An arrangement where surgical instrument having shaft with end effector mounted thereon is provided with rotation wheel to allow user to rotate shaft during use into desired angular position. To allow compact and reliable mechanism the rotation wheel, outer edge of which is generally accessible at external surface of instrument, has internal space around axis of wheel within which is provided part of actuation mechanism for end effector. To allow rotation of actuation mechanism with end effector, part of actuation mechanism located within wheel rotationally mutually engages with inner surface of internal space within wheel, wherein rotation of wheel by user causes actuation mechanism to rotate, which in turn rotates shaft wherein end effector is mounted. Providing benefits allowing otherwise redundant space within rotation wheel to accommodate part of actuation mechanism for end effector, improving compactness of device, whilst still allowing rotation of end-effector and its corresponding actuation mechanism.
