Where should the CR be directed for the AP projection of the ankle?

• A. At the lateral malleolus
• B. Midway between the malleoli
• C. At the medial malleolus
• D. At the talus

Answer: (B)

For the AP projection of the ankle, the central ray (CR) should be directed midway between the malleoli. This positioning is crucial because it provides a complete and symmetrical view of the entire ankle joint, which includes the tibia, fibula, and the surrounding structures. By centering the CR in this manner, it allows for optimal visualization of any potential fractures or joint misalignments and captures both the ankle mortise and the important anatomical landmarks.

Other choices would lead to suboptimal images. For instance, directing the CR at the lateral or medial malleolus would not effectively encompass the entire joint space between the tibia and fibula. Focusing at the talus might also restrict the visual field and not showcase the critical articulation at the ankle joint adequately. Centering midway between the malleoli ensures maximum detail and diagnostic information is captured, making it the most appropriate choice for this projection.