Bones are essentially made up, a structural element called hydroxyapatite and a protein called collagen. Hydroxyapatite consists of small crystals of calcium and phosphorus and it provides stiffness to the bone. Collagen is a protein molecule which binds the hydroxyapatite crystals together and provides tensile strength to the bone. Osteoporosis is basically a skeletal condition which affects both these components of a bone in terms of decreased quality as well as quantity. This weakens the bone and makes them more prone to fracture even with minor fall.