A sprained ankle occurs when the strong ligaments that support the ankle stretch beyond their limits and tear. Ankle sprains are common injuries that occur among people of all ages. They range from mild to severe, depending upon how much damage there is to the ligaments.
Most sprains are minor injuries that heal with home treatments like rest and applying ice. However, if your ankle is very swollen and painful to walk on — or if you are having trouble putting weight on your ankle at all, be sure to see your doctor.
Without proper treatment and rehabilitation, a more severe sprain can weaken your ankle—making it more likely that you will injure it again. Repeated ankle sprains can lead to long-term problems, including chronic ankle pain, arthritis, and ongoing instability.
Ligaments are strong, fibrous tissues that connect bones to other bones. The ligaments in the ankle help to keep the bones in proper position and stabilize the joint.
Most sprained ankles occur in the lateral ligaments on the outside of the ankle. Sprains can range from tiny tears in the fibers that make up the ligament to complete tears through the tissue.
If there is a complete tear of the ligaments, the ankle may become unstable after the initial injury phase passes. Over time, this instability can result in damage to the bones and cartilage of the ankle joint.
What causes an ankle to sprain?
Your foot can twist unexpectedly during many different activities, such as:
- Walking or exercising on an uneven surface
- Falling down
- Participating in sports that require cutting actions or rolling and twisting of the foot—such as trail running, basketball, tennis, football, and soccer
- During sports activities, someone else may step on your foot while you are running, causing your foot to twist or roll to the side.
What are the symptoms of a sprained ankle?
A sprained ankle is painful. Other symptoms may include:
- Tenderness to touch
- Instability of the ankle—this may occur when there has been complete tearing of the ligament or a complete dislocation of the ankle joint.
If there is severe tearing of the ligaments, you might also hear or feel a "pop" when the sprain occurs. Symptoms of a severe sprain are similar to those of a broken bone and require prompt medical evaluation.