Bone anchoring device including a bone anchoring element (1) having a shaft (2) for anchoring in the bone and a head (3) a receiving part (5) for coupling a rod (6) to the bone anchoring element, wherein the receiving part comprises a rod receiving portion (9) with a first end (9a) and a second end (9b) and a channel (12) with a bottom for receiving the rod, and a head receiving portion (16) at the side of the second end (9b) for accommodating the head (3), the head receiving portion having a free end (17) and being flexible so as to allow introduction and clamping of the head a locking ring (8) embracing the head receiving portion (16) wherein the head (3) is locked by compressing the head receiving portion (16) with the locking ring wherein the rod receiving portion (9) comprises two cutouts (24) which extend on either end of the channel from the bottom to the second end (9b) and wherein the locking ring has two projections (81, 83) located diametrically opposite to each other which extend through the cutouts (24) into the channel (12) when the locking ring is in a position in which the head is not locked characterized in that a first engagement portion (83, 85) is provided at the locking ring that engages a second engagement portion (25) at the inner wall of the channel to hold the locking ring in a position in which the head is pivotable in the head receiving portion and is prevented from removal therefrom.本案係關於一種骨骼固定裝置,包含骨骼固定元件(1),具有固定於骨骼用之幹部(2),和頭部(3);容納件(5),把桿件(6)聯結於骨骼固定元件,其中容納件包括桿件容納部(9),有第一端(9a)和第二端(9b),並有凹槽(12),其底部可供容納桿件,以及頭部容納部(16),在第二端(9b)側包容頭部(3),頭部容納部有自由端(17),呈撓性,得以引進和夾持頭部;鎖環(8),包圍頭部容納部(16);其中頭部(3)係藉鎖環壓縮頭部容納部(16)加以鎖定;其中桿件容納部(9)包括二缺口(24),在凹槽的任一端,從底部延伸到第二端(9b),又其中鎖環有二凸部(81,83),位於彼此徑向對立,當鎖環在頭部未被鎖定位置時,延伸貫穿缺口(24)進入凹槽(12)內;其特徵為,鎖環設有第一結合部(83,85),與凹槽內壁的第二結合部(25)結合,把鎖環保持在一位置,使頭部可在頭部容納部內樞動,而防止其脫出。1...骨骼固定元件2...螺紋幹部3...頭部4...凹部5...容納件6...桿件7...封閉元件8...鎖環8c...圓筒部9...桿件容納部9a...第一端9b...第二端12...U形凹部13...陰螺紋15...共軸開縫16...頭部容納部20...開縫20a...開縫24...缺口25...突部81...凸部82...凸
