Middle glenohumeral ligament

At a glance

English

Middle glenohumeral ligament

Latin (TA2)

Ligamentum glenohumerale medium

System

Ligament

Region

Upper limb

Side

Paired, left and right

About the middle glenohumeral ligament

The fibrous capsule of the shoulder is thin and loose, and on its front it is strengthened by three internal thickenings, the glenohumeral ligaments, named upper, middle and lower. They are hard to see from outside but stand out clearly from within the joint, viewed through an arthroscope or after opening the capsule from behind and removing the humeral head. The middle ligament is the most variable of the three.

It arises from the front of the glenoid rim and labrum, just below the superior ligament, near the upper part of the anterior margin. From there it runs obliquely downwards and laterally across the front of the joint, deep to the subscapularis tendon, with which it blends, to attach to the humerus at the front of the anatomical neck just medial to the lesser tubercle. It may be a well defined cord, a thin sheet or absent altogether. Above it lies an opening in the capsule, the foramen of Weitbrecht, through which the joint communicates with the subtendinous bursa of subscapularis. A thick cord-like middle ligament with no labrum at the front-upper glenoid, the Buford complex, is a normal variant that should not be mistaken for a tear.

The ligament restrains forward movement of the humeral head and lateral rotation of the arm, most effectively in the mid-range of abduction, about 45 degrees. During abduction it tightens along with the inferior ligament as the superior one relaxes, and lateral rotation stretches all three, while medial rotation slackens them.

When the middle ligament is thin or missing, more of the burden of anterior stability falls on the inferior ligament, which may predispose some people to forward dislocation. Variants of this ligament are important to recognise on MRI arthrography and at arthroscopy so that normal anatomy is not repaired as if it were damage.

Attachments and function

Attaches from

The anterior rim of the glenoid cavity and labrum, just below the superior glenohumeral ligament.

Attaches to

The front of the humeral anatomical neck, medial to the lesser tubercle, blending with the subscapularis tendon.

Function

Limits anterior translation of the humeral head and lateral rotation, especially with the arm partly abducted.

Nerve supply

Articular branches of the axillary, suprascapular and subscapular nerves.

Blood supply

Branches of the anterior circumflex humeral and suprascapular arteries.