Anatomic landmarks for the diagnosis of Barrett's esophagus

The squamocolumnar junction (SCJ or Z-line) is the visible line formed by the juxtaposition of squamous and columnar epithelia. The gastroesophageal junction (GEJ) is the imaginary line at which the esophagus ends and the stomach begins. The GEJ corresponds to the most proximal extent of the gastric folds. When the SCJ is located proximal to the GEJ, there is a columnar-lined segment of esophagus.