Sensory disturbances are usual manifestations of trigeminal neuropathy, but only a few cases of isolated unilateral pure trigeminal motor neuropathy were reported. We describe a rare case of a 65-year-old woman who presented with a 4-year history of progressive facial asymmetry and chewing weakness which was shown on imaging to be caused by unilateral atrophy of masticatory muscles, probably due to a neurovascular conflict between the third trigeminal branch and superior cerebellar vein. To the best of our knowledge, this probable association has never been described. We aimed through this article to describe the clinical presentation of this entity that clinicians might face in their daily practice and radiological aspect of it.