Disorders Of The Neurological System Practice Test

Anterior spinal artery syndrome occurs when the anterior two-thirds of the spinal cord are impaired, because the anterior spinal artery supplies the corticospinal tracts and the spinothalamic tracts. This pattern produces weakness of movement and loss of pain and temperature sense below the level of the lesion, while the dorsal columns that carry vibration and proprioception are spared since they are supplied by the posterior spinal arteries. So you see acute bilateral motor weakness with loss of pain and temperature below the lesion, with preserved vibration and proprioception. The other patterns don’t fit: loss of vibration and proprioception points to dorsal column involvement, pure sensory loss would reflect different pathways, and a normal exam wouldn’t align with an acute vascular insult.