Talocalcaneonavicular joint

This talocalcaneonavicular joint (Talonavicular joint) is an arthrodial joint: the rounded head of the talus being received into the concavity formed by the posterior surface of the navicular, the anterior articular surface of the calcaneus, and the upper surface of the plantar calcaneonavicular ligament. There are two ligaments in this joint: the articular capsule and the dorsal talonavicular.

The articular capsule is imperfectly developed except posteriorly, where it is considerably thickened and forms, with a part of the capsule of the talocalcaneal joint, the strong interosseous ligament which fills in the canal formed by the opposing grooves on the calcaneus and talus, as above mentioned.

The synovial membrane lines all parts of the capsule of the joint.

Movements.—This articulation permits of a considerable range of gliding movements, and some rotation; its feeble construction allows occasionally of dislocation of the other bones of the tarsus from the talus.

The talocalcaneonavicular joint is a complex, multiaxial synovial joint in the foot, formed by the articulation of the head of the talus, the anterior and middle facets of the calcaneus (including the sustentaculum tali), and the proximal surface of the navicular bone. The joint is further supported inferiorly by the plantar calcaneonavicular (spring) ligament, which forms a fibrocartilaginous socket for the talar head and is continuous with the joint capsule. The joint capsule also incorporates the tendinous sheaths of the tibialis posterior and flexor digitorum longus, which contribute to joint stability, particularly in weightbearing and dynamic activities.

The talocalcaneonavicular joint is a part part of the subtalar joint complex and the transverse tarsal (Chopart) joint. This configuration allows for complex movements, including inversion, eversion, and contributes to the flexibility and stability of the medial longitudinal arch of the foot.

The term "talonavicular joint", often used for the talocalcaneonavicular joint, is not accurate but reflect the fact that the main surface of the talocalcaneonavicular joint is located beween the talus and navicular surfaces

The sustentaculum tali of the calcaneus provides a medial support for the talar head, and the spring ligament recess is a synovium-lined space that communicates with the joint cavity.

Ligamentous support includes the spring ligament, talonavicular ligament, and connections with the interosseous talocalcaneal ligament, as well as contributions from the surrounding tendons and joint capsule.

The joint is critical for load transmission and stabilization of the talus, especially during gait and weightbearing.