The Tuck Sign helps the examiner to distinguish between a dorsal ganglion and dorsal extensor tendon tenosynovitis. Tenosynovium is attached to the extensor tendons. When the patient extends the fingers the tenosynovial tissue moves proximally with the tendons. In combined maximal finger and wrist extension the abnormal tenosynovium and dorsal skin "tuck" under the extensor retinaculam of the wrist. The Tuck sign distinguishes hypertrophic synovium from a dorsal ganglion which does not move with the tendons.
When the wrist and the fingers are simultaneously extended the dorsal skin at the edge of the retinaculum will fold "tuck" under the distal edge of the extensor retinaculum as seen in the above photo. This folding occurs in dorsal tenosynovitis because the excessive synovium is attached to the extensor tendons and skin. As the extensors move proximally under the extensor retinaculum the skin is dragged under the edge of the retinaculum creating the skin tuck or fold. When the dorsal mass is a ganglion or an extensor brevis manus hypertrophic muscle the "tuck' sign will be negative.
When the wrist and the fingers are simultaneously extended the dorsal skin at the edge of the retinaculum will not fold "tuck" under the distal edge of the extensor retinaculum. The skin on the dorsal wrist shows increased creases but no actual folding under the retinaculum. A negative tuck sign is seen with a ganglion or an extensor brevis manus hypertrophic muscle.
1. Burke FD, Melikyan EY, Bradley MJ, Dias JJ. Review primary care referral protocol for wrist ganglia. Postgrad Med J 2003; 79: 329-331.
