Polyaxial bone anchoring device that includes an anchoring element (1) with a rod (2) for anchoring in the bone and a head (3), the head with a curved outer surface of greater outer diameter (E)； a receiving part (5) with an upper end (5a) and a lower end (5b), a channel (12) for accommodating a rod, a coaxial bore (51) extending from the upper end (5a) in the direction from the lower end (5b) and a seat (52) to accommodate the head at the lower end； a pressure element (6) disposed within the bore, a pressure element (6) having a contact surface (62, 63) that contacts the curved part of the outer surface of the head (3), the element being essentially cylindrical pressure (6), with an upper end (6a) and a lower end (6b) and having a spherical recess (62) at its lower end facing the head, whereby a contact (62, 63) with the head, and having the lower end (6b) at least two opposite grooves in a circumferential direction, whereby two opposite projections (63) extending downwards are provided: the head (3) being rotatable with with respect to the receiving part (5) and being able to be fixed at an angle by exerting pressure on the head by means of the pressure element (6), and the head being oversized in the curved part of the outer surface in relation to the contact part of the head (62, 6 3) so that a pressure joint is achieved that imprisons the head by friction between the part of the outer surface and the surface part in contact with the head, characterized in that the depth of the spherical recess (62) is such that the projections (63) extend beyond the area with the largest outside diameter (E) of the head (3) when the pressure element is mounted on the head (3).Dispositivo de anclaje óseo poliaxial que incluye un elemento de anclaje (1) con un vástago (2) para anclar en el hueso y una cabeza (3), la cabeza con una superficie exterior curvada de mayor diámetro exterior (E)； una parte receptora (5) con un extremo superior (5a) y un extremo inferior (5b), un canal (
