What is the degree and direction of tube angulation for an AP axial projection of the sacrum?

For an AP axial projection of the sacrum, the correct degree and direction of tube angulation is 15 degrees cephalad. This angulation is crucial because it helps project the sacrum appropriately, reducing superimposition with the pubic symphysis and pelvic organs.

By angling the tube cephalad (upward towards the head), the anatomy of the sacrum is better visualized within the radiograph. The 15-degree angle is specifically chosen as it aligns with the natural curvature of the sacrum and helps ensure that it is clearly represented in the image.

Using a cephalad angulation also allows the x-ray beam to follow the natural slope of the sacrum more effectively, reducing distortion and helping in the assessment of any potential pathologies or anomalies. This technique is standard practice in radiographic procedures to enhance image quality and diagnostic capability.