Sister cases of "delta phalanx" which was difficult to differentiate from brachydactyly.

The authors in Octorber 1975 encountered a case that visited their hospital with the chief complaint of deformity of both middle fingers. The case closely resembled brachyhyperphalangism, but no definite diagnosis could be obtained as a findings suggestive of deltaphalanx was present in some phalanges and some ·took the view that polydactylous change of the middle finger was suggested. However, because numerous deltaphalanges were found in both index and middle fingers in a younger sister bone five years later, both of the cases were diagnosed as belonging to the category of what hand surgeons of Japan maintain is cleft hand group. However, there are literature which describe cases like these two as typical cases of brachydactyly, and it was considered that study would have to be made in future whether brachydactyly and cleft hand group had some parts of their developmental mechanism in common or whether the concept of brachydactyly is as yet unestablished. 747 views are shown in Fig. 2. Both middle fingers CASES have four phalanges and present so-called hyCase 1. perphalangism. Development of the interphaThe case is a girl born on 5 July 1975 as langeal joint was poor in both middle fingers. the first child of a 27-year-old father and a (Fig. 1, Fig. 2) 26-year-old mather. There was no abnormality In making diagnosis of this case, there were in particular during pregnancy, and delivery was two conflicting views. One view had it that it full-term and easy. The child weighed 2880 g belongs to the category of brachydactyly and at birth. Already at birth, overlapping of the was homologous to type C (Bell, 19513>) which ring with the middle finger was observed in present hyperphalangism of index and middle both hands, and because this deformity gradufinger, and the other view held that it beally aggravated, the case visited this department longed to the category of so-called cleft hand for examination in the fifth month after birth. group (Watari, 19844>) which latent polydactylThe external appearance at examination is ous change in the middle finger, from the fact as shown in Fig. 1. The hands shown almost that the most proximal phalanx showed typical identical appearance. The middle finger is redelta phalanx. With no conclusion being obmarkably :flexed ulnarly at the PIP joint, the tained in the final analysis, diagnosis was DIP joint is slightly deviated radially, and the reserved. Roentgenographic views of a case middle finger as a whole is short. Active modiagnosed as typical brachyhyperphalangism are tion, which was satisfactory at the MP joint, shown in Fig. 3, which are very interesting was not observed at the PIP or the DIP joint. indeed when compared with Fig. 2. (Fig. 3) It was a very characteristic finding that the Case 2. ring finger marked overlapped with the middle In August 1980, five years later, a sister of finger in :flexed position. Roentgenographic case 1 visited this hospital with the chief com*) mt VI!-, ~1JIEA, ::fd'¥*1-: Brachydactyly c O)~Jjlj;1J~t2E]~~1::'tl;-:> t..: Delta phalanx O)yr!JPJt-171J