The subclavian vein is a large vein located beneath the clavicle (collarbone) that carries blood from the arm back toward the heart. It joins the internal jugular vein to form the brachiocephalic vein. The subclavian vein is clinically important as a common site for central venous catheter placement and a potential site for deep vein thrombosis, particularly in patients with central lines, cancer, or thoracic outlet syndrome (Paget-Schroetter syndrome in the case of effort-related thrombosis). On ultrasound, the subclavian vein can be partially visualized, though its course beneath the clavicle limits complete assessment. Sonography evaluates for compressibility, flow patterns, and the presence of thrombus, and ultrasound guidance is increasingly used to improve the safety of subclavian vein catheterization.
Sonography Term