[Gibbous hand deformity--carpe bossu]

Fiolle (10) was the first to describe a bony protuberance of a carpometacarpal joint and named it carpe bossu. This anomalous anatomical condition occasionally becomes a--widely unknown--common clinical entity. The reasons are discussed. The clinical diagnosis can be confirmed by a lateral tangential radiograph. Discomfort and pain are rare and can be treated usually by conservative means, surgery is seldom indicated.