In abdomen, different nerve fibers from various sources collectively form a plexus around the abdominal part of aorta, called the aortic plexus. The nerve fibers that contribute include the following:
- Preganglionic sympathetic fibers
- Postganglionic sympathetic fibers
- Preganglionic parasympathetic fibers
- Visceral afferent fibers
There are local condensations of the aortic plexus around the origins of celiac, renal, superior mesenteric and inferior mesenteric arteries. According to this relation, these local condensations are called celiac plexus, renal plexus, superior mesenteric plexus and inferior mesenteric plexus respectively.
It consists of two celiac ganglia, which are connected together by a large network of fibers that surrounds the origin of the celiac artery. These two ganglia receive the preganglionic sympathetic fibers in the form of greater and lesser splanchnic nerves. The branches from this plexus accompany the branches of celiac artery and follow them to their distribution. Parasympathetic vagal fibers also follow the same route.
It is smaller than the celiac plexus and the branches are distributed along the branches of renal artery.
Superior mesenteric plexus:
It is also smaller than the celiac plexus. Its branches follow the distribution of superior mesenteric artery.
Inferior mesenteric plexus:
It is similar to the remaining except that it receives parasympathetic fibers from sacral parasympathetic supply, instead of vagal nerve. Its branches follow the distribution of inferior mesenteric artery.