page_title: Peripheral nervous system
section_title: Lumbosacral plexus (L1–Co1)
hierarchical_section_title: Peripheral nervous system / Structure / Somatic nervous system / Lumbosacral plexus (L1–Co1)
caption_attribution_description: English: 3D Medical Animation still shot of Lumbosacral Plaxus of human nervous system
context_page_description: The peripheral nervous system is one of two components that make up the nervous system of bilateral animals, with the other part being the central nervous system. The PNS consists of the nerves and ganglia outside the brain and spinal cord. The main function of the PNS is to connect the CNS to the limbs and organs, essentially serving as a relay between the brain and spinal cord and the rest of the body. Unlike the CNS, the PNS is not protected by the vertebral column and skull, or by the blood–brain barrier, which leaves it exposed to toxins and mechanical injuries.
  The peripheral nervous system is divided into the somatic nervous system and the autonomic nervous system. In the somatic nervous system, the cranial nerves are part of the PNS with the exception of the optic nerve, along with the retina. The second cranial nerve is not a true peripheral nerve but a tract of the diencephalon. Cranial nerve ganglia originated in the CNS. However, the remaining ten cranial nerve axons extend beyond the brain and are therefore considered part of the PNS. The autonomic nervous system exerts involuntary control over smooth muscle and glands.
context_section_description: The anterior divisions of the lumbar nerves, sacral nerves, and coccygeal nerve form the lumbosacral plexus, the first lumbar nerve being frequently joined by a branch from the twelfth thoracic. For descriptive purposes this plexus is usually divided into three parts:
  lumbar plexus
  sacral plexus
  pudendal plexus
caption: 3D Medical Animation still shot of Lumbosacral Plexus
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