Following an infarction in the territory of the anterior spinal artery, a patient loses motor power and pain-temperature sensation below the lesion, but vibration sense, proprioception, and light touch remain intact. Which tract accounts for the preserved modalities?
- A Dorsal columns ✓
- B Corticospinal tract
- C Spinothalamic tract
- D Spinocerebellar tract
Correct answer: A. Dorsal columns
Explanation
The anterior spinal artery supplies the anterior two-thirds of the cord, including corticospinal and spinothalamic tracts, so their functions are lost in anterior cord syndrome. The dorsal columns carrying vibration, proprioception and fine touch are supplied by the paired posterior spinal arteries and escape, producing the characteristic dissociation. This syndrome may follow flexion-compression injuries or compromise of the artery of Adamkiewicz.
Reference: Ganong's Review of Medical Physiology, 26th ed.
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Written and medically reviewed by the StethoPrep medical team.