The instrument has a handle (13) at the proximal end of a shaft (12) of the instrument which is used to operate the removable instrument head (10) which fixed to the distal end of the shaft by means of a coupling mechanism (14). The coupling mechanism on the instrument head comprises an `L' shaped slot (15) in which a pin (16) fixed to the shaft engages.The various instrument heads are held in a magazine which is located at a convenient place for the surgeon. The magazine has a funnel shaped entrance to allow for easy insertion of the shaft by the surgeon. The magazine can be mounted on a frame or held by a handle. The instrument heads can be extended so that they in turn are formed as removable shafts that are located in the magazine. These removable shafts lock onto the operating handle with a similar coupling mechanism.
