Inferior vena cava

Anatomy

The inferior vena cava arises from the confluence of the common iliac veins at the level of L5 vertebra, just inferior to the bifurcation of the abdominal aorta. It then ascends the posterior abdominal wall, to the right side of the aorta and the bodies of the L3-L5 vertebrae. After passing through its fossa on the posterior liver surface, the IVC enters the thorax by traversing the inferior vena caval foramen of the diaphragm. 

The tributaries of the IVC correspond to the branches of the abdominal aorta. Note that some professors will want you to know at which vertebral level the IVC gets its direct tributaries, so they are as follows:

• The direct tributaries are the inferior phrenic veins (T8), right suprarenal (L1), renal (L1), right testicular (gonadal) (L2), lumbar (L1-L5), common iliac (L5) and hepatic (T8). If you want an easy way to remember them just memorise the mnemonic ' Portal System Returns To Liver In Humans'.
• Left gonadal and left suprarenal renal veins drain first into the left renal vein 
• The veins of the stomach, spleen, pancreas, small and large intestines first empty into the hepatic portal vein. The hepatic portal vein carries this blood to the liver to be processed and detoxified. Then, the blood reaches the IVC through the hepatic veins.

The inferior vena cava communicates with the superior vena cava through the collateral vessels, which include the azygos vein, lumbar veins, and vertebral venous plexuses.

Feel overwhelmed by all of the tributaries to the IVC? We have an article about how to learn anatomy with mind maps to help you learn anatomy more efficiently. 

Learn more about the tributaries of the IVC and its anatomy.

Test your knowledge on the cardiovascular system with this quiz.

Function

The IVC’s function is to convey the blood from the abdomen, pelvis, and lower limbs to the right atrium of the heart. Additional IVC functions are noticeable during some health disturbances, such as hepatic portal vein obstruction or the obstruction of the IVC itself. 

Specialized vessels called the portocaval (portosystemic) anastomoses open if the hepatic portal vein is obstructed. The intestinal blood then bypasses the liver and empties into the IVC directly. In cases where the IVC is occluded, the collateral vessels to the superior vena cava open. 

Learn more about portocaval anastomoses with our article, then take this specially designed quiz to consolidate everything you’ve learned about the IVC and its tributaries.