THE PHARYNX. 



Fig. 249. 



There are also labial, ataphyline, and lingual glands; with, besides, near the frsenum, a 

 small conglomerate gland — the gland of Nnhn — which has a special duct. 



The Pharynx (Figs. 249, 250, 251). 



Preparation. — 1. Study the general disposition and situation of this vestibule in the 

 antero-posterior vertical section of the head (Fig. 250). 2. In order to examine the interior 

 conveniently, the head should be separated from the neck, leaving attached to it a certain 

 portion of the trachea and oesophagus ; then by sawing across — either through or behind the 

 temporo-maxillary articulations — all that portion of the cranium is removed, and the posterior 

 parietes of the pharynx is exposed, and may be dissected to study the muscles (Fig. 251), or 

 opened in the middle line to reach the interior of the cavity (Fig. 249). 3. The muscles 

 should be dissected with those of the tongue, and in the same manner. 



The 2jharynx is a membranous vestibule common to the digestive and air 

 passages, and situated behind the soft palate, 

 which separates it from the mouth ; above, it is 

 attached to the base of the cranium, and, be- 

 low, to the laryngeal apparatus. 



Form and internal disposition. — In conse- 

 quence of the conformation of the soft palate, 

 which, in the domesticated animals, and par- 

 ticularly in Solipeds, is prolonged to the base 

 of the epiglottis, the pharynx forms a cylindro- 

 conical cavity, elongated from before to behind, 

 enclosed laterally and posteriorly by wide thin 

 muscles, and with the soft palate for an anterior 

 wall. Between the two Eustachian tubes, under 

 the base of the cranium, the pharyngeal cavity 

 presents a triangular diverticulum, the walls of 

 which are only mucous membrane. This diverti- 

 culum is much deeper in the Ass than in the 

 Horse.^ At the two extremities of this cavity 

 are openings which allow the pharynx to com- 

 municate with the other passages or cavities, 

 which we will at once begin to study. 



At the upper extremity of the large axis of 

 the pharyngeal cavity, is to be remarked : 1. In 

 front, the two posterior openings of the nasal 

 cavities. 2. Behind, and directly opposite the 

 preceding, the two pharyngeal openings of the 

 Eustachian tubes, which are closed by a carti- 

 laginous kind of clap- valve. 2 



At the inferior extremity of this axis is found : 

 1. In the centre, a vast gaping orifice project- 

 ing into the interior of the pharyngeal cavity, 

 like a tap into a cask : this is the entrance to the 

 larynx, the salient portions of which form, on the walls of the pharynx, two 



PHARYNGEAL AND LARYNGEAL RE= 



gion; the posterior part of 

 the head incised and thrown 



FORWARD. 



1, Base of the cranium ; 2, roof of 

 the pharynx ; 3, muscles of the 

 cheek ; 4, 4, walls of the pharynx ; 

 6, posterior nares ; 7, soft palate ; 

 8, entrance to the mouth ; 9, epi- 

 glottis ; 10, posterior pillars of soft 

 palate; 11, arytenoid cartilages; 

 12, opening of the oesophagus ; 13, 

 oesophagus ; 14, trachea. 



' This pharyngeal cxcum was described for the first time by Verhsar of Utrecht. 



* This region corresponds to the posterior nares (arriere fond) of Man, a diverticulum 

 which cannot be distinguished from the pharynx in the domesticated animals. Under the 

 designation of the posterior nares of the nasal fossx, it will be understood that we mean the 

 posterior extremities of these cavities. 



