Which projection uses a 0-degree central ray angle?

Which projection uses a 0-degree central ray angle?

• A. AP mortise ankle
• B. Lateral ankle
• C. AP ankle
• D. Medial oblique ankle

Answer: (A)

A 0-degree central ray angle means the beam is perpendicular to the image receptor and aimed straight through the ankle joint. For the AP mortise ankle projection, the foot is rotated inward about 15–20 degrees to open the mortise joint, while the central ray remains perpendicular to the joint (no angulation). This setup—zero angulation with the mortise opening achieved by rotation—gives a true, undistorted view of the articulation between the tibia, fibula, and talus, making it the projection that uses a 0-degree central ray angle. Other ankle projections focus on different orientations (like lateral or oblique) to visualize other structures or angles, but the defining feature here is the mortise view used with a perpendicular central ray.

A 0-degree central ray angle means the beam is perpendicular to the image receptor and aimed straight through the ankle joint. For the AP mortise ankle projection, the foot is rotated inward about 15–20 degrees to open the mortise joint, while the central ray remains perpendicular to the joint (no angulation). This setup—zero angulation with the mortise opening achieved by rotation—gives a true, undistorted view of the articulation between the tibia, fibula, and talus, making it the projection that uses a 0-degree central ray angle. Other ankle projections focus on different orientations (like lateral or oblique) to visualize other structures or angles, but the defining feature here is the mortise view used with a perpendicular central ray.