Overview

Hemifacial spasm is a nervous system disorder in which the muscles on one side of your face twitch involuntarily. Hemifacial spasm is most often caused by a blood vessel touching a facial nerve, but it may be caused by a facial nerve injury or a tumor, or it may not have a cause.

Causes

Hemifacial spasm is most often caused by a blood vessel touching a facial nerve. It can also be caused by a facial nerve injury or a tumor. Sometimes there's no identifiable cause.