Tehran University of Medical Sciences Journal of Craniomaxillofacial Research 2345-5489 2 3-4 2016 02 17 147 150 EN Masoud Fallahi-Motlagh Department of Oral and Maxillofacial Surgery, School of Dentistry, Urmia University of Medical Science, Urmia, Iran. Yousef Janbaz Department of Oral and Maxillofacial Surgery, School of Dentistry, Urmia University of Medical Science, Urmia, Iran. Sallahadin Zahedi Department of Oral and Maxillofacial Surgery, School of Dentistry, Urmia University of Medical Science, Urmia, Iran. 2016 02 17 2016 02 17 Myositis ossificans (MO) is a pathologic bone formation in soft tissue with unknown pathogenesis. In this article, we reported a case of long standing MO of right medial pterygoid muscle with severe limitation of mouth opening. https://jcr.tums.ac.ir/index.php/jcr/article/view/46 https://jcr.tums.ac.ir/index.php/jcr/article/download/46/81