Herniation of the midgut

• By the end of the 6th week, the liver and gut have enlarged and cannot be contained by the abdominal wall -  thus herniate as the physiological hernia
• By the end of the 10th week, the abdominal wall has grown enough to accommodate the abdominal contents
• If the intestinal loop does not come back into the abdominal cavity - you develop an omphalocoele.
• Midgut rotation:
  • The midgut undergoes a 270° counterclockwise rotation around the axis of the SMA in three stages:
    • 90° during herniation.
    • 180° during return to the abdominal cavity (by the 10th week).
  • This rotation establishes the final positioning of midgut organs.

See:

• Gut malrotation
• Meckel’s diverticulum
• Omphalocoele