Three purposes of this study were to: 1) describe the sustentaculum tali in relation to surrounding structures, 2) identify its radiographic projection onto the lateral calca neus, and 3) determine optimal angles for screw placement. Twelve cadaver specimens were used. The length a width of the sustentaculum was measured. Its midpoint was measured from surrounding anatomic landmarks. A point on the lateral calcaneal wall "point A" was chosen. This marks the intersection of two lines bisecting the midpoint of the posterior facet and the lateral calcaneal height. The angles required to pass a pin from point A into the sustentaculum were determined. The sustentaculum projected as a triangular/elliptical structure on the lateral radiograph. It was superimposed on the anterior portion of the posterior facet.