An injury or ligament tear is called a sprain. When the ligament that is holding the joint of the ankle gets injured or torn, the ankle sprain happens. When your ankle gets injured, twist or turn in the position which is not normal, it sprains. This twisting and turning can stretch the ligament and sometimes cause a tear of the ligament, which makes your ankle joint unstable.
All the ligaments of the ankle make the joint stable and these ligaments have their own limit for movement. When any movement crosses the limit or boundary due to any reason it causes injury to the ligament. Ligament away from the joint is commonly injured.
Mild damage heals within 2-3 weeks.