The anterior spinal artery supplies the anterior two-thirds of the spinal cord. Its occlusion classically produces which syndrome, sparing which modality?

• A Ipsilateral motor loss and contralateral pain/temperature loss only
• B Bilateral loss of pain, temperature, and motor function below the lesion; dorsal column (proprioception/vibration) spared ✓
• C Bilateral complete sensorimotor loss including proprioception
• D Pure motor paraplegia with preserved all sensation

Explanation

The anterior spinal artery (ASA) supplies the anterior horn (lower motor neurons), lateral corticospinal tract, and spinothalamic tract — the anterior two-thirds of the cord. ASA syndrome therefore produces bilateral flaccid weakness at the lesion level (anterior horn) and spastic paraplegia below (corticospinal tract), with bilateral loss of pain and temperature below the lesion (spinothalamic tract). Proprioception, vibration, and discriminative touch (posterior columns), which are supplied by the posterior spinal arteries, are intact — the defining feature of ASA syndrome and its distinguishing point from cord transection. It can occur with aortic surgery, embolism, or hypotension.

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

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Written and medically reviewed by the StethoPrep medical team.