Which of the following structures is most likely to be obstructed?

A 22-year-old man presents to his physician complaining of nasal congestion. Rhinoscopy demonstrates focal inflammation with mucosal edema in the inferior nasal meatus. Drainage from which of the following structures is most likely to be obstructed?

Anterior ethmoidal air cells
Frontonasal duct
Maxillary sinus
Nasolacrimal duct
Posterior ethmoidal air cells

Correct answer
Nasolacrimal duct
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correct answer: D

Nasolacrimal duct (Choice D) is correct. Tears drain from the conjunctival sac into the lacrimal sac, through the nasolacrimal duct into the inferior nasal meatus.
Anterior ethmoidal air cells (Choice A), frontonasal duct (Choice B), and maxillary sinus (Choice C) all typically drain into the middle meatus. They should not be affected by obstruction of the inferior nasal meatus.

Posterior ethmoidal air cells (Choice E) usually drain into the superior meatus. They should not be affected by obstruction of the inferior nasal meatus.