602 THE VEINS. 



branches of the artery of the same name, and entering the jugular close to 

 its origin, either separately, or after forming a common trunk (Fig. 290). 



B. PosTEMOB AuKicuLAR Vein. — A volumiuous vessel which commences 

 on the concha, and descends on the external face of the parotid gland, near 

 its posterior border, where it is joined by numerous divisions from the 

 parotid lobules. It opens into the jugular vein, generally a little below, and 

 onposite to, the maxillo muscular vessels, though it is sometimes lower, and 

 even beyond the occipital vein (Fig. 290). 



C. Occipital Vein. — The occipital vein corresponds, in every respect, to 

 its fellow artery. It offers two roots : an anterior, which originates at the 

 posterior extremity of the subsphenoidal confluent ; and a posterior, com- 

 mencing beneath the transverse process, of the atlas, and formed by three 

 principal branches. 



Among the branches of the latter root, one passes with the retrograde 

 artery through the posterior foramen of the atlas, and constitutes, as 

 it were, the origin of tlie vertebral vein ; the second communicates with the 

 occipito-atloid sinuses, by traversing the atlas near its middle ; the third, 

 satellite of the cerebro-spinal artery, comes also from these sinuses, and 

 receives the venules which accompany the ramifications of the oceipito- 

 muscular artery. 



D. External Maxillary ok Glosso-facial Vein. — A satellite of the 

 artery of the same name, this vessel begins on the forehead by two roots : a 

 superior and inferior, analogous in every point to the terminal branches of 

 the artery. It descends along the anterior border of the masseter muscle, 

 gains the maxillary fissure, into which it is inflected, placing itself between 

 the artery and Stenon's duct; then proceeds backwards and downwards 

 on the internal pterygoid muscle, always accompanied by the glosso-facial 

 artery until near the anterior extremity of the maxillary gland, when 

 it leaves it to follow the inferior border of that gland, and enters the jugular, 

 after crossing the sterno-maxillaris muscle outwardly, and forming with the 

 latter vein an angle which is occupied by the inferior extremity of the parotid 

 gland (Fig. 290). 



Brandies of origin. — Of the two branches which, by their union, constitute 

 the origin of the external maxillary vein, the inferior, a satellite of 

 the nasal branch of the corresponding artery, possesses no interest. The 

 superior, or angular vein of the eye, merits particular notice, as venesection is 

 sometimes practised on it. It arises near the nasal angle of the eye, 

 and creeps to the external face of the elevator muscle of the upper lip, below 

 the lachrymal muscle. 



Collateral branches. — In its progress, the external maxillary vein 

 receives a great number of affluents, the principal of which are the alveolar 

 vein, the lahial or coronari/ veins, the buccal vein, and the sublingual vein. 



a. Aheolar i>em.--This is a considerable vessel lodged beneath the 

 masseter, and lying against the great supermaxillary bone, between the zygo- 

 matic crest and the line of the molar teeth (Fig. 291). 



The disposition of this vessel is most singular ; its anterior extremity 

 opens into the external maxillary vein, and its posterior extremity traverses 

 the ocular sheath, receives the ophthalmic veins, and passes, with the 

 ophthalmic nei-ve of the fifth pair, into one of the supra-sphonoidal canals, to 

 open into the cavernous sinus in the interior of the cranium. ^ 



' We have also seen it send into the subsphenoidal canal, to the the inner side of 

 the internal maxillary artery, a i-lender branch that joined the anterior extremity of 

 the subsphenoidal confluent. But we cannot say that this disposition is constant. 



