Anomalous extensor muscles of the hand: A review

Anomalous extensor muscles of the hand are not uncommon. Well-recognized an omalies anomalous extensor indicis proprius, extensor digitorum brevis manu s, extensor medii proprius, and extensor indicis et medii communis are revi ewed and discussed in detail. Anomalous extensor indicis proprius and exten sor digitorum brevis manus may occasionally give rise to dorsal wrist pain and the diagnosis is often confused especially in the presence of other pat hologic findings such as a ganglion. An analysis of the embryologic develop ment of the extensor muscle mass with phylogenetic comparisons between spec ies of the animal kingdom is presented to underscore the clinical relevance of these anomalous extensors. Copyright (C) 1999 by the American Society f or Surgery of the Hand.