage of Santorini 

 causes a projection (8, Fig. 157) in this; and a little 

 farther on (9) is a similar eminence on each side, caused 

 by the remaining pair of cartilages, known as the cuneiform, 

 or cartilages of Wrisberg. 



The Vocal Cords are bands of elastic tissue which reach 

 from the inner angle (Pv, Fig. 156) of the base of each 

 arytenoid cartilage to the angle on the inside of the thyroid 

 where the sides of the V unite; they thus meet in front but 

 are separated at their other ends. The cords are not, how- 

 ever, bare strings, like those of a harp, but covered over with 

 the lining mucous membrane of the larynx, a slit, called 

 the glottis (c, Fig. 157), being left between them. It is the 

 * Page 309. 



