Bone density is a term which means how much amount of bone minerals you have in the bone tissue. The concept of the bone density is the mass which you have of minerals per volume of bone. This is a definition which is given in physics sense. Also there is a medical definition in which is said that bone density is a proxy which is given from optical density per cm2 of the bone surface upon the imaging. In the medicine the bone density is used by doctors to see if you have chances of getting osteoporosis or you have broken bones in your body. In the radiology or nuclear hospitals it is used the procedure which is called densitometry which is also used to measure the bone density. When doctors are using this method, then you are not feeling pain. Also the radiation exposure is small.
This measurement process is also non – invasive. When doctors are trying to measure your bone density, then they are making these tests over the upper part of the hip and over the lumbar spine. If the hip and lumbar spine are not accessible, then doctors can scan the forearm. When you have poor density, then you have increased risk of getting fractures. People who are suffering from fractures to their pelvis and legs are one of the most common problems in the world. This is a condition which is affecting the elderly women at most. When they are affected by fractures, then they cannot move, they have big medical host also they can have a risk of death. When you are making a mineral bone density test, then you see how healthy your bones are. BMD test can show you if you have osteoporosis. Also it will show you how you are reacting of the osteoporosis treatment and if you have a risk of getting broken bones.  This test is used to scan people for osteoporosis and bone fractures and to show them how they can improve the density. People who have strong bones should not be tested about their bone density.
Here are the risk factors for low bone density for which people should do bone density test:
- Individuals with primary hyperparathyroidism 
- Individuals with a history of eating problems 
- Males age 70 
- Females age 65 
- Individual with vertebral abnormalities
- Individual being monitored to assess the response or efficacy on an approved osteoporosis drug therapy 
- People over age 50 with any of the following: low body weight; previous bone fractures from minor trauma; a parent with a hip fracture; rheumatoid arthritis
- Individuals receiving or planning to receive long – term glucocorticoid therapy (steroid therapy) 
Also there is another group which is increasing the risk of getting low bone density such as people who are smoking, people who are drinking alcohol, people who have Vitamin D deficiency and the long – term corticosteroid drugs.  When people have done the density tests, then they can be diagnosed with two conditions such as osteopenia and osteoporosis. If you have some of these conditions, then you must consult with your physician. Doctors are making the central DXA test at most. This is not painless test. It looks like when you are doing an x – ray test. When you are doing this test, then the bone density of your spine and hip can be measured. Peripheral bone density tests are measuring the bone density in the wrist, lower arm, heel or finger.
When these tests are done, then you should know that they are used for screening purposes. Also when these tests are done, they can measure if some individual will need another test for the bone density. When you are doing bone density test, then you are measuring your bone mineral density compared with some standard or norm of the bone density. This kind of test is not 100% sure, but it can be used to predict if some person will have bone fractures in the future. In most cases when you are making a bone density test, then your bone density is compared to healthy 30 years old adult and then you have a T – score. The normal bone density is between +1 and -1. If you have -2.5, then you have osteoporosis. If you have score between -1 and -2.5, then you have low bone density mass, but you are not diagnosed with osteoporosis.
Above are some of the few facts on Bone density.
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 Bandeira F, Cusano NE, Silva BC, et al. Bone disease in primary hyperparathyroidism. Arq Bras Endocrinol Metabol. 2014;58(5):553–61
 Sahni S, Mangano KM, McLean RR, et al. Dietary approaches for bone health: lessons from the Framingham Osteoporosis Study. Current Osteoporosis Reports. 2015;13(4):245–55.
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 Kelly W, Van Natta ML, Covar RA, et al. The effect of long-term corticosteroid use on bone mineral density in children: A prospective longitudinal assessment in the Childhood Asthma Management Program (CAMP) study. Pediatrics. 2008;122(1):e53–e61.