THE CIRCULATORY OR VASCULAR SYSTEM 123 



the head and face, are the internal jugular, anterior 

 jugular, external jugular, and vertebral. 



The internal jugular vein is formed by the lateral 

 and inferior petrosal sinuses outside of the jugular for- 

 amen; it unites with the subclavian to form the innomi- 

 nate vein. The facial, lingual, pharyngeal, superior, and 

 middle thyroid veins unite to make up the supply on its 

 course. At the base of the neck, where it unites with the 

 subclavian vein, is a pair of valves. 



FlG. 62. Innominate vein and its branches: i, Mylohyoid muscle; 2, 

 root of tongue; 3, larynx; 4, thyroid gland; 5, trachea; cs, superior vena 

 cava; Abd, Abs, right and left innominate veins; S, subclavian vein ; ji,je, 

 internal and external jugular veins ; tsu, ti, superior and inferior thyroid 

 vein ; cvp, deep cervical vein ; v, vertebral vein ; mini, internal mammary ; 

 is, superior intercostal vein ; sea, anterior jugular vein ; *, thyroid plexus 

 (after Henle). 



The anterior jugular begins by many small veins 

 about the hyoid bone in the median line, and enters the 

 subclavian vein. 



The external jugular vein, formed by a division of 

 the temporomaxillary and the posterior auricular, passes 

 over the sternomastoid muscle, thence downward, and 

 terminates in the subclavian vein. 



The vertebral vein follows the course of the artery, 



