Final answer:
The position of the patient for AP oblique RPO/LPO SI joint is prone position, which describes a face-down orientation. In this position, the patient lies flat on their stomach with the affected side of the body facing up.
Step-by-step explanation:
The position of the patient for AP oblique RPO/LPO SI joint is prone position. Prone position describes a face-down orientation, which is the appropriate position for imaging the sacroiliac joint from an oblique angle. In this position, the patient lies flat on their stomach with the affected side of the body facing up.