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
[{'content': 'Tympanic plexus present in - \nSelect and explain. \nA. Tunica adventitia of internal jugular vein, B. Medial projection of middle ear cavity, C. Pa of tympanic membrane, D. All', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Medial projection of middle ear cavity Tympanic nerve arises from the glossopharyngeal nerve, just below the jugular foramen. It passes through the floor of middle ear and reaches onto the mucous membrane covering the promontory(2, where it splits into branches and joint branches of internal carotid plexus to form tympanic plexus. Promontary is round bulging in the medial or labyrinthine wall of middle ear cavityQ produced by the first turn of cholea.', 'role': 'assistant'}]