‌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 ...

Though many people experience muscle twitching, it's often incorrectly identified as a muscle spasm. While both are involuntary contractions of a muscle, muscle spasms and muscle twitching aren't ...

Tight and rigid muscles are often the result of injury. Sometimes, muscle tightness and rigidity can occur with other symptoms, such as muscle pain and spasms, or reduced mobility. Mild muscle ...