A patient with a thoracic aortic dissection involving the origin of the anterior spinal artery presents with paraplegia and urinary retention but preserved dorsal column sensation (vibration and proprioception). This clinical syndrome is known as anterior spinal artery syndrome. The anterior spinal artery supplies all of the following EXCEPT:

• A Anterior horn cells (motor neurons)
• B Spinothalamic tracts (pain and temperature)
• C Posterior columns (gracile and cuneate fasciculi) ✓
• D Corticospinal tracts

Explanation

The anterior spinal artery supplies the anterior two-thirds of the spinal cord, including the anterior horn cells, corticospinal tracts, and spinothalamic tracts. The posterior columns (gracile and cuneate fasciculi) are supplied by the paired posterior spinal arteries, which arise from the posterior inferior cerebellar arteries. Therefore, anterior spinal artery occlusion preserves posterior column function (vibration, proprioception, fine touch) while causing motor paralysis (anterior horn + corticospinal) and loss of pain and temperature (spinothalamic) — the characteristic clinical triad of anterior cord syndrome.

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

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Written and medically reviewed by the StethoPrep medical team.