THF ALIMENTARY CANAL 223 



The sides of the mouth cavity are formed by the teeth and 

 the gums, covering the alveolar borders of the mandible, 

 maxillaries, and premaxillaries. 



The mouth cavity presents further for examination the 

 glands, the teeth, the tongue, and the soft palate. 



The Glands of the Mouth (Glandul/e oris). — 

 There are five pairs of salivary glands which open into the 

 mouth cavity. 



1. The parotid gland (glandula parotis) (Fig. 65, i; Fig. 

 131, 10) is flattened, rather finely lobulated, and lies ventrad of 

 the external auditory meatus and beneath the dermal muscles. 

 Its cranial border follows the caudal border of the masseter 

 muscle and overlies it somewhat ; its caudal border is about 

 three centimeters caudad of the border of the masseter. Its 

 borders are unevenly lobed. The parotid duct (ductus paro- 

 tideus: frequently called Stenon's or Steno's duct) is formed 

 by the union of several smaller ducts near the ventral end of 

 the cranial border of the gland. It passes craniad imbedded 

 in the fascia covering the masseter. At the cranial border of 

 the masseter it turns inward and lies close against the mucous 

 membrane of the mouth, so that from the inside of the mouth 

 it appears as a white ridge on the mucosa. It opens on the 

 inside of the cheek opposite the most prominent cusp of the last 

 premolar tooth. Along the course of the parotid duct in some 

 cases one or more small accessory parotid glands are found. 



2. The submaxillary gland (glandula submaxillaris) 

 (Fig. 65, 2, page 109, and Fig. 131, 11) is approximately kid- 

 ney-shaped. Its surface is nearly smooth, the lobulations not 

 being apparent externally. It lies ventrad of the parotid, at 

 the caudal edge of the masseter muscle, just caudad of the 

 angular process of the mandible. The posterior facial vein 

 (Fig. 131, d) crosses its outer surface, and its cranioventral 

 border is hidden by two lymphatic glands (Fig. 131, 12) lying 

 at the sides of the anterior facial vein. The submaxillary 

 duct (ductus submaxillaris, frequently called Wharton's duct) 

 leaves the inner surface of the gland and passes beneath the 

 digastric and mylohyoid muscles and against the outer surface 

 of the styloglossus. From the point where the styloglossus 



