Patent ID: 9131971
Filing Date: 2015-09-15
Classification: A61B

Abstract:
1. A polyaxial bone anchoring device comprising: a bone anchoring element having a shank for anchoring to a bone and a head; a head receiving part having a first end, an open second end with a bounding edge, and a hollow interior portion in communication with the open second end for receiving the head therein, the head receiving part being flexible for clamping the head; a locking ring configured to be mounted around the head receiving part and to be movable from a first position to a second position closer to the second end of the head receiving part, wherein a compressive force applied by the locking ring on the head receiving part is greater at the second position than at the first position, the locking ring having a rod receiving portion; a cap configured to be connected to and engage the head receiving part; and a locking element configured to extend from the cap to engage an inserted rod, wherein when the head is in the head receiving part, and the locking ring and the cap are connected to the head receiving part, the head is pivotable in the head receiving part, the cap engages the head receiving part, and the cap and the locking ring are rotatable relative to the head receiving part, and wherein when the locking element is tightened, an inserted rod and an angular position of the bone anchoring element are locked relative to the head receiving part.