Adrenaline increases the "alertness" of the nervous system, meaning it's ready to trigger muscle contraction. It also increases the amount of blood flow and changes the tension of the muscles, which, ...

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 ...

After undergoing six root canals over the years, Tippy McInerny wasn’t surprised when her dentist gave her several shots of a local anesthetic and stretched her mouth open for more than an hour while ...

You’re sitting at your computer when it starts — that annoying flutter in your eyelid that feels like a tiny butterfly trapped under your skin. Most of the time, eye twitching is harmless and goes ...