The left and right brachiocephalic veins (previously called innominate veins) are major veins in the upper chest, formed by the union of the ipsilateral internal jugular vein and subclavian vein (the so-called venous angle) behind the sternoclavicular joint. The left brachiocephalic vein is more than twice the length of the right brachiocephalic vein. These veins merge to form the superior vena cava, a great vessel, posterior to the junction of the first costal cartilage with the manubrium of the sternum. The brachiocephalic veins are the major veins returning blood to the superior vena cava..