Muscle Spasms and Cramps

Muscle spasms (SPAH-zumz) and cramps occur when a muscle involuntarily contracts (tightens) and does not relax. Spasms and cramps can occur in part, or all, of one or more muscles. A muscle spasm or cramp is often called a charley horse.

What Are Muscle Spasms and Cramps?

Muscle spasms and cramps are sudden, persistent contractions. They can occur in any muscle in the body but most often occur in the legs. The most common muscle groups affected by spasms and cramps include: