Expansion
Dorsal columns carry fine touch and proprioception; spinothalamic carries pain and temperature
Expansion
Dorsal column-medial lemniscus
- Modalities: fine touch, vibration, proprioception
- First order neurone ascends ipsilaterally to the medulla
- Decussates in the medulla as the internal arcuate fibres
- Damaged in subacute combined degeneration, tabes dorsalis and multiple sclerosis
Spinothalamic (anterolateral)
- Modalities: pain, temperature, crude touch
- Synapses in the dorsal horn, then decussates in the anterior white commissure within one or two segments
- Ascends contralaterally
The different decussation levels produce the classic patterns:
- Brown-Sequard (hemisection): ipsilateral loss of proprioception and power, contralateral loss of pain and temperature, a few segments below
- Syringomyelia: the expanding central cavity first interrupts the decussating fibres, giving a cape-like dissociated loss of pain and temperature with preserved touch
- Anterior spinal artery occlusion: loss of pain, temperature and power with preserved dorsal column function