HEAD AND NECK OF THE HORSE 



99 



nearer together and so narrows the intercartilaginous part of the rima 

 glottidis ; but it doubtless also causes some rotation of the cartilages 

 that results in the abduction of the vocal folds. 



Dissection. — The dissection of the remaining muscles should be con- 

 fined, for the time being, to one side of the larynx ; the other side being 

 reserved for later examination. 



Disarticulate one thyroid cornu from the hyoid bone, and cut through 

 the hyo-thyroid membrane on the same side as far as the middle line. 

 Cut through the thyroid lamina just where it joins the laryngeal pro- 



M. cricoarytjenoideus dorsalis. 

 N. recurrens. 



A. thvreoidea cranialis. 



Thyroid gland. 



M. cricoarytaenoideus lateralis. 

 Corniculate cartilage. 



Aryepiglottic fold. 



Epiglottis. 



I Soft palate. 



Cricoid cartilage. 



M. vocalis. 

 Appendix of ventricle. 



/ Hyoid bone. 



M. hyo-epiglotticus. 



' Cuneiform cartilage. 

 Thyroid cartilage (in section). 

 M. ventricularis. 



Fig. 38. — Lateral aspect of the larynx. The right lamina of the thyroid 

 cartilage has been removed. 



minence. Incise the crico-thyroid membrane close to the margin of the 

 thyroid lamina. Disarticulate the crico-thyroid joint, and cut across the 

 crico-thyroid muscle. Xow carefully remove the piece of thyroid cartilage 

 thus isolated. 



Clean the three muscles uoav exposed to view, and define the appendix 

 of the laryngeal ventricle. 



M. CRICOARYT^NOIDEUS LATERALIS. — The lateral crico-arytenoid 

 muscle is much smaller than the dorsal muscle of the same name. 

 Its origin is from the anterior border of the cricoid arch, and its 

 insertion is into the muscular process of the arytenoid cartilage. 

 Through rotation of the arytenoid cartilage, contraction of this muscle 

 results in adduction of the vocal fold. 



