Facts about sprains and strains
The body is meant to move. Muscles allow that movement to happen by contracting and making joints flex, extend and rotate. Muscles attach on each side of the joint to bone by thick bands of fibrous tissue called tendons. When a muscle contracts, it shortens and pulls on the tendon, which allows the joint to go through a range of motion.
A strain occurs when the muscle tendon unit is stretched or torn. The most common reason is the overuse and stretching of the muscle. The damage may occur in three areas:
- The muscle itself may tear.
- The area where the muscle and tendon blend can tear.
- The tendon may tear partially or completely (rupture).
Joints are stabilized by thick bands of tissue called ligaments which surround them. These ligaments allow the joint to move only in specific directions. Some joints move in multiple planes; therefore, they need more than one group of ligaments to hold the joint in proper alignment. The ligaments are anchored to bone on each side of the joint. If a ligament is stretched or torn, the injury is called a sprain.
What causes sprains and strains?
Sprains and strains occur when the body is put under stress. In these situations, muscles and joints are forced to perform movements for which they are not prepared or designed to perform. An injury can occur from a single stressful incident, or it may gradually arise after many repetitions of a motion.
What are signs and symptoms of sprains and strains?
The first symptom of a sprain or strain injury is pain. Other symptoms, such as swelling and spasm, can take time (from minutes to hours) to develop.
- Pain is always a symptom that indicates that there is something wrong with the body. It is the message to the brain that warns that a muscle or joint should be protected from further harm. In work, exercise, or sport, the pain may come on after a specific incident or it may gradually progress after many repetitions of a motion.
- Swelling almost always occurs with injury, but it may take from minutes to hours to be noticed. Any time fibers of a ligament, muscle, or tendon are damaged, some bleeding occurs. The bleeding (such as bruising on the surface of the skin) may take time to be noticed.
- Because of pain and swelling, the body starts to favor the injured part. This may cause the muscles that surround the injured area to go into spasm. Hard knots of muscle might be felt near the site of the injury.
- The combination of pain, swelling, and spasm causes the body to further protect the injured part, which results in difficulty with use. Limping is a good example of the body trying to protect an injured leg.
Medically reviewed by Aimee V. HachigianGould, MD; American Board of Orthopaedic Surgery
Young, Craig C. "Ankle Sprain." Medscape.com. Dec. 16, 2014. <http://emedicine.medscape.com/article/1907229-overview>.