164 HEAD AND NECK 



From under cover of the anterior border, which rests upon 

 the masseter, the duct of the gland (Stensen's), the transverse 

 facial artery, and the zygomatic, buccal, and mandibular 

 branches of the facial nerve pass forwards ; and the transverse 

 facial vein disappears under cover of it. 



The duct of the parotid gland (Stensen's), after appearing 

 from under cover of the anterior border of the gland, runs 

 forwards, across the masseter, at the level of a line drawn 

 from the lobule of the auricle to a point situated midway 

 between the red margin of the upper lip and the ala of 

 the nose. At the anterior border of the masseter it turns 

 inwards, at right angles to its former course, and after piercing 

 the sucking pad of fat, the buccinator fascia, the buccinator 

 muscle and the mucous membrane of the vestibule of the 

 mouth, it opens into the vestibule, on the apex of a papilla, 

 opposite the second molar tooth of the maxilla. 



Immediately in front of the anterior border of the gland, 

 below the zygoma and above the duct, lies a small separated 

 portion of the gland substance called the accessory parotid its 

 duct opens into the main duct. 



Dissection. The gland must be removed piecemeal as the 

 structures which pass through it are dissected out. The facial 

 nerve and its branches are the most superficial structures in the 

 substance of the parotid ; therefore they must be dissected first. 

 Trace the terminal branches backwards into the gland until they 

 join the main divisions, which are the upper and the lower. 

 The temporal and zygomatic branches spring from the upper 

 division ; the buccal, mandibular, and cervical spring from 

 the lower division. Follow the divisions backwards, across the 

 posterior facial vein, to their union with the trunk of the nerve, 

 which pierces the postero-medial surface of the gland ; then trace 

 the trunk, across the root of the styloid process, to the stylo-mastoid 

 foramen, and secure the branch which springs from it to supply 

 the posterior belly of the digastric and the stylo-hyoid muscles, 

 and the posterior auricular branch. As the trunk of the nerve 

 is being cleaned the posterior auricular branch of the external 

 carotid artery will probably be exposed, passing upwards and 

 backwards, along the upper border of the posterior belly of the 

 digastric, to the back of the external meatus, and crossing either 

 superficial or deep to the nerve. Next, remove the deeper parts 

 of the gland and expose the posterior facial vein, descending 

 towards the angle of the mandible. It receives the transverse 

 facial and the internal maxillary veins, and it gives off a com- 

 municating branch to the external jugular vein ; then it passes 

 out of the lower end of the gland and unites with the anterior 

 facial vein to form the common facial vein. Deep to the veins 

 will be found the upper end of the external carotid artery dividing 

 into its superficial temporal and internal maxillary branches ; 



