Congenital failure of formation of the upper limb.

This article provides an overview of the various classification systems for radial longitudinal, central longitudinal, and ulnar longitudinal deficiencies. It looks specifically at radius deficiency, hypoplastic thumb, index finger pollicization, narrowed thumb web, forearm-elbow deformities, and hand abnormalities. Various surgical approaches to these conditions and their results are explored. The authors conclude that longitudinal failure of formation deformities comprises a substantial portion of the anomalies of the upper limb. Although much of the past and current congenital hand literature has been devoted to these conditions, they continue to be a reconstructive challenge to hand surgeons involved in their care.