parietoacanthial projection, a technique for producing a radiographic image of the facial bones and maxillary sinuses. The patient faces the image receptor (IR) and tilts the forehead away from the IR, with the nose barely touching and the chin resting on the surface of the IR. The orbitomeatal line forms a 37-degree angle with the plane of the IR. The x-ray beam is perpendicular and passes through the parietal bones and exits at the junction of the patient’s nose and upper lip or at the location of the anterior nasal spine. Formerly called Waters method. See also orbitomeatal line.
