434 



VOICE. 



[CHAP. xxxi. 



movement of the one cartilage may take place on the other, round 

 an axis passing transversely through the cricoid. By this move- 

 ment, the crico-thyroid space may be enlarged or diminished ac- 

 cording as the cartilages separate from or approximate each other 

 in front. 



Fig. 211. 



A. Thyroid cartilage, a. The notch, b. Superior cornu. c. Inferior cornu. d. Slight 

 prominence at median lines of inferior margin for the attachment of crico-thyroid ligament. 

 g, h. Superior and inferior tubercles, e. Ala. /. Pomum Adami. 



B. Cricoid cartilage seen from the side. a. Posterior superior margin, b. Articulating 

 surface of arytenoid cartilages. /. Superior descending margin, h. The right surface articu- 

 lating with inferior cornu of thyroid. 



C. The right arytenoid cartilage, a. Base ; position of the crico-arytenoid articulating 

 grooves, c. Lateral prominence at base, which gives attachment to the crico-arytenoideus 

 lateralis and posticus. d, b. Convex triangular surfaces for the attachment of the superior 

 thyro-arytenoid ligaments. /. Corniculum laryngis ; between / and e, the posterior aspect of 

 the arytenoid cartilage and concave surfaces giving attachment to the oblique and transverse 

 arytenoid muscles, g. Vertical portion of cuneiform cartilage. 



The arytenoid cartilages are two pyramidal bodies articulated 

 by their bases with the oval articular surfaces, already described 

 on the upper margin of the cricoid cartilage. Each presents a 

 concave posterior surface in which is implanted the arytenoid 

 muscle which passes from one cartilage to the other ; an inner 

 smooth surface covered by mucous membrane, and an outer 

 surface which gives attachment to the crico-arytenoid muscles. 

 From the anterior angles of the bases of the arytenoid cartilages 

 proceed the vocal chords to be inserted into the angle of . the 

 thyroid. The mobility of the articulation of the arytenoids with 

 the cricoid, and their connexion with the vocal ligaments give 

 them great importance in the mechanism of the larynx. 



The cornicula and the cuneiform cartilages are placed beneath 

 the mucous membrane the former at the apex, the latter parallel 

 to the anterior border of the arytenoid cartilages. 



