Ankle sprains occur when
ligaments that connect the bones in the foot, ankle,
and lower leg stretch or tear.
An inversion injury, the most
common cause of ankle sprains, occurs when the ankle rolls outward and the foot
turns inward. It results in stretching and tearing of the ligaments on the
outside of the ankle.
In an eversion injury, the ankle rolls
inward and the foot turns outward, damaging the ligaments at the inside of the
In a "high" ankle sprain, a less common type of injury,
ligaments that join the two lower leg bones together above the ankle, called
the syndesmosis, are injured. This usually happens if the foot is forced up, or
if the leg is forcefully twisted while the foot is planted. This injury can
occur either by itself or with an inversion or eversion sprain. If the
ligaments of the syndesmosis are injured, the sprain is more severe and takes
longer to heal.
See a picture of
types of ankle sprains .
Damage to the ligament varies from simply
stretched or slightly torn to completely torn. Your doctor will grade your
- Grade I is stretching or
slight tearing of the ligament with mild tenderness, swelling, and stiffness.
The ankle feels stable, and it is usually possible to walk with minimal
- Grade II is a larger but incomplete
tear with moderate pain, swelling, and bruising. The ankle sometimes
feels stable, but the damaged areas are tender to the touch, and walking is
- Grade III is a complete tear of
the affected ligament or ligaments with severe
swelling and bruising . The ankle is unstable and may feel "wobbly." Walking is
usually not possible, because the ankle gives out and there is intense pain,
although initial pain may quickly subside. See a picture of an
ankle sprain .