Locking Element for a Polyaxial Bone Anchor, Bone Plate Assembly and Tool

摘要

A locking element is configured to be used with a polyaxial bone anchor. The locking element including a central axis, a bottom side, a top side opposite to the bottom side, and a peripheral surface portion that extending completely around the locking element that has an external thread. The bottom side defines a first recess facing toward the bottom side for accommodating and applying a force in a direction toward the bottom side to at least the portion of the head of the polyaxial bone anchor. The top side defines a second recess having a non-circular cross-section in a plane perpendicular to the central axis for torqueable engagement with a driver.