A Sporadic Case Of Bilateral Triphalangeal Thumbs

Abstract

Triphalangeal thumb is a rare congenital malformation characterized by presence of an extra phalanx, varying from a very small  phalanx to a full extra phalanx. The true incidence is unknown, but is estimated at 1:25,000 live births. It is commoner in Caucasians, Asians and Native Americans; males are more commonly affected than females. Very few cases are reported in Africa, coexisting with other congenital anomalies. First described by Renaldi Columbi in 1559; it has an uncertain pathogenesis. Plain radiographs and magnetic resonance imaging (MRI) are useful in investigating this anomaly. We report the case of a 10-year-old boy who presented in
our facility with difficulty in flexing both thumbs.

Key words: Triphalangeal thumbs, flexion difficulty, radiographs, Trapezoidal phalanx, preaxial polydactyly