Ankle sprains

[Jason Yan]

Ankle sprains are tears in the ligaments that hold the ankle in place.

Usually, ankle sprains occur when people walk or run on uneven ground and the foot turns in, stretching the ligaments of the ankle beyond their limits and tearing them.
Typically, the ankle is swollen, and walking is painful.
Doctors can usually diagnose ankle sprains based on the physical examination and sometimes x-rays.
Treatment usually includes PRICE (protection, rest, ice, compression with a bandage, and elevation of the leg) for mild sprains, immobilization and physical therapy for moderate and severe sprains, and sometimes surgery for very severe sprains.

(See also Overview of Sprains and Other Soft-Tissue Injuries.)
In the United States, about 25,000 ankle sprains are reported each day.
The ankle joint consists of the shinbone (tibia), smaller leg bone (fibula), ankle bone (talus), and several ligaments, which hold the bones of the ankle in place (see figure Ligaments: Holding the Ankle Together).
The severity of the sprain depends on which ligaments are injured and how badly they are stretched or torn. Based on severity, doctors classify sprains as

1st-degree: Mild
2nd-degree: Moderate to severe
3rd-degree: Very severe

Most ankle sprains are mild.
Sprains usually occur when the foot turns in, causing the sole of the foot to face the other foot (called inversion). This injury usually damages the ligaments on the outside of the ankle. Inversion can occur when people walk on uneven ground, especially when they step on a rock or off the edge of a curb.
Less commonly, the ankle is sprained when the foot turns out (called eversion).
When the foot turns out, several other injuries may occur:

An avulsion fracture: The ligament that attaches the shinbone (tibia) to one of the foot bones on the inside of the ankle may pull a small piece of bone off the shinbone. Turning the foot out tends to cause an avulsion fracture rather than a sprain because this ligament is so strong.
A high ankle sprain: The ligaments that hold the shinbone and the other lower leg bone (fibula) together at their lower ends may be torn.
Fracture of the fibula: The fibula may be broken at the ankle or sometimes near the knee.

When the ankle is sprained, nerves may also be damaged.
Certain conditions tend to cause the foot to turn (or ankle to roll) out and thus increase the risk of a sprain:

Having had a previous sprain that made the ligaments in the ankle loose
Having weak leg muscles or nerve damage in the legs
Wearing certain types of shoes, such as spiked heels