Abstract: A spinal fusion implant comprises a rigid hollow elongate member for insertion in a direction parallel to the longitudinal extent of the member between the vertebrae of a human spine, the rigid member having a height (when considered in an use implanted position with a patient's spine vertical) greater than its width w so that the member can be inserted between the two vertebrae and then displaced angularly through 90° to an in use position. The member has a body portion which has a plurality of apertures for allowing bone growth inducing material introduced into the hollow member to extend therethrough and a plurality of arcuate teeth which bite into the vertebrae when the member is in an in use position.