DEXA scans measure density at which sites?

• A. Radius and ulna
• B. Skull and mandible
• C. Hips and lumbar spine
• D. Ribs and clavicles

Answer: (C)

DEXA measures bone mineral density at sites that best reflect fracture risk and give reliable, reproducible results. The most informative regions are the hips and the lumbar spine. The spine has a high content of trabecular bone, which tends to lose minerals earlier in osteoporosis, so it detects changes quickly. The hip, particularly the femoral neck and total hip, is a common fracture site and its measurement correlates strongly with hip fracture risk, making it a crucial target for diagnosis and risk assessment.

Other areas like the skull, ribs, clavicles, or peripheral sites (such as the radius) are not standard diagnostic targets for osteoporosis because they are less predictive of major fracture risk or are less reliable due to anatomical or degenerative changes. Peripheral measurements can be useful in specific scenarios, but the hip and lumbar spine remain the primary sites for routine DEXA assessment and for applying diagnostic thresholds.