Hepatic plexus

Hepatic plexus refers to a meshwork of autonomic neurons and ganglia situated around the hepatic artery, the portal vein and bile duct (i.e. three components of the portal triad). It is considered to be an extension of the celiac prevertebral plexus.

The segment of hepatic plexus that surrounds the hepatic artery forms the anterior hepatic plexus, while the remaining component surrounding the portal vein and bile duct is referred to as the posterior hepatic plexus.

The hepatic plexus comprises of parasympathetic and sympathetic efferent neurons, accompanied by sensory visceral afferent neurons.

The parasympathetic neurons are preganglionic that originate from the dorsal motor nucleus of vagus and enter the hepatic plexus via the hepatic branches of anterior vagal trunk. They run transversely through the peritoneal layers of the lesser omentum > cross the free edge of lesser omentum > reach the hilum of liver.

The sympathetic neurons are post-ganglionic that arise from the celiac ganglia to reach the hepatic plexus. The pre-ganglionic sympathetic fibers come off from the lateral gray horns of upper thoracic spinal cord and reach out to the celiac ganglia via the thoracic splanchnic nerves.

The hepatic plexus provides autonomic innervation to the liver parenchyma and vasculature. It gives rise to various secondary plexuses around cystic, right gastric, gastroduodenal, right gastroepiploic and pancreaticoduodenal arteries, which help innervate the biliary tree and gall bladder, the structures in the free edge of lesser omentum, the pylorus, duodenum and pancreas.