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Scallop sign

Last revised by Dr Yuranga Weerakkody on 15 Mar 2021

The scallop sign is a radiological sign initially described in rheumatoid arthritis of the wrist.

It refers to the appearance of the ulnar aspect of the distal radius on a plain radiograph of the wrist, where it has a scalloped shape with a sclerotic border 1,2. It occurs due to progressive erosive changes at the distal radioulnar joint 1,2. While initially described in rheumatoid arthritis, it has also been described in osteoarthritis of the wrist 2.

The scallop sign, swelling in the extensor compartment of the hand, and severe dorsal subluxation are predictive of rupture of the extensor tendons of the hand, including Vaughan-Jackson syndrome 1,3.

History and etymology

The sign was first described by RA Freiberg and A Weinstein in 1972 1.

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Cases and figures

  • Case 1: annotated
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