What is the appropriate central ray angulation and entrance point for an anteroposterior (AP) axial projection of the coccyx?

The correct choice indicates a central ray angulation of 10 degrees caudad, entering the midsagittal plane at 2 inches superior to the pubic symphysis, which is precisely what is needed for an effective anteroposterior axial projection of the coccyx.

To capture the coccyx in the axial view, it is essential to angle the central ray appropriately to prevent obscuration by surrounding structures and ensure that the coccyx is properly visualized in relation to the pelvic anatomy. The caudad angulation helps to align the radiation beam with the anatomical curvature of the sacrum and coccyx, allowing for a clearer image with minimal distortion.

Entering at the midsagittal plane, specifically located 2 inches superior to the pubic symphysis, targets the region of the coccyx effectively. This entry point is strategically chosen to optimize visualization and to maintain the central ray’s focus on the coccygeal area without interference from other pelvic structures.

Contrasting the other options, the incorrect angles, entry points, or direction would not effectively capture the desired anatomical area of the coccyx, possibly leading to blurring or misrepresentation of the anatomy in imaging.