A neonate born after an uneventful pregnancy develops severe respiratory distress within hours. Chest X-ray shows multiple air-filled bowel loops occupying the left hemithorax with mediastinal shift to the right and scaphoid abdomen. The defect arises from failure of which structure to close?

• A Septum transversum contribution to the central tendon
• B Pleuroperitoneal membrane on the left ✓
• C Dorsal mesentery of the oesophagus
• D Left pleuropericardial fold

Explanation

Congenital diaphragmatic hernia of Bochdalek results from failure of one pleuroperitoneal membrane to fuse with the other diaphragm components, closing the pleuroperitoneal canal. It is left-sided far more often because the right canal closes earlier and the liver occupies the right side. Herniated bowel compresses the developing lungs, causing pulmonary hypoplasia, hence the scaphoid abdomen with bowel seen in the chest. Pleuropericardial fold failure gives pericardial defects, not herniation of viscera.

Reference: Langman's Medical Embryology, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.