Many of us have felt a muscle in some part of our body suddenly and involuntarily tighten, causing a twitch or even severe ...

"Muscle spasms usually occur in the calf or thigh ... But they can also happen in one's arms, feet, or hands, and sometimes even in one's stomach muscles or along the rib cage.

Lip twitching, when your lip shakes or trembles involuntarily, may result from muscle spasms associated with drinking too much coffee or a potassium deficiency. However, a twitching lip can ...