Plexus

Collection of Nerve Fibres from One Source with Specific Destinations

• Somatic/Visceral

• Lumbar Plexus → L1-L4 (& T12: Subcostal Nerve)
• Sacral Plexus → L4-S4

Organisation

• Ventral/Dorsal Root
  • Efferent/Afferent
• Branches: Meningeal, Anterior/Posterior Rami, White Ramus Communicans

Lumbar Plexus

• What nerve roots are the lumbar plexus derived from? Ventral/Dorsal Rami?
• Inside which muscle does the lumbar plexus form?
• What are the 6 named branches of the lumbar plexus? (Cranial → Caudal)
• Which of these nerves emerge medial to the psoas?
• Which nerve emerges anterior to the psoas?
• Which nerves emerge lateral to the psoas major?
• Nerve Pathway & Structures Innervated
• How can you remember which nerve roots each nerve derives from?