The skull has flat bones (occipital parietal frontal nasal and lacrimal) and the thoracic cavity (sternum and spine), and the pelvis (ilium and the ischium). These bones are designed to safeguard internal organs such as the brain, heart, and the pelvic. Flat bones tend to be flat and provide protection, http://treatment67726.vblogetin.com/11297067/what-is-the-relationship-between-bones-and-the-problem-of-arthritis