Coracohumeral ligament

At a glance

English

Coracohumeral ligament

Latin (TA2)

Ligamentum coracohumerale

System

Ligament

Region

Upper limb

Side

Paired, left and right

About the coracohumeral ligament

The shoulder joint trades stability for range, and its loose capsule is reinforced at several points. Over the top, the main reinforcement is the coracohumeral ligament, a wide, strong band that fills the gap between the supraspinatus and subscapularis tendons, the region known as the rotator interval.

It begins on the outer edge of the coracoid process, close to its root, and runs downwards and laterally above the humeral head. As it approaches the humerus it splits into two bands that straddle the intertubercular groove: a posterior band to the greater tubercle, blending with the supraspinatus tendon, and an anterior band to the lesser tubercle, blending with the subscapularis tendon. Between them the bands roof over the tendon of the long head of biceps, helping hold it in the groove. The lower and back edge of the ligament is fused with the joint capsule, while its upper and front edge is free and overlaps the capsule. The superior glenohumeral ligament lies beneath it, and the two together form a sling for the biceps tendon.

With the arm at the side the ligament is tight. It resists the humeral head sliding downwards when the arm hangs or carries a weight, and it checks lateral rotation of the humerus, particularly with the arm by the side. It also limits extension.

In frozen shoulder (adhesive capsulitis) the coracohumeral ligament and the rotator interval become thickened and scarred. The resulting contracture produces the typical early loss of lateral rotation, and surgical or arthroscopic release of the ligament is one way of restoring movement. Thickening of the ligament can be seen on MRI and ultrasound and helps confirm the diagnosis.

Attachments and function

Attaches from

The outer edge of the coracoid process, close to its root.

Attaches to

The greater and lesser tubercles of the humerus, by posterior and anterior bands either side of the intertubercular groove.

Function

Strengthens the upper capsule, supports the hanging arm against downward pull and limits lateral rotation and extension.

Nerve supply

Branches of the suprascapular and axillary nerves.

Blood supply

Branches of the anterior circumflex humeral and suprascapular arteries.