Unusual Presentation of Familial Unilateral Postaxial Polydactyly With Metacarpal Delta Phalanx: A Report of a Rare Case.

The term "delta phalanx" is proposed to characterize an uncommon deformity that typically affects the middle phalanx of a finger. It has the appearance of the Greek capital letter delta, meaning it is shaped like a triangle. Because the faulty epiphysis occurs proximally to distally instead of along its usual horizontal course, the bone has a semilunar shape. Functional impairment or significant finger shortening are indications for surgery. A variety of congenital hand anomalies are linked to the delta phalanx. Few cases of middle delta phalanx in the ulnar polydactyly finger have been documented. This case study investigates an extremely uncommon occurrence of metacarpal delta phalanx in an ulnar polydactyly finger.