COUPLING ASSEMBLY FOR COUPLING ROD TO BONE ANCHORING ELEMENT, AND POLYAXIAL BONE ANCHORING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a coupling assembly for coupling a rod to a bone anchoring element, and a polyaxial bone anchoring device.SOLUTION: A coupling assembly (4) comprises: a receiving part (5) having a first end (5a), a second end (5b) and a central axis (C); a recess (52) for receiving a rod (100); an accommodation space (54) for accommodating a head (3) and having a bore (51) extending from the accommodation space (54) to the first end (51); a retainer element (6) configured to be positioned at least partially in the accommodation space (54) and sized so as to at least partially encompass an inserted head (3); and a spring element (7) configured to be arranged at least partially in the accommodation space (54). The spring member (7) is configured to be compressed in the axial direction, and has such a length in the axial direction that it can be engaged by the inserted rod when the retainer element (6) and the spring element (7) are arranged in the accommodation space (54).