A polyaxial bone anchoring device is provided including a bone anchoring element (1) comprising a head (3) and a shank (2) a receiving part (4, 4) for receiving a rod (100) for coupling the rod to the bone anchoring element, the receiving part comprising a first end (4a), an opposite second end (4b) and a central axis (C) extending through the first end and the second end, and a channel (9) for receiving the rod and an accommodation space (11) for receiving the head a pressure element (6, 6) arranged in the receiving part and configured to exert pressure onto the head wherein the pressure element (6) comprises flexible sections (66a, 66b) facing away from the head (3), characterized in that flexible sections (66a, 66b) comprise a free end portion (69a, 69b) with respect to the central axis (C) that cooperates with an inclined surface portion (15a, 15b) of the receiving part (4) such as to hold the pressure element (6) in a position in which it exerts a pre-load onto the head before the head is locked.本案提供一種多軸式骨骼固定裝置,包含:-骨骼固定元件(1),包括一頭部(3)和一幹部(2);-容納件(4,4),供容納一桿件(100),把該桿件聯結於該骨骼固定元件,該容納件包括一第一端(4a)、對立之一第二端(4b),以及延伸貫穿該第一端和該第一端和該第二端之一中心軸線(C);-槽溝(9),容納該桿件,和一包容空間(4),容納該頭部;-壓力元件(6,6),配置於該容納件內,並構成施壓於該頭部;其中該壓力元件(6)包括背離該頭部(3)之撓性段(66a,66b),其特徵為,該撓性段(66a,66b)包括相對於該中心軸線(C)之一自由端部(69a,69b),與該容納件(4)之一傾斜表面部(15a,15b)合作,保持該壓力元件(6)在一位置,於該頭部被鎖定之前,對該頭部施以預負載。1‧‧‧骨骼固定元件3‧‧‧頭部4"‧‧‧容納件4a‧‧‧容納件頂端4b‧‧‧容納件底端5‧‧‧套筒式插件6"‧‧‧壓力元件6a‧‧‧壓力元件第一圓筒部上表面8‧‧‧共軸腔孔8a‧‧‧共軸圓筒形腔孔部8b‧‧‧止動部9‧‧‧U形凹部10‧‧‧U形凹部自由股部陰螺紋11‧‧‧包容空間16‧‧‧切口部64‧‧‧共軸貫穿孔65‧‧‧淺凹部66a,66b‧‧‧彈性指桿
