Bone Density
<p ><b>Bone density</b> (or <b><a href="http://en.wikipedia.org/wiki/Bone_mineral" title="Bone mineral" >bone mineral</a> density</b>) is a <a href="http://en.wikipedia.org/wiki/Medical_term" title="Medical term" class="mw-redirect" >medical term</a> normally referring to the amount of mineral matter per square centimeter of<a href="http://en.wikipedia.org/wiki/Bone" title="Bone" >bones</a>.<sup id="cite_ref-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Bone_density#cite_note-0" >[1]</a></sup> Bone density (or <b>BMD</b>) is used in clinical medicine as an indirect indicator of <a href="http://en.wikipedia.org/wiki/Osteoporosis" title="Osteoporosis" >osteoporosis</a> and <a href="http://en.wikipedia.org/wiki/Fracture" title="Fracture" >fracture</a> risk.</p>
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There may be associations between some forms of <a href="http://en.wikipedia.org/wiki/BMD" title="BMD" >BMD</a> and diet<sup id="cite_ref-7" class="reference" ><a href="http://en.wikipedia.org/wiki/Bone_density#cite_note-7" >[8]</a></sup></p>
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This medical bone density is not the true <a href="http://en.wikipedia.org/wiki/Physics" title="Physics" >physical</a> "density" of the bone, which would be computed as mass per volume. It is measured by a procedure called <i><a href="http://en.wikipedia.org/wiki/Densitometry" title="Densitometry" >densitometry</a></i>, often performed in the <a href="http://en.wikipedia.org/wiki/Radiology" title="Radiology" >radiology</a> or <a href="http://en.wikipedia.org/wiki/Nuclear_medicine" title="Nuclear medicine" >nuclear medicine</a> departments of <a href="http://en.wikipedia.org/wiki/Hospital" title="Hospital" >hospitals</a> or <a href="http://en.wikipedia.org/wiki/Clinic" title="Clinic" >clinics</a>. The measurement is painless and non-invasive and involves low <a href="http://en.wikipedia.org/wiki/Radiation" title="Radiation" >radiation</a> exposure. Measurements are most commonly made over the <a href="http://en.wikipedia.org/wiki/Lumbar_spine" title="Lumbar spine" class="mw-redirect" >lumbar spine</a> and over the upper part of the <a href="http://en.wikipedia.org/wiki/Hip" title="Hip" >hip</a>.<sup id="cite_ref-pmid18587077_1-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Bone_density#cite_note-pmid18587077-1" >[2]</a></sup> The forearm may be scanned if the hip and lumbar spine are not accessible. Average density is around 1500 kg m<sup >−3</sup></p>
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There is a <a href="http://en.wikipedia.org/wiki/Statistics" title="Statistics" >statistical</a> association between poor bone density and higher probability of fracture. Fractures of the legs and <a href="http://en.wikipedia.org/wiki/Pelvis" title="Pelvis" >pelvis</a> due to falls are a significant <a href="http://en.wikipedia.org/wiki/Public_health" title="Public health" >public health</a> problem, especially in elderly women, leading to much medical cost, inability to live independently, and even risk of death. Bone density measurements are used to screen women for osteoporosis risk and to identify those who might benefit from measures to improve bone strength.</p>