Nerve · Shoulders

Nerve to the subclavius

Nervus subclavius

A very fine nerve leaving the upper trunk of the brachial plexus at the root of the neck, descending in front of the plexus and the subclavian vessels to reach the small muscle slung under the collarbone. What makes it worth a page is not the muscle but a habit it has: in many people it carries an accessory phrenic nerve — a bundle of fibres that leaves it, joins the phrenic nerve low in the neck or in the chest, and goes on to help supply the diaphragm. A nerve to a small clavicular muscle is therefore also, sometimes, a back road to the muscle of breathing.