538 YEINS. 



The Internal Maxillary Vein is a vessel of considerable size, receiving branches 

 which correspond with those of the internal maxillary artery. Thus it receives 

 the middle meningeal veins, the deep temporal, the pterygoid, masseteric, and 

 buccal, some palatine veins, and the inferior dental. These branches form a 

 large plexus, the pterygoid, which is placed between the Temporal and External 

 Pterygoid, and partly between the Pterygoid muscles. This plexus communi- 

 cates very freely with the facial vein, and with the cavernous sinus, by branches 

 through the base of the skull. The trunk of the vein then passes backwards, 

 behind the neck of the lower jaw, and unites with the temporal vein, forming 

 the temporo-maxillary. 



The Temporo -maxillary Vein, formed by the union of the temporal and inter- 

 nal maxillary vein, descends in the substance of the parotid gland, between the 

 ramus of the jaw and the Sterno-mastoid muscle, and divides into two branches, 

 one of which passes inwards to join the facial vein, the other is continuous with 

 the external jugular. It receives near its termination the posterior auricular 

 vein. 



The Posterior Auricular Vein commences upon the side of the head, by a 

 plexus which communicates with the branches of the temporal and occipital 

 veins. The vein descends behind the external ear and joins the temporo-maxil- 

 lary, just before that vessel terminates in the external jugular. This vessel 

 receives the stylo-rnastoid vein, and some branches from the back part of the 

 external ear. 



The Occipital Vein commences at the back part of the vertex of the skull, by 

 a plexus in a similar manner with the other veins. It follows the course of the 

 occipital artery, passing deeply beneath the muscles of the back part of the 

 neck, and terminates in the internal jugular, occasionally in the external jugular. 

 As this vein passes opposite the mastoid process, it receives the mastoid vein, 

 which establishes a communication with the lateral sinus. 



The Yeins of the Neck, which return the blood from the head and face, are 

 the 



External jugular. Anterior jugular. 



Posterior external jugular. Internal jugular. 



Vertebral. 



The External Jugular Vein receives the greater part of the blood from the 

 exterior of the cranium and deep parts of the face, being a continuation of the 

 temporo-maxillary and posterior auricular veins. It commences in the substance 

 of the parotid gland, on a level with the angle of the lower jaw, and runs per- 

 pendicularly down the neck, in the direction of a line drawn from the angle of 

 the jaw to the middle of the clavicle. In its course it crosses the Sterno- 

 mastoid muscle, and runs parallel with its posterior border as far as its attach- 

 ment to the clavicle, where it perforates the deep fascia, and terminates in the 

 subclavian vein, on the outer side of the internal jugular. In the neck, it is 

 separated from the Sterno-mastoid by the anterior layer of the deep cervical 

 fascia, and is covered by the Platysma, the superficial fascia, and the integument. 

 This vein is crossed about its centre by the superficial cervical nerve, and its 

 upper half is accompanied by the auricularis magnus nerve. The external 

 jugular vein varies in size, bearing an inverse proportion to that of the other 

 veins of the neck; it is occasionally double. It is provided with two pairs of 

 valves, the lower pair being placed at its entrance into the subclavian vein, the 

 upper pair in most cases about an inch and a half above the clavicle. These 

 valves do not prevent the regurgitation of the blood, or the passage of injection 

 from below upwards. 1 



1 The student may refer to an interesting paper by Dr. Struthers, " On Jugular Venesection 

 in Asphyxia, Anatomically and Experimentally Considered, including the Demonstration of 

 Valves in the Veins of the Neck," in the Edinburgh Medical Journal, for November, 1856. 



