948 THE ORGANS OF DIGESTION 



temporal bone, liehind the condyle of the jaw, and in contact with the tympanic 

 plate; the supt-rtieial temporal artery and the temi)oral branch of the facial nerve 

 emerge from its' outer side. The lower extremity rests u^ton the stylo-maxillary 

 ligament which separates it from the posterior end of the submaxillary gkmd. 



Within the substance of the gland are the following structures: Tlie upper part 

 of the external carotid artery with its superticial, temporal, and internal maxillary 

 branches; the commencements of the transverse facial, orbital, and middle tem- 

 poral branches of the superticial temporal artery, and the deep auricular branch of 

 the internal maxillary trunk; the temporo-maxillary vein, its tributaries, and its 

 two terminal l)ranches; the facial nerve, its cervico-facial and temporo-facial 

 divisions crossing the temporo-maxillary vein horizontally, and their terminal 

 l)ranches; the auriculo-temi)oral nerve, branches of the great auricular nerve, and 

 a few deep lymphatic glands which receive afferent vessels from the posterior part 

 of the nasal fossa, the soft })alate, and the external auditory meatus. 



The duct of the parotid (Stenson's) issues from the anterior border of the 

 gland and crosses the masseter a finger's breadth below the zygoma. It ])enetrates 

 the fat of the cheek and the fibres of the buccinator muscle, between which and the 

 mucous membrane it runs for a short distance before it terminates on the summit 

 of a little i)apilla, by a minute orifice. This opening is placed opposite the crown 

 of the second upper molar tooth. The duct commences by numerous branches, 

 Avhich converge towards the anterior border of the gland, and receives in its passage 

 across the masseter the duct of the socia parotidis. The canal is about the size of a 

 crow-t|uill. Its mucous membrane is covered by a columnar e])ithelium. The 

 coat of the duct is thick and tough, and consists of fil)rous tissue intermixed with 

 contractile fibres. 



The arteries are derived from those lying in the gland substance and from the 

 posterior auricular arter}'. 



The veins terminate in the temporo-maxillary trunk. 



The nerves are derived from the facial, great auricular, the carotid plexus of the 

 sympathetic, and the auriculo-temporal. The latter also conveys a branch derived 

 from the giosso-pharyngeal through the lesser petrosal and the otic ganglion. The 

 lymphatics terminate in the superficial and deep cervical glands. 



The parotid gland has been observed to retain its primitive condition, lying over 

 the mandil)le and masseter muscle. Its lobes are absent in early childhood. 



The SUBMAXILLARY GLAND weighs from two to three drachms and it is 

 enclosed in a capsule of deep cervical fascia, except externally, where it is in con- 

 tact with the body of the jaw. It consists of two portions, the superficial and the 

 deei*. The superficial portion is much larger than the deep portion; it occupies 

 the fore part of the submaxillary triangle and is prismatic in form, possessing three 

 surfaces and two extremities. The external surface lies in the submaxillary fossa 

 on the inner side of the body of the jaw, and is in relation posteriorly with the 

 internal pterygoid muscle. The lower surface looks downwards and outwards; it 

 is covered by deep fascia, platysma, superficial fascia, and skin; several suj^erficial 

 lymi)hatic glands, which receive afferent vessels from the lower part of the face, lie 

 upon or embedded in it, and it is crossed by the facial vein and some branches of 

 the facial nerve. The internal surface rests upon the mylo-hyoid, hyo-glossus, 

 and stylo-glossus muscles, and between it and the mylo-hyoid muscle are the mylo- 

 hyoid nerve and artery and the submental branch of the facial artery. The ante- 

 rior extremity is in contact with the anterior belly of the digastric; the posterior 

 extremity is grooved by the facial artery and is in relation with the stylo-maxillary 

 ligament and the posterior belly of the digastric. 



The dee):) portion is a m(n-e tongue-like projection Avhich rises from the internal 

 surface of the superficial portion at the posterior l)order of the mylo-hyoid muscle. 

 It runs forwards and upwards, in comi^any with the duct, under cover of the mylo- 

 hyoid and upon the hyo-glossus, stylo-glossus, and genio-glossus muscles; at its 

 commencement the sul)maxillary ganglion lies just above it, and at its termination 

 it is in close relation AvitJi the sublingual gland. 



The duct of the submaxillary gland (Wharton's) springs from the deep sur- 

 face of the superficial }»art ^A the gland; it passes forwards and inwards acc()mj)anying 



