The solar plexus, or celiac plexus, is a large cluster of nerves that relay messages from the major organs of the abdomen to the brain. These organs, called visceral organs, are important to metabolism and to general life functioning. The solar plexus monitors them and makes sure they are functioning correctly.
The solar plexus consists of two secondary nerve bundles, called the celiac ganglia, which branch off to enervate a large number of visceral organs. The organs enervated by the solar plexus include the kidneys, stomach, liver, pancreas, reproductive organs, spleen, rectum, intestines and suprarenal gland.
The solar plexus is so called because it is the largest nerve cluster, or plexus, in the body and radiates nerves to many different places like light rays from the sun. It is located behind the stomach and in front of the diaphragm. Unlike the cardiac plexus above it, the solar plexus is completely unprotected by bone. A blow to the nerve cluster will produce great pain and incapacitation, so it is frequently a target taught to beginners in self-defense classes. Contrariwise, a solar plexus block is an injection of pain medication that alleviates chronic abdominal pain. It is especially used to treat pain from chronic pancreatitis.