Spinal Nerves: Plexus II

The lumbar, sacral, and coccygeal plexuses serve the lower body.

The lumbar plexus is mainly composed of the first four lumbar spinal nerves, that branch out into the iliohypogastric, ilioinguinal, genitofemoral, lateral femoral cutaneous, femoral, and obturator, nerves.

It provides sensory and motor innervation to the muscles and the skin of the abdomen, pelvis, and parts of the lower limbs.

The sacral plexus — primarily located in the pelvis — comprises the nerves between the fourth lumbar and fourth sacral.

The sacral plexus branches out into several nerves, including the pudendal, superior and inferior gluteal, posterior femoral cutaneous, and sciatic nerves — the thickest and longest nerves in the body.

These nerves provide sensory and motor innervation mainly to the pelvis and legs.

Sometimes, the lumbar and sacral plexus are collectively called the lumbosacral plexus because their nerves substantially overlap.

The coccygeal plexus is the smallest, located at the coccyx. It is composed of only one nerve — called the anococcygeal nerve — that innervates the skin of the coccygeal region.