What is the tube tilt for an AP coccyx projection?

For an anterior-posterior (AP) coccyx projection, the correct tube tilt is 5-10° caudad. This specific angling is essential for accurately visualizing the coccyx and minimizing the overlap of the sacrum, which can obscure the view of the coccyx.

The caudad angle directs the x-ray beam towards the head, helping to align the projection with the anatomy of interest, which is particularly important given the natural curve of the sacrum and coccyx. This positioning aids in obtaining a clearer image of the coccyx while reducing distortion.

Additionally, an excessive tilt, like 15-20° caudad, may cause the coccyx to appear projected too far back, while having no tilt (0°) would not provide the angled view necessary to achieve the best visualization. Hence, applying a tube tilt of 5-10° caudad is critical for producing a diagnostic-quality image of the coccyx.