Scaphoid fat pad sign

The scaphoid fat pad or stripe sign is defined as obliteration or lateral displacement of the normal scaphoid fat pad. A positive sign usually indicates a scaphoid fracture, although it may also be associated with a radial styloid or proximal first metacarpal fracture. Is it best visualized on posteroanterior and oblique views of the wrist.

Anatomy

The normal scaphoid fat pad is a small triangular or linear radiolucent collection of fat adjacent to the radial aspect of the scaphoid. The ulnar border is formed by the radial collateral ligament of the carpus, which extends from the radial styloid to the ulnar aspect of the scaphoid. The radial margin is formed by the tendon sheaths of extensor pollicis brevis and abductor pollicis longus, which originate from the dorsal forearm and insert on the base of the first metacarpal and proximal phalanx of the thumb respectively. Radiolucency of the scaphoid fat pad is normal. It is not consistently identifiable in children.

History and etymology

First described by Daniel W Terry and James E Ramin, American radiologists, in 1975 .