The lateral collateral ligament of the ankle, more accurately a complex of three ligaments, stabilizes the ankle joint against excessive inversion.
It's frequently injured, especially during sports activities, and is a common cause of ankle sprains.
The anterior talofibular ligament is most vulnerable during plantar flexion and inversion.
These calcaneofibular ligament is most vulnerable during dorsiflexion and inversion.
The posterior talofibular ligament is most vulnerable with the ankle joint in neutral and inversion.