The anterior spinal artery (ASA) supplies the anterior two-thirds of the spinal cord. Anterior cord syndrome typically results from ASA occlusion. The posterior columns are SPARED because they receive blood from which separate vessels?

• A Posterior spinal arteries (PSA), arising from the posterior inferior cerebellar arteries and forming a plexiform network on the cord surface ✓
• B Radicular arteries entering at each segment, which supply only the posterior columns
• C The basilar artery via the posterior spinal arteries as a direct, unpaired vessel
• D Anterior spinal artery dorsal branches that wrap posteriorly via the posterolateral sulcus

Explanation

The posterior spinal arteries (two, one on each side) arise from the posterior inferior cerebellar arteries (PICA) and descend on the dorsolateral surface of the cord, reinforced at each level by posterior radicular arteries. They supply the posterior columns (fasciculus gracilis and cuneatus), dorsal horns, and posterolateral tracts. The anterior spinal artery supplies the anterior two-thirds including anterior horns, corticospinal tracts, and spinothalamic tracts. In anterior cord syndrome (flexion injury, aortic surgery), the posterior columns are intact, so proprioception and vibration are preserved while motor function and pain/temperature are lost. The PSA is not a single unpaired vessel.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.