THE INVENTION RELATES TO AN OSTEOSYNTHESIS DEVICE COMPRISING A PLATE (10) AND MEANS FOR FIXING A PIN (20) THAT EXTENDS THROUGH THE PLATE, IN WHICH THE PLATE (10) INCLUDES A RECESS (12) FOR RECEIVING THE FIXING MEANS AND THE RECESS DEFINES AN INNER EDGE (22), SAID FIXING MEANS COMPRISING A RING (14) DESIGNED TO RECEIVE THE PIN (20) AND SCREWABLE LOCKING MEANS (32). ACCORDING TO THE INVENTION, THE PLATE (10) HAS A THREADED OPENING (26) ON THE EDGE OF THE RECESS (12), WHICH OPENS INTO THE INNER EDGE (22), WHILE THE RING (14) IS SLIT RADIALLY. THE SCREWABLE LOCKING MEANS COMPRISE A SCREW (32) THAT CAN BE SCREWED THROUGH THE THREADED OPENING (26) SO AS TO BEAR AGAINST THE RING (14) AND CAUSE THE RING (14) TO BEAR WITH FORCE AGAINST A PORTION OF THE INNER EDGE (22) AND TIGHTEN THE RING (14) ON THE PIN (20).
