Patent ID: 7951179

Claim:
A bone attachment screw for use with a bone plate in a bone having an outer wall comprising an elongate shaft having a proximal portion and a distal portion and a central portion intermediate the proximal and distal portions, the shaft having external threads formed by a raised helical ridge with an outer diameter and a recessed helical base with an inner diameter extending between adjacent portions of the helical ridge, a head joined to the proximal portion of the shaft, the outer diameter of the helical ridge being substantially constant along the shaft and the inner diameter of the base at the proximal portion and the distal portion tapering inwardly as such portions extend away from the head and the inner diameter of the base at the central portion being substantially constant whereby the tapered inner diameter at each of the proximal and distal portions of the shaft is adapted to extend into the outer wall of the bone when securing the bone plate to the bone and serves to enhance the pullout force of the screw in the outer wall of the bone.