A polyaxial bone an choring device is provided including an anchoring element (2) having a shaft (3) for anchoring in a bone and a head (4)； a receiving part (5) having a top end (51) and a bottom end (52), a channel (56) for receiving a rod therein and a passage (53) extending from the top end (51) to the bottom end (52) and including a seat (54) for receiving the head (4)； a pressure element (6) which is arranged in the passage (53) and configured to exert pressure onto the head (4), wherein the head is pivotable with respect to the receiving part (5) and can be locked at an angle by means of the pressure element (6)； the pressure element (6) comprising at least one recess (600a, 600b； 610a, 610b； 620a, 620b) facing the inner wall of the receiving part； the receiving part comprising at least one protrusion (502a, 502b) provided at its inner wall, and wherein, when the pressure element is inserted into the receiving part and rests on the head, the protrusion (502a, 502b) engages the lower edge (601a, 601b； 611a, 611b； 621a, 621b) such that by the engagement a force is exerted by the pressure element onto the head (4) to maintain the head at an angular position by friction before locking the head.本案提供一種多軸式骨骼固定裝置，包含固定元件(2)，有固定於骨骼之軸部(3)，和頭部(4)；容納件(5)，有頂端(51)和底端(52)，容納桿件之凹槽(56)，以及從頂端(51)延伸至底端(52)之通道(53)，含有底座(54)，以容納頭部(4)；壓力元件(6)，配置於通道(53)內，構成對頭部(4)施壓，其中頭部可相對於容納件(5)樞動，並可利用壓力元件(6)鎖定在一角度；壓力元件(6)包括至少一凹部(600a,600b；610a,610b；620a,620b)，面朝容納件之內壁；容納件包括設在其內壁之至少一凸部(502a,502b)，當壓力元件插入容納件內，定置於頭部時，凸部(502a,502b)即結合於下緣(601a,601b；611a,611b；621a,621b)，在結合時，利用壓力元件施力於頭部(4)，在鎖定頭部之前，利用摩擦，維持頭部於一角度位置。
