What projection requires the patient to be supine with specific alignment of the skull and CR?

The anteroposterior (AP) axial projection, specifically the Towne method, requires the patient to be supine with precise alignment of the skull and the central ray (CR) to obtain accurate and diagnostic images of the skull. In this projection, the patient's head is positioned such that the OML (orbitomeatal line) is perpendicular to the film or image receptor, and the CR is angled appropriately, typically 30 degrees caudad when using the OML or 37 degrees when using the IOML (infraorbitomeatal line). This specific alignment helps to capture the occipital region and the foramen magnum clearly in the resulting radiograph.

Other projections, such as the lateral projection, submentovertex (SMV) projection, and posteroanterior (PA) projection, have different positioning and alignment requirements that do not necessitate the supine position or the same degree of specificity in skull alignment and CR angulation as seen in the Towne method. This makes the Towne method distinct in its requirements for optimal imaging of the skull anatomy.