Provided is a medical screw which can be readily extracted from bones after fusion of bone fractures or at replacement of the screw. The medical screw 11 has a screw thread 11b extending on the outer surface of a distal end portion of the screw 11 and an inner reverse thread extending on the inner surface of a proximal end portion 11d of the screw 11 and made in the opposite direction to the thread direction of the screw thread 11b. An outer reverse thread at a distal end portion of the removal jig 17 is engaged with the inner reverse thread of the screw 11, while being rotated in the opposite direction to the thread direction of the screw thread 11b. This engagement integrates the screw 11 with the removal jig 17. The removal jig 17 is then rotated in the opposite direction to the drilled direction of the screw 11 to detach the screw thread 11b of the screw 11 from the bone fractured region D.【課題】 骨が癒合した後又は交換するときに、捩じ込んだ骨内から容易に抜去できる医療用スクリューを得る。【解決手段】 医療用スクリュー11の先端部の外表面にスクリューねじ部11bを設け、後端部11d側にスクリューねじ部11bと逆ねじ方向に刻設した逆内ねじ部とを設け、この逆内ねじ部に抜去操作治具17の先端部に刻設した逆外ねじ部をスクリューねじ部11bのねじ方向と逆方向に回動して螺合させることにより、スクリュー11と抜去操作治具17とを一体化し、スクリュー11を捩じ込み方向と逆方向に抜去操作治具17を回転させることで、スクリュー11のスクリューねじ部11bを骨折部位Dから抜去する。【選択図】 図11
