Venae Cavae

About the Venae Cavae

The venae cavae are the two largest veins in the body, returning deoxygenated blood from the systemic circulation to the right atrium of the heart. The superior vena cava, formed by the joining of the left and right brachiocephalic veins, drains the head, neck, arms, and upper chest. The inferior vena cava, the larger of the two, forms from the joining of the common iliac veins in the lower abdomen and ascends alongside the aorta, collecting blood from the legs, pelvis, kidneys, and liver before passing through the diaphragm. Compression of the superior vena cava, most often by tumors in the chest, causes superior vena cava syndrome, with swelling of the face and arms. In late pregnancy, the uterus can compress the inferior vena cava when a woman lies on her back, reducing return of blood to the heart. Filters are sometimes placed in the inferior vena cava to catch blood clots traveling from the legs.