188 THE ANATOMY OF THE HORSE. 



and in doing this the dissector should find the branch from the inferior 

 maxillary division of the 5th nerve which enters the muscle through 

 the corono-condyloid notch. The masseter having been removed, the 

 buccinator muscle will now be fully exposed (see page 183), and the 

 dissector is to examine the alveolar vein, the buccal glands, the buccal 

 nerve and vessels, and the interior of the cheek. 



The Alveolar Vein. This vessel rests on the superior maxilla, along 

 the alveoli for the molar teeth. Inferiorly it joins the submaxillary 

 vein, and is here comparatively small. It speedily becomes of large 

 size, and is continued round the upper extremity of the superior 

 maxilla to reach the orbit, where it will afterwards be followed. 



The Superior Buccal Gland. This" consists of a string of lobules 

 resting on the anterior ed§e of the buccinator. The string is thickest 

 above, and thinnest below, where its lobules are placed at intervals. 

 The ducts of the lobules perforate the buccinator, and will afterwards 

 be seen opening on the cheek. 



The Buccal Artery will be found crossing the upper end of the 

 superior buccal gland. It is distributed to the buccinator muscle and 

 the other textures of the cheek. Its origin from the internal maxillary 

 artery, at the floor of the orbit, will subsequently be dissected. 



The Buccal Vein begins at the inferior edge of the masseter, where 

 it joins the submaxillary vein. Above the cheek it is continued as the 

 internal maxillary vein. 



Directions. — The buccinator muscle should be cut at its anterior 

 edge, and turned backwards so as to expose the interior of the cheek. 

 On the mucous membrane will be seen the following : — 



1. A linear series of small papilla) opposite the upper molar teeth. 

 Each papilla is perforated at its summit by a duct from one of the 

 lobules of the superior buccal gland. 



2. A large rounded elevation opposite the third superior molar. 

 Stenson's duct opens on its summit. 



3. A linear series of small papillae opposite the inferior molars. Each 

 papilla is perforated by a duct from the inferior buccal gland. 



' The Inferior Buccal Gland will be exposed by incising the mucous 

 membrane along the last-mentioned series of papillae. It is composed 

 of a string of lobules included between the mucous membrane and the 

 buccinator. 



The Buccal Nerve will be found in close relation to the inferior 

 buccal gland. It is the sensory nerve to the cheek, and is derived from 

 the inferior maxillary division of the 5th cranial nerve. 



