Osteosynthesis system comprising means for straightening a bone anchoring element relative to a screw head and anchoring screw implemented in such a system

摘要

The invention concerns an osteosynthesis system comprising at least one anchoring screw (1) for a vertebra comprising a bone anchoring element (2) and a screw head, the anchoring element comprising a threaded rod (4) and a coupling head (5) for coupling with the screw head, the screw head comprising a body (30) traversed longitudinally by a channel (7) having, in the lower portion, a receiving cavity for receiving the coupling head (5). The receiving cavity comprises a first area and a second area communicating with each other and having a cross-section that increases and decreases respectively towards the anchoring element, and a third area communicating with the second area and arranged with the latter in order to allow the displacement of the screw head on the coupling head (5) which comprises a contact portion having a shape matching that of the second area.