A 64-year-old hypertensive man suddenly develops weakness of the LEFT limbs with loss of vibration and joint position sense on the LEFT side. On protrusion, the tongue deviates to the RIGHT, and there is wasting of the right half of the tongue. MRI shows an infarct in the medial medulla. Which artery supplies the infarcted territory?

• A Posterior inferior cerebellar artery
• B Anterior spinal artery ✓
• C Anterior inferior cerebellar artery
• D Posterior spinal artery

Explanation

This is medial medullary (Dejerine) syndrome: corticospinal tract, medial lemniscus, and hypoglossal nerve fascicles all lie in the paramedian medulla supplied by the anterior spinal artery (with upper medullary contribution from the vertebral artery). PICA occlusion causes the lateral medullary syndrome with pain temperature loss and ataxia, not tongue weakness, so A is the killer distractor. The triad of contralateral hemiplegia, contralateral loss of proprioception, and ipsilateral hypoglossal palsy localises to the medial medulla.

Reference: Snell's Clinical Neuroanatomy, 9th ed.

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Written and medically reviewed by the StethoPrep medical team.