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Rotator cuff enthesitis in ankylosing spondylitis

Case contributed by Andrew Dixon
Diagnosis certain


Ankylosing spondylitis with very limited left shoudler movement. ? synovitis

Patient Data

Age: 30 years
Gender: Male

Left shoulder


Irregular osseous erosion of the supero-lateral humeral head, at the site of supraspinatus tendon insertion, consistent with the hatchet-shaped (hatchet sign) deformity due to enthesitis in ankylosing spondylitis. 

Left shoudler


 Features of acute on chronic rotator cuff inflammatory enthesitis typical of ankylosing spondylitis. Chronic erosion with subchondral cystic change of the superolateral humeral head, at the insertion site of the supraspinatus tendon. Marked underlying marrow edema within the humeral head. No high grade rotator cuff tear.

5 years earlier


A preceding shoulder x-ray 5 years earlier demonstrating early erosion of the humeral head at the supraspinatus insertion site.

Case Discussion

Typical appearance of ankylosing spondylitis related humeral head enthesitis with an excellent example of the radiographic hatchet sign.

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