| 摘要 |
An anchoring member for anchoring in a bone is provided with a bone screw having a screw member (1) comprising a threaded portion (2) and a head (3) with a spherical segment shaped portion, and a seat part (5) for receiving the head (3) of the screw member and a rod (15) for connection with the bone screws, whereby the seat part (5) has a first end (6) and an opposite second end (7), an axis of symmetry (8) passing through the first and second end, a bore (9) for passing the threaded portion (2) therethrough, the bore being coaxial with the axis of symmetry, and a first region adjacent to said first end (6) having a substantially U-shaped cross-section with two free legs (11, 12) comprising an internal screw thread (13) for receiving the rod (15) therein, whereby the bore (9) conically tapers towards the second end (7) in a second portion (16) adjacent to the second end (7) with a cone angle and whereby a pressure member (20) embracing the screw head (3) from its side opposite to the threaded portion (2) is provided, the pressure member having an outer surface which conically tapers towards the second end (7) in a region (24) laterally surrounding the screw head (3), the cone angle corresponding to that of the portion (16) of the bore (9).
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