The atlas and axis from 52 cadavers, 33 male and 19 female were measured from the outer contour and microradiographs of sectioned samples. The vertical diameter of the anterior arch of the atlas was 11.3mm in men and 10.9mm in women. The height of the body of the axis was 38.1mm in men and 33.8mm in women. The angle between the axes of the dens and the lower surface of the body of the axis was 58.6 degrees in men and 57.1 degrees in women. An anterior buttress plate to prevent atlanto-axial subluxation was designed based on the measurements of this study.