Interosseous talocalcaneal ligament

The interosseous talocalcaneal ligament (talocalcaneal interosseous ligament; ITCL) is a key stabilizer of the subtalar joint, located within the tarsal canal between the talus and calcaneus. It is attached, above, to the groove between the articular facets of the under surface of the talus; below, to a corresponding depression on the upper surface of the calcaneus. It is very thick and strong, being at least 2.5 cm. in breadth from side to side, and serves to bind the calcaneus and talus firmly together.

It is a thin, single band of dense connective tissue that runs obliquely from the upper medial aspect of the talus to the lower lateral aspect of the calcaneus, deep within the tarsal canal. Its fibers are oriented in a manner that allows it to resist excessive inversion and eversion of the subtalar joint, contributing significantly to joint stability.

The ITCL is closely associated with the medial root of the inferior extensor retinaculum, and together these structures form a V-shaped ligamentous complex within the tarsal canal. The ITCL is distinct from the cervical ligament, which lies more anteriorly in the tarsal sinus and is thicker and more robust.