Figure 2 - Endoscopic landmarks, part 1.

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 most proximal extent of the gastric folds has been proposed as a marker for the GEJ. When the SCJ is located proximal to the GEJ, there is a columnar-lined segment of esophagus. (Source: Spechler,³⁷ with permission from American Gastroenterological Association.)