The superior and inferior vena cava
are collectively called the venae cavae
. They are the veins
that return deoxygenated blood
from the body into the heart
. They both empty into the right atrium
The inferior vena cava (or posterior vena cava in animals) travels up alongside the abdominal aorta with blood from the lower part of the body. It is the largest vein in the body.
The superior vena cava (or anterior vena cava in animals) is above the heart, and forms from a convergence of the left and right brachiocephalic veins that contain blood from the head and the arms.