Greater splanchnic nn.

The greater splanchnic nerves arise from the sympathetic trunk in the thorax and travel inferiorly to provide sympathetic innervation to the abdominal viscera. The nerves contain preganglionic sympathetic and visceral afferent fibers.

The greater splanchnic nerves travel through the diaphragm and enter the abdominal cavity, where their fibers synapse in the celiac ganglia. Some fibers also go to  the adrenal medulla, stimulating catecholamine release.

The greater splanchnic nerves contribute to the celiac plexus, a network of nerves located around the celiac trunk (artery) as it branches off of the abdominal aorta. The celiac plexus modulates the activity of the enteric nervous system of the foregut.