Bladder: Page 3 of 3

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There are 4 pathways for autonomic (sympathetic and parasympathetic) nerves to enter the pelvic cavity:

1. The left and right sacral sympathetic trunks enter the pelvic cavity anterior to the sacrum and converge at the coccyx as the ganglion impar. These fiber primarily provide sympathetic innervation to the lower limb.
2. Provides a postganglionic sympathetic periarterial plexus to the superior rectal, ovarian and internal iliac arteries
3. The hypogastric plexes (superior and inferior are networks of sympathetic and visceral afferent fibers. The superior hypogastric plexus divides into the left and right hypogastric nerves and merge with the pelvic splanchnic (parasympathetic) nerves to form the right and left inferior hypogastric plexes which then form the pelvic plexes. The pelvic plexes pass to the rectum, urinary bladder, prostate and seminal glands in males. In females they pass to the rectum, urinary bladder, uterus and vagina.
4. The pelvic splanchnics are preganglionic parasympatheic and viseral afferent fibers from S2-S4. The pelvic splanchnics merge with the inferior hypogastrics and pelvic plexes. The sympathetic components produce vasomotor activity, inhibit peristaltic contraction of the rectum and stimulates contractions of the genital organs during orgasm. The parasympatethics fibers stimulate contraction of the rectum (defecation) and bladder (urination). Parasympatheic fibers penetrate the pelvic floor to supply erectile bodies of the external genitalia to produce erection.