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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Which valve is present at opening of nasolacrimal duct?
assistant
The correct answer is  Nasolacrimal duct opens into inferior meatus and is closed by a mucosal flap called Hasner's valve.Heister valve (spiral valve) is present in cyctic duct.