176 DISSECTION OF THE DOG 



surface also is largely free, but gives attachment to the glosso-epiglottic fold 

 of mucous membrane and the hyo-epiglottic muscle. 



Cartilagines cuneiformes. — The cuneiform cartilages are relatively large and 

 of an irregularly triangular outline. The laterally flattened base of each is 

 intimately associated with a corniculate cartilage, while the apex forms an 

 elongated curved projection. 



Cavum laryngis. — If the interior of the cavity of the larynx be regarded 

 it wall be observed that its lumen is constricted opposite two lateral folds of 

 mucous membrane. These are known as the vocal folds (plicae vocales) and 

 form sharp and prominent ridges running from the angle of convergence of 

 the two thyroid laminae to the vocal processes of the arytenoid cartilages. 

 The folds are close together at their ventral ends, but diverge dorsally. The 

 interval between the folds is known as the intermembranous part (pars inter - 

 membranacea) of the glottis (rima glottidis) : its continuation between the 

 arytenoid cartilages being the intercartilaginous part (pars intercartilaginea) 

 of the glottis. Immediately lateral to each vocal fold there is a slit-like 

 depression, the ventricle of the larynx (ventriculus laryngis). The depression 

 or opening has two lips, of which one is formed by the vocal fold ; the other by 

 a very inconspicuous ventricular fold (plica ventricularis) . 



Oral to the vocal folds the cavity of the larynx is more spacious and is 

 distinguished as the vestibule (vestibulum laryngis). Its boundaries are formed 

 mainly by the epiglottic and arytenoid cartilages and the folds of mucous 

 membrane which connect them with each other. 



The entrance to the vestibule from the pharynx should receive attention. 

 The prominent epiglottis, which forms the anterior boundary of the entrance, 

 is connected with the tongue by the glosso-epiglottic fold of mucous membrane, 

 to the side of which is the epiglottic vallecula, a deep and somewhat triangular 

 depression. Joining the lateral angles of the epiglottis to the apices of the 

 arytenoid and corniculate cartilages are the two ary- epiglottic folds. Each of 

 these may be considered as divided into two parts. The first part is 

 prominent and transverse in direction, passing from the epiglottis to the 

 cuneiform cartilage, which forms a distinct projection. Then follows a much 

 more feeble part, sagittal in direction, and running from the cuneiform to the 

 corniculate cartilage. Between the ary-epiglottic fold and the lamina of 

 the thyroid cartilage is a rather shalloAV pyriform sinus. 



Beyond the vocal folds the cavity of the larynx is roomy, somewhat 

 compressed laterally, and directly continuous with the lumen of the trachea. 



The mucous membrane (tunica mucosa laryngis) lining the cavity of the 

 larynx is continuous in one direction with that of the pharynx, and in the 

 other with the mucous membrane of the trachea. It is firmly adherent to 

 the dorsal surface of the epiglottis, and very thin over the vocal folds. 



Dissection. — Remove the remains of the pharyngeal, the sterno-hyoid , 



