Fig. 12-21 A, Child's knee, lateral view. Note the epiphyses for the inferior end of the femur and the superior end of the tibia. The patella has begun to ossify, and the fat deep to the ligamentum patellae is visible as a radiolucent area. B, lateral radiograph of the knee, showing fabella (arrow). C, Radiograph of the flexed knee. Note the radiological joint space between the femur and patella. The lateral condyle of the femur is that on the right-hand side of the illustration. D, Radiograph of dried bones of a 5-year old boy. Note the outline of the cartilage. E, Pneumoarthrogram of the knee produced by injecting air into the joint cavity. Note the medial meniscus and the cruciate ligaments. (A courtesy of V. C. Johnson, M.D., Detroit, Michigan. E courtesy of Sir Thomas lodge, Sheffield, England.) Click for high resolution image.