Presentation
Ankylosing spondylitis with very limited left shoudler movement. ? synovitis
Patient Data
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.
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.
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.