A method of radiographing target pins in a known repeatable position was devised so that the outline of the focal area in the panoramic radiograph unit could be delineated. A pin-holding device was so designed that target pins could be moved across the area of focus in three parallel planes. A series of 52 exposures was made with the target pins in various positions. Two dentists, whose evaluations previously had been standardized, determined which target pin images on the radiographs were in focus. A grid system was used to record those images that were considered in focus. Outlines of the area of focus were obtained in three horizontal planes within the target area. These outlines reveal a horseshoe configuration that permits a comparison with anatomic placement and dimension. Little difference in the configuration of the outline was found in the three planes examined.