Our human body is built to move: we can easily make fluid motions with over 360 joints and about 700 skeletal muscles inside us.However, sometimes people break their legs due to intensive sports or experience pains in their bones, joints and even spines because of improper use over a long period of time.You go to see a doctor who recommends X-rays, a CT scan or magnetic resonance imaging (MRI), and during these procedures you're told not to move your body.