All of the following are features of myositis ossificans except -

Ans. is 'b' i.e., It matures from inside out Myositis ossificanso Myositis ossificans is the extraskeletal hetrotropic ossification that occurs in muscles and other soft tissueso Myositis ossificans may be:-i) Traumatic (most common - 80%)ii) Non - traumatic (Pseudomalignant myositis ossificans)iii) Progressive (Myositis ossificans progressive)Traumatic (Post-traumatic) myositis ossificanso Trauma is the most important cause of myositis ossificans. Usually there is history of severe single injury. It is more common in children.o Most commonly involved joint is elbowfollowed by hip.o There is history of trauma around the elbow, i.e. fracture supracondylar humerus, dislocation of elbow or surgery with extensive periosteal stripping.o Massage to the elbow and vigorous passive stretching to restore movements are aggravating factor. It occurs in muscles which are vulnerable to tear under heavy loads, such as quadriceps, adductors, brachicilis, biceps, and deltoid.o X-ray finding is characteristic and shows distinct peripheral margin of mature ossification and a radiolucent center of immature osteoid & primitive mesenchymal tissue.