What additional instruction is given to the patient for the lateral sacrum projection aside from remaining still?

For the lateral sacrum projection, instructing the patient to take a deep breath in and breathe out aids in achieving the best image quality. This breathing technique helps to minimize movement artifacts that can occur due to natural respiration, ensuring that the sacral region is captured clearly and accurately in the X-ray. By asking the patient to take a deep breath and then hold it, you can help stabilize the area of interest during the exposure, leading to a more precise representation of the anatomical structures being imaged. This is especially important for the lateral view, where any bodily motion can distort the visualization of the sacrum.

The other suggestions, while potentially beneficial in different contexts, do not specifically assist in the stabilization and clarity of the lateral sacrum projection.