The Z line in the esophagus is the term for a faint zig-zag impression at the gastro-esophageal junction that demarcates the transition between the stratified squamous epithelium in the esophagus and the intestinal epithelium of the gastric cardia (the squamocolumnar junction).
The Z line is a normal finding but is not seen in every study. An irregular or elevated Z line indicates potential distal esophageal metaplasia / Barrett esophagus, although the actual risk of this finding is debated.
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