The general cause of osteoporosis is that bone is reabsorbed faster than it is replenished. Bone is reabsorbed in a matter of weeks by osteoclasts in contrast to osteoblasts that need months to produce new bone. Over time, any process that accelerates the rate of bone remodeling will result in net bone loss. Phosphate, calcium and vitamin D help maintain bone homeostasis. Malnutrition or the bodies inability to absorb these compounds can contribute to disease progression. Relatively minor falls or impacts can result in severe fractures to people with osteoporosis. Both types of bone have a similar molecular composition but cortical bone and cancellous bone are different in their architecture. Cortical bone is dense and compact. Cancellous bone forms a web like spongy net work that gives bone internal strength while minimizing overall weight. In persons with osteoporosis both the hard exterior shell and internal support structure of bone is weakened by decreased mass and poor matrix