Point A revisited.

Point A cannot be accurately identified in all cephalometric radiographs. In instances where this landmark is not clearly discernible, an alternative means of estimating the anterior extremity of the maxillary base is shown. A point plotted 3.0 mm. labial to a point between the upper third and lower two thirds of the long axis of the root of the maxillary central incisor was found to be a suitable point (estimated point A) through which to draw the NAE line and one which most closely approximates the true NA plane.