On a DXA scan, which vertebras resemble a "U" shape?

• A. L1, L2, and L3
• B. L4, L5, and S1
• C. T1, T2, and T3
• D. T12, L1, and L2

Answer: (A)

The correct answer indicates that the lumbar vertebrae, specifically L1, L2, and L3, have a characteristic "U" shape in a DXA scan. This morphology is primarily due to the unique anatomical features of these vertebrae, which include a broader body and a more pronounced arch compared to other vertebrae.

In the context of bone density assessments, the identification of vertebrae shapes is crucial for accurately assessing bone health. The "U" shape can be beneficial in distinguishing normal vertebral morphology from pathological changes, such as fractures or deformities that may arise from osteoporosis.

The shapes of the other vertebrae mentioned in the options do not exhibit this same "U" configuration. For instance, T12, L1, and L2 share some similarities with the lumbar vertebrae but are not as distinctly shaped in this manner as L1, L2, and L3. Furthermore, the thoracic vertebrae (like T1, T2, and T3) tend to have a different structure due to the need to articulate with the ribs, resulting in a different appearance altogether, lacking the characteristic "U" shape.

Understanding these morphological differences helps in both recognizing normal anatomy and identifying potential