In a PA projection, where should the central ray be directed?

In a PA (posteroanterior) projection of the skull, the central ray is directed at the glabella, which is the smooth part of the forehead located above the nose and between the eyebrows. This specific positioning allows for a clear visualization of the frontal sinuses, orbits, and nasal structures.

Directing the central ray at the glabella ensures that the projection captures the anatomical structures in a symmetrical manner, providing essential diagnostic information about any possible abnormalities or pathologies of these areas. The glabella is specifically chosen because it is centrally located on the frontal bone, giving a balanced view of the skull. This technique is crucial in radiographic imaging, particularly for assessing the frontal region of the skull in a standardized way.