Myositis ossificans traumatica Myositis ossificans traumatica (MOT) is an inflammatory process of muscle in its early stage. There is heterotrophic growth of bone in muscle and other soft tissues previously exposed to trauma and hematoma. Common examples are Horse Riders Bone and Infantrymen's drill bone on the deltoid. The commonly involved muscles are quadriceps femoris, brachialis anticus, adductor muscles of the thigh and deltoid muscle. It usually occurs in adolescents and adults.