The subclavian vein is a major blood vessel located beneath the collarbone, or clavicle. It plays a crucial role in draining blood from the upper limbs and parts of the neck and head. The vein runs alongside the subclavian artery and is responsible for returning deoxygenated blood to the heart. This vein is formed by the merging of the axillary vein and the internal jugular vein. It eventually joins with the internal jugular vein to form the brachiocephalic vein, which leads to the superior vena cava. The subclavian vein is important for various medical procedures, including the placement of central venous catheters.