What are the three possible pathways a preganglionic sympathetic axon can take after reaching a trunk ganglion?

A preganglionic sympathetic axon can synapse in the same trunk ganglion, at the same level. It can ascend or descend the sympathetic trunk to synapse in a trunk ganglion at a higher or lower level. Or it can pass through the trunk ganglion without synapsing, travel via splanchnic nerves, and synapse in a distant collateral (prevertebral) ganglion.

The three pathways are defined by where the preganglionic fiber synapses with a postganglionic neuron. First, it may synapse in the same trunk ganglion it entered, meaning the synapse occurs at the same spinal cord level. Second, it may travel up or down the sympathetic trunk and synapse in a trunk ganglion at a different level. Third, it may pass through the trunk ganglion without any synapse there, emerge as part of a splanchnic nerve, and synapse in a collateral ganglion located anterior to the vertebral column.