A polyaxial bone anchoring device is provided comprising a bone anchoring element (1) having a shank (2) to be anchored in the bone and a head (3) a receiving part (5) coupled to the shank and configured to pivotably receive the head, and having a channel (56) for receiving a rod (6) and a central axis (C) a pressure member (7,7) arranged in the receiving part and configured to exert pressure onto the head to lock the head in the receiving part a locking member (8,8) that is insertable into the channel, the locking member comprising a top end (81) and a bottom end (82) facing the pressure member wherein the pressure member (7,7) has a deformable portion (77,78 76,107a,107b) and wherein, when the locking member (8,8) is advanced into the channel in the direction of the central axis (C), first the locking member (8,8) contacts the pressure member (7,7) resulting in a load applied to the pressure member that clamps the head (3), and thereafter the locking member (8,8) contacts the pressure member (7,7) such that the deformable portion (77,78 76,107a,107b) is deformed and the locking member comes into contact with the rod and clamps the rod (6).本案提供一種多軸式骨骼固定裝置,包括骨骼固定元件(1),具有要固定於骨骼之幹部(2),和頭部(3);容納件(5),聯結於幹部,構成可樞動容納頭部,並有容納桿件(6)用之槽溝(56),以及中心軸線(C);壓力構件(7,7),配置在容納件內,構成對頭部施壓,把頭部鎖定於容納件內;鎖定構件(8,8),可插入於槽溝內,鎖定構件包括頂端(81),和朝向壓力構件之底端(82);其中壓力構件(7,7)具有可變形部(77,78;76,107a,107b);且其中,當鎖定構件(8,8)按中心軸線(C)方向推進入槽溝內,先是鎖定構件(8,8)接觸到壓力構件(7,7),造成施於壓力構件之負載,並夾持頭部(3),然後是鎖定構件(8,8)接觸壓力構件(7,7),使可變形部(77,78;76,107a,107b)變形,而鎖定構件即與桿件接觸,並夾持桿件(6)。1‧‧‧骨骼固定元件2‧‧‧幹部3‧‧‧頭部4‧‧‧凹部5‧‧‧容納件6‧‧‧桿件7‧‧‧壓力構件8‧‧‧鎖定構件51‧‧‧容納件頂端52‧‧‧容納件底端53‧‧‧腔孔56‧‧‧U形凹部57,58‧‧‧股部59‧‧‧陰螺紋71‧‧‧壓力構件頂端72‧‧‧壓力構件底端76‧‧‧凹部77,78‧‧‧壁部C‧‧‧中心軸線
