subtalarjoint

The subtalar joint, also called the talocalcaneal joint, is a synovial articulation in the hindfoot between the talus and the calcaneus. It enables key rotational adjustments of the foot and plays a central role in adapting to uneven surfaces during gait.

Anatomy and articulations: The joint surfaces lie on the inferior aspect of the talus and the superior aspect of the calcaneus. Traditionally, the articulation is described as three facet contacts—posterior, and the middle and anterior facets—forming a continuous subtalar joint complex. The primary stabilizer is the interosseous talocalcaneal ligament, located within the tarsal canal, with additional support from the cervical ligaments around the joint and from the surrounding joint capsule. The sinus tarsi, a narrow space between the talus and calcaneus, contains ligaments and neurovascular structures relevant to subtalar function.

Biomechanics: Movement occurs about an oblique axis, permitting inversion and eversion of the foot. This motion is integrated with the adjacent talonavicular joint to produce the broader pronation and supination complex necessary for adapting to varied terrain and for efficient gait.

Clinical relevance: Subtalar problems include sprains and degenerative arthritis, which can be associated with hindfoot valgus deformities. Subtalar coalition—abnormal bony or fibrous connections between talus and calcaneus—can restrict motion, especially in children. Management ranges from conservative therapies to subtalar arthrodesis (fusion) in cases of painful arthritis or significant deformity. Imaging and assessment focus on the subtalar joint’s surfaces, ligaments, and its relationship with the sinus tarsi.