US Patent 7717947 Bone screw

A bone screw has a screw head and a threaded shank. An axial bore into which a plurality of radial bores set at a distance from each other open, extends through the threaded shaft. The axial bore is open at the screw head side end, and the radial bores are also open at the radially outer end. The axial bore is closed in an axial direction in the area of the end of the screw shank that lies opposite the screw head.