A receiving part for coupling a bone anchor to a rod is provided, wherein the bone anchor includes a shank (2, 2) for anchoring in a bone or a vertebra, the receiving part (3, 3, 3", 3, 30, 30, 30", 30) including a first end (3a) and a second end (3b), the second end (3b) being connected to the shank (2, 2), a bore (7) extending from the first end (3a) into the receiving part for receiving a fixation device (9), the bore having a bore axis (C), a recess (4, 4, 4") for receiving a rod (100, 1000), the recess being open at the first end (3a) of the receiving part for allowing insertion of the rod, wherein when a rod is inserted into the recess a longitudinal axis of the rod extends substantially perpendicular to the bore axis (C), wherein the recess (4, 4, 4") comprises opposing sidewalls (4b) on at least one side of the bore (7) characterized in that a resilient retention element (40, 400, 400, 400", 400) is provided on at least one of the opposing sidewalls (4b), wherein the resilient retention element is deflectable toward the at least one side wall (4b) when the rod (100, 1000) is inserted.一種聯結骨骼固定器於桿件用之容納件,其中該骨骼固定器包含一幹部(2,2),供固定於一骨骼或一椎骨,該容納件(3,3,3",3,30,30,30",30)包含一第一端(3a)和一第二端(3b),該第二端(3b)係連接於該幹部(2,2);一腔孔(7),從該第一端(3a)延伸進入該容納件內,供容納一固止裝置(9),該腔孔具有一腔孔軸線(C);一凹部(4,4,4"),供容納一桿件(100,1000),該凹部係在該容納件的該第一端(3a)開口,容許桿件插入,其中當一桿件插入該凹部內時,該桿件之一縱軸線,即實質上垂直於該腔孔軸線(C)延伸,且其中該凹部(4,4,4")包括對立側壁(4b),在該腔孔(7)之至少一側;其特徵為在該對立側壁(4b)至少其一,設有彈性扣持元件(40,400,400,400",400),其中該桿件(100,1000)插入時,該彈性扣持元件即朝向至少一側壁(4b)折曲。1‧‧‧骨骼固定裝置2‧‧‧幹部3‧‧‧容納件4‧‧‧凹部4a‧‧‧凹部底4b‧‧‧側壁5,6‧‧‧股部7‧‧‧腔孔8‧‧‧陰螺紋9‧‧‧固止元件40‧‧‧彈性扣持元件41‧‧‧凹部100‧‧‧桿件C‧‧‧腔孔軸線L‧‧‧桿件縱軸線
