Brown-Séquard Syndrome: The Daily PANCE Blueprint
A 22-year-old man is brought to the emergency department after being stabbed in the back, just to the right of the midline at the mid-thoracic level. He has weakness of the right leg with a brisk right knee reflex and an upgoing right toe, and he cannot feel vibration or sense the position of his right great toe. On pinprick and cold testing, pain and temperature sensation are lost in the left leg, starting about two levels below the wound. Which spinal cord lesion best explains these findings?
A. Damage to the anterior two-thirds of the cord
B. Damage around the central canal of the cord
C. Hemisection of the right side of the cord
D. Hemisection of the left side of the cord
E. Isolated damage to the dorsal columns
Answer and topic summary
The answer is C. Hemisection of the right side of the cord
This is Brown-Séquard syndrome, a hemisection of the spinal cord, classically from a penetrating injury. The findings follow where each tract crosses. The corticospinal tract has already crossed in the medulla, so weakness and upper motor neuron signs are ipsilateral. The dorsal columns (vibration and proprioception) ascend on the same side and also cross in the medulla, so those losses are ipsilateral too. The spinothalamic tract (pain and temperature) crosses within 1 to 2 segments of entering the cord, so the lesion causes contralateral pain and temperature loss starting 1 to 2 levels below the injury. Same-side weakness and vibration loss plus opposite-side pain loss puts this lesion on the right. Anterior cord syndrome causes weakness and pain loss on both sides with vibration preserved. Central cord syndrome weakens the arms more than the legs, usually after a neck hyperextension injury in an older adult. Isolated dorsal column loss, as in B12 deficiency or tabes dorsalis, spares strength and pain sensation. Of the incomplete cord syndromes, Brown-Séquard has the best prognosis.
View blueprint lesson
Smarty PANCE Content Blueprint Review:
Covered under ⇒ PANCE Blueprint Neurology ⇒ ⇒
