Final answer:
For the right obturator foramen to be open on an AP pelvis image, the patient must be rotated to the left. The obturator foramen is bordered by the pubic bone and the ischium, and correct rotation is critical for clear imaging in radiographic examinations.
Step-by-step explanation:
If a patient rotated to position the right obturator foramen to be open on an AP (anteroposterior) pelvis image, then the patient must be rotated to the left. The obturator foramen is an opening in the pelvis which is bordered by the pubic bone in front and the ischium behind. When a patient is undergoing an AP pelvis imaging procedure, rotation to the left can cause the right obturator foramen to appear 'open' or unobstructed, as it aligns orthogonally to the direction of the X-ray beam.
In specific radiographic examinations, the position of the obturator foramen can be quite important for diagnostic purposes. Hence, understanding how to manipulate the patient's position to achieve the best view of the obturator foramen is crucial for healthcare professionals performing such imaging processes.