Hirschsprung's disease (congenital aganglionic megacolon) results from failure of neural crest cells to migrate to the hindgut. The aganglionic segment characteristically begins at the internal anal sphincter and extends proximally. The neural crest cells that fail to migrate arise from which region?

• A Trunk neural crest (thoracic level)
• B Sacral neural crest cells
• C Cranial neural crest cells (rhombomeres 6–8)
• D Vagal neural crest cells (adjacent to somites 1–7) ✓

Explanation

The enteric nervous system (Meissner's and Auerbach's plexuses throughout the entire gut) is derived primarily from vagal neural crest cells originating adjacent to somites 1–7. These cells colonise the entire gut from oesophagus to anus in a rostrocaudal wave. Failure of these cells to complete migration to the hindgut results in Hirschsprung's disease. Sacral neural crest cells contribute to the distal colorectum, explaining why sacral anomalies may extend the length of aganglionosis. Mutations in RET proto-oncogene and EDNRB gene are most commonly implicated.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.