We examined the anatomical structure of a ligament (ligamentum meniscofibulare) between apex fibulae and lateral meniscus by macroscopic and microscopic dissection and transillumination method in 50 knees of 25 cadavers (5 were fresh). We analyzed the function of this ligament, which runs between the head of the fibulae and lateral meniscus. The existence of a connection between knee joint and proximal tibiofibular joint was demonstrated by injecting colored liquid into the knee joint space and transillumination. The mensicofibular ligament is a capsular ligament originating from the lateral meniscus that is anterior to the popliteal muscle tendon. The meniscofibular ligament, which is attached to fibula with rotatory motion at one end and to the lateral meniscus at the other, is believed to position the lateral meniscus and therefore to play a key role in the knee joint.