TRIBUTARIES OF INFERIOR VENA CAVA. 367 



it is internal to its companion artery, and lies between the psoas and position to 

 pectineus muscles ; but as it ascends it gradually passes behind the ar 

 artery. 



The veins opening into it are the epigastric and circumflex iliac tributaries, 

 and a pu.hic branch from the obturator vein. 



The COMMON ILIAC VEIN (^>) ascends by the side of its accompany- Common 

 ing artery, the right almost vertically, and the left obliquely, to the 

 front of the body of the fifth lumbar vertebra (the right half), where 

 it blends with its fellow in one trunk the Aena cava. 



The right- vein is the shorter, and lies at first behind, but after- difference Jin 

 wards outside the artery of the same name. The left is internal to StionTf 

 and below the artery of its own side, and crosses beneath the right 

 common iliac artery to the commencement of the vena cava. 



Each vein receives the ilio-lumbar branch ; and the common iliac tributaries, 

 of the left side is joined by the middle sacral vein. 



The INFERIOR or ASCENDING VENA CAVA (ra) collects and conveys Vena cava 

 to the heart the blood of the lower half of the body. Taking origin mfenor: 

 opposite the fifth lumbar vertebra, lower than the bifurcation of the 

 aorta, this large vein ascends on the right side of the arterial trunk, extent; 

 and reaches the heart by perforating the diaphragm. Its relations relations ; 

 to surrounding parts have been already noticed (p. 320), but the 

 description may be again referred to, as the position of the branches 

 of the aorta to it can be better seen now. 



TRIBUTARIES. The cava receives parietal branches (lumbar and receives 

 diaphragmatic) from the wall of the abdomen and the diaphragm ; 

 and visceral branches from the testicle, the kidney, the suprarenal from 

 body, and the liver. abdomen ' 



The veins belonging to the stomach, the intestinal canal, the except those 

 spleen, and the pancreas, are united to form the vena portse (p. 334) ; apparatus. 

 and the blood contained in those vessels reaches the cava by the 

 hepatic veins, after it has circulated through the liver. 



The spermatic vein (6) enters the abdomen by the internal Spermatic 

 abdominal ring, after forming the spermatic plexus in the cord. 

 At first there are two branches in the abdomen, which lie 

 on the sides of the spermatic artery ; but these soon join into 

 one trunk. On the left side it opens into the renal vein at a ends differ- 

 right angle, and there is generally a small valve over the aperture ; i^ftand 1 

 on the right side it enters the inferior cava below the renal vein. ri ht sides '> 

 As the vein a c cends to its destination, it receives one or more 

 branches from the wall of the abdomen, and the fat about the branches: 

 kidney. 



In the female the corresponding vein (ovarian) has the same ending vein in the 

 as in the male, and it forms a plexus in the broad ligament of the 

 uterus. Valves are absent from the vein and its branches, but 

 commonly there is one at its union with the renal. 



The renal or emulgent vein (n) is of large size, and joins the vena Renal vein; 

 cava at a right angle. It commences by many branches in the 

 kidney ; and the trunk resulting from their union is superficial to position to 

 the renal arterv. 



