Cortical bone comprises what percentage of skeletal body mass?

• A. 50%
• B. 70%
• C. 80%
• D. 90%

Answer: (C)

Cortical bone accounts for approximately 80% of skeletal body mass. It is the dense outer surface of bone that comprises the majority of the long bones in the body, providing strength and stability. This type of bone is much denser than trabecular (or cancellous) bone, which makes up the remaining portion of the skeletal mass and is typically found in the vertebrae and ends of long bones. Understanding the significance of cortical bone is vital in bone densitometry, as it plays a critical role in assessing overall bone health and fracture risk.

While the other percentages provided suggest significant portions of skeletal mass, none accurately reflect the well-established proportion that cortical bone occupies in the human skeletal system.