An instrument (12) for assembling a bone anchoring device (11) is provided. The device includes a shank (2), which has a shaft section (21) to be anchored in a bone and a engagement end (22), a head (3) being separate from the shank (2) and having a through-hole (32) extending therethrough, and a receiving part (4) having a first end (41), a second end (42) and a longitudinal bore (48) extending from the first to the second end, the head (3) being positionable within that bore (48) at the second end. The instrument (12) comprises: a holding portion (9) arranged to hold a pin (8), which has a rod section (81) with a length and a diameter suited to fit and extend at least through the bore of the head (3), and which has a free end portion (82) extending from the rod section (81) such as to project from the through-hole (32) of the head when the pin is inserted, and configured to engage with the engagement end (22) of the shank. In one specific embodiment, the instrument further has a spring force means (10), wherein the pin (8) further comprises: a support section (85) that is adapted to move with respect to the holding portion (9) along a longitudinal axis of the pin (8) against a resilient force due to the spring force means (10).本案提供一種組裝骨骼固定裝置(11)用之器具(12)。此裝置包含幹部(2),有要固定於骨骼內之軸段(21),和結合端(22);頭部(3),與幹部(2)分開,有延伸穿過之貫穿孔(32);以及容納件(4),有第一端(41)、第二端(42),和從第一端延伸至第二端之縱向徑孔(48),頭部(3)可在第二端定位於徑孔(48)內。器具(12)包括:保持部(9),配置來保持銷(8),有桿段(81),其長度和直徑適於套合並延伸至少穿過頭部(3)之徑孔,且具有自由端部(82),在銷插入時,從桿段(81)伸出,諸如從頭部之貫穿孔(32)突出,其造型係與幹部之結合端(22)結合。在一特別具體例中,器具又有彈力機構(10),其中銷(8)又包括:支持段(85),適於沿銷(8)之縱向軸線,運動保持部(9),對抗彈力機構(10)之彈性力。2...幹部3...頭部4...容納件5...壓力元件7...部份開口環8...銷9...保持部10...彈力機構11...骨骼固定裝置12...器具21...螺紋部22...結合端23...端面24...凹溝25...徑向徑孔31...球形外表面32...徑孔33...隙縫34...沿周凹溝41...容納件第一端42...容納件第二端43...開口44,45...股部46...U形凹部47...陰螺紋48...縱向徑孔51...球形表面52...中心徑孔81...桿段82...自由端部83...過渡部84...尖端85...支持段86...止動部91...支持徑孔92...陽螺紋101...蝸形彈簧
