Nerves in Your Lower Back
You have five pairs of lumbar spinal nerves labeled L1 to L5 . These nerves branch off your spinal cord, and exit through small holes between the bones called foramina. The part of the nerve that exits out of the spine is called the nerve root.
Your low back spinal nerves travel down each leg and are formed by 2 types of fibers. One type are sensory nerves that send (pain) messages to your brain. Motor fibers receive messages from your brain directing your muscles to move.
L1 spinal nerves provide sensation to your genital regions and groin. They contribute to hip movement.
L2, L3, and L4 spinal nerves provide sensation to the inner side of your lower leg, as well as the front part of your thigh. These nerves also control hip movements, as well as knee muscles.
L5 spinal nerves provide sensation to the big toe, upper part of the foot and the outer side of your lower leg. L5 nerves control your hip, knee, foot, and toe movements.
The L4 and L5 nerves (along with other nerves) contribute to the formation of the largest nerve in your body, the sciatic nerve. The sciatic nerve runs down the back of the butt into the back of your leg into your foot.