You're relaxing on the sofa when suddenly your eyelid starts twitching. Or perhaps it's a muscle in your arm, your leg, or ...

If you've ever slammed your brakes to avoid hitting an animal darting across the road, scored the game-winning point during a ballgame, or experienced what seems like superhuman strength or speed when ...

Infectious agents can cause muscle twitching and spasms, too. The most commonly known is probably tetanus, which causes a phenomenon called lockjaw, where the neck and jaw muscles contract to the ...