Disorders of the Neurological System Practice Test

Brown-Séquard syndrome comes from a hemisection of the spinal cord, so it presents a split in sensory loss due to the way different pathways cross.

The dorsal columns carry proprioception and vibration and stay on the same side as the lesion. When the cord is partially cut, those fibers on the same side are disrupted below the lesion, leading to ipsilateral loss of proprioception and vibration.

Pain and temperature fibers (the spinothalamic tract) cross to the opposite side within a couple of segments after they enter the spinal cord, then travel upward. Because they cross early, the pain and temperature loss appears on the opposite side, below the level of the lesion, starting a few segments below.

So the described pattern—loss of proprioception and vibration on the same side as the injury, and loss of pain and temperature on the opposite side below the lesion—fits Brown-Séquard syndrome. Patterns suggesting bilateral loss or ipsilateral pain/temperature loss don’t match the way these pathways cross and organize.