SALIVARY GLANDS. 



423 



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 (jrapa near, and oi>s the ear). It fills 

 up the space of the same name, and is conse- 

 quently bounded in front by the posterior 

 edge of the rainus 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 zygoma 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 " Soda 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 -g-V of an inch, the smallest measuring T ig-, 

 and the largest about -^ inch across. 



The relations of the external carotid artery, 

 and its terminal branches, the external jugular 

 vein, the facial and the anterior auricular 

 nerve, and the further relative anatomy of the 

 gland, have been already fully entered into.* 

 We may mention, however, that in the sub- 

 stance of the parotid, i. <?. in the cellular tis- 

 sue between its lobules a little below the 

 surface, are embedded one or more lymphatic 

 glands which can at a glance be recognised 

 from the structure of the parotid by their 

 brown colour, smooth surface, and compara- 

 tive density. These glands not unfrequently 

 undergo morbid changes, and by their gradual 

 enlargement cause progressive atrophy of the 

 parotid itself, and ultimately assume its ana- 

 tomical position. This circumstance consti- 

 tutes therefore an important element in the 

 inquiry as to the nature of any morbid growth 

 occupying the parotid space, but which it 

 would be out of place here further to allude to. 



The Duct of the Parotid Gland, called also 

 the Duct of Steno, emerges from above the 

 middle of its anterior border, accompanied by 

 several branches of the portio dura, runs hori- 

 zontally forwards across the masseter muscle 

 as far as its buccal border, passing about half 

 an inch below the zygoma, and immediately 

 below the accessory gland and transverse facial 

 artery. Having reached the anterior border of 

 the masseter, it curves over a mass of fat 

 between it and the buccinator ; forming then 

 a very obtuse angle, it perforates the latter, 

 and glides between it and the mucous mem- 

 brane of the mouth, which it perforates oppo- 

 site the second upper molar tooth. 



This terminal oblique portion is about the 

 fifth of an inch in extent, and has justly been 

 compared by Cruveilhier to the vesical portion 

 of the ureter, which, after having perforated 



* See PAROTID REGION. 



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