The celiac plexus, also called solar plexus, is an intertwined network of nerve fibers and ganglia, which is located throughout the upper abdominal region. It belongs to the autonomic nervous system and innervates both the viscera and the arteries of the abdominal cavity.
This network of nerves includes two celiac ganglia, which lie right above the celiac trunk (artery) on the anterior side of abdominal aorta, the superior mesenteric ganglion, which is located above the superior mesenteric artery at the point where it originates from the aorta, and the inferior mesenteric ganglion, situated also on anterior aspect of abdominal aorta, right above the inferior mesenteric artery.
The ganglia of the celiac plexus are interconnected with the ganglia of the sympathetic trunk, which are the two vertical chains of ganglia stringing along and parallel to the vertebral column, lying on both sides of it in two strands. The neurons of these ganglia send and receive afferent and efferent nerves to and from the spinal cord. Since they belong to the autonomic nervous system, the innervation of the smooth muscles of the viscera as well as the contraction and relaxation of the arteries walls, do not depends on our will; in other words, they are independent of the cerebral cortex.
Below, a diagram of the solar/celiac plexus. The schematic drawing is from an old Russian, State-printed encyclopedia on human anatomy.
