A male patient undergoes anterior resection of rectum. Postoperatively he reports erectile dysfunction and inability to ejaculate. Which nerve plexus was most likely injured?

• A Lumbar sympathetic chain
• B Inferior hypogastric plexus (pelvic plexus) ✓
• C Sacral parasympathetic (pelvic splanchnic nerves)
• D Superior hypogastric plexus

Explanation

The inferior hypogastric plexus (pelvic plexus) is formed by the hypogastric nerves (sympathetic, from L1-L3 via superior hypogastric plexus) and pelvic splanchnic nerves (parasympathetic, S2-S4). This plexus lies on the lateral side of the rectum and distributes fibers to the bladder, prostate, seminal vesicles, and erectile tissue. Injury during anterior resection causes combined sympathetic and parasympathetic dysfunction: inability to ejaculate (sympathetic) and erectile dysfunction (parasympathetic = loss of erection via cavernous nerves). Nerve-sparing techniques preserve the neurovascular bundle (cavernous nerves of Walsh) along the posterolateral prostate.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.