Lumbar part of sympathetic system
- Sympathetic chain (paravertebral) ganglia are 4 in number on each side present in sympathetic chains. Lumbar sympathetic chain gives 4 lumbar splanchnic nerves carrying preganglionic fibers. The first lumbar splanchnic nerve joins coeliac plexus, the second joins the intermesenteric plexus and 3rd and 4th join the superior hypogastric plexus.
- Prevertebral ganglia include coeliac, superior mesenteric, aorticorenal and inferior mesenteric ganglia lying in front of aorta close to the origin of respective arteries. These ganglia contain postganglionic sympathetic fibers innervating abdominal organs. These ganglia receive preganglionic sympathetic fibers from 3 thoracic splanchnic nerve (greater splanchnic, T5 - T9; lesser splanchnic T1O-T11; and least splanchnic, T12) and two lumbar splanchnic nerves.
- Coeliac ganglion and coeliac plexus
- Coeliac ganglion is the largest ganglion in the body, situated on each side of coeliac trunk. It is divided into large upper part which receives greater splanchnic nerve (T5- T9) and smaller detached lower aortico-renal ganglia which receives lesser splanchnic nerve (T10-T11),
- Coeliac plexus (solar plexus) consists of a pair of coeliac ganglion, superior mesenteric ganglion and a few detached aortico-renal ganglia. It is located around the origin of coeliac artery from ventral surface of aorta. Fibers making the plexus are as follows:
- Preganglionic sympathetic fibers reach it through greater and lesser splanchnic nerves.
- Postganglionic sympathetic fibers arising from coeliac ganglion.
- Parasympathetic fibers come through right and left vagi (right vagus predominates).
- Sensory fibers from diaphragm reach the coeliac plexus through inferior phrenic nerves.
- Branches from the coeliac plexus extend along the arteries and from the following secondary plexuses: - phrenic, hepatic, gastric, splenic, superior mesenteric, renal and suprarenal.
- Superior mesenteric plexus
- Inferior mesenteric plexus
- Intermesenteric (abdominal aortic) plexus