What area is referred to by the 'Lumbar region' in human anatomy?

The lumbar region in human anatomy specifically refers to the lower back area, which is situated between the thoracic region (upper back) and the sacral region (near the pelvis). It encompasses the five lumbar vertebrae, labeled L1 to L5, and is critical for several functions, including supporting the weight of the upper body, allowing for various movements such as bending and twisting, and providing stability to the spine.

This distinction is important for understanding regional anatomy, as the lumbar area plays a significant role in posture and mobility, and it is a common site for pain and injury due to its structural role in weight-bearing and movement. In contrast, the other options describe different anatomical regions that do not align with the definition of the lumbar region.