L1, L2, L3, L4, L5

L1, L2, L3, L4, and L5 refer to levels of spinal nerves originating from the lumbar and sacral regions of the spine. L1 is the first lumbar nerve, and as you go down to L5, it exits lower in the lower back. These nerves form part of the peripheral nervous system, controlling various muscles and sensations in the lower back, hips, legs, and feet. The higher the number, the closer to the waist; the lower the number, the closer to the legs. They are critical for movement, sensation, and functions in the lower body.