A Morgagni hernia is one of four types of diaphragmatic hernias; the other types include a Bochdalek hernia, where the defect is posterolateral, a hiatal hernia, where the defect is at the esophageal hiatus, and a paraesophageal hernia, where the defect is located adjacent to the esophageal hiatus. The Morgagni hernia, in which the defect is found in an anterior and retrosternal location, was first described by Morgagni in 1769. It is rarer than the other type of congenital diaphragmatic hernia (Bochdalek hernia) and comprises only 2% to 5% of all congenital diaphragmatic hernias. Morgagni hernias tend to be less symptomatic as pulmonary hypoplasia is uncommon, leading to a delayed diagnosis of these defects.
Svetanoff, W., Rentea, R. M. Morgagni Hernia StatPearls , (2020).