Fig. 1

Parasagittal P45 section of the knee joint including the tibiofibular joint. The tiny and sparse bone trabeculae can be seen perpendicular to the tibiofibular joint surface, above the tibiofibular joint. The fibula forms an arch with the posterolateral cortex of the tibial shaft, through the tibiofibular joint. The distribution of trabecular bone in the lateral condyle of the tibia is nonuniform, while longitudinal trabeculae are densely distributed in the posterolateral part of the lateral tibial condyle. The longitudinal trabeculae passing through the epiphyseal line are distributed between the arch and the articular surface of the lateral tibial plateau. The posterior part of the fibular head shows parallel trabeculae perpendicular to the tibiofibular articular surface. In the anterior part of the fibular head, the internal trabeculae are sparse; no obvious longitudinal trabeculae are seen. F, femur; T, tibia; P, patella; dotted line, arch beam between the fibula and tibial plateau; black arrow, bone trabeculae arranged vertically. Black triangle, sparse trabeculae in anterior part of tibia. White triangle, sparse trabeculae in posterior tibia. Black square frame, longitudinally distributed trabeculae in the fibular head