THE HEAD AND NECK. 247 
exposed; also on the lateral wall the pharyngeal aperture 
of the auditory tube (ostium pharyngeum tubae). 
10) Examination of the larynx. 
By cutting around the base of the tongue on the opposite side 
of the body, the whole structure, together with the hyoid, larynx, 
and a portion of the trachea back to about the end of the thyreoid 
gland may be removed. This affords a good opportunity of re- 
dissecting on the opposite side from the medial surface of the 
mandible outward, also of clearing and examining the hyoid appar- 
atus, which is not usually available with the prepared skeleton 
(Fig. 65). The laryngeal cartilages should be cleared externally 
and the parts made out as follows: 
(a) 
(b) 
(c) 
(d) 
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 projects forward as the 
cornu superior; connected by ligament with the greater 
cornu of the hyoid. The corresponding posterodorsal 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. 
The cricoid cartilage (cartilago cricoidea) is an annular 
cartilage, partly enclosed by the posterior portions of the 
thyreoid laminae and surrounding the first tracheal ring. 
Its ventral portion, the arch of the cricoid cartilage, falls 
some distance behind the thyreoid cartilage, the intervening 
space being largely occupied by the cricothyreoidei 
muscles. Its dorsal portion, the lamina of the cricoid, 
forms a greatly expanded plate serving for the support of the 
arytenoid cartilages. 
The paired arytenoid cartilages (cartilagines arytenoi- 
deae) lie one on either side of the anterior tip of the cricoid 
plate. 
The corniculate cartilages (cartilagines corniculatae) are 
slender curved terminal cartilages supported by the ary- 
tenoids. 
