Gastroesophageal vestibule and lower esophageal sphincter: the same thing

The anatomic transition between the lower end of the esophagus and the stomach is complex. The tubular esophagus terminates as a bell-shaped structure called the gastroesophageal vestibule (GEV). The anatomy and physiology of this segment has been widely studied. However, there is no detailed description of its muscular architecture and its relationship with the muscular fibers of the lower esophageal sphincter (LES). Therefore, the purpose of the present study was to describe the muscular structure of the GEV and to establish its relationship with the LES.

Twenty human gastroesophageal specimens were obtained from fresh cadavers. The specimens were filled with water until reaching the maximal distension of the vestibule. The upper and lower limits were marked with stitches and their lengths and perimeters were measured. The specimens were opened and fixed in 10% formalin. The mucosa of the vestibule was stripped off, allowing fibers of internal muscular coat to be seen.

The length of the vestibule measured at the lesser curvature was 3.7 cm (3.0-6.5 cm), which was longer than at the greater curvature measuring 2.8 cm (2.0-4.5 cm). The perimeter of its base, on basal condition was 7.1 cm (6.0-8.5 cm) but it reached up to 11.6 cm (10.0-15.0 cm) when it was dilated. The Z-line is located at the union of the lower third with the middle third of the vestibule. The walls of the GV were formed by 'Clasp' fibers and oblique (Sling) fibers.

The GEV is the only dilatable structure at the gastroesophageal junction, and it is formed by the muscular fibers of the LES. Therefore, the GEV corresponds to this sphincter.