314 



SUPERIOR INTERCOSTAL VEINS. 



behind the right sterno-mastoid muscle, into the right subclavian 

 and right internal jugular. 



The branches of the superior cava, Fig. 178.* 



which thus intervene between the 

 great trunk and the subdivisions 

 behind the sterno-mastoid muscles, 

 are often called the Subclavian 

 Veins ; but they do not appear to be 

 accurately named.f For, 1st, they 

 are not situated under the clavicle, 

 and, 2dly, they are the common 

 trunks of the subclavians and internal 

 jugulars united. 



There is a difference in the places 

 where some of the smaller veins origi- 

 nate on each side. The internal 

 mammary and the inferior thyroid, 

 on the right side, arise from the supe- 

 rior cava, or from the subclavian at 

 its origin. On the left side, they 

 arise from the subclavian. 



The Superior Intercostal Veins 



Are somewhat different on the 

 two sides. That on the right is 

 often the smallest and the least ex- 



* The veins of the trunk and neck. 1. The superior vena cava. 2. The left 

 vena innominata. 3. The right vena innominata. 4. The right subclavian 

 vein. 5. The internal jugular vein. 6. The external jugular. 7. The ante- 

 rior jugular. 8. The inferior vena cava. 9. The external iliac vein. 10. The 

 internal iliac vein. 11. The common iliac veins ; the small vein between these 

 is the vena sacra media. 12, 12. Lumbar veins. 13. The right spermatic 

 vein. 14. The left spermatic, opening into the left renal vein. 15. The right 

 renal vein. 16. The trunk of the hepatic veins. 17. The greater vena azygos, 

 commencing inferiorly in the lumbar veins. 18. The lesser vena azygos, also 

 commencing in the lumbar veins. 19. A branch of communication with the 

 left renal vein. 20. The termination of the lesser in the greater vena azygos, 

 21. The superior intercostal vein ; communicating inferiorly with the lesser 

 vena azygos, and terminating superiorly in the left vena innominata. 

 f They are now called vena innominate. p. 



