The lesser splanchnic nerve emerges from the unification of the medial branches of the ninth and tenth thoracic sympathetic ganglia and their interconnecting trunk.  It consists of myelinated preganglionic efferent and visceral afferent fibers.  It descends infero-medially on the vertebral bodies, piercing the crus of the diaphragm along with the greater splanchnic nerve to terminate in the aorticorenal ganglion.