What type of bone do DXA measurements typically integrate?

• A. Cortical bone only
• B. Trabecular bone only
• C. Cortical and trabecular bone
• D. Soft tissue and muscle

Answer: (C)

DXA, or Dual-energy X-ray Absorptiometry, is a technique specifically designed to measure bone mineral density (BMD) by utilizing two different X-ray energies. This method is capable of evaluating both cortical and trabecular bone, which are the two primary types of bone found in the human skeleton.

Cortical bone, also known as compact bone, forms the outer layer of bones and provides strength and support. It is dense and makes up about 80% of the total bone mass in the body. Trabecular bone, on the other hand, is spongy and less dense, found primarily at the ends of long bones and within the vertebrae. This type of bone is crucial for providing structural support and for metabolic activities.

DXA measurements are particularly important as they reflect the overall health of the skeleton, capturing the density of both types of bone to provide a comprehensive assessment of bone strength. This integrated measurement is valuable for diagnosing conditions like osteoporosis, as both cortical and trabecular bone contribute to overall fracture risk. Therefore, the combination of both types of bone in DXA measurements allows healthcare providers to make more informed decisions about patient care and treatment strategies.