Thickening of the coracohumeral ligament and the capsule in the axillary recess with obliteration of the fat under the coracoid (rotator interval) — supporting a clinical diagnosis of painful loss of external rotation.
Orient first
- Clinical diagnosis: global restriction, especially external rotation, with normal radiographs.
- Associated with diabetes and thyroid disease.
- Imaging mainly excludes other causes (cuff tear, osteoarthritis, calcific tendinopathy).
Acquire the study
- Shoulder MRI: sagittal oblique T1 and T2 fat-saturated, coronal oblique PD fat-saturated; post-gadolinium T1 optional.
The manoeuvre
- Sagittal oblique T1: fat in the subcoracoid triangle obliterated by soft tissue.
- Coracohumeral ligament thickness in mm.
- Coronal oblique: axillary recess capsule thickness in mm and signal; enhancement.
- Rotator cuff and joint surfaces for alternative causes.
What confirms it
- Clinical restriction with rotator interval and capsular thickening on imaging.
What licenses you to exclude it
- A normal rotator interval and capsule make adhesive capsulitis less likely; imaging cannot exclude an early stage.
The classic misread
- Reporting a normal MRI in a stiff shoulder without looking at the rotator interval.
- Missing a posterior dislocation that causes restricted external rotation.