Superior vena cava

The superior vena cava (SVC, Latin: vena cava superior) is a short, large-diameter vein of the thorax. It is situated vertically within the mediastinum and drains into the right atrium of the heart. The SVC collects venous blood from the upper half of the body. Most of the SVC lies on the anterior and right side of the superior mediastinum. However, the lower half of the SVC is covered by the pericardium and is therefore contained within the middle mediastinum.

The SVC begins by merging of the right and left brachiocephalic veins. The fusion happens posterior to the lower edge of the 1st right costal cartilage. The SVC descends vertically and ends at the lower edge of the right 3rd costal cartilage, where it drains into the right atrium of the heart. Immediately before entering the pericardial sac (at the level of the 2nd costal cartilage), the SVC receives the azygos vein and may also receive pericardial and mediastinal veins.

The superior vena cava is one of the two large veins of the systemic circulation by which deoxygenated blood is returned from the body to the right side of the heart. The other large vein is the inferior vena cava (IVC). The SVC drains everything above the diaphragm, while the IVC collects blood from the lower part of the body below the diaphragm.