CN III Interpeduncular Fossa — FRCA Primary MCQ

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HardAnatomyCN III Interpeduncular FossaFRCA Primary

The oculomotor nerve (CN III) exits the brainstem at which location?

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Correct answer: E — The interpeduncular fossa (between the cerebral peduncles)

CN III emerges from the interpeduncular fossa on the ventral surface of the midbrain between the cerebral peduncles. It passes forward through the cavernous sinus (lateral wall) and enters the orbit via the superior orbital fissure. It carries motor fibres to most extraocular muscles and parasympathetic fibres (Edinger-Westphal nucleus) for pupillary constriction and accommodation.

Reference: RCoA 2021 Primary FRCA Curriculum