344 PRACTICAL ANATOMY. 



on elevation of the larynx, as in swallowing, it is de- 

 pressed and serves to cover the glottis. 



The arytenoid cartilages are trilateral pyramids 

 which rotate on their bases. They are placed upon 

 the upper posterior part of the cricoid. Upon the apex 

 of each cartilage is placed a small nodule of fibro-car- 

 tilage, the cornicula laryngis. The cuneiform are two 

 plates of cartilage placed in the aryteno-epiglottidian 

 folds. 



The ligaments of the larynx are intrinsic and ex- 

 trinsic ; the extrinsic are the two thyro-hyoid ligaments 

 which connect the superior cornua of the thyroid carti- 

 lage with the greater cornua of the hyoid bone and the 

 thyro-hyoid membrane, which is stretched between the 

 upper border of the thyroid cartilage and the inferior 

 border of the hyoid bone. The intrinsic ligaments are : 

 The crico-thyroid membrane, passes between the inferior 

 border of the thyroid cartilage and superior border of 

 the cricoid, and is composed of yellow elastic tissue ; two 

 capsular ligaments, for the crico-thyroid articulations : 

 two capsular crico-arytenoid ligaments. These liga- 

 ments are much thicker posteriorly. The two epiglottic 

 ligaments from the posterior part of the body of the 

 hyoid to the anterior surface of the epiglottis are a plane 

 of elastic fibres. The thyro-epiglottic ligament is a long, 

 narrow band of elastic fibres, which runs from the upper 

 part of the epiglottis to the inner surface of the thyroid 

 cartilage near the median line. The glosso-epiglottic 

 folds, formed by the reduplication of the mucous mem- 

 brane, are the two lateral and the median. 



The muscles of the larynx consist of eight pairs. 

 They are those which control the vocal cords and 

 those of the epiglottis. The muscles of the vocal cords 

 are : 



