The distal end of the fibula is firmly anchored to the larger distal end of the tibia by strong ligaments. Together, the fibula and tibia create a deep bracket-shaped socket for the upper expanded part of the body of the talus:
The roof of the socket is formed by the inferior surface of the distal end of the tibia.
The medial side of the socket is formed by the medial malleolus of the tibia.