The ankle joint (also talocrural joint, latin: articulatio talocruralis) is a cylindrical shaped joint that is formed by three bones: tibia, fibula and talus.
The articular surfaces of the ankle joint are the following:
- superior surface of the talus,
- inferior articular surface of the tibia,
- medial malleolar surface of the talus,
- medial malleolar articular surface of the tibia,
- lateral malleolar surface of the talus,
- lateral malleolar articular surface of the fibula.
The ankle joint is surrounded by an articular capsule, which attaches to the margins of the articular surfaces and also to the neck of the talus.
The bones of the ankle joint are bound together by strong ligaments:
- medial collateral ligament (or deltoid ligament), which is attached to the medial malleolus and consists of four parts: the anterior tibiotalar, posterior tibiotalar, tibionavicular and tibiocalcaneal; all parts of the medial collateral ligament attach to the talus, calcaneus and navicular bones;
- lateral collateral ligament, which arises from the lateral malleolus and consists of three separate ligaments: the anterior and posterior talofibular, calcaneofibular ligaments.
The anterior talofibular ligament is situated between the lateral malleolus and the head of the talus.
The posterior talofibular ligament stretches between the lateral malleolus and the posterior aspect of the talus.
The calcaneofibular ligament is situated between the lateral malleolus and the lateral surface of the calcaneus.
The ankle joint permits two movements: flexion and extension of the foot.