Definition

Noun: 1. A network of nerves: Specifically, a nerve plexus formed by the ventral (anterior) branches of the first four lumbar spinal nerves (L1-L4). It is located in the posterior abdominal wall, within the psoas major muscle. 2. A network of lymphatic vessels: A less common anatomical usage referring to a lymphatic plexus situated along the lower portion of the aorta and the iliac blood vessels.

Usage Examples

• Primary Meaning (Nerve Plexus):
  • The lumbar plexus supplies motor and sensory innervation to parts of the abdominal wall, thigh, and leg.
  • An injury to the lumbar plexus can cause weakness or numbness in the front of the thigh.
  • The femoral nerve is a major branch arising from the lumbar plexus.
• Secondary Meaning (Lymphatic Plexus):
  • The lumbar plexus of lymph vessels drains lymph from the lower limbs and pelvic organs.

Advanced Usage

• Clinical Context: In medical diagnosis, "lumbar plexus block" refers to an anesthetic injection targeting this nerve network to provide pain relief for surgery on the hip or thigh.
• Anatomical Description: Often discussed in relation to adjacent structures, e.g., "The lumbar plexus is embedded in the substance of the psoas major muscle."

Variants and Related Words

• Lumbosacral Plexus: A term sometimes used to describe the combined lumbar and sacral plexuses as a functional unit for the lower limb.
• Plexus (n.): A general term for a network of nerves, blood vessels, or lymphatic vessels.

Synonyms

• Nerve network (for the primary definition).
• Plexus lumbalis (the Latin anatomical term).

Related Phrases

• Lumbar plexus neuropathy: Damage or disease affecting the nerves of the lumbar plexus.
• Lumbar plexus injury: Trauma resulting in dysfunction of the plexus.

Noun

1. a plexus of nerves formed by the ventral branches of the first four lumbar nerves
2. a lymphatic plexus located along the lower portion of the aorta and iliac vessels