Description
Five of the 31 pairs of spinal nerves emerge from the lumbar spine. These five pairs of spinal nerves are known as the lumbar nerves and are numbered from the first to the fifth lumbar nerves.
The lumbar nerves are mixed nerves as each is formed by the union of a posterior nerve root (sensory nerve fibers) and an anterior nerve root (motor nerve fibers). A spinal (dorsal root) ganglion is located at the distal end of each posterior nerve root. These ganglia contain the cell bodies of sensory nerve fibers. Each of the five lumbar nerves terminates by dividing into anterior and posterior rami. These rami convey sensory information from and send motor innervation to the pelvic region and lower limbs.
The first and second lumbar nerves send sympathetic axons to the sympathetic chain, which target the hindgut, pelvis, and lower limb.
