PROBLEM TO BE SOLVED: To provide a lug screw which can be assembled in only one of screw-in directions in a short period of time without the need for special expertise, and which enables the connection and disconnection of a bone to be easily and stably performed without looseness by a relatively weak force.SOLUTION: In a structure for assembling a nail and a lug screw by a screw-in operation, the lug screw has a tip provided with a double thread screw with high stationary stability and a double-sided cutting edge for screw-in and unwinding, has a rear end surface provided with three or more leaf-shaped thread-stripping-prevention concave grooves for a screw-in tool, and has the master screw function of coupling the nail and a thin-walled sleeve by a square screw. Furthermore, a structure for screwing the thin-walled sleeve to the lug screw by a connector and caulking-engaging the connector to the nail is provided.COPYRIGHT: (C)2014,JPO&INPIT【課題】特殊な専門技術を必要とせずに、短時間にねじ込み方向の一方向だけで組付けでき、容易に比較的小さい力で、緩みなく安定的に骨の接合と脱着ができるラグスクリュウを提供すること。【解決手段】ねじ込みによりネイルとラグスクリュウとを組付ける構造にあって、ラグスクリュウが先端に静止安定性の高い二条ねじとねじ込みと巻き戻しのための両面刃先と後端面にねじ込み工具のためのナメ防止の三つ葉以上の葉形凹面溝を備えると共に、ネイルと薄肉スリーブを角形ねじ結合するマスタースクリュウ機能を備え、さらにラグスクリュウに対して薄肉スリーブをコネクターでねじ止めしてさらにコネクターをネイルにカシメ係合する構造を備えることを特徴とする。【選択図】図7
