The inferior vena cava is also referred to as the posterior vena cava. It’s the largest vein in the human body.

The inferior vena cava carries deoxygenated blood from the lower body to the heart.

Deoxygenated blood means most of the oxygen has been removed by tissues, and therefore the blood is darker. This blood comes from the legs and the body’s lower torso.

The inferior vena cava empties into the right atrium of the heart. The right atrium is located on the right back side of the heart.

The inferior vena cava runs posterior, or behind, the abdominal cavity. This vein also runs alongside the right vertebral column of the spine.

The inferior vena cava is the result of two major leg veins coming together. These leg veins are called iliac veins.

The iliac veins come together at the small of the back, at the fifth lumbar vertebra. Once the iliac veins have merged, they form the inferior vena cava, which transports the deoxygenated blood to the heart.