SALIVARY GLANDS. 6o5 



dense, of considerable thickness, and its canal is about the size of a crow-quill ; it 

 consists of an external or fibrous coat, of considerable density, containing con- - 

 tractile fibres, and of an internal or mucous coat, lined with columnar epithelium. 



Vessels and Nerves. The arteries supplying the parotid gland are derived from 

 the external carotid, and from the branches of that vessel in or near its substance. 

 The veins follow a similar course. The lymphatics terminate in the superficial 

 and deep cervical glands, passing in their course through two or three lymphatic 

 glands, placed on its surface and in its substance. The nerves are derived from 

 the carotid plexus of the sympathetic, the facial, superficial, temporal, and great 

 auricular nerves. 



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

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

 drachms. It is covered by the integument, Platysma, deep cervical fascia, and 

 the body of the lower jaw, corresponding to a depression on its inner surface, 

 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 in a groove in its posterior and 

 upper border. 



Wharton's duct, the duct of the submaxillary gland, is about two inches in 

 length, and its walls much thinner than those of the parotid duct. It commences 

 by a narrow orifice on the summit of a small papilla, at the side of the fraenum 

 linguae. Passing between the sublingual gland and the Genio-hyo-glossus mus- 

 cle, it runs backwards and outwards between the Mylo-hyoid, and the Hyo-glossus 

 and Genio-hyo-glossus muscles, and beneath the gustatory nerve, to the deep por- 

 tion of the gland, where it divides into numerous branches. 



Vessels and Nerves. The arteries supplying the subrnaxillary gland are branches 

 of the facial and lingual. Its veins follow the course of the arteries. The nerves 

 are derived from the submaxillary ganglion, from the mylo-hyoid branch of the 

 inferior dental, and from the sympathetic. 



The Sublingual gland is the smallest of the salivary glands. It is situated 

 beneath the mucous membrane of the floor of the mouth, on either side of the 

 fraenum linguae, in contact with the inner surface of the lower jaw, close to the 

 symphysis. It is narrow, flattened, in shape somewhat like an almond, and 

 weighs about a drachm. It is in relation, above, with the mucous membrane ; 

 below, with the Mylo-hyoid muscle ; in front, with the depression on the side of 

 the symphysis of the lower jaw, and with its fellow of the opposite side ; behind, 

 with the deep part of the submaxillary gland ; and internally, with the Genio- 

 hyo-glossus, from which it is separated by the lingual nerve and Wharton's duct. 

 Its excretory ducts (ductus Riviniani), from eight to twenty in number, open sepa- 

 rately into the mouth, on the elevated crest of mucous membrane, caused by the 

 projection of the gland, on either side of the fraenum linguae. One or more join 

 to form a tube which opens into the Whartonian duct ; it is called the duct of 

 Bartholine. 



Vessels and Nerves. The sublingual gland is supplied with blood from the sub, 

 lingual and submental arteries. Its nerves are derived from the gustatory. 



Structure. The salivary are conglomerate glands, consisting of numerous lobes, 

 which are made up of smaller lobules, connected together by dense areolar tissue, 

 vessels, and ducts. Each lobule consists of numerous closed vesicles, which open 

 into a common duct ; the wall of each vesicle is formed of a delicate basement 

 membrane, lined by epithelium, and covered on its outer surface with a dense capil- 

 lary network. In the submaxillary and sublingual glands, the lobes are larger 

 and more loosely united than in the parotid. 



