464 UPPER VENA CAVA. 



the fore part of the walls of the abdomen, where they anastomose with 



Fig. 309. 



Fig. 309. SKETCH OP THE PRINCIPAL VENOUS 

 TRCNKS, TOGETHER WITH THE THORACIC DUCT. ^ 



a, the basilar process of the occipital bone, 

 through which and the temporal bones a trans- 

 verse incision has been made so as to lay open the 

 jugular foramen on both sides ; b, the body of the 

 fifth cervical vertebra ; c, the first rib ; tZ, the 

 sixth ; e, the twelfth ; /, the body of the fifth 

 lumbar vertebra ; 1, trunk of the vena cava supe- 

 rior divided at the place of its entrance into the 

 right auricle ; 2, right, 2', left subclavian veins ; 

 3, right internal jugular vein ; the left is cut 

 short immediately above the place where it joins 

 the subclavian vein. ; 3', 3', lower part of the 

 lateral sinuses of the dura inater ; that of the left 

 side is divided inferiorly ; that of the right side 

 shows at its junction with the jugular vein the 

 bulb which lies in the jugular depression of the 

 temporal bone ; 4, right, and 4', left external 

 jugular veins ; 5, right, and 5', left vertebral veins 

 anastomosing with 5", external vertebral viens, 

 before joining the subclavian veins ; 6, placed on 

 left subclaviau vein below the opening of the last, 

 and of the thoracic duct ; below b, the inferior thy- 

 roid veins ; 7, 7', the internal mammary veins; 8, 

 the left superior intercostal vein joining the left 

 brachio-cephalic vein, and anastomosing below 

 with intercostal veins which join the trunk of the 

 azygos ; the right superior intercostal vein is seen 

 joining the azygos vein; 9, main or right azygos vein ; 

 the uppermost figure points to the curved portion, 

 which passes over the right bronchus before joining 

 the vena cava superior ; 9', the left azygos, repre- 

 sented here as crossing the vertebral column on the 

 eighth vertebra; 10, the thoracic duct; the upper 

 figure is on the fourth dorsal vertebra, the lower 

 on the first lumbar close to the receptaculum chyli; 

 11, trunk of the inferior vena cava divided below 

 the liver ; the figure is immediately over the place 

 of origin of the renal veins ; below it is seen 

 dividing on the fourth lumbar vertebra into the 

 two common iliac veins ; 12, the union of the left 

 azygos vein with the left renal vein ; 13, on the 

 right side, the commencement of the right azygos 

 vein in the lumbar region, joined by several lumbar 

 veins; 13', the commencement of the azygos vein 

 of the left side, joining similar veins on that side ; 

 14, 14', the external iliac veins ; 15, placed on 

 the promontory of the sacrum, points on either 

 side to the prolongation of the lower branches of 

 the right and left lumbar veins into the pelvis, and 

 their union with sacral and other branches of the 

 internal iliac veins. 



the epigastric veins ; thence proceeding 

 upwards between the cartilages of the ribs 

 and the pleura, they receive the anterior 

 intercostal veins which correspond with the 

 branches of the internal mammary artery, 

 together with some small diaphragmatic, thymic and mediastinal veins, and, 



