Ulnar Polydactyly and Ulnar Dimelia

Ulnar polydactyly and ulnar dimelia represent the most frequent and the most unusual forms of congenital duplication. Ulnar polydactyly is common in affected families and in individuals of African ancestry while ulnar dimelia is one of the least common of congenital hand anomalies. Both conditions demonstrate variable pathologic anatomy due to failure of formation or differentiation of the anterior–posterior axis of the upper limb. Ulnar polydactyly may occur as an element of several congenital syndromes. Ulnar polydactyly and ulnar dimelia may be diagnosed prenatally. Evaluation of affected children should consider the possibility of associated abnormalities. Surgical reconstruction of the affected extremity should normalize appearance and maximize functional capabilities.