Physical Location
The parasympathetic nerves (PSNS) are autonomic (aka "visceral") branches of the peripheral nervous system (PNS). Parasympathetic nerve fibers arise from the central nervous system with the S2, S3, and S4 spinal nerves and from the third, seventh, ninth, and tenth cranial nerves. Because of its location, the parasympathetic system is commonly referred to as having "craniosacral outflow", which stands in contrast to the sympathetic nervous system, which is said to have "thoracolumbar outflow".
The parasympathetic nerves that arise from the S2, S3, and S4 spinal nerves are commonly referred to as the pelvic splanchnic nerves or the "nervi erigentes".
Read more about this topic: Parasympathetic Nervous System
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