| 摘要 |
<p>A bone anchoring device is provided including an anchoring element (2) having a shaft (3) for anchoring in the bone and a head (4), a receiving part having a top end (51) and a bottom end (52), a recess (55) for receiving a rod therein, a coaxial bore (53) extending from the top end (51) in the direction of the bottom end (52) and a seat (54) for receiving the head near the bottom end; a pressure element (6) which is movable within the bore (53); wherein the head (4) is pivotable with respect to the receiving part (5) and can be fixed at an angle by exerting pressure via the pressure element onto the head, and wherein so the pressure element (6) has an outer wall portion with a recess (67a,67b) or a projection and wherein the receiving part (5) has an inner wall portion with a projection (59a, 59b) or a recess which cooperates with said recess (67a,67b) or projection of the pressure element; and wherein the pressure element can assume a first position (P 1 ) in which the recess (67a,67b) and the projection (59a, 59b) cooperate in such a way that the pressure element exerts a preload onto the head in which the head is prevented from freely pivoting but is not locked.</p> |
