Which side is most commonly affected in congenital diaphragmatic hernia?

Which side is most commonly affected in congenital diaphragmatic hernia?

• A. Right
• B. Bilateral
• C. Midline
• D. Left

Answer: (D)

The main idea is that congenital diaphragmatic hernia most often involves the left side. This occurs because the left posterolateral (Bochdalek) foramen fails to close more commonly than on the right. The liver sits on the right side and acts as a physical barrier, making right-sided herniation less likely. Consequently, abdominal contents herniate into the left chest, leading to left-sided defects being by far the most frequent presentation. This left-sided movement of viscera also explains why the left lung is more severely underdeveloped (hypoplastic) and why newborns with this condition often have respiratory distress shortly after birth. Right-sided CDH is rare, and bilateral CDH is much less common than a unilateral left defect. Imaging typically shows bowel or stomach in the left thorax with the mediastinum shifted to the right, reflecting the impact of the left-sided herniation.

The main idea is that congenital diaphragmatic hernia most often involves the left side. This occurs because the left posterolateral (Bochdalek) foramen fails to close more commonly than on the right. The liver sits on the right side and acts as a physical barrier, making right-sided herniation less likely. Consequently, abdominal contents herniate into the left chest, leading to left-sided defects being by far the most frequent presentation. This left-sided movement of viscera also explains why the left lung is more severely underdeveloped (hypoplastic) and why newborns with this condition often have respiratory distress shortly after birth. Right-sided CDH is rare, and bilateral CDH is much less common than a unilateral left defect. Imaging typically shows bowel or stomach in the left thorax with the mediastinum shifted to the right, reflecting the impact of the left-sided herniation.