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: ENT
[{'content': 'Facial recess or the posterior sinus is bounded by - \nSelect and explain. \nA. Medially by the vertical part of VII nerve, B. Laterally by the chorda tympani, C. Above by the fossa incudis, D. All of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Facial recess or Posterior sinus – It is a depression in the posterior wall of the middle ear.\nIt is bounded by:\nMedially – Vertical part of VIII nerve\nLaterally – Chorda tympani\nAbove – Fossa incudis\nImportance – This recess is important surgically, as direct access can be made through this into the middle ear without disturbing posterior canal wall. (Posterior tympanotomy approach)', 'role': 'assistant'}]