THE ANTERIOR VENA CAVA. 605 



internal maxillary artery. This vein issues from the parieto-temporal 

 conduit, behind the supereondyloid eminence ; it receives one or two 

 branches which escape from this conduit by the foramina in the temporal 

 fossa, crosses the temporal muscle, and is charged with venules which arise 

 in the interior of that muscle, as well as in the textures of the external ear. 

 2. The subzygomatic vein, a satellite of the homonymous artery, and 

 like it, divided into two branches : one accompanying the transverse artery 

 of the face, the other the masseteric artery. The latter branch com- 

 municates by its inferior extremity with the external maxillo-muscular vein ; 

 it joins, by its other extremity, an enormous branch which comes from the 

 temporal muscle, and which passes into the corono-condyloid notch, after being 

 largely anastomosed with the deep temporal branches of the internal 

 maxillary vein. 



2. Internal Maxillary Vein. 



Remarkable for its enormous volume, this vein creeps between the internal 

 masseter muscle and the maxilla, in an oblique direction upwards and 

 backwards. Arriving within the articulation of the jaw, a little below the 

 maxillary condyle and the external pterygoid muscle, it joins the temporal 

 trunk after being slightly inflected downwards. It, therefore, runs its course 

 at a certain distance from the corresponding artery (Fig. 290). 



The internal maxillary has for its root the buccal vein, which it succeeds 

 near the superior extremity of the alveolo-labialis muscle. 



Satellite of the artery and nerve of the same name, this buccal vein, re- 

 markable for its volume, is situated beneath the masseter muscle, near the 

 inferior border of the alveo-labialis muscle ; by its anterior extremity it 

 communicates directly with the internal maxillary vein, nearly opposite to 

 the embouchure of the inferior coronary vein ; its posterior extremity is 

 continued directly with the internal maxillary. The collateral branches 

 it receives in its course come from the masseter muscle and the parietes of 

 the cheek. 



On its way it receives a great number of affluents : these are : 



1. A large lingual vein, accompanying the small hypoglossal nerve. 



2. The inferior dental vein. 



8. The trunk of tlte deep temporal veins, a large vessel situated in front 

 and to the inside of the ternporo-maxillary articulation, where it com- 

 municates with the masseteric. This vessel arises in the texture of the 

 temporal muscle, but particularly in the parieto-temporal confluent, with 

 which it joins by the foramina in the temporal fossa. 



4. The pterygoid veins (Fig. 291), numerous branches, only a portion of 

 which come from the pterygoid muscles. The others, springing from the 

 subsphenoidal confluent of the sinuses of the dura mater, form, on the 

 superficial face of the external pterygoid muscle, a wide-meshed network 

 which communicates posteriorly with the temporal trunk, and anteriorly 

 with the confluent of the deep temporal veins. But as these two vessels are 

 bound together, outside the temporo-maxillary articulation, by means of the 

 masseteric artery, it results that this articulation is enlaced on every side 

 by one of the richest venous plexuses in the whole economy. 



3. Sinuses of the Dura Mater. 



We will here describe not only the sinuses of the encephalic dura mater 

 which supply the roots of the jugular vein, but also those of the spinal dura 



