A 58-year-old man develops right hypoglossal-type tongue weakness, right-sided loss of vibration and proprioception, and left hemiplegia with sparing of the face. MRI shows an infarct in the paramedian medulla. Which artery is occluded?

• A Posterior inferior cerebellar artery
• B Anterior spinal artery branch ✓
• C Paramedian branches of the basilar artery
• D Posterior cerebral artery

Explanation

This is medial medullary syndrome, or alternating hypoglossal hemiplegia, caused by occlusion of the anterior spinal artery branch or vertebral paramedian branches supplying the medial medulla. The triad involves the hypoglossal nerve fibres, the medial lemniscus carrying vibration and proprioception, and the pyramid containing corticospinal fibres. Facial sparing reflects the intact corticobulbar fibres, which leave higher in the brainstem. PICA occlusion gives the lateral medullary syndrome with cerebellar signs and pain temperature loss, none of which appear here.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.