For an anteroposterior (AP) axial projection using the Béclère method, the affected knee should be flexed to place the long axis of the femur at what angle?

In the Béclère method for anteroposterior (AP) axial projection, the affected knee is flexed to position the long axis of the femur at an angle of 40 to 60 degrees. This specific angle is important because it ensures proper alignment for visualization of the intercondylar fossa and the knee joint structures. By flexing the knee within this range, the x-ray beam angle can be appropriately directed to penetrate through the area of interest, which is critical for obtaining clear and diagnostic images.

Choosing the correct angle helps to minimize distortion and maintain a consistent projection, thereby allowing for improved assessment of fractures, bone lesions, or other pathologies within the knee region. Achieving an angle between 40 and 60 degrees also aids in reducing superimposition of the femoral condyles over the tibia, enhancing the quality of the resulting radiographic image.