Superior Vena Cava
The superior vena cava (SVC, also known as the cava or cva) is a short, but large diameter vein located in the anterior right superior mediastinum. Embryologically, the SVC is formed by the left and right brachiocephalic veins (also known as the innominate veins) that also receive blood from the upper limbs, eyes, and neck.
There is no valve that divides the SVC from the right atrium, which conducts blood from right atrial and right ventricular contractions upwards into the internal jugular vein (seen as the jugular venous pressure) and sternocleidomastoid muscle.
Positionally, the SVC begins behind the lower border of the 1st right costal cartilage and descends vertically behind the 2nd and 3rd intercostal spaces to drain into the right atrium at the level of the 3rd costal cartilage. Its lower half is covered by a fibrous pericardium, which is pierced by the SVC at the level of the 2nd costal cartilage.
The SVC is one of the 2 large veins by which blood is returned from the body to the right side of the heart. After circulating through the body systemically, deoxygenated blood returns to the right atrium of the heart through either the SVC, which drains the upper body, or the inferior vena cava (IVC) that drains everything below the diaphragm.