Inferior Vena Cava

The largest vein in the body is the vena cava which brings deoxygenated blood from the body back to the heart and lungs to be reoxygenated. The vena cava enters the heart at the right atrium. The right and left internal and external jugular veins carry deoxygenate blood away from the head and neck, and drain into the vena cava just before it reaches the right atrium.