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Gastro-esophageal junction

Last revised by Dr Balint Botz on 23 Feb 2021

The gastro-esophageal junction (GEJ) (also known as the esophagogastric junction) is the part of the gastrointestinal tract where the esophagus and stomach are joined.

The GEJ is normally mostly intra-abdominal and is 3-4 cm in length. To some extent, the esophagus slides in and out of the abdomen during respiration and when there is elevation of intra-abdominal pressure.

It is comprised of two histologically distinct areas:

  • stratified squamous epithelium (same as the esophageal folds superiorly)
  • columnar epithelium (same as the gastric rugae inferiorly)

Where these two distinct areas join, there is an abrupt but non-linear change in the mucosal layer: this is called the Z-line. The non-linear, zig zagging nature of the Z-line explains that the GEJ can be several centimeters in length, while the histological transition from esophageal folds to gastric rugae is abrupt.

Unfortunately the GEJ is not directly visualized on plain film, which is of particular importance during the assessment of the position of nasogastric tubes. According to one study tube tips below the level of the disc between the 11th and 12th thoracic vertebra and/or more than 16 mm from the left side of the spine can be considered to be in the stomach 2. However for practical purposes the tube tip should ideally be at least 10 cm beyond from the expected location of the GEJ.

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