Sympathetic nervous system fibers of the upper abdomen

Sympathetic nervous system fibers in the upper abdomen are anatomical nerve fibers originating from the thoracic portion of the sympathetic trunk (primarily T5–T12). These fibers, via the greater, lesser, and least splanchnic nerves, synapse in prevertebral ganglia such as the celiac, superior mesenteric, and aorticorenal ganglia. They regulate blood flow, modulate smooth muscle activity in the gastrointestinal tract, transmit visceral pain, and mediate stress responses through their effects on abdominal organs such as the liver, stomach, intestines, pancreas, spleen, adrenal glands, and kidneys. They are not molecular entities but multi-neuronal anatomical pathways within the peripheral nervous system.

Other names

Thoracic splanchnic nerves (greater, lesser, least)Sympathetic fibers to celiac, superior mesenteric, aorticorenal plexuses

Blockade or modulation of sympathetic neurotransmission (e.g., adrenergic inhibition, chemical nerve blockade)