Describe the typical technique for AP coccyx radiography.

• A. AP projection with the patient supine; CR directed to the midline near the coccyx; angle as per protocol to project coccyx clearly.
• B. AP projection with the patient supine; CR directed to the midline near the coccyx; no angle.
• C. AP projection with the patient upright; CR directed to the coccyx.
• D. Lateral projection with the patient supine; CR directed to the coccyx.

Answer: (A)

The key idea is to image the coccyx with an AP projection while the patient is supine and the beam angled slightly axially to bring the coccyx into clear view. Positioning the patient supine stabilizes the pelvis and reduces motion, and directing the CR to the midline near the coccyx centers the structure in the image. The small axial angle, used per protocol, helps to minimize overlap from the pelvic bones and opening of the coccygeal joints so the coccyx can be seen more clearly. An upright AP view or a lateral projection isn’t the typical approach for a standard AP coccyx image, and omitting the angle can obscure the coccyx due to superimposition.