THE LARYNX 313 



The laryngeal cartilages should now be thoroughly and carefully 

 cleared externally b>- the removal of all soft tissues so that the fol- 

 lowing parts are clearly seen. 



(a) The thyreoid cartilage (cartilago thyreoidea) forms the 

 largest portion of the structure. It is an unpaired saddle- 

 shaped cartilage, described as consisting of right and left 

 laminae. Its anterodorsal angle at each side projects 

 forward as the cornu superior, connected by ligament with 

 the greater cornu of the hyoid. The corresponding postero- 

 dorsal angle, the cornu inferior, overlies the dorsolateral 

 portion of the cricoid cartilage. The anterior dorsal portion 

 of each plate bears a small thyreoid foramen (foramen 

 thyreoideum) for the entrance of the superior laryngeal 

 nerve and just ventral to this a longitudinal ridge serves 

 for the attachment of the sternothyreoid, thyreohyoid, and 

 thyreolaryngeal muscles. 



(b) The cricoid cartilage (cartilago cricoidea) is annular, 

 surrounding the first tracheal ring. Its ventral portion, 

 the arch of the cricoid cartilage, is situated some distance 

 caudal to the thyreoid cartilage, the intervening space 

 being largely occupied by the cricothyreoidei muscles. Its 

 lateral part slants obliquely anterodorsad and expands into 

 the dorsal portion, the lamina of the cricoid, which is 

 partly enclosed at the sides by the posterodorsal angles of 

 the thyreoid laminae and has a firm ligamentous attach- 

 ment to these. The lamina of the cricoid extends craniad 

 and forms the larger part of the dorsal wall of the larynx, 

 its anterior margin having a blunt median point and slanting 

 obliquely laterocaudad at either side. 



(c) The paired arytenoid cartilages (cartilagines arytenoideae) 

 lie obliquely one on each side of the anterior tip of the 

 cricoid plate, closely articulated with its margin. Each ap- 

 pears curved and somewhat irregularly pear-shaped in dorsal 

 view, tapering to a point anteromedially. From the lateral 

 angle of the broader posterior end there is a prominent ven- 

 tral projection for the attachment of one end of a vocal fold. 



