“…tomography, 9 sonography, 10 intraoperative detection, 11 or manometry. 3 These tests show different accuracy for the diagnosis of HH and discordant results, especially as a result of the fact that the definition of HH is still controversial, because authors have debated for more than a century 12 if the transition from the esophagus to the stomach is defined by the epithelial change (inside perspective) or by the variation in shape from tubular to the saccular organ (outside perspective). Also, provocative tests such as change in decubitus, stomach inflation and abdominal compression, and sedation are performed in some tests but not in others.…”