**Core Concept**
A DEXA (Dual-Energy X-ray Absorptiometry) scan is a widely used non-invasive imaging technique for assessing bone mineral density (BMD), particularly in postmenopausal women at risk of osteoporosis. BMD is a critical factor in determining the risk of fractures and osteoporotic-related complications.

**Why the Correct Answer is Right**
The assessment of BMD via DEXA scan in lumbar vertebrae and femoral neck is crucial for evaluating the risk of fractures and osteoporosis in menopausal women. The lumbar spine and femoral neck are common sites for osteoporotic fractures, and measuring BMD at these sites helps clinicians to identify individuals at high risk of fractures. This information enables targeted interventions to prevent or treat osteoporosis.

**Why Each Wrong Option is Incorrect**
* **Option A:** Osteopenia is a condition characterized by a bone mineral density that is lower than normal but not low enough to be classified as osteoporosis. DEXA scans are indeed used to diagnose osteopenia, making this option incorrect.
* **Option B:** Osteoporosis is a condition that results from a decrease in bone mass and density, leading to an increased risk of fractures. DEXA scans are used to assess BMD, which is a key factor in diagnosing osteoporosis, making this option incorrect.
* **Option C:** Osteomalacia is a condition characterized by softening of the bones due to a deficiency of vitamin D or calcium. While DEXA scans can be used to assess BMD in patients with osteomalacia, this is not the primary reason for assessing BMD in menopausal women, making this option incorrect.

**Clinical Pearl / High-Yield Fact**
A DEXA scan score is classified as follows: T-score: -1 to 1 (normal), -1 to -2.5 (osteopenia), and less than -2.5 (osteoporosis). A T-score of less than -2.5 indicates a higher risk of fractures and osteoporotic-related complications.

**Correct Answer: D. Osteomalacia is not a primary indication for assessing bone mineral density in menopausal women via DEXA scan.**