Anterior spinal artery syndrome of the cervical hemicord.

Three patients developed signs of a unilateral cervical cord lesion 6 to 36 h after the acute onset of severe cervico-brachial pain. The neurological deficit progressed over 6 to 18 h. On the painful side a central Horner's syndrome, a hemiparesis with plegia of the hand, and a slight pallhypaesthesia were found. On the opposite side thermhypaesthesia and hypalgesia were noted with a level at the dermatome C5 or C6. T2-weighted MR images revealed in one patient a small area of increased signal intensity restricted to one half of the cervical cord, and electromyography in another patient showed after 6 months evidence of segmental chronic denervation. Both abnormalities were found at the clinically expected level. The findings are consistent with a small infarction of the cervical cord in the perfusion territory of a central (sulco-commissural) artery, a duplicated anterior spinal artery or an anterior spinal branch of the vertebral artery.