In its passage through the esophageal hiatus of the diaphragm, the esophagus is surrounded by the phreno-esophageal ligament, also known as the phrenico-esophageal ligament and diaphragmatico-esophageal ligament.  The phreno-esophageal ligament arises from the circumference of the hiatus as an extension of the inferior fascia of the diaphragm, which is continuous with the transversalis fascia.  At the margin of the hiatus, it divides into an ascending leaf and a descending leaf.  The ascending leaf passes upward through the hiatus and surrounds the esophagus in a tentlike fashion.  It extends for several centimeters above the hiatus, where it is inserted circumferentially into the adventitia of the esophagus.  The descending leaf passes downward and is inserted around the cardia deep to the peritoneum.  Within the cavity thus formed by the phreno-esophageal ligament and below the diaphragmatic hernia lies a ring of rather dense fat.