The splanchnic nerves are part of the sympathetic nervous system, which is part of the autonomic nervous system. Most sympathetic preganglionic nerves synapse in the sympathetic trunk lying beside the spinal cord, but splanchnic nerves pass through the trunk, travel near their target organ, and synapse in prevertebral ganglia.

Thoracic splanchnic nerves provide sympathetic innervation to the abdomen, regulating a wide range of digestive functions. They consist of three branches:

1. Greater splanchnic (T5-T9): modulates the activity of the enteric nervous system of the foregut by contributing to the coeliac plexus lying around the coeliac artery's branch point from the abdominal aorta. Also, innervation of the adrenal medulla to stimulate catecholamine release.
2. Lesser splanchnic (T10-11): modulates the activity of the enteric nervous system of the midgut by contributing to the superior mesenteric plexus lying around the superior mesenteric artery branch point.
3. Least splanchnic (T12): modulates the activity of the enteric nervous system of the hindgut by contributing to the inferior mesenteric plexus lying around the inferior mesenteric artery branch point.

Pelvic splanchnic nerves (S2-S4) provide parasympathetic innervation to the hindgut. They innervate the pelvic and genital organs, regulating the emptying of the urinary bladder and the rectum as well as sexual functions like ejaculation and orgasm. The sexual function of erection is mediated by the parasympathetic nerves and is not sympathetically controlled through splanchnic nerves.

Sacral splanchnic nerves innervate the inferior hypogastric plexus.

External links

Nervous system

Nerf splanchnique