Patent ID: 7517182

Claim:
A screw anchor comprising: a deformable central portion in which main longitudinal slots are formed, the main longitudinal slots each being formed in a plane, extending essentially parallel to a plane on which a longitudinal axis of the screw anchor lies, and defining deformable main longitudinal anchoring tongues which lie on opposite sides of the plane and which have a substantially serrated profile; secondary longitudinal through slots formed in the same central portion, the secondary slots each being formed in a plane, essentially parallel with the planes of the main longitudinal slots and having a length which is different from the length of the main longitudinal slots, and wherein said secondary longitudinal slots, define, with an adjacent main longitudinal slot, deformable secondary longitudinal anchoring tongues, the main longitudinal slots and the secondary longitudinal slots being non-equidistantly arranged about the periphery of the screw anchor.