has part has part characteristic of has modifier Bifid distal phalanx of the thumb Note that with bifid distal phalanx, the terminal phalanx of the thumb is clefted but is still one bone. With duplication of the terminal phalanx of the thumb, the distal phalanx is split into two bones that are located side by side. With triphalangeal thumb, the thumb has three phalanxes located one after the other. Duplication of the distal phalanx of the thumb Partial duplication of thumb phalanx Partial duplication of the distal phalanges of the hand cleft abnormal distal phalanx of manual digit 1