During a DXA scan of the forearm, which bones are predominantly measured?

• A. Humerus and radius
• B. Radius and ulna
• C. Ulna and carpals
• D. Humerus and ulna

Answer: (B)

During a DXA (Dual-energy X-ray Absorptiometry) scan of the forearm, the measurement primarily focuses on the radius and ulna. These two bones are significant in evaluating bone density, particularly in assessing conditions such as osteoporosis. The radius is favored because it is a weight-bearing bone and is often involved in fractures associated with low bone density. The ulna is measured alongside the radius to provide a comprehensive analysis of the bone density in the forearm region.

The reason the other options aren't the correct choice is that they include bones that are either not measured as primary targets (like the humerus or carpals) or do not represent the most relevant bones when assessing forearm bone density. Overall, the inclusion of both the radius and ulna provides a better understanding of the bone health in this area, making it the correct choice for measurement during a DXA scan of the forearm.