Now that you understand some of the anatomy involved at the ankle joint, you are ready to learn about the different types of ankle sprain, how they are graded and how they are caused. Once you have a good foundation of the anatomy and the injury we can begin to discuss how to go about minimizing the chances of sustaining this common injury. A sprain is the term used when a ligament is damaged or ruptured. There two ways in which sprains happen. One way is to put a sustained stretch on a ligament.
When a ligament is held in a stretched position for a long period of time it loses some of its elasticity. These sprains are typically midland can heal quickly if the ligament is allowed to return to its proper length. The other mechanism for sprains is an explosive stretch on a ligament. This force can stretch, tear, or completely rupture a ligament. This is the mechanism that is most common to ankle sprains. There are three basic types of ankle sprains. They are inversion sprains, eversion sprains and syndesmosis or "high-ankle" sprains. The most common of the three is the inversion sprain. This is the injury that is commonly sustained when people say that they "rolled" their ankle. Inversion sprains occur when you foot is pointed toward the floor and the foot rolls inward so that all of the weight of the body is over the outside of the foot and on the outer part of the ankle joint. The way this usually happens is by stepping or landing on uneven ground or when making a cutting motion. Inversion sprains damage the ligaments on the outside of the ankle. The anterior talofibular ligament is the most commonly sprained ligament. More severe sprains may involve the calcaneofibular ligament as well.
The posterior talofibular ligament is only damaged in severe ankle sprains. Eversion sprains are less common than inversion sprains. A big part of the reason for this is that the outer malleolus extends lower than the inner one. Since it goes lower the range of movement toward this bone is limited. The difference is easy to see if you try to roll your foot inward as opposed to outward. Eversion ankle sprains require a great deal of force to occur. Often it happens when an athlete has a foot planted and there is a blow from the side to the planted leg. In the most severe cases of eversion ankle sprain, the outer malleolus can fracture as well. The syndesmosis or "high-ankle" sprain can be a common occurrence with inversion sprains. It is a sprain of the distal talofibular ligament which connects the tibia and fibula just above the ankle joint. This occurs when the talus bone twists between the inner and outer malleoli. This twisting motion can pry the tibia and fibula apart and is typically rather painful. These injuries typically occur when the foot is planted and the body twists over the planted foot. Ankle sprains are frequently associated with some muscle strain. You have peronei muscles which reach from the knee and outer leg to the foot. Their job is to properly position the foot while you are walking, jumping, dancing, etc. When an inversion sprains occur the rapid stretch on the peronei muscles can cause some tearing and strain to the muscle. Joint sprains are graded using the following scale2:
- Mild pain with little to no swelling
- Minor tears and / or stretching of the ligament
- Minimal loss of function with some joint stiffness
- Full symptomatic / functional recovery takes a few days *
- Moderate to severe pain with swelling
- Partial tear of ligaments
- Moderate loss of function with some joint stiffness
- Full symptomatic / functional recovery takes 2-3 months *
- Severe initial pain followed by little or no pain
- Profuse swelling and joint stiffness
- Complete rupture of ligaments (severe laxity in the absence of swelling)
- Complete loss of function
- Full symptomatic / functional recovery can take up to 4 months *
* Ligaments may not recover full strength for a year or more. Now that you understand the anatomy and mechanism of ankle sprains there is only one more topic to explore before we can begin to explore some ways that ankle sprains can be prevented. This is the issue of risk factors for ankle sprains. There are proven ways to limit your risk. The following articles will examine the roles that shoes, ankle braces, ankle taping, and exercises play in preventing ankle sprains.
 Hamill J, Knutzen KM. Biomechanical Basis of Human Movement 2nd ed. Baltimore: Lippincott Williams & Wilkins 2003.
 Carnes MA, Vizniak NA. Quick Reference Clinical Chiropractic Conditions Manual. 1st ed. DC Publishing International 2004.
 Taylor, M. "Talofibular Ligament Injury". EMedicine.com 2005, 25 February 2007 Http://www.emedicine.com/sports/topic126.htm
 Carnes, Michael. Personal communication. February 2007.