Suprascapular nerve

At a glance

English

Suprascapular nerve

Latin (TA2)

Nervus suprascapularis

System

Nerve

Region

Upper limb

Side

Paired, left and right

About the suprascapular nerve

The suprascapular nerve leaves the plexus's upper trunk in the neck's posterior triangle and carries fibres from C5 and C6, sometimes with a share from C4. It is a mixed nerve, with motor fibres for two rotator cuff muscles and sensory fibres for the shoulder joints. From its origin it runs laterally above the brachial plexus, alongside the lower belly of omohyoid and deep to trapezius, towards the upper border of the scapula.

At the scapula it passes through the suprascapular notch, below the superior transverse scapular ligament that bridges it, while the suprascapular artery and vein usually pass above the ligament. In the supraspinous fossa it lies under supraspinatus and gives that muscle two branches, along with twigs to the shoulder and acromioclavicular joints. It then curves round the lateral edge of the scapular spine, through the spinoglenoid notch, often under a thin spinoglenoid ligament, and enters the infraspinous fossa to supply infraspinatus.

Supraspinatus helps to start abduction of the arm and holds the head of the humerus in the glenoid cavity, while infraspinatus is the main lateral rotator of the shoulder. The sensory branches carry much of the feeling, including pain, from the back and top of the shoulder joint and from the acromioclavicular joint. The nerve does not supply any skin in most people.

The nerve can be trapped at either notch. Compression at the suprascapular notch, by a tight ligament, a fracture or repeated overhead movement, weakens and wastes both muscles, causing deep, poorly localised shoulder pain and weak abduction and lateral rotation. Compression at the spinoglenoid notch, often by a cyst arising from the joint, affects only infraspinatus, a picture seen in volleyball players and other overhead athletes. Because it carries so much of the sensation from the shoulder joint, the nerve is blocked with local anaesthetic to control pain after shoulder surgery and in chronic shoulder pain.

Course and supply

Arises from

Upper trunk of the plexus (C5, C6, sometimes C4), in the neck's posterior triangle.

Ends in

Ends in supraspinatus and, after passing through the spinoglenoid notch, in infraspinatus.

Supplies

Motor to supraspinatus and infraspinatus; sensory to the shoulder (glenohumeral) and acromioclavicular joints.