What is the most appropriate next step in the treatment of a 16-year-old male presents with a firm, moderately tender mass in the lateral distal right upper arm and he was HIT in the same area about two weeks ago during football practice? Initially, his coach noticed prominent hematology in the same area.  Does evidence of a calcified mass lightly separated from the humeral shaft?

Avoidance of activity until resolution of pain-the patient in this vignette has myositis ossificans of the brachialis muscle. following blunt trauma, a hematoma develops that gradually becomes increasingly bony as tenderness subsides. calcification then develops within the hematoma, forming mature-appearing bone. the bony mass is always slightly separated from the humeral shaft, which helps to differentiate this condition from osteosarcoma. treatment is rest with avoidance of both active and passive range of motion exercises until pain is absent. resection during the active stage of formation is contraindicated because new bone formation will quickly recur. resection of ectopic bone is usually not indicated once new bone formation is complete unless range of motion is adversely affected. board testing point: recognize the signs and symptoms of myositis ossificans and determine the most appropriate next step in the treatment of the patient.