| 摘要 |
<p>PROBLEM TO BE SOLVED: To specify a bone screw that can make a larger rotational angle. SOLUTION: The bone screw is provided with a screw member (1) equipped with a screw thread (2) and a head (3), and a receiving part (5) at the head end to receive a rod to be connected to the bone screw. The receiving part (5), having a first opening bore (6), is a U-shaped cross section materially with two treaded free legs. Furthermore, the receiving part has a second bore at the end in opposition to the first bore (6). The diameter of the second bore is larger than that of the screw thread (2) and smaller than that of the head (3). A bearing surface for the head (3) is provided on the bottom of the first bore. An edge, bounding with the free end of the second bore, is an unsymmetrical structure in the view of the axial center line of the first bore (6) so that the screw thread can rotate with a spread angle to at least one side.</p> |
