Inferior Vena Cava
The inferior vena cava (or IVC), also known as the posterior vena cava, is the large vein that carries de-oxygenated blood from the lower half of the body into the right atrium of the heart. It is posterior to the abdominal cavity and runs alongside of the vertebral column on its right side (i.e. it is a retro-peritoneal structure). It enters the right atrium at the lower right, back side of the heart.