The sympathetic division of the ANS originates from thoracolumbar segments of the spinal cord (approximately T-1 to L-4, bilaterally).

For all regions of the body, the initial pathway for sympathetic preganglionic axons is identical:
       ventral root
       spinal nerve
       ramus communicans
       sympathetic trunk.

Only rami communicantes T-1 to L-4 contain myelinated preganglionic axons. All rami communicantes contain non-myelinated postganglionic axons.

Axons from sympathetic preganglionic neurons synapse in autonomic ganglia, shown in yellow to the left.

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to view the pathway to a particular region.)

The cell bodies of sympathetic preganglionic neurons are located in intermediolateral nuclei of the spinal cord. (A nucleus is a profile of a neuron column.) Each intermediolateral column forms a lateral gray horn in a thoracolumbar spinal cord transection.