The tibia, fibula and talus meet to form a complex hinge that does move to a mild degree towards the inside and outside, as well as rotates clockwise and counter-clockwise.
Foot and Ankle Anatomy
Three bones of the ankle are surrounded by a thick layer of cartilage in the ankle joint and are held together by the ankle joint capsule, which supports, nourishes, and helps stabilize the ankle joint. In addition to the bony architecture of the ankle, ligaments hold the ankle together and give it stability and allow the ankle to function as a unit as it responds to the forces acted upon by the muscles about the leg. The ligaments on the inside and outside of the ankle limit excessive sideways motion of the ankle preventing a dislocation of unexpected forces move the foot in the wrong direction as occurs when someone trips or falls.
Tendons that arise from the three compartments of the leg span the ankle joint to attach to the foot. There are three main muscles on the front of the leg whose tendons cross the ankle to attach onto the foot and are responsible for bringing the foot up. The calf muscles in the back of the leg attach to the back of the heel bone (calcaneous) through the Achilles’ tendon. There is one main muscle on the inside of the leg called the Tibialis Posterior that becomes a tendon at or near the level of the ankle that inserts onto the foot and is responsible for turning the foot inward towards the big toe. There are two main muscles on the outside of the leg that become tendons at or near the level of the ankle that inserts onto the foot that pulls the foot outwards towards the small toe.