The cephalic vein originates over the anatomical snuffbox at the base of the thumb, passes laterally around the distal forearm to reach the anterolateral surface of the limb, and then continues proximally. It crosses the elbow, then passes up the arm into a triangular depression—the clavipectoral triangle (deltopectoral triangle)—between the pectoralis major muscle, deltoid muscle, and clavicle. In this depression, the vein passes into the axilla by penetrating deep fascia just inferior to the clavicle.