An instrument for holding and inserting a bone anchor into the bone, in particular for use with a pedicle screw, is provided, wherein the bone anchor (100) comprises a shank (101) for anchoring in the bone and a head (102)； the instrument comprising a holding member (2) for holding the head (102) of the bone anchor, the holding member (2) comprising at least two arms (25a, 25b) that are configured to at least partially encompass the head (102) of the bone anchor and wherein the at least two arms (25a, 25b) comprise an inner surface forming a seat (26) for the head； a drive shaft (1) for engaging the head (102) of the bone anchor, the drive shaft (1) defining a longitudinal axis (L) of the instrument； and a displacement member (3) that is configured to act onto the holding member (2) such that the holding member (2) can assume a first configuration in which it is configured to permit the head to enter the seat (26) and a second configuration in which it is configured to hold the head in the seat (26)； characterized in that； the drive shaft (1) comprises an abutment surface (14a) for the head and that the seat (26) is provided at such an axial position of the holding member (2) relative to the drive shaft (1) that an inserted head (102) is pressed against the abutment surface (14a) in the second configuration.本案提供一種把持骨骼固定器並插入骨骼所用儀器，尤指使用於椎腳螺釘，其中該骨骼固定器(100)包括一幹部(101)，供固定於該骨骼，和一頭部(102)；該儀器包括：一把持構件(2)，供把持該骨骼固定器之該頭部(102)，該把持構件(2)包括至少二臂部(25a,25b)，構成至少部份包圍該骨骼固定器之該頭部(102)，且其中至少二臂部(25a,25b)包括一內表面，形成該頭部用之底座(26)；一驅動軸(1)，供結合該骨骼固定器之該頭部(102)，該驅動軸(1)界定該儀器之一縱軸線(L)；一位移構件(3)，構成作用於該把持構件(2)，使該把持構件(2)可呈一第一組態，構成容許該頭部進入該底座(26)，和呈一第二組態，構成把該頭部把持於該底座(26)內；其特徵為，該驅動軸(1)包括該頭部之一支座表面(14a)，而該底座(26)係設在該把持構件(2)相對於該驅動軸(1)之一軸向位置，使得在該第二組態時，把一插入頭部(102)壓緊於該支座表面(14a)。
