Zygomatico coronoid ankylosis is a rare type of extra articular ankylosis. The most common cause is Jacobs Disease, which is due to osteochondroma of the coronoid process. In this pa-per we present a case where in the zygomatico-coronoid ankylosis is due to heterotopic ossi-fication, secondary to surgical trauma from previous operations. A literature search does not show any similar reported case. Brief review of possible prophylactic modalities for het-erotopic ossification is discussed.