| 摘要 |
<p>A multi-axial bone screw assembly (10) includes a bone screw (11) having a partially spherical head (22). The bone screw head (22) is truncated at an upper surface (24) in which a tool receiving recess (25) is defined. The assembly includes a receiver member (12) including a central bore (34) that defines a tapered recess (35) to receive the head (22) of the bone screw (11). The bore (34) of the receiver member also defines a channel (33) communicating with the recess (35) and configured to receive a spinal rod (R) therein. A portion (37) of the channel is threaded to receive a set screw (14) above the rod. The assembly (10) also includes a crown member (13) disposed between the rod (R) and the head (22) of the bone screw (11). As the set screw (14) is tightened into the receiver member (12), the set screw (14) compresses the rod (R) against the crown member (13), which presses the head (22) of the bone screw (11) into the tapered recess (35). In one embodiment, the head (22) of the bone screw (11) includes a flared edge (26) that penetrates at least the crown member (13) as the assembly (10) is tightened.</p> |
