946 



THE ORGANS OF DIGESTION. 



situated in front of the styloid process, and passes into the back part of the glenoid 

 fossa, behind the articulation of the lower jaw. The structures passing through 

 the parotid gland are the external carotid artery, giving off its three terminal 

 branches : the posterior auricular artery emerges from the gland behind ; the 

 temporal artery above ; the transverse facial, a branch of the temporal, in front ; 



FIG. 569. The salivary glands. 



and the internal maxillary winds through it as it passes inward, behind the neck 

 of the jaw. Superficial to the external carotid is the trunk formed by the union 

 of the temporal and internal maxillary veins ; a branch, connecting this trunk 

 with the internal jugular, also passes through the gland. It is also traversed by 

 the facial nerve and its branches, which emerge at its anterior border ; branches of 

 the great auricular nerve pierce the gland to join the facial, and the auriculo- 

 temporal branch of the inferior maxillary nerve emerges from the upper part of the 

 gland. The internal carotid artery and internal jugular vein lie close to its deep 

 surface. 



The duct of the parotid gland (Stenson's) is about two inches and a half in 

 length. It commences by numerous branches from the anterior part of the gland, 

 crosses the Masseter muscle, and at its anterior border dips down into the substance 

 of. the Buccinator muscle, which it pierces ; it then runs for a short distance obliquely 

 forward between the Buccinator and mucous membrane of the mouth, and opens 

 upon the inner surface of the cheek by a small orifice opposite the second molar 

 tooth of the upper jaw. While crossing the Masseter it receives the duct of a small 

 detached portion of the gland, soda parotidis, which occasionally exists as a separate 

 lobe, just beneath the zygomatic arch. In this position it has the transverse facial 

 artery above it and some branches of the facial nerve below it. 



Structure. The parotid duct is dense, of considerable thickness, and its canal 

 about the size of a crowquill ; it consists of an external or fibrous coat, of 

 considerable density, containing contractile fibres, and of an internal or mucous 

 coat lined with short columnar epithelium. 



