A surgical instrument having a handle, elongate shaft protruding from handle and end-effector located at end of shaft is described. To allow for rotation of the end-effector the shaft is connected to a rotation wheel mounted on handle, towards rearward end of handle proximal to the user. The rotation wheel is in the form of a thumbwheel, having an ergonomically designed shape that tapers from distal direction to proximal direction, with angle of the taper matching angle of the outer surface of the handle. The outer tapered surface of the thumbwheel has a number of shaped cut-out or scalloped portions arranged around the outer circumference of the wheel, and arranged in use to receive the tip of a user's thumb to allow the user to rotate the wheel in order to set the rotational orientation of the end-effector. Such an arrangement provides a comfortable and easy to use instrument.
