436 



THE DIGESTIVE APPARATUS IN MAMMALIA. 



masseter muscle, to the level of the inferior molars, when it passes beneath its 

 two satellite vessels, obliquely crosses their direction, and pierces the cheek 

 towards the third upper molar tooth, opening into the mouth by a large tubercle. 

 The parotid duct is composed of two membranes : the internal, mucous, with 

 cylindrical epithelium ; and the external, made up of connective tissue, and 

 circular and longitudinal elastic fibres. 



2. Maxillary or Submaxillary Gland (Figs. 247, 248). 



Preparation. — To expose this gland, as well as the sublingual, divide the inferior maxilla, 

 as in preparing the muscles of the tongue for dissection (see p. 400). 



This gland, smaller than the preceding, is situated in the submaxillary space, 



on the side of the larynx, and 

 within the parotid gland. 



It is long and nan'ow, flattened 

 on both sides, and describes a 

 slight curve with the concavity 

 turned upwards : a form which 

 allows it to be studied, with regard 

 to relations, on two faces, two 

 borders, and two extremities. 



By its external fare, it responds 

 to the internal pterygoid and digas- 

 tricus muscles, the sterno-maxil- 

 laris tendon, and the cellulo-apo- 

 neurotic layer separating it from 

 the parotid. Its internal face, ap- 

 pHed to the side of the larynx, 

 responds, superiorly, to the guttural 

 pouch, to the carotid artery, and 

 to the nerves which accompany 

 that vessel in the upper part of the 

 neck. 



The superior border, thin and 

 concave, is margined by the middle 

 part of the digastricus. The in- 

 ferior, thick and concave, is in con- 

 tact wath the glosso-facial vein. 



The posterior extremity is main- 

 tained beneath the transverse pro- 

 cess of the atlas, by an extremely 

 loose and abundant connective 

 tissue ; the anterior is insinuated 

 between the internal pterygoid and 

 the thyro-hyoideus muscle. 



Vessels and nerves. — The blood, 

 is distributed to the maxillary 



INFERIOR ASPKCT OF MEAD AND NECK. 



1, Inferior border of lower jaw ; 2, genio-hyoideus ; 3, 

 mylo-hyoideus ; 4, submaxillaiy artery; 5, ditto 

 vein; 6, parotid duct; 7, sterno-ma.xillaris tendon; 

 8, parotid gland; 9, steruo-ma.xillaris muscle; 10, 

 11, 12, submaxillary glands; 13, sterno-thyro- 

 hyoideus and subscapulo-hyoideus muscles; 14, 

 thyroid gland; 15, pterygoideus internus. 



gland by various small innominate 

 arteries, like those of the parotid gland, and which are most frequently derived 

 from the external carotid and the glosso-facial The nerves are principally 

 furnished by the carotid plexas. 



