Surgical cable tensioning instrument

A surgical instrument for applying tension to a cable for straightening a spinal column, said instrument having first and second hinged together at a main hinge, each handle having an extension beyond the hinge so arranged that movement about the hinge of the two handles toward one another causes the two extensions to move away from one another, wherein one extension has, at the end remote from the hinge, cable receiving means consisting essentially of a bifurcated arm defining a slot open at one end to receive a cable, and wherein the second extension has, at the end remote from the hinge, two jaws between which a metal cable can be gripped, the instrument having means to ensure that movement together of the two handles causes the jaws, if open, to close and movement away from one another of the two handles causes the jaws, if closed, to open prior to causing any movement of the two extensions relative to one another.