Ankle joint

The ankle joint (also talocrural joint; Latin: articulatio talocruralis) is a cylindrical-shaped synovial joint. It is a complex hinge-type joint formed between the bones of the leg and foot - tibia, fibula and talus. Therefore, the ankle joint marks the transition between the foot and the leg.

Articulating structures of ankle joint

The articular surfaces of the ankle joint are as follows:

  • Superior articular 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

Joint capsule

The ankle joint is surrounded by the fibrous joint capsule. It is attached to the margins of the articular surfaces of all bones and the neck of the talus.

Ligaments of ankle joint

The bones of the ankle joint are bound together by two strong ligaments:

  • Medial collateral ligament (or the deltoid ligament) - it is attached to the medial malleolus and consists of four parts (anterior and posterior tibiotalar, tibionavicular and tibiocalcaneal); all parts stretch from the tibia to the bones of the foot;
  • Lateral collateral ligament - it is connected to the lateral malleolus and consists of three separate ligaments (anterior and posterior talofibular and calcaneofibular ligaments).

The anterior tibiotalar part of the medial collateral ligament extends from the tibia to the head of the talus, while the posterior tibiotalar component to the posterior end of the body of the talus. The tibionavicular part connects the tibia with the navicular bone, and the tibiocalcaneal part links the tibia with the calcaneus.

The anterior talofibular ligament of the lateral collateral ligament is situated between the lateral malleolus and the head of the talus, while the posterior talofibular ligament stretches between the lateral malleolus and the posterior end of the talus. The calcaneofibular ligament is situated between the lateral malleolus and the lateral surface of the calcaneus.

Movements of ankle joint

The ankle joint is a uniaxial joint. Therefore, it permits two movements:

  • Flexion of the foot
  • Extension of the foot