PROBLEM TO BE SOLVED: To provide a medical drill, after forming a through-hole in a bone, inhibiting a cylindrical drill member 10 from damaging a tissue in the periphery of the bone.SOLUTION: A medical drill 100 for forming a through-hole in a bone, includes: a rotatable cylindrical drill member 10 a drive force transmission member 30 that transmits rotary driving force from a drive source to the cylindrical drill member 10 via a projection member 20 provided at an inner peripheral side of the cylindrical drill member 10, to rotate the cylindrical drill member 10 and a spring 34. When the cylindrical drill member 10 cuts the bone, the projection member 20, while compressing the spring 34 in a rotation axis direction, is engaged with the cylindrical drill member 10 to move to an engagement position for transmitting the rotary driving force, when the cylindrical drill member 10 penetrates through the bone, receives elastic force from the spring 34 in the insertion direction of the cylindrical drill member 10 to project from the through-hole and moves to a non-engagement position where no rotary driving force is transmitted to the cylindrical drill member 10.COPYRIGHT: (C)2016,JPO&INPIT【課題】骨に貫通孔を形成した後、円筒状ドリル部材10が骨の周りの組織を損傷することを抑制する。【解決手段】骨に貫通孔を形成する医療用ドリル100であって、回転可能な円筒状ドリル部材10と、円筒状ドリル部材10の内周側に設けられる突出部材20を介して、駆動源からの回転駆動力を円筒状ドリル部材10へ伝達して、円筒状ドリル部材10を回転させる駆動力伝達部材30と、スプリングバネ34と、を有し、突出部材20は、円筒状ドリル部材10が骨を切削する際、スプリングバネ34を回転軸方向に圧縮しつつ、円筒状ドリル部材10と係合して回転駆動力を伝達する係合位置に移動し、円筒状ドリル部材10が骨を貫通した時、円筒状ドリル部材10の挿通方向にスプリングバネ34から弾性力を受けて貫通孔から突出し、円筒状ドリル部材10に回転駆動力を伝達しない非係合位置に移動する。【選択図】図6
