VEINS OF THE HEAD AND NECK. 253 



the lower jaw, about the trunk of the facial vein, and is so large 

 as to explain the difference of opinion among anatomists in re- 

 gard to the latter's termination. Sometimes the occipital vein, 

 or a large trunk from it, joins the external jugular. At the 

 lower part of the neck, the external jugular is augmented by 

 the superficial cervical veins. Some of these come from the" 

 lower part of the neck, near the shoulder, and join the jugular 

 just above the clavicle; others are placed on the lower front 

 part of the neck, above the sternum, and there form with each 

 other a remarkable and an irregular plexus, consisting in nu- 

 merous meshes. It frequently happens that the external jugu- 

 lars of the two sides, just before they terminate, anastomose 

 with each other by a large horizontal trunk, which runs ju>t 

 above the end of the sternum, in front of the sterno-mastoid, 

 sterno-hyoid, and the sterno-thyroid muscles: this trunk, on 

 other occasions, goes more deeply, and behind these muscles, 

 from one subclavian vein to another, or to a jugular; its mode 

 of attachment is, indeed, much varied : when it exists, however, 

 it frequently receives several of the superficial veins of the 

 neck, arid the inferior thyroideal. 



The Internal Jugular Vein (Vena Jugularis Interna) extends 

 from the basis of the cranium to the internal margin of the first 

 rib, at the insertion of the scalenus anticus muscle. The lateral 

 sinuses of the dura mater, receiving ultimately all the blood of 

 the brain, of the eye, and a portion of that of the nose, convey 

 it from the cranium through the posterior foramina lacera, 

 where they are joined to the upper end of the internal jugular 

 veins, the lining membrane of each sinus being continuous with 

 that of its respective vein. Each vein is somewhat enlarged 

 at its commencement, which is therefore called its Gulf or Sinus; 

 the right vein is frequently larger than the left. The internal 

 jugular then descends in front of the transverse processes of the 

 vertebrae of the neck, on the outer side of the internal end of 

 the primitive carotid artery, and of the pneumogastric nerve. 

 It is concealed above by the styloid process of the temporal 

 bone, and the muscles belonging to it; it is crossed, half way 

 down the neck, by the omo-hyoideus muscle; and, in the great- 

 er part of its course, is beneath, and nearly parallel with the 

 anterior edge of the sterno-mastoideus. Having got behind the 



VOL. II. 23 



