424 



SALIVARY GLANDS. 



the muscular tunic of the bladder, runs for the 

 extent of an inch between it and the mucous 

 membrane. 



The parotid duct is from two and a half to 

 three inches in length, and is covered over by 

 a prolongation of the areolar tissue which 

 forms the investment of the body of the gland. 

 This can be distinctly traced as far as the 

 point at which it perforates the buccinator, 

 and here it is surrounded by an aponeurotic 

 expansion derived from the tendon of that 

 muscle, and by a series of glands continuous 

 with the genial glands, the ducts of which 

 open partly into it and partly into the mouth. 

 Having removed the external cellular covering 

 of the duct, its true middle or fibrous coat 

 is observed, giving it a distinct opaque white 

 appearance. It is strong, dense, and elastic. 

 Its thinnest portion is over the oblique part 

 of the duct that glides between the muscular 

 and mucous lining of the buccal cavity, its 

 thickest that covering that part of it between 

 the buccinator and the masseter, the remainder 

 of the duct having this coat developed to an 

 intermediate extent. Beneath the middle coat 

 is the mucous lining, the cylindrical epithelium 

 of which commences, according to Henle, 

 suddenly at the excretory orifice, and con- 

 tinues as far as the delicate divisions of the 

 duct in the substance of the gland. The cells 

 of this epithelium in the main duct range 



from the T7r Vo to ^ ne Blhr P art f an ^ ncn m 

 their long diameter. 



The parotid derives its arterial supply from 

 the main trunk of the external carotid, the 

 superficial temporal, transverse facial, anterior 

 and posterior auricular : its venous, from ves- 

 sels of the same name. The lymphatics ter- 

 minate in the superficial and deep facial and 

 cervical glands. The nerves are derived from 

 the facial, the anterior auricular, and the ex- 

 ternal carotid plexus. 



The Submaxillary gland, much smaller than 

 the parotid and larger than the sublingual, is 

 situated in the anterior portion of the digas- 

 tric space. It is irregularly oblong in form, 

 and is enclosed in a loose investment of 

 areolar tissue more delicate than that cover- 

 ing the parotid. Its long axis is directed 

 from before backwards, and is about an inch 

 and a half in extent. Its external or maxil- 

 lary surface is slightly concave, is lodged in 

 a groove in the bone, and is in immediate 

 contact with the mylo-hyoid nerve. The 

 inferior or platysmal surface is in relation 

 with the platysma-myoides and superficial 

 cervical fascia, constituting, in fact, that part 

 of the gland which is seen on reflecting that 

 muscle. The internal surface, which looks 

 slightly upwards, is in relation with the pos- 

 terior third of the mylo-hyoid muscle, the 

 tendon of the digastric, and the stylo-hyoid 

 and stylo-glossus. The anterior extremity, 

 which is smaller than the posterior, impinges 

 on the anterior belly of the digastric. The 

 posterior border is deeply grooved by the facial 

 artery and vein, which are occasionally sur- 

 rounded entirely by the structure of the gland. 

 From _the narrowest portion of the gland, 



which would be represented by the confluence 

 of the inner and outer surfaces above, gene- 

 rally proceeds a process, longer than the gland 

 itself, and passing along the upper surface of 

 the mylo-hyoid muscle in company with the 

 excretory duct, but above it, as far as the 

 sublingual gland in front, with which it is oc- 

 casionally incorporated. This process may 

 be regarded as analogous to the accessory 

 gland of the parotid, and like it varies con- 

 siderably in size and relation to the body of 

 the gland. In a subject recently examined, 

 we found it represented by two accessory 

 glands, the upper or larger being about the 

 size of a horse-bean, embracing the poste- 

 rior half of the lower border of the sublin- 

 gual gland, and grooved behind by the trunk 

 of the gustatory nerve. It opened by a dis- 

 tinct duct, more than half an inch in length, 

 into the main canal about the middle of its 

 upper border : the other accessory gland, very 

 small, situate half an inch further back, and 

 also communicating with the lower border of 

 the main duct by a canal one-sixth of an inch 

 long. The primary lobes of the submaxillary 

 gland are much larger than those of the paro- 

 tid, and the lobules have an irregularly trian- 

 gular arrangement. 



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- 

 byo-glossus muscle to the side of the fraenum 

 linguae, 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 fraenum linguae, 

 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 submaxillary 

 gland, are derived from the facial and lingual. 

 The nerves are from the mylo-hyoid branch of 

 the dental, ^nd 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 fraenum. It 



