Internal Iliac Plexus, Anterior View

Description

Centered over the anterior sacrum and pelvic brim, the internal iliac (inferior hypogastric) plexus forms a dense autonomic network on either side of the rectum and posterolateral to the urinary bladder in the male pelvis. Preganglionic fibers descending via the hypogastric nerves converge with pelvic splanchnic nerves (S2 to S4) and distribute along the internal iliac artery and its branches toward pelvic viscera. Bony landmarks include the lumbosacral junction, sacrum, iliac bones, and acetabula, with the hip joints framing the inferior margin of the field. Nerve trunks course inferiorly from the spinal canal into the deep pelvic basin. Anterior orientation makes the topography of the internal iliac plexus clinically legible because it mirrors the operative corridor used in pelvic surgery, where the plexus sits close to the lateral pelvic fascia, uterosacral equivalents in the male (sacrogenital folds), and the course of the ureter as it crosses the iliac vessels toward the bladder. Nerve-sparing radical prostatectomy and cystectomy hinge on respecting these autonomic fibers; traction, thermal spread, or ligation near the lateral vesical pedicles can injure cavernous nerves and contribute to erectile dysfunction or bladder dysfunction. Small space. High stakes. Use this plate in gross anatomy and neuroanatomy teaching to connect sacral outflow (pelvic splanchnics) with visceral function, or in urology and colorectal surgery materials to illustrate where autonomic injury occurs during pelvic lymph node dissection and total mesorectal excision. It also supports patient-facing explanations of postoperative urinary retention or sexual dysfunction after pelvic operations. Anatomical accuracy verified by SciePro's Medical Advisory Board.