vena cava, superior

vena cava, superior The large vein that returns blood to the right atrium of the heart from the head, neck, and both upper limbs. The superior vena cava is located in the middle of the chest and is surrounded by rigid structures and lymph nodes. Structures bordering the superior vena cava include the trachea, aorta, thymus, right bronchus of the lung, and pulmonary artery. Compression of the superior vena cava by disease of any of the structures or lymph nodes surrounding it can cause superior vena cava syndrome. See also superior vena cava syndrome.