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Maxillary Sinus Floor — NDEB AFK MCQ

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EasyBiomedical SciencesMaxillary Sinus FloorNDEB AFK

Which structure forms the floor of the maxillary sinus?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: BAlveolar process of the maxilla

The floor of the maxillary sinus is formed by the alveolar process of the maxilla. The root apices of the maxillary premolars and molars (especially the second premolar, first molar, and second molar) often project into or are in intimate contact with the sinus floor. This anatomical relationship explains: (1) why maxillary posterior tooth infections can cause sinusitis; (2) the risk of oroantral communication during extraction; and (3) why sinus augmentation (sinus lift) may be needed before implant placement.

Reference: Moore – Clinically Oriented Anatomy, 9th ed., 2019