A 13-year-old Quarter Horse mare presented to the Cornell Large Animal Internal Medicine Service for left-sided facial nerve paralysis and a corneal ulcer in the left eye. She had atrophy of the left temporalis muscle and masseter muscle, and her mandible deviated to the right, indicative of trigeminal nerve dysfunction. Neurologic exam did not reveal vestibular deficits or ataxia. Guttural pouch endoscopy confirmed diagnosis of unilateral temporohyoid osteoarthropathy (THO). Computed tomography revealed a fracture of the left stylohyoid bone mid-shaft as well as a fracture of the left temporal bone. There was gas near the trigeminal canal which would account for the trigeminal nerve deficits. A left-sided ceratohyoidectomy was performed to remove mechanical stress on the temporohyoid joint. The combination of trigeminal and facial nerves deficits with the absence of vestibular nerve deficits is a unique presentation for THO which has not been reported in the literature.