HEAD AND NECK OF THE HORSE 95 



the arytenoid cartilages (facies articularis arytsenoidea). The caudal 

 border of the lamina is thin and irregular, and overhangs the first ring 

 of the trachea. The dorsal or outer surface of the lamina carries a 

 median ridge-like muscular process (processus muscularis). On each 

 side, at the junction of the arch and the lamina, there is a projecting, 

 bracket-like articular surface for the reception of the caudal cornu of 

 the thyroid (facies articularis thyreoidea). The whole of the internal 

 surface of the cricoid cartilage is smooth and covered by the laryngeal 

 mucous membrane. 



The two arytenoid ^ cartilages (cartilagines arytaenoidese), irregularly 

 pyramidal in shape, rest on the cranial border of the lamina of the 

 cricoid. The apex of each cartilage is directed towards the mouth, and 

 is continued by a curved and sharply pointed corniculate cartilage 

 (cartilage corniculata), which is yellow and elastic and pitted with 

 depressions, while the arytenoid itself, like the thyroid and cricoid, is 

 bluish in colour, rigid and smooth. The pointed tips of the corniculate 

 cartilages curve upwards and backwards, and approach each other in the 

 median plane, where, covered by mucous membrane, they form a 

 characteristic projection in the undissected larynx. The triangular base 

 of each arytenoid cartilage has a prominent ventral angle, the vocal 

 process (processus vocalis) to which the vocal fold is attached, and a blunt 

 lateral angle, the muscular process (processus muscularis), on which 

 certain muscles terminate. The lateral part of the base carries an oval 

 concave surface (facies articularis) for articulation with the cricoid 

 cartilage. The lateral and dorsal surfaces of the arytenoid are concave, 

 while the medial surface, larger than the other two, is flattened and 

 covered by the laryngeal mucous membrane. 



The epiglottis - (cartilago epiglottica) has the form of a sessile leaf, 

 resting within the laryngeal prominence of the thyroid by a broad base, 

 from each corner of which an irregular rod of cartilage — the cuneiform^ 

 cartilage (cartilago cuneiforme) projects towards the arytenoid. The 

 anterior angle or apex of the epiglottis is free and sharply curved, pro- 

 jects towards the base of the tongue, and rests on the edge of the soft 

 palate. Of the two surfaces, the dor.sal is entirely free and saddle- 

 shaped (convex longitudinally and concave transversely), and is covered 

 by firmly adherent mucous membrane. The ventral surface is also 

 saddle-shaped (in the reverse direction) and partly free, but it affords 

 attachment to the glosso-epiglottic mucous fold and the hyo-epiglottic 

 muscle and ligament. The borders are thin and irregular. 



1 dpiraiva (arytaina) [Gr.], a pitcher, a ladle. elSos (eidos) [Gr.], form. 

 2e7rt (epi) [Gr.], upon. yXurris (glottis) [Gr.], the mouth of the windpipe (Galen), 

 the mouthpiece of a flute. ^ Cuneus [L.], a wedge. 



