A polyaxial bone anchoring device including an anchoring element (1) having a shaft (2) for anchoring in the bone and a head (3), the head having a spherically-shaped outer surface portion (3a) a receiving part (4, 4, 4") pivotably connected to said head (3), the receiving part having a top end (4a) and a bottom end (4b), a longitudinal axis (C) extending through the top end and the bottom end, a transverse channel (9) for receiving a rod (100) and an accommodation space (11, 11, 11") for accommodating the head (3), the accommodation space (11, 11) having a lower opening (12) at the bottom end (4b), a sleeve-like insert piece (5) encompassing a portion of the head (3) having an outer spherical surface portion (51) and being configured to pivot in the receiving part, wherein a lower edge (5b) of the sleeve-like insert piece (5) extends through the lower opening (12) when the sleeve-like insert piece is seated in the receiving part in a position in which its sleeve axis (5c) is coaxial with the longitudinal axis (C) a pressure member (6, 6, 6", 6), the pressure member being arranged at least partially in the accommodation space (11, 11, 11"), wherein the pressure member has a lower surface portion (61) that contacts the head (3) to exert pressure onto the head wherein the anchoring element (1) is pivotable with respect to the receiving part (4, 4, 4") and can be locked at an angle by exerting pressure with the pressure member (6, 6, 6", 6) onto the head (3) to lock the head and the sleeve-like insert piece (5) simultaneously in the receiving part.一種多軸式骨骼固定裝置,包含固定元件(1),有幹部(2),供固定於骨骼內,和頭部(3),頭部有球形外表面部(3a);容納件(4,4,4")樞動連接於該頭部(3),容納件有頂端(4a)和底端(4b),縱軸線(C)延伸貫穿頂端和底端,橫溝(9)可容納桿件(100),和包容空間(11,11,11")可包容頭部(3),包容空間(11,11)在底端(4b)有下方開口(12),套筒般插件(5)包圍頭部(3)之一部份,有球形外表面部(51),構成在容納件內樞動,其中當套筒般插件(5)定座於容納件內,在其套筒軸線(5c)與縱軸線(C)共軸時,套筒般插件(5)之下緣(5b)即延伸貫穿下方開口(12);壓力構件(6,6,6",6),係至少部份配置在包容空間(11,11,11")內,其中壓力構件有下方表面部(61),與頭部(3)接觸,對頭部施壓;其中固定元件(1)可相對於容納件(4,4,4")樞動,藉壓力構件(6,6,6",6)施壓於頭部(3),而鎖定在一角度,把頭部
