Calcium and other minerals finish the job by hardening the area. This on going process of breakdown and replacement is known as bone remodeling. From infancy to early adulthood, more bone is built than removed. After early adulthood, more bone is taken away that is built or replaced. Osteoporosis occurs when we lose too much bone.
Healthy bone looks like a honey comb, with strong interconnection strands.
In osteoporosis, cortical bone thins out. The once uniform holes of the trabecular bone become irregular and large, leaving frail bone which is easily fractured. When osteoporosis is present in the spine, pressure from the normal body weight can cause what is known as a compression fracture. Over time, these fractures may lead to back pain, loss of height, and a rounded curvature of the spine known as dowagers hump. In long bones, such as those of the legs, the ends have a relatively large amount of porous trabecular bone.