The inferior vena cava (or IVC) is a large vein that carries de-oxygenated blood from the lower half of the body into the heart. The vein connects to the heart at a valve attached to the right atrium. In the other direction the vein travels retroperitoneally along the posterior wall of the abdominal cavity, anterior to the vertebrae and to the right of the abdominal aorta until it branches into the iliac veins which receive blood from the legs.

There are exceptions to this in anastomoses between the two. Two good examples are the azygos vein system and in the venous plexuses next to the spinal cord but the preceding statement is largely true.

Health problems attributed to the IVC are typically associated to something pressing against it, and not to ruptures. Two common sources or pressure are the aorta, and, a fetus within a pregnant woman.

The vein that carries de-oxyginated blood from the upper half of the body is the superior vena cava.