1138 



THE DIGESTIVE SYSTEM. 



The external maxillary artery lies embedded in a groove in the superior and 

 posterior part of the gland. 



The gland is enclosed in an extremely delicate capsule of connective tissue 

 derived from the deep cervical fascia. 



In considering the relations of the gland, it is well to remark that there is in this region a 

 three-sided space bounded laterally by the medial surface of the mandible below the mylo-hyoid 

 line, medially and above by the mylo-hyoid muscle, and below by the skin and fascia passing 

 from the margin of the jaw to the side of the neck. In this space the gland lies with lateral, 

 medial, and inferior surfaces corresponding to the walls of the space. 



The posterior end of the gland, which is its most bulky portion, either abuts 

 against, or lies very close to, the sterno-mastoid, and is often overlapped by the 

 inferior end of the parotid gland. 



Ductus Submaxillaris. The submaxillary duct (O.T. Wharton's) leaves 

 the deep surface of the gland about its middle, and runs forwards beneath the 

 mylo-hyoid muscle, along the superior and medial aspect of the deep process of 



Parotid duct 



Accessory parotid gland 

 / ^'Internal pterygoid 



Mandible 

 Submaxillary duct 

 Mucous membrane 

 Sublingual gland 

 Tong 



Mylo-hyoid 

 Anterior belly of digastri 



Lingual nerve 

 Mandible 



---Mylo-hyoid 



Surface of submaxil- 

 ^-- lary gland covered 



by mandible 

 Surface covered by 

 integument and fasciae 



FIG. 899. THE SALIVARY GLANDS AND THEIR DUCTS. 



the gland (Fig. 899). Pursuing its course forwards beneath the floor of the 

 mouth, on the medial side of the sublingual gland, the duct crosses the hyoglossu 

 and the genioglossus muscles, and finally opens on the floor of the mouth at the side 

 of the frenulum linguae, where its small orifice is placed on the summit of a soft 

 papilla (caruncula sublingualis) close to its fellow of the opposite side. 



While running forward beneath the floor of the mouth the duct, which is about two inches long 

 (50 mm.), is crossed by the lingual nerve near the anterior border of the hyoglossus, that i 

 opposite the 2nd molar tooth. The nerve passes from the posterior end of the mylo-hyoid ridge 

 (against which it lies) forwards and medially in order to reach the inferior surface of the tongue,, 

 and it passes below the duct at the point indicated. As in the case of the parotid duct, the 

 calibre of the submaxillary duct is much greater than that of the orifice by which it opens ; for 

 this reason it likewise may be looked upon as forming, to some extent, a reservoir for the saliva 

 secreted by the gland. 



Vessels and Nerves. The arteries come chiefly from the external maxillary artery and i 

 submental branch: the veins accompany the arteries. The nerves are derived through the sub- 

 maxillary ganglion (which lies above the deep process of the gland), from the chorda tympani and 

 lingual, and from the sympathetic plexus around the external maxillary artery. The lymph 

 vessels pass to the submaxillary lymph glands. 



Glandulae Sublinguales. The sublingual glands, the smallest of the principal 

 salivary glands, are situated more deeply than the others. 



