The spinal segments L1 to L5 refer to the five lumbar vertebrae located in the lower back. These segments are part of the lumbar spine, which supports the upper body and allows for movement and flexibility. Each lumbar vertebra is numbered from L1 at the top to L5 at the bottom, with L5 connecting to the sacrum. The L1-L5 segments protect the spinal cord and provide attachment points for muscles and ligaments. They play a crucial role in bearing weight and facilitating activities such as bending and lifting. Proper function of these segments is essential for overall mobility and stability.