This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Surgery
A patient with external hemorrhoids develops pain while passing stools. The nerve mediating this pain is: 
Select and explain. 
A. Hypogastric nerve, B. Pudendal nerve, C. Splanchnic visceral nerve, D. Sympathetic plexus
B: Pudendal nerve
Answer: B: Pudendal nerve 
Explanation: Pudendal nerve: Root Value Course Branches and supply S2, S3,S4 Leaves pelvis through greater sciatic foramen Enter perineum through lesser sciatic foramen Main sensory motor nerve of perineum and sensory nerve of external genitalia Dorsal nerve of penis/Clitoris Inferior rectal nerve supply anal mucosa (lower 1/2) perineal skin and external anal sphincter Perineal nerve Ref: Gray&;s 40th edition Pgno: 1098