Post-infectious myositis ossificans in medial, lateral pterygoid muscles: A case report and review of the literature.

Myositis ossificans (MO) is a disease where heterotropic bone forms within a muscle or other type of soft tissue. MO is classified into two groups, MO progressiva and post-traumatic MO. It rarely occurs in the masticatory muscles and thus, only 20 cases involving the masticatory muscles have been reported since 2001. The majority of the reported cases occurred due to trauma, repeated injury or surgical manipulation. However, in a small number of cases, no specific traumatic event was identified as the cause of MO. To the best of our knowledge, this is the first case of post-infectious MO to be reported in the medial and lateral pterygoid muscles.