126 LARYNX. 



The base^ is concave, and articulates with the heads of the cricoid ; 

 the apices^ have attached to them a small cartilage called corniculum 

 laryngis, or tubercles of Santorini. The posterior surface* is 

 triangular and concave, for the insertion of the posterior crico- 

 arytenoid muscle ; the internal surface is flat, and can be adjusted 

 to its fellow ; the anterior surface is uneven, to which are attached 

 the superior and inferior thyreo-arytenoid ligaments. (Fig. 108.) 



The epiglottis cartilage is a thin, oval, cartilaginous plate, behind 

 the root of the tongue, and attached to the angle of the larynx ; it 

 resembles a leaf in shape ; its direction is vertical ; its inferior ex- 

 tremity* is thin and pointed ; its superior edge is thin, its anterior 

 surface* is slightly convex, and its posterior^ concave. It is per- 

 forated by numerous foramina. (Fig. 109.) 



These cartilages are held together by numerous ligaments, of 

 which the principal are, the 'tniddle thyreo-hyoid ; a thin membranous 

 expansion between the inferior circumference of the hyoid bone and 

 the superior edge of the thyroid cartilage : the lateral thyreo-hyoid ; 

 which is funicular, extending from the great cornu of the thyroid 

 cartilage to the tubercle of the cornu of the hyoid bone ; in it is 

 found a small oval cartilage or bone, called cartilago triticea ; the 

 tniddle crico-thyroid, a thick membrane filling up the space between 

 the superior edge of the cricoid and inferior edge of the thyroid 

 cartilages ; this is usually divided in the operation of laryngotomy ; 

 the lateral crico-thyroid^ reaching from the inferior cornu of the 

 thyroid to the side of the cricoid ; a capsular ligament surrounds 

 the joint between the arytenoid and cricoid. 



Within the larynx are two thyreo-arytenoid ligaments on either 

 side. The inferio?- ligaments extend from the angle of the thyroid to 

 the base of the arytenoid, and are usually called the vocal cords ; the 

 space between them is the rima glottidis. The superior WgOiXnenXs 

 extend from the angle of the thyroid to the middle of the arytenoid 

 cartilages. These ligaments are not cords as they appear, but 

 merely edges of a membrane lining the larynx, and composed of 

 yellow elastic fibrous tissue. 



The mucous membrane lining the larynx is continuous with that 

 of the mouth, and forms numerous folds between the cartilages, of 

 which the most remarkable is a pouch between the superior and 

 inferior thyreo-arytenoid ligaments, which has been called the ven- 

 tricle of the larynx. To the ventricle of either side is attached an 

 additional pouch, which is called the sinus of Morgagni. In the 

 fold between the arytenoid and epiglottis cartilages is a small gland 

 called the arytenoid, which is of the shape of the letter L. 



l^ie muscles of the larynx move the various cartilages and 

 modulate the voice. 



Thyreo-hyoid. — This was described with the muscles of the neck. 



CricO'thyroid^ arises from the anterior and lateral surfaces of the 



