This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
Referred otalgia from base of tongue or oropharynx is carried by nerve? 
Select and explain. 
A. Cranial nerve V, B. Cranial nerve VII, C. Cranial nerve IX, D. Cranial nerve X
C: Cranial nerve IX
Answer: C: Cranial nerve IX 
Explanation: The Jacobson nerve, tympanic branch of glossopharyngeal nerve (cranial nerve IX) directly innervates the ear but also has pharyngeal, lingual, and tonsillar branches to supply the posterior one-third poion of the tongue, tonsillar fossa, pharynx, eustachian tube, and parapharyngeal and retropharyngeal spaces. So any pathology involving those areas can lead to referred otalgia. Must know: Referred Otalgia: the source of the pain does not reside within the ear but, rather it originates from a source distant from the ear hence it is called as "referred otalgia". Any pathology residing within the sensory net of cranial nerves V, VII, IX, and X and upper cervical nerves C2 and C3 can potentially cause referred otalgia.