Bone decalcification is the decrease in the amount of calcium in the bones, calcium being one of the elements that ensures their strength. It can affect a single bone or the entire skeletal system. The symptoms include mainly pain along the affected bones. The bones are weakened and more susceptible to fractures even from minor injuries at the advanced stages. Bone decalcification has various causes, the main one being a diet low in calcium and vitamin D deficiency (needed for calcium uptake in the bones) common in the elderly. Other diseases such as osteoporosis, osteomalacia, or bone tumors are responsible for decalcification.