Lumbar plexus

1. What 2 branches does L1 give off? What nerves arise from the upper branch? The lower branch?
2. What nerve roots come together to form the obturator nerve? Where does the accessory obturator nerve come off?
3. What nerve roots join together to form the lateral cutaneous nerve of the thigh?
4. What nerve roots joint to form the femoral nerve?
5. What happens to the rest of L4?

Answers:
1. The lower branch goins with a branch from L2 to from the genitofemoral nerve to the scrotum. The upper branch gives off the iliohypogastric and ilioinguinal nerves to the lower abdominal wall.
2. The anterior branch of L2-L4 form the obturator nerve while branches from L3 and L4 may form the accessory obturator nerve (10% people).
3. The ventral rami of L2 and L3 form the lateral cutaneous nerve of the thigh.
4. The posterior rami of L2 and L3 and part of L4 form the femoral nerve.
5. The rest of L4 joins the sacral plexus.