Nerve to Subclavius

nervus subclavius

The nerve to subclavius arises from the upper trunk of the brachial plexus (C5-C6) near the junction with the suprascapular nerve. It is a short nerve that descends anterior to the subclavian artery and vein to enter the deep surface of the subclavius muscle. In approximately 50% of individuals it also gives an accessory phrenic branch that joins the phrenic nerve, contributing to diaphragm motor supply and potentially influencing hiccup and ventilatory responses.

Region: Shoulder

Clinical Relevance

Clinical Notes

The accessory phrenic branch from the nerve to subclavius has important surgical implications: in procedures aimed at interrupting the phrenic nerve for hiccup treatment or during phrenic nerve identification near the subclavian vessels, this accessory branch may maintain partial diaphragmatic function if the main phrenic is blocked. Injury to the nerve to subclavius is clinically silent in isolation as subclavius is a functionally minor muscle; however, it serves as an electrophysiological localising landmark for upper trunk brachial plexus injuries. Isolated denervation confirms a lesion proximal to the clavicle.

Pathology

Common Injuries & Conditions

Upper Trunk Brachial Plexus Injury Localisation

Denervation of the subclavius on electromyography, combined with supraspinatus and infraspinatus changes, localises a brachial plexus injury to the upper trunk proximal to the clavicle, influencing surgical planning for nerve exploration and grafting in obstetric palsy and traumatic plexus injuries.