Camp-Coventry radiograph of the knee

This is a method that will enable you to image the intercondylar fossa of the knee joint. This method is easier on the patient than the Holmblad method. This image can also be obtained with the patient supine, but the flexion of the knee in that position results in extra magnification.
BTW, if you have an old "cylinder cone" lying around, you can put a rolled up towel on top of it and it will be almost a perfect elevation for the patient's foot in the prone position.