Calcaneofibular ligament
Ligamentum calcaneofibulare
A rounded cord on the outer side of the ankle passing down from the lowest point of the fibula to the side of the heel bone.
At a glance
- English
- Calcaneofibular ligament
- Latin (TA2)
- Ligamentum calcaneofibulare
- System
- Ligament
- Region
- Foot
- Side
- Paired, left and right
About the calcaneofibular ligament
The calcaneofibular ligament is the middle of the three bands that make up the lateral collateral ligament of the ankle, between the anterior and posterior talofibular ligaments. Unlike its flat neighbours it is a narrow, round cord, and it lies outside the joint capsule rather than forming part of it.
It begins at the apex of the lateral malleolus, just below and in front of its lowest point, and runs down and slightly backwards to a small tubercle on the outer face of the heel bone. Because the fibula reaches the calcaneus by passing over the talus, this ligament crosses two joints at once: the ankle joint and the subtalar joint. It is the only lateral ligament to do so. The tendons of fibularis longus and fibularis brevis, in their shared sheath, run across its outer surface behind the malleolus.
The ligament tightens when the foot is pulled upwards (dorsiflexion) and when the heel is turned inwards. It is therefore the main restraint against excessive inversion of the subtalar joint and helps keep the talus from tilting in the ankle mortise. In this way it complements the anterior talofibular ligament, which does most of the work when the foot points down.
In a mild ankle sprain only the anterior talofibular ligament tears, but in more severe sprains the calcaneofibular ligament gives way as well, and with very severe injuries the posterior talofibular ligament may be damaged too. A combined tear lets the talus tilt in the mortise on a stress X-ray. Injury to the overlying fibular tendons can accompany it, and both are checked when the ankle remains unstable after a sprain.
Attachments and function
- Attaches from
- The apex of the lateral malleolus.
- Attaches to
- A small tubercle on the outer face of the calcaneus, behind the fibular trochlea.
- Function
- Resists inversion of the heel at the subtalar joint and talar tilt in the ankle joint, especially with the foot dorsiflexed.
- Nerve supply
- Branches of the sural nerve and deep fibular nerve to the lateral ankle.
- Blood supply
- Branches of the fibular artery, including its lateral calcaneal branches.
Anthromica
See the calcaneofibular ligament where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
