THE SALIVARY GLANDS (Les Glandes Salivaires, Fr. : Die Speieliel-Driisen, Germ. ; Le Glandule Salivali, Ital.), A series of conglomerate glands, arranged in a curved manner, and following the circumfe rence of the inferior maxilla from the posterior border of one side to that of the other, and pouring their secretion into the mouth by means of excretory ducts, are thus denomi nated. They present a distinctly lohulated granular appearance, the component lobes and lobules being more or less loosely connected together by areolar tissue derived from the surface, and which, though serving the pur pose of an investing membrane, is not of a sufficiently definite character to constitute a distinct capsule. They have a yellowish or greyish-red appearance, and are thus at once distinguished from the soft structures with which they are in immediate connection, namely, the cellular membrane and the lym phatic glands, the former being perfectly white, and the latter pale brown.
They are three in number on either side, and are named from above downvvards the Parotid, Submaxillary, and Sublingual, and have in the same direction a relation as to their size, the parotid having the largest, the sublingual the smallest, and the submaxillary an intermediate volume. Though usually se parated from each other by a slight interval, they not unfrequently impinge the one upon the other, the lower edge of the parotid ap pearing to be structurally connected with the posterior border of the submaxillary, and the latter forming a junction with the sublingual. An uninterrupted glandular chain then in these instances surrounds the lower jaw.
The saliva secreted by them is poured by the ducts of the two last into the floor of the mouth, and by the duct of the first into the posterior part of the side of the cavity between the cheek and the upper and lower dentar arches.
The Parotid Gland is so named from its si tuation in the immediate vicinity of the exter nal ear (rap& near, and ok the ear). It fills up the space of the same name, and is conse quently bounded in front by the posterior edge of the ramus of the lower jaw, behind by the meatus auditorius externus above, and the mastoid process, digastric and sterno-mastoid muscles below : internally by the styloid pro cess and muscles attached to it, together with the internal and external pterygoid muscles : superiorly by the posterior or parotidean divi sion of the glenoid cavity within, and the zygomatic process without : inferiorly by a line continued on a level with the lower bor der of the horizontal ramus of the jaw from its angle to the anterior border of the sterno mastoid muscle. The dimensions and form of the gland can only be well ascertained after re moving it from its various connections, and in so doing it will be found that its posterior surface adheres very strongly by condensed cellular membrane to the cartilaginous portion of the meatus auditorius externus, while from its inner edge will be observed a process ex tending between the styloid muscles and the internal pterygoid as far as the pharynx. A
dense fibrous septum, the stylo-maxillary, con stituting one of the fixed points of attachment of the deep cervical fascia, separates it usually from the submaxillary gland. It has a triangu lar or pyramidal form. The base, which is su perficial and slightly convex, represents its ex ternal surface, and is covered over by a dense areolar tissue, known as the "parotid fascia," from which the different processes which sepa rate the component parts of the gland are ob served to proceed. The apex is the deepest seated portion of the gland, and is represented by the prolOngation already alluded to. The gland is bent, as it were, upon itself from be hind forwards, so that its anterior surface presents a deep vertical groove, corresponding with the convexity of the ramus of the jaw, which is consequently overlapped by it ex ternally and internally, in the former situation extending to a greater or less degree over the masseter, in the latter over the internal pterygoid muscle, and stylo-maxillary liga ment. The part overlapping the masseter externally gives off above a process which runs between the zygonta and the duct of the gland, is horizontal in direction, and some what triangular in form, and is known as the Accessory Parotid Gland or "Socia Parotidis." It varies as to size, extent, and relation with the gland itself. It is ordinarily about two thirds of an inch in length, a third of an inch in the longest part of its vertical diameter, and from one.sixth to one-eighth of an inch in thickness. It is generally, as it were, an offset from the body of the gland, and has no imme diate connection with Steno's duct : at other times it is distinct from the body of the gland, and opens by one or more excretory ducts' into this canal. It occasionally becomes hyper trophied when the body of the parotid itself is atrophied. Cruveilhier has observed two small accessory glands, one at the middle and the other at the anterior part of the masseter muscle. The parotid measures in a vertical direction from an inch and a half to two inches, from before backwards from an inch and a quarter to an inch and a half, and from with out inwards about an inch. The lobes which enter into its composition are irregularly rounded, and considerably smaller than those of the submaxillary gland. They range from the one-eighth to the one-fifth of an inch in diameter; and these again are constituted of lobules having an average diameter of about the 7?-5 of an inch, the smallest measuring Th, and the largest about .„2-6 inch across.