 Hemi-facial spasm is a facial movement disorder that consists of tonic and chronic involuntary movements of muscles observed by the facial nerve. In this patient's example, you can see movements around the eye, around the mentalus, and I think it's easiest to see that these movements particularly are chronic. Occasionally, you'll see superimposed tonic movements, particularly around the mouth. Here's another example of a patient's facial movements. His are secondary to a cerebellopontin-angle epidermoid tumor. The first patient's was a sequelae of a Bell's palsy. Here you can see the movements around the obicularis muscles, and here movements around the mentalus. Although oftentimes this disorder is idiopathic, one should suspect compression of the seventh nerve, perhaps from a tumor or a dolicoactatic basilar artery. Other times it can be the sequelae of trauma or a Bell's palsy. Oftentimes, however, it's simply idiopathic.