Near-approach radiographic view to decrease likelihood of anterior screw penetration. When drill (or screw or probe) tip is actually at anterior cortex, lateral view (0 degrees) misleadingly shows tip still to be some distance (A) away from cortex. When angle of view is too oblique (60 degrees), tip appears to be some distance (B) from cortex. Only when view is tangent to point of penetration (30 degrees in this illustration) does tip appear most nearly to approach actual breakthrough.