| 摘要 |
<p>A medical implant bone screw (10) having a shank (16) for implanting into a bone and a U-shaped head (15) with a pair of spaced and upward extending arms (18) forming a channel (19) adapted to receive a rod (12) therebetween and further including a closure member (11) for closing the channel (19) after the rod (12) is placed in the channel (19), the closure member (11) having a first form (2) that mates with helical forms (3) on interior facing surfaces of the arms (18), the forms (2, 3) having thrust surfaces (4, 5) that are outwardly non-linear and each have at least one bead portion that extends parallel to closure axis and that engages a matingly shaped portion of the opposite thrust surfaces so as to prevent radial movement of the thrust surfaces relative to one another and so as to resist splaying of the arms (18) relative to the closure member (11).</p> |
