Anatomy, Abdomen and Pelvis, Splanchnic Nerves

The abdominopelvic viscera receive innervation via the autonomic nervous system's sympathetic and parasympathetic components (see . Autonomic Nervous System). The splanchnic nerves are paired preganglionic autonomic nerves running along either side of the vertebral column. These nerves are composed of preganglionic motor (visceral efferent) and sensory (visceral afferent) nerve fibers supplying the abdominopelvic organs. The thoracic, lumbar, and sacral splanchnic nerves carry presynaptic sympathetic fibers, while the pelvic splanchnic nerves carry preganglionic parasympathetic fibers. The foregut and midgut receive parasympathetic innervation from the vagus nerve and sympathetic innervation from the superior splanchnic nerves. The hindgut and pelvic viscera receive sympathetic innervation from the sacral splanchnic nerves and parasympathetic innervation from the pelvic splanchnic nerves. Splanchnic nerves are targeted during nerve blocks or neurolysis when providing palliative care to patients with advanced abdominopelvic malignancies. In surgery, iatrogenic splanchnic nerve injury can cause gastrointestinal problems, urinary retention, or sexual dysfunction. Understanding the splanchnic nerves' anatomy and function is essential in diagnosing and managing various abdominopelvic disorders.