Medial collateral ligament (deltoid ligament) attaches to the medial malleolus of the tibia and the navicular, talus, and calcaneus bones. This ligament prevents medial distraction (eversion) and excessive range of motion. It is subdivided into four pas:Tibionavicular pa attaches the margin of the plantar calcaneonavicular ligament (spring ligament).Tibiocalcaneal pa attaches to the sustentaculum tali of the calcaneus bone.Posterior tibiotalar pa attaches to the medial side and medial tubercle of the talus.Anterior tibiotalar pa attaches to the medial surface of the talus.