Corpus3D

Lower limb

Anterior talofibular ligament (ATFL)

Ligamentum talofibulare anterius (ATFL)

Origin
Anterior border of the lateral malleolus, about a centimetre above the tip
Insertion
Neck of the talus, just in front of the lateral articular facet
Function
Checks anterior translation of the talus in the mortise and inversion in plantar flexion. The weakest and shortest of the three lateral ligaments, and therefore the first to tear.
Innervation
Superficial fibular nerve; rich in mechanoreceptors contributing to ankle proprioception
Movement & chain
Taut in plantar flexion and slack in dorsiflexion. That explains why an ankle almost always sprains in plantar flexion with inversion: in that position this ligament carries the load almost alone.
Palpation
Find the tip of the lateral malleolus and move obliquely forward and slightly upward, towards the neck of the talus. The ligament runs just under the skin there; in slight plantar flexion it can be felt as a cord.
Clinical
In roughly two thirds of all inversion injuries this is the only damaged ligament. The ankle anterior drawer test targets it specifically. The Ottawa ankle rules decide whether imaging is needed: tenderness on the posterior edge of a malleolus, or inability to bear weight for four steps.
Segmental innervation
Segmentally L5-S1 via the superficial fibular nerve
In clinical practice
For an acute sprain, functional treatment with a brace and early weight bearing beats a cast. Proprioceptive training substantially lowers the chance of recurrence, which matters: without it up to a third sprain again.
Region in the model
Lower limb

Tests that come back to this

Conditions this turns up in