Which knee projection uses a 45-degree rotation?

• A. AP knee
• B. Medial oblique projection
• C. Lateral knee
• D. Skyline projection

Answer: (B)

Rotating the knee into an oblique position is how this view is achieved. A medial oblique view uses about a 45-degree rotation toward the midline, so the knee is angled with the medial side closer to the image receptor. This specific rotation changes which structures are seen clearly by reducing overlapping of bones and bringing the medial portions of the knee into better profile, making joint surfaces and surrounding contours easier to evaluate.

Other knee views don’t rely on this exact 45-degree medial rotation: the AP knee is taken with the knee in a straight-on position; the lateral knee uses a different setup with knee flexed and the leg rotated laterally; and the skyline (tangential) projection positions the knee for a view of the patellofemoral articulation by flexing the knee rather than achieving a 45-degree medial rotation.