1. Psoas and iliacus have similar actions but different nerve supplies. What is the nerve supply of each?
   
   
2. Which muscle holds down the 12th rib on respiration?
   
   
3. Iliohypogastric and ilio-inguinal nerves are both L1. Which one is the main nerve and which one is the collateral branch? What is the evidence for this in the sensory distribution of the buttock skin?
   
   

Answers