In one aspect, an anchor may include a threaded body, and a coaxial nut, wherein the anchor has a driving mode and an anchoring mode with the nut drawn rearwardly into the body by a threaded fastener to open the body radially outwardly. In another aspect, a one-piece self-drilling anchor includes a generally cylindrical threaded body with a pair of diametrically opposed inverted Y-shaped slits each having a generally axial slit and an inverted V-shaped pair of slits, a nut having splines for engage a threaded fastener, a pair of diametrically opposed inverted V-shaped wedges that are demarcated from the body by the V-shaped slits so that the body is relasably connected to the body, and a generally flat V-shaped drill tip. In still another aspect, a self-drilling anchor includes a threaded body that forks into a pair of diametrically opposed legs, a coaxially nut having splines for engaging a threaded fastener and a pair of diametrically opposed wedges, wherein when in the driving mode the wedges are connected between the legs to form a generally cylindrical portion, and wherein when in the anchoring mode the nut is drawn rearwardly into the body by the threaded fastener to pivot the legs radially outwardly.