A quarter of an inch below the part at which the accessory process is ordinarily given off, appears the commencement of the excre tory canal, or Wharton's duct, winding behind the posterior border of the mylo-hyoid muscle. It first lies below the gustatory nerve between it and the lingual, and after a course of a quarter of an inch, crosses the former at an acute angle, and again gets below it, resting on the hyo-glossus muscle. It accompanies the gustatory towards the tip of the tongue be tween the sublingual gland and the genio hyo-glossus muscle to the side of the frmnum linguze, where it terminates. In the terminal part of its course it is directed forward, lies immediately beneath the mucous membrane, and opens by a very narrow orifice into the mouth, in the centre of a papilla of mucous membrane. This papilla forms an obvious prominence by the side of the frmnum and is situated above the eminence formed by the anterior part of the upper edge of the sublingual gland, behind the incisor teeth. The duct is about two inches in length, its coats much more delicate, and consequently more extensible, than those of the parotid. Its calibre exceeds that of the parotid duct, and, like it, its narrowest portion is that im mediately beneath the mucous membrane, and this gradually contracts more and more, so that the terminal orifice becomes so small as scarcely to be visible by the naked eye. The arteries and veins that supply the subrnaxillary gland, are derived from the facial and lingual. The nerves are from the mylo-hyoid branch of the dental, and the gustatory, but chiefly from the submaxillary ganglion. The lymphatics communicate with the deep cervical glands.
The Sublingual gland forms a distinct eminence underneath the anterior part of the tongue by the side of the &minim. It can be felt in the floor of the mouth, and forms a prominent ridge which elevates the mucous membrane. Its long axis is from before backwards, following, in fact, the di rection of the horizontal ramus of the javr, to which the gland is applied. The inferior sur face rests upon the mylo-hyoid muscle ; the external is received into the sublingual fossa; the internal is in relation with the genio hyo-glossus and hyo-glossus below, and the mucous membrane above, the upper edge being covered by the latter. It is shaped somewhat like an almond, flattened from side to side, having its large extremity anteriorly. It is more compact in front than behind, in which latter situation its component lobes are occasionally separated the one from the other, and exist under the form of distinct irregularly rounded glands, with separate ex cretory ducts about a quarter of an inch in length, coming from their upper surface. The sublingual gland is from one inch and a half to two inches in its long axis, three quarters of an inch in the longest part of its vertical diameter, and about a quarter of an inch from side to side. It has a more granular feel, and
its lobules, which are mutually connected by a very delicate areolar tissue, are more dis tinct, harder, and smaller than in either the submaxillary or parotid.
The ducts of the sublingual are very nume rous, and their orifices can be seen without much difficulty, opening into the floor of the mouth, behind the movable papilla of Whar ton's duct, and along the crest of mucous membrane which is elevated by the upper border of the gland from which they take their origin. They are extremely thin and delicate, and pour out, when pressure is made on the body of the gland, a distinctly viscid saliva. They range from one-tenth to one third of an inch in length, vary much in their direction and relative situation, and are in number from 7 to 15. The anterior are very short, curve slightly on themselves from behind forwards, are about four or five in number, and some of thern, according to many anatomists, form a communication with Whar ton's duct, the remainder piercing the mucous membrane of the mouth. The ducts from the middle and posterior part of the gland arise at unequal intervals from each other, run in a parallel, divergent, or convergent direction, and pierce the mucous membrane by straight orifices, the posterior two or three not being longer than the one-tenth or one eighth of an inch. They are known under the name of the Ducts of Rivinus. Bartholi nus* has described another duct in connection with the sublingual gland, and which some times proceeds from the accessory gland of the submaxillary. It runs parallel to Whar ton's duct, and pierces the mucous membrane by the side of it. It frequently opens, how ever, into Wharton's duct, and both terminate by a common mouth. It is by no means usually met with. In a young male, whose salivary glands we recently dissected, the duct of Bartholinus was very distinct (a a,fig.139).
It arose from a large lobe at the upper third of the internal surface of the sublingual gland, midway between its anterior and posterior extremity. It was nearly equal in calibre to the duct of Wharton, and was more than half an inch in length, and opened on the left side close to the orifice of that duct in the centre of the loose papilla of mucous membrane. The two orifices were so closely approximated that it was difficult to determine their indi vidual identity. The duct of Bartholinus of the right sublingual, on the other hand, al though arising from the corresponding part of the body of the gland, and being of the same length and calibre, opened at the anterior part of the crest of the mucous membrane, the one-eighth of an inch behind the orifice of Wharton's duct.
The sublingual gland derives its arterial supply from the sublingual branch of the lin gual, and the submental. Its nerves are de rived from the gustatory branch of the fifth. Its lymphatics communicate with the deep cervical glands.