Where should the central ray enter for a lateral ankle radiograph?

Where should the central ray enter for a lateral ankle radiograph?

• A. Lateral malleolus
• B. Calcaneus
• C. Talus
• D. Medial malleolus

Answer: (D)

Placing the central ray at the medial malleolus helps center the ankle joint in a true lateral view and minimizes distortion. In this position, with the patient on their side and the foot in profile, the beam is directed horizontally and perpendicular to the image receptor so it passes through the ankle joint near the medial malleolus. This alignment keeps the distal tibia and fibula superimposed and provides a clear view of the tibiotalar joint, which is essential for identifying fractures or dislocations around the ankle. Directing the beam over the lateral malleolus, calcaneus, or talus would miscenter the projection and distort the anatomy of interest, making degeneration or injuries harder to assess.

Placing the central ray at the medial malleolus helps center the ankle joint in a true lateral view and minimizes distortion. In this position, with the patient on their side and the foot in profile, the beam is directed horizontally and perpendicular to the image receptor so it passes through the ankle joint near the medial malleolus. This alignment keeps the distal tibia and fibula superimposed and provides a clear view of the tibiotalar joint, which is essential for identifying fractures or dislocations around the ankle. Directing the beam over the lateral malleolus, calcaneus, or talus would miscenter the projection and distort the anatomy of interest, making degeneration or injuries harder to assess.