A 6-year-old female spayed Pitbull presented for a 'crooked facial expression'. In this video, note the synchronicity between the EMG activity in the upper lip muscles with the fasciculations of the eyelids on the left side. This suggests involvement of proximal facial nerve segments in the generation of these spontaneous muscle movements. Disappearance of the abnormal facial expression under general anesthesia and return upon recovery, together with EMG findings, is supportive of hemifacial tetanus. In the human literature, hemifacial spasm is the commonly employed term. However, in veterinary literature, it is argued that hemifacial tetany/tetanus is the correct term.

We are grateful to Dr. Koen Santifort at Evidensia Arnhem for providing this amazing video.