Lower Esophageal Ring (Schatzki Ring; B Ring) By Kristle Lee Lynch, MD, Perelman School of Medicine at The University of Pennsylvania Reviewed / Revised Mar 2022 | Modified Sep 2022 View Patient Education Topic Resources Esophageal Ring Barium Swallow Showing Esophageal... A lower esophageal ring is a 2 - to 4-mm mucosal stricture that causes a ringlike narrowing of the distal esophagus at the squamocolumnar junction that often causes dysphagia.