Hands and Feet: Brachydactyly
Brachydactyly may be isolated or associated with a syndrome. Isolated forms of brachydactyly have been typed A1–5, B, C, D, E, IV, Sugarman brachydactyly, and Kirner deformity as an extension of the original Bell classification system. Isolated brachydactyly is rare except for types A3 (short middle phalanx of the little finger) and D (short distal phalanx of the thumb). Over 260 syndromes and genetic disorders have brachydactyly as a feature and several of them are listed below. Delta phalanx (longitudinally bracketed epiphysis) is a triangular phalanx with continuous epiphy-seal cartilage bridging the base and head ( Fig. 5.100 ).