Posterior talofibular ligament

At a glance

English

Posterior talofibular ligament

Latin (TA2)

Ligamentum talofibulare posterius

System

Ligament

Region

Foot

Side

Paired, left and right

About the posterior talofibular ligament

The posterior talofibular ligament is one of three bands that form the lateral collateral ligament of the ankle, together with the anterior talofibular and calcaneofibular ligaments. It is a thick, strong band set deep at the back of the outer ankle. It starts in the malleolar fossa, the hollow on the inner, back part of the fibular malleolus, and runs almost horizontally backwards and medially to the posterior process of the talus.

Its talar end is fixed to the lateral tubercle of the posterior process, immediately lateral to the groove that carries the tendon of flexor hallucis longus down behind the ankle. Some of its fibres also reach the posterior margin of the tibia, forming a band often called the posterior intermalleolar ligament. It lies just below the transverse tibiofibular ligament, which crosses the back of the joint from the lateral malleolus to the tibia. Behind it run the fibular tendons as they curve round the malleolus, and further back lies the Achilles tendon.

The ligament is tight when the foot is pulled upwards (dorsiflexion) and becomes slack as the foot points down. It resists backward displacement of the fibula on the talus, and stops the talus rotating outwards or sliding backwards in the ankle mortise. In plantarflexion and inversion, when the anterior talofibular ligament is under strain, the posterior band is relaxed.

This explains why it is the least often injured of the lateral ankle ligaments. A common inversion sprain tears the anterior talofibular band first and the calcaneofibular next; the posterior talofibular ligament is usually damaged only in a complete ankle dislocation or a severe fracture-dislocation.

Attachments and function

Attaches from

The malleolar fossa, on the inner back part of the fibular (lateral) malleolus.

Attaches to

The lateral tubercle of the posterior process of the talus, beside the groove for flexor hallucis longus.

Function

Holds the fibula to the back of the talus, limits backward sliding and lateral rotation of the talus in the mortise and is tight in dorsiflexion.

Nerve supply

Articular branches of the sural nerve and deep fibular nerve.

Blood supply

Branches of the fibular (peroneal) artery, including its malleolar branches.