Patent ID: 8292932

Claim:
A bone anchoring element comprising: a shaft for anchoring in a bone, the shaft having a tubular body defined by a peripheral wall having a thickness, the peripheral wall defining an interior space of the tubular body extending along a shaft axis from a first end to a second end of the tubular body, wherein said shaft comprises a plurality of barb elements, wherein each barb element is formed as a continuous one-piece part with the tubular body; wherein each barb element is moveable between a first position adjacent to a surface of the tubular body and a second position farther from the surface of the tubular body than the first position to define an opening completely through the peripheral wall to the interior space of the tubular body; wherein each barb element comprises a base being a continuous one-piece part with the tubular body, opposing side walls extending from the base, and a free cutting edge opposite to the base relative to the side walls and extending between the side walls; and wherein the free cutting edges of the barb elements are inclined at an angle corresponding to a helical angle that extends for at least one full turn around the shaft axis such that after insertion of the shaft into a core hole, turning of the shaft in a first direction causes the shaft to be moved in an insertion direction deeper in the core hole, and turning of the shaft in a second direction causes the shaft to be moved in the core hole opposite to the insertion direction.