Muscle · Shoulders

Subclavius

Musculus subclavius

A short muscle tucked into the gap between the first rib and the collarbone, hidden under pectoralis major and completely inaccessible from the skin. It runs from the first rib at its junction with its cartilage, outward and upward into a groove on the underside of the middle of the clavicle. Two things follow from that position. It pulls the clavicle down and forward and steadies it on the sternum during arm movement — and, being slung across that gap, it lies directly over the subclavian vessels and the brachial plexus as they pass from the neck into the arm, forming the soft roof of the corridor they travel through.