The lumbar plexus is a network of nerves in the lumbar region of the human body. It is formed by the ventral branches of the twelfth thoracic, and the first, second, third and fourth lumbar spinal nerves (T12, L1 - L4).
The lumbar plexus is situated within the psoas major muscle. Short motor branches arise from the lumbar plexus, that supply the psoas major, psoas minor and quadratus lumborum muscles.
Six long branches arise from the lumbar plexus: