Which ligament limits eversion of the subtalar joint?

• A. Interosseous talocalcaneal ligament
• B. Deltoid ligament
• C. Calcaneofibular ligament
• D. Posterior talofibular ligament

Answer: (A)

Subtalar joint stability hinges on ligaments that tie the talus to the calcaneus, so resisting movements that tend to separate these two bones. The interosseous talocalcaneal ligament runs inside the tarsal canal between the talus and calcaneus and acts as the primary restraint to subtalar motion, directly limiting eversion of the subtalar joint. The other ligaments have different primary roles: the deltoid ligament mainly guards eversion at the ankle joint (talocrural) and provides medial stability, while the calcaneofibular ligament resists inversion of the subtalar joint, and the posterior talofibular ligament adds lateral/posterior stability. Therefore, the interosseous talocalcaneal ligament best limits subtalar eversion.