<prompt> Most useful investigation in sliding hernia in female -FluoroscopyBarium-mealPalpation methodUltrasound  <response>: The hernia may be visible on a plain radiograph of the chest as a gas bubble, often with a fluid level behind the heart. A barium meal is the best method of diagnosis. The endoscopic appearances may be confusing, especially in large hernias when it is easy to become disorientated. 