Lumbar plexus

Lumbar plexus
Plan of lumbar plexus.
The lumbar plexus and its branches.
Details
FromT12, L1-L4
Identifiers
Latinplexus lumbalis
plexus lumbaris
TA98A14.2.07.002
TA26517
FMA5908
Anatomical terms of neuroanatomy

The lumbar plexus is a web of nerves (a nerve plexus) 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. Additionally, the ventral rami of the fourth lumbar nerve pass communicating branches, the lumbosacral trunk, to the sacral plexus. The nerves of the lumbar plexus pass in front of the hip joint and mainly support the anterior part of the thigh.[1]

The plexus is formed lateral to the intervertebral foramina and passes through psoas major. Its smaller motor branches are distributed directly to psoas major, while the larger branches leave the muscle at various sites to run obliquely down through the pelvis to leave under the inguinal ligament with the exception of the obturator nerve which exits the pelvis through the obturator foramen.[1]

  1. ^ a b Thieme Atlas of anatomy (2006), pp 470-471

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