A ratchet wrench for use in connection with medical instruments comprises a handle (1), a drive element (2) which is rotatable around an axis (M) with respect to the handle (1) and which is adapted to tighten or loosen a respective element and a ratchet mechanism (3) which is in connection with said drive element (2) and which permits movement with respect to the handle (1) in a first direction of rotation (R1) and blocks movement in the other direction of rotation (R2). Said handle (1) comprises a flat arm (4), wherein said ratchet mechanism (3) is arranged on a bearing surface (40) of said flat arm (4), and wherein said drive element (2) extends through an opening (41) in said flat arm (4) in which opening (41) said drive element (2) is arranged rotatable.
