Congenital hand anomalies: etiology, classification, and treatment.

Congenital hand anomalies have a wide range of presentations and functional consequences. Understanding and treatment of these deformities require an understanding of embryology of upper-extremity development. In this report, common anomalies of the hand and upper extremity have been reviewed according to the International Federation for Societies for Surgery of the Hand classification system. We examine the epidemiology, etiology, functional consequences, and current treatments available for each anomaly.