Stapedius Innervation — MFDS Part 1 MCQ

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ModerateAnatomy (Head & Neck)Stapedius InnervationMFDS Part 1

During middle-ear surgery, a small motor nerve entering the stapedius muscle is damaged. From which cranial nerve does this branch arise?

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Correct answer: E — Facial nerve (VII)

The correct answer is **A, the facial nerve (VII)**. Stapedius receives motor fibres through the nerve to stapedius, a branch of the facial nerve within the facial canal. Loss of this supply impairs contraction of stapedius and may produce hyperacusis. The principal anatomical distractor is V3: its motor supply is to the other middle-ear muscle, tensor tympani. The glossopharyngeal nerve contributes sensory fibres to the middle ear through the tympanic plexus but does not innervate stapedius. The vagus provides limited sensory innervation around the external ear, while the vestibulocochlear nerve carries auditory and vestibular sensory information and forms the afferent side of auditory reflex pathways; neither supplies motor fibres to stapedius.

Reference: StatPearls Publishing, Anatomy, Head and Neck: Middle Ear, section on middle-ear muscle innervation, updated 2026. https://pubmed.ncbi.nlm.nih.gov/29493963/