What degree of obliquity is required for the RPO position for the acetabulum?

• A. 30°
• B. 45°
• C. 60°
• D. 90°

Answer: (B)

For the Right Posterior Oblique (RPO) position used in acetabulum radiography, a 45-degree obliquity is ideal. This specific angle allows the anatomy of the acetabulum to be well visualized by projecting the femoral head and neck away from the significantly overlying structures. When the patient is positioned at a 45-degree angle, it ensures that the beam can properly penetrate and highlight the structures of interest, facilitating a clearer image for diagnostic purposes. This positioning technique effectively reduces superimposition from adjacent bone structures, resulting in improved clarity and detail of the acetabulum in the radiographic image.