Superior transverse scapular ligament

At a glance

English

Superior transverse scapular ligament

Latin (TA2)

Ligamentum transversum superius scapulae

System

Ligament

Region

Upper limb

Side

Paired, left and right

About the superior transverse scapular ligament

On the upper border of the scapula, just medial to the root of the coracoid process, is a small U-shaped gap called the suprascapular notch. The superior transverse scapular ligament (also called the transverse or suprascapular ligament) stretches across the top of the gap and closes it, so that the notch becomes a short osteofibrous tunnel, the suprascapular foramen.

The ligament is a thin, flat bundle of fibres, narrower in the middle than at its two ends. Laterally it is fixed to the coracoid root and medially to the inner end of the notch. The suprascapular nerve, on its way from the upper trunk of the brachial plexus to supraspinatus and infraspinatus, always passes beneath the ligament, through the foramen. The suprascapular artery and vein, in most people, pass above it. A useful memory aid is that the army (artery) goes over the bridge and the navy (nerve) goes under it.

The ligament varies. It may be partly or completely turned to bone, making the notch a complete bony ring, and occasionally it splits into two bands so that the notch has a double opening. A small inferior transverse scapular ligament, at the spinoglenoid notch farther down, is a separate structure.

Because the nerve is held under the ligament, it can be compressed or stretched there. Suprascapular nerve entrapment, often in athletes who make repeated overhead movements such as volleyball or throwing, causes deep shoulder pain and weakness or wasting of supraspinatus and infraspinatus. A narrow notch or an ossified ligament increases the risk. Treatment may include arthroscopic division of the ligament to free the nerve, and the notch is also a target for suprascapular nerve blocks used to relieve shoulder pain.

Attachments and function

Attaches from

The root of the coracoid process.

Attaches to

The medial end of the suprascapular notch on the superior border of the scapula.

Function

Bridges the suprascapular notch to make a foramen, keeping the suprascapular nerve beneath it and the suprascapular vessels usually above.

Nerve supply

Not innervated in any notable way; the suprascapular nerve passes directly beneath it.

Blood supply

Lies under the suprascapular artery, which usually crosses over it.