Radial ray deficiency Type III radial ray deficiency 2025-08-10T08:02:08Z A type of radial ray deficiency characterized by partial absence of the radius. The radius is partially absent. The defect can be in the proximal, middle, or distal third. All have been reported , but the most frequent is the absence of the distal one or two thirds. The hand is radially displaced . The ulna is thickened, shortened , and bowed radially, and the wrist is unsupported.