If you've sprained your ankle, you know what severe pain is.

But maybe that sprain was a strain or possibly even a break.

The amount of pain in each case can be virtually equal. So, oftentimes the only way to find out what you have is to see a doctor.

Here are some facts on musculoskeletal injuries:

• Sprains are a stretch or tear of a ligament, the tissue connecting two bones. Ligaments stabilize and support the body's joints. For example, ligaments in the knee connect the upper leg with the lower leg. This lets you walk and run.
• Strains are a twist, pull, or tear of a muscle and sometimes a tendon. Tendons are cords of tissue that connect muscles to bones.
• Breaks are a fracture, chip, or complete break in bone, often caused by accidents, sports injuries, or bone weakness.

A sprain is caused by an injury that stresses a joint and overstretches or even ruptures supporting ligaments. This can happen from a fall, twist, or blow to the body,

In a mild sprain, a ligament is stretched, but the joint remains stable and is not loosened. A moderate sprain partially tears the ligament, causing the joint to be unstable. With a severe sprain, ligaments tear completely or separate from the bone. This loosening interferes with how the joint functions. You may feel a tear or pop in the joint. Although the intensity varies, all sprains commonly cause pain, swelling, bruising, and inflammation.

The ankle is the most commonly sprained joint. And a sprained ankle is more likely if you've had a previous sprain there. Repeated sprains can lead to ankle arthritis, a loose ankle, or tendon injury.

Acute strains are caused by stretching or pulling a muscle or tendon. Chronic strains are the result of overuse of muscles and tendons through prolonged, repetitive movement. Not getting enough rest during intense training can cause a strain.

Typical symptoms of a strain include:

• Pain
• Muscle spasm
• Muscle weakness
• Swelling
• Inflammation
• Cramping
• Bruising

In severe strains, the muscle, tendon, or both are partially or completely ruptured, resulting in serious injury. Some muscle function will be lost with a moderate strain, in which the muscle, tendon, or both are overstretched and slightly torn. With a mild strain, the muscle or tendon is stretched or pulled slightly.

These are some common strains:

• Back strain. This happens when the muscles that support the spine are twisted, pulled, or torn. Athletes who engage in excessive jumping or twisting—during basketball or volleyball, for example—are at risk for this injury.
• Hamstring muscle strain. This is when a major muscle in the back of the thigh tears or stretches. The injury can sideline a person for up to 6 months. The likely cause is muscle strength imbalance between the hamstrings and the quadriceps, the muscles in the front of the thigh. Kicking a football, running, or leaping to make a basket can pull a hamstring. Hamstring injuries tend to happen again.

The medical term for a broken bone is a fracture. An X-ray is usually needed to diagnose a fracture. Most fractures result in a visit to the doctor or urgent care because they require casting to immobilize the bone for healing. Seek urgent medical care if you have numbness, weakness, an open wound, visible bone, or deformed bone.

All sports and exercises, even walking, carry a risk of sprains. The areas of the body most at risk for a sprain depend on the specific activities involved. For example, basketball, volleyball, soccer, and other jumping sports share a risk for foot, leg, and ankle sprains.

Soccer, football, hockey, boxing, wrestling, and other contact sports put athletes at risk for strains. So do sports that feature quick starts, like hurdling, long jump, and running races. Gymnastics, tennis, rowing, golf, and other sports that need extensive gripping put participants at higher risk for hand strains. Elbow strains often happen in racquet, throwing, and contact sports.

A severe sprain or strain may need surgery or immobilization, followed by physical therapy. Mild sprains and strains may need rehab exercises and a change in activity during recovery.

In all but mild cases, your doctor should evaluate the injury and establish a treatment and rehab plan.

Meanwhile, rest, ice, compression, and elevation (called RICE) usually will help reduce damage caused by sprains and strains. Start RICE right away after the injury.

RICE relieves pain, limits swelling, and speeds healing. It's often the best treatment for soft-tissue injuries, like sprains and strains. Here's what to do:

• Rest. Move the injured area as little as possible to allow healing to begin.
• Ice. Apply ice right away to reduce inflammation, which causes more pain and slows healing. Cover the injured area with an ice pack wrapped in a thin towel for about 15 to 20 minutes, 3 to 4 times a day.
• Compression. Using a pressure bandage helps prevent or reduce swelling. Use an elastic bandage and wrap the injured area without making it so tight that it will cut off the blood supply.
• Elevation. Raise the injured area above the level of the heart. Prop up a leg or arm while resting it. You may need to lie down to get your leg above your heart level.

Do all four parts of the RICE treatment at the same time. If you think you have a more serious injury, like a broken bone, call your doctor right away.

No one is immune to sprains and strains. But here are some tips to help reduce your risk for injury:

• Take part in a conditioning program to build muscle strength.
• Do stretching exercises every day.
• Always wear shoes that fit correctly.
• Nourish your muscles by eating a well-balanced diet.
• Warm up before any sports activity, including practice, and use or wear protective equipment that's right for that sport.
• If you smoke, quit smoking. Smoking increases the chance of strains, sprains and broken bones and can slow or prevent healing.