Where are central sites of the skeleton located?

• A. Distal forearm and fingers
• B. Thoracic spine and lumbar spine
• C. Pelvic girdle and limbs
• D. Hands and feet

Answer: (B)

The central sites of the skeleton are primarily located in the thoracic spine and lumbar spine. These areas are crucial for bone densitometry because they represent sites where significant bone mass is typically found, and they are commonly affected by osteoporosis and other bone-related conditions. The lumbar spine, particularly, is where we often assess bone mineral density (BMD) to evaluate fracture risk and diagnose osteoporosis. The thoracic spine also houses vertebrae that are essential for overall spinal structure and health.

In contrast, the other options focus on locations that are not considered central sites for assessing density in the context of osteoporosis. The distal forearm and fingers, hands, and feet generally represent peripheral sites, which may demonstrate less sensitivity in detecting changes in bone density associated with osteoporosis compared to the central sites in the spine. The pelvic girdle and limbs, while important for movement and overall skeletal health, are not the primary focus in evaluating central bone density for conditions like osteoporosis.