Anatomic features of sliding hiatus hernia

Representation of the anatomic features of a sliding hiatus hernia viewed radiographically during swallowing. The "A" ring is a muscular ring visible during swallowing which demarcates the superior margin of the lower esophageal sphincter. The "B" ring at the squamocolumnar junction is present in only about 15 percent of individuals; it permits accurate division of the phrenic ampulla into the esophageal vestibule (A ring to B ring) and the sliding hiatus hernia (B ring to the subdiaphragmatic stomach). Rugal folds traversing the hiatus support the conviction that a portion of the stomach is supradiaphragmatic.