Hirschsprung disease (congenital aganglionosis of the colon) results from failure of neural crest cell migration into the colon wall. The aganglionic segment lacks which specific neural plexuses?
- A Only the myenteric plexus (Auerbach's)
- B Sympathetic chain ganglia only
- C Meissner's (submucosal) and Auerbach's (myenteric) plexuses ✓
- D Hypogastric plexus fibers
Explanation
Hirschsprung disease affects both the submucosal (Meissner's) plexus and the myenteric (Auerbach's) plexus — both enteric nervous system plexuses are absent in the aganglionic segment. Neural crest cells from the vagal region (rhombomeres 1–7) migrate caudo-cranially to populate the entire gut wall, arriving in the rectum last. Failure to complete migration causes aganglionosis in the rectosigmoid most commonly. The absence of both plexuses prevents coordinated peristalsis and relaxation of the internal anal sphincter, causing functional obstruction proximal to the aganglionic segment.
Reference: BD Chaurasia's Human Anatomy, 8th ed.
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