Most ankle sprains happen when the foot turns inward as a person runs, turns, falls, or lands on the ankle after a jump. This type of sprain is called an inversion injury. One or more of the lateral ligaments are injured, usually the anterior talofibular ligament. The calcaneofibular ligament is the second most frequently torn ligament. The knee is another common site for a sprain.
Sprains frequently occur at the wrist, typically when people fall and land on an outstretched hand.
However, these signs and symptoms can vary in intensity, depending on the severity of the sprain. Sometimes people feel a pop or tear when the injury happens. Doctors use many criteria to diagnose the severity of a sprain. In general, a grade I or mild sprain causes overstretching or slight tearing of the ligaments with no joint instability. A person with a mild sprain usually experiences minimal pain, swelling, and little or no loss of functional ability.