A ligament injury, also known as a sprain, causes pain, inflammation and possible bruising, according to WebMD. The most common type of sprain occurs in the ankle, and it usually occurs when a person twists or falls in a way to force the foot out of its typical position.
Sprains have grades that run on a scale of I to III, explains WebMD. A grade I sprain is one in which the ligament stretches, or experiences a mild tear, but there is no or very little joint instability. A grade II sprain is more serious, but the tear is still incomplete. A grade III sprain means that the tear in the ligament is complete, and though the bone does not have a break, the pain is similar, and the person cannot put weight on the foot.
Someone who develops a minor sprain can usually treat the injury at home by resting the foot, icing it, using compression and elevating it, states WebMD. Someone with a more severe sprain must see a doctor. The doctor may take an X-ray or do other tests to look at the severity of the sprain and must cast or immobilize the foot to allow it to heal. In some cases, surgery is necessary to repair the tear in the ligament, and physical therapy or rehabilitation may also strengthen the foot.