what is the main vein of the human body
Veins can vary greatly in size. The largest vein in the body is called the vena cava, which is Latin for 'hollow vein.' There are two sections of the vena cava, one below the heart and one above it. The section above the heart is called the superior vena cava, and it returns blood from the head, neck, chest, and upper limbs back to the heart.