Primary Motility  Disorders of the  Esophagus
 The Esophageal
 Mucosa
 The
 Esophagogastric  Junction
 Barrett's
 Esophagus

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OESO©2015
 
Volume: Barrett's Esophagus
Chapter: Diagnosis
 

What is the definition of the junction between the esophagus and stomach from an endoscopic perspective?

H.W. Boyce (Tampa)

If minimal air insufflation of the proximal and mid-esophagus is utilized during endoscopy, the closed lower esophageal sphincter (LES) region may be readily demonstrated. At the point of closure of the proximal end of the sphincter, several (usually 4 to 6) longitudinal symmetrical mucosal folds can be seen to disappear in the center of the closed lumen. This closure produces a rosette appearance with the lumen being precisely centered at the point where these longitudinal folds converge. The tone of the LES relaxes with primary or secondary peristalsis and also opens in response to gentle insufflation. As the closed normal esophageal sphincter is approached with the endoscope it will relax with gentle scope pressure, and with passage through the sphincter there is little or no detectable resistance. As the high pressure sphincter zone relaxes, one can identify the squamocolumnar mucosal junction 1.5 to 2 cm beyond.

The squamous mucosa of the esophagus is pearly pink or pinkish-grey in color and contrasts sharply with the orange-red color of the gastric columnar epithelium. The esophageal squamous mucosa is only slightly transparent and reflects light moderately.

With minimal inflation, the junction of the squamous or columnar epithelium appears at or less than 2 cm above the hiatus as a slightly irregular or undulating line, the so-called ora serrata or "Z"-line. With continued inflation pressure the irregular junction often becomes straighter with only minimal or no serrated contour. This junction normally is located in the distal half of the LES segment at or just below the esophageal diaphragmatic hiatus. This line of demarcation between the two types of mucosa is readily identifiable in the absence of pathologic changes. If there is uncertainty about the location of this mucosal junction, it can be dramatically demonstrated by application of several milliliters of Lugol's solution through an endoscopic catheter [1]. This will promptly stain the glycogen in the esophageal squamous mucosa. In addition to surface characteristics and color, the normal distal extent of the esophageal squamous epithelium is also clearly demarcated by the level of abrupt disappearance of multiple, linear, frequently branching, small blood vessels just proximal to the upper end of the gastric folds of the cardia at the junction of squamous and columnar epithelium [2].

After the endoscope is passed into the proximal stomach, a retroversion maneuver should be performed to view the cardia and fundus from below. In the normal setting, the insertion tube of the endoscope can be seen coming through a snugly fitting intraabdominal segment of the esophagus. The snug fit in this region is sustained throughout respiration and during moderate insufflation of the stomach, except that transient relaxation in response to primary or secondary peristalsis can be detected. The classic snug appearance of the region is always demonstrated in patients with achalasia because of the increased tone in the LES segment. The angle of His on the greater curvature aspect demarcates the distal end of the crural sphincter segment, also call the submerged or abdominal segment of the esophagus [3].

Several linear gastric folds normally are seen in the cardia, and always when a hiatal hernia (HH) is present [1, 4, 5]. These folds normally terminate within 0.5 cm of the normal location of the squamocolumnar mucosal junction. Therefore, this termination point of the folds can be utilized endoscopically and radiographically as a marker for the approximate location of the normal squamocolumnar mucosal junction. The cephalad margins of the longitudinal gastric folds correspond to the level of the esophagogastric muscular junction as well. The proximal margins of these folds combined with the distal extent of the linear esophageal vessels provide the best endoscopic landmark for the muscular junction between esophagus and stomach, and as a marker for the expected normal location of the squamocolumnar mucosal junction. These relationships to the esophagogastric muscular junction can be demonstrated on surgical and autopsy specimens as well.

It is important to observe carefully and record the characteristics of the distal esophagus and proximal stomach in all patients. The location of the diaphragmatic hiatus in relation to the proximal stomach, the level of the squamocolumnar mucosal junction, the level of disappearance of the linear esophageal vessels, and the proximal extent of the gastric mucosal folds are characteristics utilized in the precise endoscopic diagnosis of HH and reflux sequelae, including the columnar-lined or Barrett esophagus. The levels of these landmarks should be recorded on every esophagoscopy report.

References

1. Boyce HW. Endoscopic definitions of esophagogastric junction regional anatomy. Gastrointest Endosc 2000;51(5):586592.

2. De Carvalho CAF. Sur l'angio-architecture veineuse de la zone de transition oesophagogastrique et son interpretation fonctionnelle. Acta Anat 1966;64:125-162.

3. Hill LD, Kozarek RA, Kraemer SJM, et al. The gastroesophageal flap valve: in vitro and in vivo observations. Gastrointest Endosc 1997;336:924-932.

4. McClave SA, Boyce HW, Gottfried MR. Early diagnosis of columnar-lined esophagus: a new endoscopic diagnostic criterion. Gastrointest Endosc 1987;33:413-416.

5. Boyce HW. Hiatus hernia and peptic diseases of the esophagus. In: Sivak MV, ed. Gastroenterologic endoscopy, 2nd edition. Philadelphia: WB Saunders, 2000:580-597.


Publication date: August 2003 OESO©2015