The left and right brachiocephalic veins (previously called innominate veins) are major veins in the upper chest, formed by the union of each corresponding internal jugular vein and subclavian vein. This is at the level of the sternoclavicular joint. The left brachiocephalic vein is nearly always longer than the right. 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.