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Orbital Blow-Out Fracture — NDEB AFK MCQ

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ModerateOral SurgeryOrbital Blow-Out FractureNDEB AFK

Which bone is fractured in a 'blow-out' fracture of the orbit?

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

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Correct answer: COrbital floor (thin bone of the maxilla forming the roof of the maxillary sinus)

A blow-out fracture involves fracture of the orbital floor — the thin bone of the maxilla (and sometimes the medial orbital wall/lamina papyracea of the ethmoid) — caused by a sudden increase in intraorbital pressure from blunt trauma to the globe or orbital rim. Orbital contents (periorbital fat, inferior rectus or inferior oblique muscles) can herniate through the fracture into the maxillary sinus, causing enophthalmos (sunken eye), diplopia (restricted upward gaze from muscle entrapment), and infraorbital nerve paraesthesia. Orbital CT is diagnostic. Surgical repair is indicated for significant enophthalmos, persistent diplopia, or large floor defects.

Reference: Hupp – Contemporary Oral and Maxillofacial Surgery, 7th ed., 2019