This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: NEET Jan 2020, Subject name: ENT
Cough reflex on scratching the floor of external auditory meatus is due to which nerve? 
Select and explain. 
A. Auricular branch of vagus, B. Auriculo temporal, C. Greater auricular nerve, D. Facial nerve
A: Auricular branch of vagus
Answer: A: Auricular branch of vagus 
Explanation: Nerve Supply of External acoustic meatus Anterior wall and roof by auriculotemporal nerve Posterior wall and floor by auricular branch of vagus nerve (Arnold N) Posterior wall of auditory canal also receives innervations by facial nerve through auricular branch of vagus Cough reflex is d/t internal laryngeal N. Cough's reflex during syringing is d/t Arnold's Nerve