This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: JIPMER 2019, Subject name: Anatomy
[{'content': 'Posterior ethmoidal sinus drains into (JIPMER May 2019) \nSelect and explain. \nA. Spheno-ethmoidal recess, B. Superior meatus, C. Middle meatus, D. Inferior meatus', 'role': 'user'}, {'content': 'Answer: B \nExplanation: - There are 3 groups of ethmoidal air sinuses Anterior Middle Posterior - Posterior ethmoidal sinus is opening in lateral wall of the nose. - Lateral wall of the nose has 3 elevations called superior, middle & inferior turbinates / conchae - Under each turbinate, there is space called meatus called superior, middle & inferior meatus - Posterior ethmoidal sinus is opening in superior meatus - Anterior & middle sinus is opening in middle meatus - Middle meatus have hiatus semilunaris At front of hiatus semilunaris frontal air sinus opens The anterior, middle ethmoidal sinus respectively Maxillary sinus opens slightly posterior; In the region of hiatus semilunaris in middle meatus - Naso-lacrimal duct opens in the inferior meatus on Anterior aspect - Inferior turbinate is largest turbinate & its meatus is largest meatus - Eustachian tube opens behind inferior turbinate in lateral wall of nasopharynx', 'role': 'assistant'}]