Does an anatomical sphincter exist in the distal esophagus?

The presence or absence of a lower esophageal sphincter (LES) has been a matter of debate. The aim of the present study was to revisit the gastro-esophageal region in an attempt to elucidate further the presence or absence of such a structure. The distal part of the esophagus was investigated in 12 fixed and 2 fresh cadavers with the aid of a dissecting microscope. Our findings demonstrated a clear thickening of the circular muscle layer of the gastro-esophageal region in all specimens. The mean length of this muscular thickening was measured to be 3.1 cm. The thickest part of this segment was at its midsection. This midpart had a mean thickness of 5.4 mm. The thickness of the esophagus immediately superior to the sphincter had a mean of 2.7 mm. We believe that the findings of the present study strongly suggest the presence of an internal esophageal sphincter in the distal esophagus. Physiologic experimentation would now be necessary to verify our morphological findings.