What is a sprained ankle?
A sprained ankle, or twisted ankle, is a ligament injury. It occurs when the ligaments that support and stabilize the ankle stretch beyond their limits and tear. Ankle sprains range from mild to severe, depending upon how much damage there is to the ligaments.
Most sprained ankles occur in the lateral ligaments, those on the outside of the ankle. Your ankle becomes painful to walk on and swollen. Without proper treatment, more severe sprains can weaken your ankle, making it more likely that you injure it again.