Polyaxial bone anchoring device including an anchoring element (1) having a shank (2) for anchoring in the bone and a head (3) a receiving part (5, 5 , 5 ) for coupling a rod (6) to the bone anchoring element (1) including the receiving part a housing portion of rod (9, 9 , 9 ) having a first end (9a) and a second end (9b) and a recess (12) with a bottom for receiving the rod ( 6) therein, a part of head housing (19, 19 , 19 ) having a first end (19a) and a second open end (19b) with a delimiting edge and an interior hollow (23) communicating with the second open end (19b) for the head (3), the flexible housing portion to allow insertion head and immobilization of the head (3) a locking ring (8) mounted around part of head housing (19) being the head (3) rotatable in the head housing part and lockable at an angle by compressing part of the head housing (19) by means of the locking ring (8) delimiting edge being configured such that allows the anchoring element (1) rotate at an angle of greater spin on a first anchor edge (19c) in a second location thereof and the part of head housing (19, 19 , 19 ) pivotally connected to the housing portion of rod (9, 9, 9 ) being characterized in that the housing part of head (19 , 19 , 19 ) includes multiple slots (24) are open to the second end (19b), wherein the part of head housing (19, 19, 19 ) having a 20 flexibility and a size such that the locking ring (8) can be mounted from the open end (19b) of the head accommodation portion.Dispositivo de anclaje óseo poliaxial, que incluye un elemento de anclaje (1) que tiene un vástago (2) para anclarlo en el hueso y una cabeza (3) una pieza de alojamiento (5, 5, 5) para acoplar una varilla (6) al elemento de anclaje óseo (1) incluyendo la pieza de alojamiento una parte de alojamiento de varilla (9, 9, 9) que presenta un primer extremo (9a) y un segundo extremo (9b) y un entrante (12) con un fondo para alojar la varilla (6) dentro del mismo, una parte de alojamiento de cabeza (19, 19,
