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 (sensory nerve fibers) and an anterior root (motor nerve fibers). A spinal (dorsal root) ganglion is located at the proximal end of each posterior 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.
The first to fourth lumbar nerves give rise to anterior rami that together form the lumbar plexus. The fourth and fifth lumbar nerves give rise to anterior rami that combine with anterior rami from the first to fourth sacral nerves, forming the sacral plexus. Often, the sacral and lumbar plexus are collectively referred to as the lumbosacral plexus.
Related parts of the anatomy
