Abstract: The invention relates to a retractor. The retractor comprises an elongate support member having a screw thread along at least part of its length and a first arm having a first anatomy engaging member depending therefrom. The retractor also comprises a second arm having a second anatomy engaging member depending therefrom and a threaded portion which cooperates with the screw thread to move the second arm along the support member. The retractor also comprises a driver operable to move the second arm along the support member by cooperation of the threaded portion and the screw thread whereby separation between the first and second arms changes. The retractor further comprises a bridging part attached towards a first end thereof to the first arm and attached towards a second, opposite end thereof to the second arm, the bridging part having a third anatomy engaging member depending therefrom.