PROBLEM TO BE SOLVED: To provide a lug screw which can be fixed in a single direction of a screwing direction in a short time without requiring special dedicated techniques, and can easily achieve stable bonding and detaching of bones without causing loose with a relatively small force.SOLUTION: In a structure for fixing a nail 1 and a lug screw 4 by screwing them, the lug screw 4 includes a double thread screw having high static stability on the front end, a double sided edge for screwing and unscrewing on and three or more leaf-like concave surface grooves in the rear end surface to prevent thread strip for the screwing tool, and the lug screw further includes a locking screw 2 which splines the lug screw 4 to the sleeve 3 to smooth the movement in an axial direction, can be inserted in a bone by making the outer dimension of the spline smaller than the dimension of a valley of the double thread screw, has a shoulder portion for positioning with the sleeve and is fixed to the nail 1.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に固定でき、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1とラグスクリュウ4とを固定する構造にあって、ラグスクリュウ4が先端に静止安定性の高い二条ねじとねじ込みとねじ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形凹面溝を備えると共に、ラグスクリュウ4とスリーブ3をスプライン結合させて軸方向の動きを滑らかにし、二条ねじ部の谷径よりスプラインの外径を小さくして骨部に挿入でき、さらにスリーブとの位置決めのための肩部を有して、ネイル1に固定するロックねじ2を備える構造を特徴とする。【選択図】図4
