There are many causes of trismus. Aetiology can be roughly divided into muscle spasm, mechanical interference, extracapsular ankylosis, intracapsular ankylosis. Trismus caused by mechanical interference between postero-lateral wall of zygoma-maxillary complex and coronoid process following reduction of fractured facial bone is rare. Especially on maxillary bone fracture, when we faced the trismus following removal of intermaxillary fixation, we got used to solve that problem by physical exercise. We obtained good results by coronoidectomy on patients with limited mouth opening who were referred from department of plastic surgery, St. Marys' hospital, the Catholic university of Korea. We report our experience with literature review.