Maxillary Sinus Anatomy — MFDS Part 1 MCQ

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EasyAnatomy (Head & Neck)Maxillary Sinus AnatomyMFDS Part 1

The floor of the maxillary sinus is most commonly in close anatomical relation to the apices of which group of teeth?

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Correct answer: D — Maxillary premolars and molars

The correct answer is D: maxillary premolars and molars. The floor of the maxillary sinus descends into the posterior maxillary alveolar process and may lie very close to, or between, the roots of these teeth. This relationship explains the risk of oro-antral communication following extraction of an upper posterior tooth and the potential spread of posterior dental infection to the sinus. Maxillary incisors and canines are generally situated anterior to the main sinus floor, although anatomical extension towards the canine region can occur. All mandibular options are incorrect because the maxillary sinus lies within the maxilla, not the mandible. The identity of the single closest posterior root varies between individuals, so no particular first-molar root should be described as universally closest.

Reference: Royal Devon and Exeter NHS Foundation Trust. Dental Extractions, section: Sinus problems. November 2018. https://www.royaldevon.nhs.uk/media/l3zdavmg/dental-extractions-rde-18-184-001-north-devon.pdf