Glenohumeral Ligaments MRI Anatomy: Middle Gleno Humeral Ligament How to identify the Gleno Humeral Ligaments made Easy…er

MGHL: How to identify the Gleno Humeral Ligaments made Easy…er

Identifying the gleno humeral ligaments on MRI can be challenging as they are small and on lower field strength scanners there is inadequate resolution to see them properly. However if we understand the anatomy of the ligaments it becomes easier to know where to look even if we cant directly identify the ligament.

This post is an adaptation of a talk given at Radiology Asia in Singapore titled Gleno Humeral Ligaments made Easy…er.

1. Which Ligaments are we talking about?

There are 3 main glenohumeral ligaments.

1. SGHL: Superior GlenoHumeral Ligament

2. MGHL: Middle GlenoHumeral Ligament

3. IGHL: Inferior GlenoHumeral Ligament

4. The Coraco Humeral Ligament (CHL) is extra capsular and is not part of the glenohumeral ligaments but we will also look at as it helps to identify the SGHL and it also fuses with the joint capsule at the rotator interval.

2. How to find the Middle Gleno Humeral Ligament: When an Octopus meets the ligaments.

The ligaments arise in an orderly fashion and using analogies often helps to understand anatomy. On sagittal scans the ligaments have the appearance of tentacles of an octopus radiating from the biceps insertion on the supra glenoid tubercle.

After having identified the CHL ( blue arrow) and SGHL ( pink arrow), the next structure that you see immediately below it on sagittal scans is the MGHL ( white arrow).

KEY POINTS IN FINDING THE MGHL

The MGHL arises most commonly from the antero superior labrum or neck of glenoid.
It can be bifid.
Its best seen on axial scans.
Look for a linear structure ( blue arrow) running anterior to the labrum ( pink arrow) which eventually inserts into the anterior capsule ( yellow arrows) posterior to subscapularis.

How to Differentiate the MGHL from a Torn displaced labrum

Image above: Two black, linear structures. Which is the labrum and which is the MGHL?

The key to differentiating the MGHL from a torn labrum is to follow the two structures from superior to inferior on the axial scans.
The MGHL ( pink arrow) will be more anterior but most importantly can be followed inferiorly to its attachment with the anterior capsule posterior to subscapularis ( yellow arrow).
The labrum ( blue arrow) whilst displaced, is more posterior and as you scroll inferiorly, does not attach to the anterior capsule.
Green arrow ( torn proximal MGHL which is ill defined and hyperintense).
Red Arrow ( tear through the base of the anterior labrum).