Fig. 1.

Nelson and Orbay coined the watershed line (WS) as “a theoretical line marking the most volar aspect of the volar margin of the radius,” to serve as the distal margin for volar plating to minimize tendon injuries. ^{1 2 3} PQ, pronator quadratus line, or PQ line; VR, volar radial ridge; WS, watershed line; X, volar radial tuberosity; (with permission from http://eradius.com/AnatomyOfDistalRadius.htm ³ ).