‌Hemifacial spasm is a disorder of the nerves and muscles that causes nonpainful involuntary twitching on one side of the face. Many people refer to hemifacial spasms as lip muscle spasms. Hemifacial ...

Add Yahoo as a preferred source to see more of our stories on Google. A muscle spasm, also known as a cramp, twitch or charley horse, is the sudden and involuntary forced contraction of a muscle.

A muscle cramp is a painful tightness in a muscle due to a sudden, involuntary contraction. Various factors may contribute to muscle cramping, but the underlying cause is often unclear. Muscle cramps ...

Dehydration may be one cause of muscle cramps, and some evidence suggests that electrolyte imbalances also contribute to them. Muscle cramps are painful, involuntary contractions of the muscles that ...