Disruption of the radial/ulnar axis:congenital longitudinal deficiencies.

Radial, ulnar, and central deficiencies represent a spectrum of abnormalities in the development of the upper limb. Radial longitudinal deficiency is often associated with abnormalities in other organ systems, such as cardiac and renal, and so requires a comprehensive medical evaluation. On the other hand, ulnar longitudinal deficiency tends to be associated only with other musculoskeletal abnormalities. In all of these conditions, there is a high incidence of ipsilateral thumb abnormalities. Given the importance of the thumb in overall hand function, abnormalities of the thumb often guide treatment for these conditions. Surgical treatment of the wrist and forearm in radial longitudinal deficiency is controversial, as will be outlined in this review.