The skull is comprised of flat bones (occipital parietal frontal, lacrimal and nasal) and the thoracic cavity (sternum and spine), and the pelvis (ilium and ischium). These bones are used to guard internal organs such the brain, heart as well as the pelvic and pelvic. Flat bones are a little http://andrespemvc.bloggosite.com/11574633/what-is-the-relationship-between-arthritis-and-bones