<prompt> What is the most common site of osteosarcoma:Lower end of femurUpper end of humerusLower end of tibiaUpper end of femur  <response>: Ans. is a i.e. lower end of femur Common sites in decreasing order of frequency:Lower end of femurUpper end of tibia Upper end of humerusSome other common sites Osteoclastoma - lower end of femur Ewings -tibia Ivory osteoma -frontal sinus Osteoid osteoma -tibia adamantinoma -mandible Chordoma -sacrum and cervical spine Multiple myeloma -vertebra Enchondroma -small bones of hand and feet Simple bone cyst -upper end of humerus Aneurysmal bone cyst -lower end of humerus Bone secondaries -vertebra Osteochondroma -metaphysis of femur Rhabdomyosarcoma -head and neck area 