How many degrees of caudal angulation is needed for the AP axial projection of the coccyx?

• A. 15°
• B. 10°
• C. 20°
• D. 25°

Answer: (B)

For the AP axial projection of the coccyx, a caudal angulation of 10 degrees is required. This angulation is designed to direct the x-ray beam towards the coccyx, which is anatomically positioned at an angle posteriorly from its vertical line. By angling the x-ray beam caudally, this positioning helps to obtain a clear image of the coccyx without superimposition by the pubic symphysis or other pelvic structures. Additionally, the 10-degree angulation aids in optimizing the visualization of the area of interest, allowing for better assessment of potential fractures or abnormalities in the coccyx region.