Through an anatomical and biochemical study, utilizing sixty-five cadaver specimens, the extensor retinaculum of the wrist was examined. It is a complex variable fibrous structure, whose functions are to prevent dorsal bowstringing of the extensor tendons and to prevent radial and ulnar displacement of extensor tendons. We recommend that a portion of the extensor retinaculum be preserved or reconstructed at the time of dorsal wrist surgery.