Where should the petrous pyramid be projected in the PA axial projection (Caldwell method) of the skull using a 15° caudal tube angle?

Where should the petrous pyramid be projected in the PA axial projection (Caldwell method) of the skull using a 15° caudal tube angle?

• A. In the upper 1/3 of the orbits
• B. In the lower 1/3 of the orbits
• C. In the center of the orbits
• D. Above the orbits

Answer: (B)

In the PA axial projection using the Caldwell method, the petrous pyramids should be projected in the lower third of the orbits. This positioning is crucial for achieving a clear visualization of the frontal bone and the orbits while minimizing distortion of other anatomical structures.

When using a 15° caudal tube angle, the cranial base is angled appropriately to project the petrous pyramids downward into a position that ideally sits within the lower third of the orbits. This provides a good balance of detail and avoidance of superimposition with other critical areas of the skull, such as the orbits and nasal sinuses.

The lower third placement allows radiologists and clinicians to assess the frontal sinuses while ensuring that the important anatomical landmarks of the skull are correctly displayed and not obscured. Proper technique and accurate tube angulation are key to achieving this positioning in the resulting radiograph.