Tracts

• spinothalamic tract for temperature and pain
• spinothalmic tract 1st order neuron is the drg

  2nd order neuron decussate in anterior white commissure and leaves contralaterally

  3rd order neuron: primary somatosensory cortex
• spinothalamic first synapse :posterior horn of spinal cord

  2nd synapse: VML
• dorsal column for pressure vibration concious proprioception fine touch
• dorsal column

  1st order neuron DRG

  2nd order neuron decussate in medulla and ascend contralerally as medial leminiscus

  3rd order primary somatosensory cortex
• dorsal column synapses

  1s synapse : nucleus gracilis nucleus cuneatus

  2nd synapse: VPL
• Corticospinal tract

  1st order neuron: upper motor neuron descend ipsilaterally through posterior limb of internal capsule and the cerebral peduncle decussate at caudal medulla (pyramidal decussation) then descend contralaterally

  2nd order neuron LMN
• corticospinal synapses

  1st synapse Anterior horn

  2nd synapse NMJ