Lumbar plexus

The Lumbar Plexus is a web of nerves (a nervous plexus) located in the lumbar region of the body which forms part of the larger lumbosacral plexus. It is formed by the divisions of the first four lumbar nerves (L1-L4) and from contributions of the subcostal nerve (T12), which is the last thoracic nerve.

Anatomy

The lumbar plexus is formed within the psoas major muscle and is arranged into anterior and posterior divisions, with the anterior divisions of the upper three lumbar nerves connected to the posterior divisions of the lower two lumbar nerves.

Nerves

The nerves of the lumbar plexus include:

• Iliohypogastric nerve (L1)
• Ilioinguinal nerve (L1)
• Genitofemoral nerve (L1-L2)
• Lateral femoral cutaneous nerve (L2-L3)
• Obturator nerve (L2-L4)
• Femoral nerve (L2-L4)
• Lumbosacral trunk (L4-L5)

Function

The lumbar plexus and its nerves provide motor and sensory function to the lower body, including the back, abdomen, groin, thighs, knees, and calves.

Clinical significance

Damage to the lumbar plexus can result in lumbar plexus injury, which can cause various symptoms such as pain, numbness, or weakness in the legs.

See also

• Nervous system
• Spinal nerve
• Lumbosacral plexus

External links

• Lumbar Plexus at the National Library of Medicine's Medical Subject Headings (MeSH)

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  Diagram of the lumbar plexus
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  Gray's Anatomy illustration of the lumbar plexus
• Branches of the lumbar plexus
  Branches of the lumbar plexus
• Schematic of the lumbar plexus
  Schematic of the lumbar plexus