Question:easy
Which valve is present at the opening of the nasolacrimal duct?
Which valve is present at the opening of the nasolacrimal duct?
Show Hint
It is the mucosal flap where the duct enters the inferior meatus.
Updated On: Jun 24, 2026
- Hasner's valve
- Heister valve
- Spiral valve
- None
Show Solution
The Correct Option is A
Solution and Explanation
Step 1: Trace the tear pathway: punctum, canaliculus, lacrimal sac, then nasolacrimal duct, which drains into the inferior meatus of the nose.
Step 2: Guarding the terminal opening of this duct is a mucosal flap that functions as a one-way valve. This structure is named after Hasner, so the valve of Hasner is correct.
Step 3: The other choices belong elsewhere. Heister valve, which is the same as the spiral valve, lies within the cystic duct and regulates bile flow, so it has no role here.
\[\boxed{\text{Hasner's valve}}\]
Step 2: Guarding the terminal opening of this duct is a mucosal flap that functions as a one-way valve. This structure is named after Hasner, so the valve of Hasner is correct.
Step 3: The other choices belong elsewhere. Heister valve, which is the same as the spiral valve, lies within the cystic duct and regulates bile flow, so it has no role here.
\[\boxed{\text{Hasner's valve}}\]
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