One aspect of the invention concerns a spinal midline indicator (10) which has a body (14) of radiolucent material for insertion between adjacent vertebrae (18, 20) and a radiographic marker (12) associated centrally with the body to indicate, in an A-P radiograph, the position of the spinal midline (22) when the body is centrally located between the vertebrae. The radiographic marker is typically an elongate handle which is connected to the body to facilitate placement of the body between the vertebrae and which is made of a radiographic material. In the preferred embodiment, the body also carries further radiographic markers (16) on opposite sides of and equidistant from the handle so that the handle indicates the position of the spinal midline when the body is placed centrally between the vertebrae and the second markers are seen in the radiograph to be equidistant from lateral edges of the vertebrae. Another aspect of the invention concerns the use of the midline indicator to identify the spinal midline.
