THE SALIVARY GLANDS. 947 



Surface Form. The direction of the duct corresponds to a line drawn across the face about 

 a finger > breadth below the zygoma : that is. from the lower part of the tragus to midway 

 between the tree margin of the upper lip and the ala of the nose. 



Vessels and Nerves. The art^ri-'* supplying the parotid gland are derived from 

 the external carotid, and from the branches given off by that vessel in or near its 

 substance. The veins empty themselves into the external jugular through some 

 of its tributaries The lymphnti<>$ terminate in the superficial and deep cervical 



M Cresccnt of Gianuza. 



FIG. 570. A highly magnified section of the submaxillary gland of the dog, stained with carmine. (Kolliker.) 



glands, passing in their course through two or three lymphatic glands placed on 

 the surface and in the substance of the parotid. The nerves are derived from the 

 carotid plexus of the sympathetic, the facial, the auriculo-temporal, and great 

 auricular nerves. 



It is probable that the branch from the auriculo-temporal nerve is derived 

 from the glosso-pharyngeal through the otic ganglion (which see). At all events, 

 in some of the lower animals this has been proved experimentally to be the 

 case. 



The submaxillary gland is situated below the jaw, in the anterior part of the 

 submaxillary triangle of the neck. It is irregular in form and weighs about two 

 drachms (8-10 grammes). It is covered by the integument, Platysma, deep cer- 

 vical fascia, and the body of the lower jaw. corresponding to a depression on the 

 inner surface of the bone, and lies upon the Mylo-hyoid, Hyo-glossus, and Stylo- 

 glossus muscles, a portion of the gland passing beneath the posterior border of 

 the Mylo-hyoid. In front of it is the anterior belly of the Digastric ; behind, it 

 is separated from the parotid gland by the stylo-maxillary ligament, and from the 

 sublingual gland in front by the Mylo-hyoid muscle. The facial artery lies im- 

 bedded in a groove in its posterior and upper border. 



The duct of the submaxillary gland ( Whartons) is about two inches in length, 

 and its walls are much thinner than those of the parotid duct.. It commences by 

 numerous branches from the deep portion of the gland, and passes forward and 

 inward between the Mylo-hyoid and the Hyo-glossus and Genio-hyo-glossus mus- 

 cles, then between the sublingual gland and the Genio-hyo-glossus, and opens bv 

 a narrow orifice on the summit of a small papilla at the side of the fraenum linguae. 

 On the Hyo-glossus muscle it lies between the lingual and hypoglossal nerves, but 

 at the anterior border of the muscle it crosses under the lingual nerve, and is then 

 placed above it. 



Vessels and Nerves. The arteries supplying the submaxillary gland are 

 branches of the facial and lingual. Its wins follow the course of the arteries. 

 The nerves are derived from the submaxillary ganglion, through which it receives 

 filaments from the chorda tympani of the facial and lingual branch of the 

 inferior maxillary, from the mylo-hyoid branch of the inferior dental, and from 

 the sympathetic. 



