US Patent 8080044 Bone anchoring device

A bone anchoring device includes a shaft for anchoring in a bone and a head, the shaft including a first section having a plurality of barb elements, the barb elements being elastically deformable relative to the body of the shaft, and a second section including a bone thread for engagement with the bone. The first section is located near the tip of the shaft and allows insertion by pushing whereas the second section provides enhanced resistance against pull-out.