The Lumbar Plexus

Question 0

Origin

Answer 0

Ventral rami of L1-L4 nerves

Question 1

Location

Answer 1

• Post. part of psoas major

- Ant. to lumbar transverse processes

Question 2

Branches

Answer 2

1. Obturator nerve (originates from L2, L3, L4)
2. Femoral nerve (originates from L2, L3, L4)
3. Ilioinguinal nerve (originates from L1)
4. Iliohypogastric nerve (originates from L1)
5. Genitofemoral nerve (originates from L1, L2)

Question 3

Which muscle does the obturator nerve innervate?

Answer 3

• Emerges from med. border of psoas major
• Passes through pelvis to med. thigh
• Supplies adductor muscles of thigh

Question 4

Which muscle does femoral nerve innervate?

Answer 4

• Emerges from lat. border of psoas major
• Passes deep to inguinal ligament to ant. thigh
• Innervates iliacus muscle

Question 5

What are the cutaneous branches of the lumbar plexus?

Answer 5

Lateral femoral cutaneous nerve:

• Originates from L2, L3
• Runs inferolaterally on iliacus
• Enters thigh post. to inguinal ligament just med. to ASIS
• Innervates skin on anterolateral surface of thigh