Tibiocalcaneal ligament

At a glance

English

Tibiocalcaneal ligament

Latin (TA2)

Ligamentum calcaneotibiale

System

Ligament

Region

Foot

Side

Paired, left and right

About the tibiocalcaneal ligament

The tibiocalcaneal ligament is one of the superficial parts of the ankle's medial collateral ligament, the fan-shaped structure usually called the deltoid ligament. The deltoid has a superficial layer, which crosses both the ankle and the subtalar joint, and a deep layer, which crosses only the ankle. The tibiocalcaneal band lies in the superficial layer, between the tibionavicular fibres in front and the superficial posterior tibiotalar fibres behind.

Its upper end arises from the front part of the medial malleolus, the inner projection at the lower end of the tibia. From there its fibres run down almost straight, crossing the side of the talus without attaching to it, and end along the full length of the sustentaculum tali, the shelf of bone that juts from the inner side of the calcaneus. Over its superficial face pass the tendons of tibialis posterior and flexor digitorum longus as they curve round behind and below the malleolus; the tibial nerve and posterior tibial vessels lie a little further back in the tarsal tunnel.

Because it spans two joints, the band links the tibia directly to the calcaneus. It is therefore one of the main restraints against eversion of the heel, the outward tilt of the calcaneus under the talus, as well as against outward tilting of the talus within the ankle mortise. The deep tibiotalar fibres, short and thick, add most of the resistance at the ankle itself.

Injury to the deltoid ligament is much rarer than injury to the lateral ankle ligaments, as the medial side is stronger. When it happens it is usually caused by forced eversion and external rotation, and it often accompanies a fracture of the fibula. A complete tear allows the talus to shift outwards in the mortise, which widens the gap seen medially on radiographs.

Attachments and function

Attaches from

The anterior part of the medial malleolus of the tibia.

Attaches to

The calcaneal sustentaculum tali, along its full length.

Function

Links the tibia to the calcaneus across the ankle and subtalar joints, resisting eversion of the heel and outward tilting of the talus.

Nerve supply

Articular branches of the tibial nerve and saphenous nerve.

Blood supply

Medial malleolar branches of the anterior and posterior tibial arteries.