Nerve to subclavius !

The nerve to subclavius is a thin branch of the brachial plexus above the collarbone; it supplies the subclavius and often joins the phrenic nerve.

Official name: Subclavian nerve

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What it is

A small nerve from the upper trunk of the brachial plexus (C5–C6) that runs down in front of the plexus and the subclavian artery.

What it does

Supplies the subclavius muscle; often carries an accessory branch to the phrenic nerve.

Key facts

Roots: C5–C6 via the upper trunk of the brachial plexus
Moves: Subclavius; often an accessory phrenic branch to the diaphragm
Feeling from: Sternoclavicular joint (small twigs)

Relations

Course: Leaves the front of the upper trunk (or arises by separate twigs from C5 and C6), descends in front of the trunks and the third part of the subclavian artery, passes behind the clavicle and enters the subclavius
Behind: The brachial plexus trunks and the third part of the subclavian artery
In front: The clavicle, with the subclavius in the groove on its underside
Medial: The phrenic nerve on the anterior scalene, which its accessory phrenic branch, when present, crosses to join

How to find it

Not palpable. In a supraclavicular exposure of the brachial plexus it is seen as a thread running down on the front of the upper trunk toward the clavicle; when an accessory phrenic branch is present it can be followed medially to the phrenic nerve.

Common problems

Its accessory phrenic branch can keep part of the diaphragm working when the phrenic nerve is injured.

Clinical notes

An accessory phrenic nerve from it explains why part of the hemidiaphragm can keep working after the phrenic nerve is cut or blocked in the neck above where the two join
A landmark on the anterior surface of the upper trunk in supraclavicular plexus exploration; its loss alone causes no noticeable deficit
Resection of subclavius in venous thoracic outlet decompression removes its only target muscle; any accessory phrenic branch is looked for and kept
An accessory phrenic branch passing in front of the subclavian vein can be injured during subclavian vein catheterisation, clavicle fracture fixation or supraclavicular surgery

Anatomical variants

The accessory phrenic nerve, frequently a branch of the nerve to subclavius, joins the phrenic nerve at a variable level, from the root of the neck to the first rib
It may arise from the upper trunk, by separate twigs from C5 and C6, or from C5 alone; a C4 contribution is described in a prefixed plexus

Test yourself

Think of the answer, then tap the question to see it.

From which part of the brachial plexus does the nerve to subclavius arise?

The upper trunk (C5–C6), above the clavicle; it is a supraclavicular branch of the plexus.

Which nerve does the nerve to subclavius often send fibres to?

The phrenic nerve, through an accessory phrenic branch that adds fibres for the diaphragm.

What are the supraclavicular branches of the brachial plexus?

Dorsal scapular and long thoracic nerves (from the roots), suprascapular nerve and nerve to subclavius (from the upper trunk).

Why may part of the diaphragm keep working after a phrenic nerve injury in the neck?

An accessory phrenic nerve, often from the nerve to subclavius, joins the phrenic nerve below the level of injury.

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Educational information, not medical advice. For any symptom, see a health professional.

Its names

Official Latin (TA2): nervus subclavius TA2 6412
Official Spanish (DeCS): Nervio subclavio
English (TA2): Subclavian nerve

Sources: Terminologia Anatomica (TA2); Anatomía humana (4.ª ed.), tomo 1, cap. 55: Cintura escapular; Anatomía humana (4.ª ed.), tomo 1, cap. 62: Nervios del miembro superior.

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Representative model, for educational purposes only.