Sustentaculum tali

At the upper and forepart of the medial surface of the calcaneus is a horizontal eminence, the sustentaculum tali, which gives attachment to a slip of the tendon of the Tibialis posterior.

This eminence is concave above, and articulates with the middle calcaneal articular surface of the talus; below, it is grooved for the tendon of the Flexor hallucis longus; its anterior margin gives attachment to the plantar calcaneonavicular ligament, and its medial, to a part of the deltoid ligament of the ankle-joint.