THE SALIVARY GLANDS. 



367 



Vessels and nerves of tlie parotid gland. This gland receives its blood 

 by a multitude of arterial branches from the large vessels it covers. Its 

 nerves are very numerous, and are derived from the facial and inferior 

 maxillary nerves, and the carotid plexus. 



Excretory canal. The parotid gland is provided with a single excretory 

 canal, the duct of Stenon, so named from the anatomist who gave the first 

 good description of it. It is 

 detached from the anterior 

 border of the gland, near its 

 inferior extremity, where the 

 eye may readily follow it be- 

 tween the lobules to the three 

 or four principal branches 

 from which it originates (Fig. 

 172). At first in contact 

 with the terminal tendon of 

 the stern o-maxillaris, it after- 

 wards turns round the pos- 

 terior border of the digastric 

 muscle (stylo-maxillaris por- 

 tion), advances into the sub- 

 maxillary space, creeps over 

 the internal masseter muscle 

 (pterygoid), beneath the 

 glosso-facial vein, and arrives 

 at the maxillary fissure, into 

 which it enters with the 

 aforesaid vein and corre- 

 sponding artery, but behind 

 both. It then ascends ex- 

 ternally along the anterior 

 border of the masseter 

 muscle to the level of the 

 inferior molars, when it 

 passes beneath its two satel- 

 lite 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 com- 

 posed of two membranes : 

 the internal, mucous, with 

 columnar epithelium ; and 

 the external, made up of con- 

 nective tissue, and circular and longitudinal elastic fibres. 



2. Maxillary or Submaxillary Gland. (Figs. 172, 173.) 

 Preparation. To expose this p;land, as well as the sublingual, divide the maxilla, as 

 in preparing the muscles of the tongue for dissection (see p. 334). 



This gland, smaller than the preceding, is situated in the intermaxillary 

 space, on the lateral plane of the larynx, and within the parotid gland. 



INFERIOR ASPECT OF HEAD AND NECK. 



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

 Mylo-hyoideus ; 4, Submaxillary artery ; 5, Ditto 

 vein ; 6, Parotid duct ; 7, Sterno-maxillaris tendon ; 

 8, Parotid gland; 9, Sterno-maxillaris muscle; 10, 

 11, 12, Submaxillary glands; 13, Sterno-thyro- 

 hyoideus aiii subscapulo-hyoideus muscles ; 14, Thy- 

 roid gland ; 15, Pterygoideus internus. 



