Intermittent open-mouth locking of the temporomandibular joint in a cat

Impingement of a mandibular coronoid process on the ipsilateral zygomatic arch resulted in intermittent open-mouth locking of the temporomandibular joint in a 3-year-old male cat. Radiographic evaluation of the temporomandibular joints did not reveal abnormalities. Locking could not be recreated by manipulation of the mandible in the anesthetized cat, but the left coronoid process briefly contacted the left zygomatic arch. Excision of the rostroventral portion of the left zygomatic arch failed to stop the locking episodes; however, later excision of the rostroventral portion of the right zygomatic arch did prevent recurrence of locking.