THE SALIVARY GLANDS. 



435 



border is thicker than the preceding, and is separated from the transverse process 

 of the atlas by the terminal aponeurosis of the levator humeri, to which it is 

 only feebly adherent : it can also be easily separated from it, in order to raise 

 the parotid and pass through the stylo-hyoideus muscle, in the operation of 

 hyo-vertebrotomy. 



The superior extremity is bifurcated, and embraces the base of the concha of 

 the ear. The inferior extremity is comprised in the angle formed by the union 

 of the jugular and glosso-facial veins. 



Vessels mid nerves of the 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. 

 The excito-secretory nerve, says Moussu, is isolable on leaving the Gasserian 

 ganglion ; it is composed of four or five filaments which lie alongside the sub- 

 zygomatic or inferior maxillary nerve for about a centimetre, then on the surface 



Fig. 246. 



MODES OF TERMINATION OF THE NERVES IN THE SALIVARY GLANDS. 



1, 2, Branching of the nerves between the salivary cells ; 3, termination of the nerve in the nucleus ; 

 4, union of a ganglion cell with a salivary cell ; 5, varicose nerve-fibres entering the cylindrical 

 cells of the excretory ducts. 



of the guttural pouch until it reaches the posterior border of the inferior maxilla 

 and the internal maxillary vein, when it enters the gland. It is diificult to discover. 



Small lymphatic glands are believed to have been seen in the substance of 

 the parotid. 



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

 canal — the duct of Steno or 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 between 

 the lobules to the three or four principal branches from which it originates (Fig. 

 247). At first in contact with the terminal tendon of the sterno-maxillaris, 

 it afterwards turns round the posterior border of the digastric muscle (stylo- 

 maxillaris portion), advances into the submaxillary space, creeps over the 

 pterygoid muscle, beneath the glosso-facial vein, and arrives at the maxillary 

 fissure, into which it enters with the aforesaid vein and corresponding artery, 

 but behind both. It then ascends externally along the anterior border of the 



