What is a Sprain?
What Is the Difference Between a Sprain and
A sprain is a stretch
and/or tear of a ligament (a band of fibrous tissue that
connects two or more bones at a joint). One or more
ligaments can be injured at the same time. The severity of
the injury will depend on the extent of injury (whether a
tear is partial or complete) and the number of ligaments
A strain is an injury to
either a muscle or a tendon (fibrous cords of tissue that
connect muscle to bone). Depending on the severity of the
injury, a strain may be a simple overstretch of the muscle
or tendon, or it can result from a partial or complete tear.
What Causes a Sprain?
A sprain can result from a fall, a
sudden twist, or a blow to the body that forces a joint out
of its normal position and stretches or tears the ligament
supporting that joint. Typically, sprains occur when people
fall and land on an outstretched arm, slide into a baseball
base, land on the side of their foot, or twist a knee with
the foot planted firmly on the ground.
Where Do Sprains Usually Occur?
Although sprains can occur in both
the upper and lower parts of the body, the most common site
is the ankle. More than 25,000 individuals sprain an ankle
each day in the United States.
The ankle joint is supported by
several lateral (outside) ligaments and medial (inside)
fig. 1). Most ankle sprains happen when the foot turns
inward as a person runs, turns, falls, or lands on the ankle
after a jump. This type of sprain is called an inversion
injury. The knee is another common site for a sprain. A blow
to the knee or a fall is often the cause; sudden twisting
can also result in a sprain (see
frequently occur at the wrist, typically when people fall
and land on an outstretched hand. A sprain to the thumb is
common in skiing and other sports. This injury often occurs
when a ligament near the base of the thumb (the ulnar
collateral ligament of the metacarpo-phalangeal joint) is