Superior subscapular nerve

At a glance

English

Superior subscapular nerve

Latin (TA2)

Nervus subscapularis superior

System

Nerve

Region

Upper limb

Side

Paired, left and right

About the superior subscapular nerve

The superior, or upper, subscapular nerve is the first and shortest of the branches leaving the posterior cord of the brachial plexus. Its fibres come mainly from the fifth cervical nerve, with some from the sixth. It arises in the upper axilla, behind the axillary artery, above the thoracodorsal and inferior subscapular nerves.

It runs only a short distance downwards and backwards before entering the anterior surface of subscapularis, on the posterior wall of the axilla. It is often double, with two or more small twigs sinking into the upper part of the muscle. It has no sensory field of skin of its own. In some people it leaves the posterior division of the superior trunk instead of the cord itself.

Subscapularis is the largest muscle of the rotator cuff. It rotates the arm medially and, with the other cuff muscles, holds the head of the humerus in the shallow glenoid cavity; its upper part is a key front barrier against the shoulder slipping forwards. Knowledge of the nerve matters in shoulder surgery from the front, in which the muscle is split or detached, and in nerve blocks around the shoulder. Like the inferior subscapular nerve, it may be damaged together with other posterior cord branches in traction injuries of the plexus.

Course and supply

Arises from

Posterior cord of the brachial plexus (C5, C6) in the axilla.

Ends in

Enters the anterior surface of the upper part of subscapularis.

Supplies

Motor to the upper part of subscapularis, which rotates the arm medially and stabilises the shoulder joint.