Clinical anatomy of the splanchnic nerves

The splanchnic nerves are bilateral autonomic nerves that supply abdominal and pelvic viscera. They are constituted of motor nerve fibers going to the internal organs (visceral efferent fibers) and sensory nerve fibers coming from these organs (visceral afferent fibers). On each side of the human body, they include the thoracic splanchnic nerves (greater, lesser and least or lowest), lumbar splanchnic nerve, sacral splanchnic nerve and pelvic splanchnic nerve (nervus erigentis). All splanchnic nerves carry preganglionic (presynaptic) sympathetic fibers except for the pelvic splanchnic nerves that carry preganglionic parasympathetic fibers. Splanchnicectomy is the procedure used mainly for the control of intractable visceral pain. Detailed knowledge of the anatomy and variations of the splanchnic nerves is mandatory for proper performance of splanchnicectomies (Figure 1).