A bone anchor is provided comprising an anchor member (1, 1) having an open first end (11) and a second end (12) and an tubular section (13) between the first end (11) and the second end (12), a longitudinal axis (L) extending from the first end to the second end, and a bone engagement structure (16) for engaging the bone in at least a portion of the tubular section (13) wherein the anchor member (1) is made of a first material a core member (2, 2) having a first end (21) and a second end (22) and being insertable into the anchor member and connectable thereto wherein the core member (2) is made of a second material that is different from the first material.本案提供一種骨骼固定器,包括固定器構件(1,1),有開口第一端(11)和第二端(12),以及介於第一端(11)和第二端(12)間之管狀段(13),從第一端延伸至第二端之縱軸線(L),還有骨骼結合結構(16),供骨骼結合於管狀段(13)之至少一部份;其中固定器構件(1)係由第一種材料製成;芯部構件(2,2),有第一端(21)和第二端(22),可插入固定器構件內,加以連接;其中芯部構件(2)係由與第一種材料不同之第二種材料製成。1‧‧‧固定器構件2‧‧‧芯部構件3‧‧‧頭部11‧‧‧固定器構件第一端12‧‧‧固定器構件第二端15‧‧‧開縫16‧‧‧骨骼螺紋17‧‧‧凹部21‧‧‧芯部構件第一端22‧‧‧芯部構件第二端23‧‧‧桿狀中央部24‧‧‧尖部24a‧‧‧尖部基座25‧‧‧圓筒形部26‧‧‧導部26a‧‧‧斜面部31‧‧‧結合部32‧‧‧球形表面部34‧‧‧頸部34a‧‧‧凸部
