A 55-year-old man has an infarct of the upper lateral medulla. He shows drooping of the ipsilateral soft palate, hoarseness, dysphagia, and loss of the gag reflex on the side of the lesion with intact tongue movement. Which nucleus is destroyed?

• A Nucleus solitarius
• B Hypoglossal nucleus
• C Spinal nucleus of the trigeminal nerve
• D Nucleus ambiguus ✓

Explanation

The nucleus ambiguus in the medulla gives motor fibres to striated muscles of the pharynx, larynx and palate via the glossopharyngeal and vagus nerves. Its lesion produces ipsilateral palatal paralysis, hoarseness, dysphagia and an absent efferent limb of the gag reflex. The hypoglossal nucleus moves the tongue and is intact here, the solitary nucleus is sensory and visceral, and the spinal trigeminal nucleus mediates facial pain and temperature, none of which matches this pattern.

Reference: Gray's Anatomy, 42nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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