A newborn baby was diagnosed with eventration of the diaphragm. In this condition, half of the diaphragm ascends into the thorax during inspiration, while the other half contracts normally. What is the cause of this condition?

An absence of musculature in one half of the diaphragm causes it to protrude into the thoracic cavity forming a pouch into which the abdominal viscera protrude. Pleuropericardial folds are responsible for separating the pericardial cavity from the pleural cavity. Typically, the diaphragm migrates to its position with the fibrous pericardium. The septum transversum is the primordial central tendon of the diaphragm that separates the heart from the liver. The pleuroperitoneal folds form the pleuroperitoneal membranes that separate the pleural cavity from the peritoneal cavity. Absence of any of these would not have anything to do with eventration of the diaphragm.