Which statement about patellar positioning on an AP knee radiograph is true?

Which statement about patellar positioning on an AP knee radiograph is true?

• A. The patella should be overlapped by the tibia
• B. The patella should be superimposed over the distal femur
• C. The patella should be projected medially
• D. The patella should be lateral to the distal femur

Answer: (B)

In an AP knee radiograph, proper alignment is achieved when the patella sits directly over the distal femur, appearing superimposed on the distal femoral articular surface. This position reflects a true AP projection with the knee extended and no rotation, allowing the patellofemoral joint to be evaluated without distortion. If the knee is rotated, the patella may shift off-center or appear projected medially or laterally, and improper technique can cause the patella to be overlooked or misrepresented. Therefore, the patella being superimposed over the distal femur best describes correct patellar positioning on an AP knee radiograph.

In an AP knee radiograph, proper alignment is achieved when the patella sits directly over the distal femur, appearing superimposed on the distal femoral articular surface. This position reflects a true AP projection with the knee extended and no rotation, allowing the patellofemoral joint to be evaluated without distortion. If the knee is rotated, the patella may shift off-center or appear projected medially or laterally, and improper technique can cause the patella to be overlooked or misrepresented. Therefore, the patella being superimposed over the distal femur best describes correct patellar positioning on an AP knee radiograph.