Triphalangeal Thumb in the Typical Cleft Hand

Ten hands of six patients with only a single digit retained on the radial side of the cleft were observed from a group of 63 patients with typical cleft hand. All patients were bilaterally involved, and five were complicated with cleft foot. There were two types of retained thumb: a triphalangeal thumb with characteristic metacarpal bone(s), six hands of four patients; and a normal diphalangeal thumb, four hands of two patients. The metacarpal and distal phalangeal bone(s) of the triphalangeal thumb in typical cleft hand had signs of digital ray union: double epiphysis, deltametacarpal, bifurcated or perforated distal phalanx.