Which part of the spine corresponds to the lower back?

The lumbar region of the spine corresponds to the lower back and consists of five vertebrae, labeled L1 to L5. This area is crucial for bearing the body's weight and facilitating movement, as it provides support and flexibility for activities such as bending and lifting.

The lumbar vertebrae are larger and stronger than those in the cervical and thoracic regions due to the increased load they support. The lumbar area also houses important structures for the spinal nerves that extend to the lower limbs and pelvic organs, making it integral to both movement and sensation in the lower body.

In contrast, the cervical region is located in the neck, consisting of seven vertebrae, and primarily supports the head and facilitates its movement. The thoracic region, located in the upper and mid-back, includes twelve vertebrae and is designed to support the rib cage and protect the heart and lungs. The sacral region is situated below the lumbar vertebrae and consists of five fused vertebrae, forming the back of the pelvis. It plays a role in connecting the spine to the hip bones but does not correspond to the lower back in the same way as the lumbar region.