Bone density: Bone density is the amount of bone tissue in a certain volume of bone. The most widely recognized BMD test is called a central dual-energy x-ray absorptiometry, or central DXA test. From Healthy Resources Is Your Back Pain Ankylosing Spondylitis?Osteoporosis: Bone Fracture Protection Featured Centers What Are the Best PsA Treatments for You?Understanding Biologics 10 Things People With Depression Wish You Knew Health Solutions From Our Sponsors Shot-Free MS Treatment Your Child and COVID-19