A sprained ankle occurs following a sudden sideways or twisting movement of the foot. An ankle sprain can occur during athletic events or during everyday activities. All it takes is an awkward step or an uneven surface to cause an ankle sprain--that is why sprained ankles are among the most common foot and ankle injury. Even though ankle sprains are common, they are not always minor injuries. Some people with repeated or severe sprains can develop long-term joint pain and weakness. Treating a sprained ankle can help prevent ongoing ankle problems. How does an ankle sprain occur? A sprained ankle usually occurs when a person lands from jumping or running on to an uneven surface. For example, sprained ankles are often seen when basketball players come down from a jump and land on another player's foot. Ankle sprains also occur with more routine daily activities such as stepping off a curb or slipping on ice. What happens inside the ankle when it is sprained? An ankle sprain is an injury to the ligaments in the ankle. Ligaments are bands of tissue?like rubber bands?that connect one bone to another and bind the joints together. In the ankle joint, ligaments provide stability by limiting side-to-side movement. The severity of an ankle sprain depends on whether the ligament is stretched, partially torn, or completely torn, as well as on the number of ligaments involved. Ankle sprains are not the same as strains, which affect muscles rather than ligaments. There are two broad categories of ankle sprain: Inversion Ankle Sprains: This the most common type of ankle sprain and occurs when the foot is inverted, falling inward. When this type of ankle sprain happens, the outer, or lateral, ligaments are stretched too far. There are three ligaments that attach to the outer side of the ankle. About 90% of ankle sprains are inversion injuries. Pain is always on the outside of the ankle, and there is usually no pain on the inside of the ankle joint.

Eversion Ankle Sprains: The other type of sprained ankle is called an eversion injury, where the foot is twisted outwards. When this occurs, the inner ligament, called the deltoid ligament, is stretched too far. Patients will have pain on the inner side of the ankle.

What are the symptoms of an ankle sprain? Common symptoms associated with an ankle sprain are pain at the site of the tear with immediate swelling and bruising. The ankle area is usually tender to touch, and it hurts to move. In more severe sprains, you may hear and/or feel something tear, along with a pop or snap. You will probably have extreme pain at first and will not be able to walk or even put weight on your foot. The degree of symptoms tends to correlate well with the extent of the damage to these ligaments. Grade I Ankle Sprain: Grade I ankle sprains cause stretching of the ligament. The symptoms tend to be limited to pain and swelling. Most patients can walk without crutches, but may not be able to jog or jump. Grade II Ankle Sprain: A grade II ankle sprain is more severe partial tearing of the ligament. There is usually more significant swelling and bruising caused by bleeding under the skin. Patients usually have pain with walking, but can take a few steps. Grade III Ankle Sprain: Grade III ankle sprains are complete tears of the ligaments. The ankle is usually quite painful, and walking can be difficult. Patients may complain of instability, or a giving-way sensation in the ankle joint. As said before, pain and swelling are the most common symptoms of an ankle sprain. Patients often notice bruising over the area of injury. This bruising will move down the foot towards the toes in the days after the ankle sprain--the reason for this is gravity pulling the blood downwards in the foot.

Why is prompt medical attention needed? There are four key reasons why an ankle sprain should be promptly evaluated and treated by a foot and ankle specialist:

1. An untreated ankle sprain may lead to chronic ankle instability, a condition marked by persistent discomfort and a "giving way" of the ankle. You may also develop weakness in the leg.

2. You may have suffered a more severe ankle injury along with the sprain. This might include a serious bone fracture that could lead to troubling complications if it goes untreated.

3. An ankle sprain may be accompanied by a foot injury that causes discomfort but has gone unnoticed thus far.

4. Rehabilitation of a sprained ankle needs to begin right away. If rehabilitation is delayed, the injury may be less likely to heal properly. In my next article I will talk more about how to diagnose and treat ankle sprains.