THE INFERIOR CAVAL SYSTEM. 



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pancreas, and spleen ; and those from the lower limb. It receives its name from its 

 principal vessel, the inferior vena cava, which conveys its blood to the right auricle. 



The Inferior Vena Cava. 



The inferior or ascending vena cava (vena cava inferior) (Figs. 765, 766) is formed 

 by the union of the two common iliac veins either on the right side of the intervertebral 

 disk separating the fourth and fifth lumbar vertebrae or on the right side of the fifth 

 lumbar vertebra. From this point it ascends directly upward to the level of the first 



Fig. 766. 



Hepatic veins 



Right suprarenal 

 body 



Vena cava-i--7^^' 

 Right renal vein 



Right kidney. 

 Right ureter 



Right spermatic- 

 vein 



Right spermatic 

 artery 



Psoas magnus 



Ureter 



External iliac 

 arterv 



Vas deferens 

 Spermatic cord 



Coeliac axis 



Superior mesenteric aiiery 

 Left suprarenal 

 body 



Left renal^jFein 



Left kidney 

 Left renal artery 



Inferior mesen- 

 teric artery 

 Left ureter 



Quadratus 

 lumborum 



Left spermatic 

 artery 



Common iliac 

 artery 



Common iliac 

 vein 



J^-i Psoas magnus 



Left ureter, 

 pelvic portion 



Rectum (cut) 



Vas deferens 

 Bladder 



Inferior vena cava and iliac veins. 



lumbar vertebra and there begins to bend slightly to the right to reach the fissure 

 of the liver which separates the Spigelian and right lobes. Passing upward *m this 

 fissure, it reaches the diaphragm and perforates the left lobe of the centrum tendineum 

 of that structure, so entering the cavity of the thorax, then bends slightly forward and 

 to the left, and opens into the lower and back part of the right auricle of the heart. 

 It is the largest vein of the body, measuring at its entrance into the auricle about 

 33 mm. in diameter. It increases in size from below upward with the accession of its 

 various tributaries, somewhat sudden increases succeeding the entrance into it of its 

 largest tributaries, the renal and hepatic veins. It contains no valves, unless the 

 Eustachian valve guarding its entrance into the auricle be regarded as belonging to it. 



