The length of the intra-abdominal segment in the normal state averages 1.5 to 2 cm. The lower esophagus segment is subdivided into the supradiaphragmatic portion, inferior esophageal constriction, vestibule, and cardia. This segment is supplied by an ascending branch of the left gastric artery. Venous drainage of that segment enters the coronary vein and pericardial venous plexus below the diaphragm. Preganglionic fibers of the vagus nerve synapse with ganglion cells in the myenteric plexus of the esophagus.
Sympathetic innervation occurs from the thoracic ganglia.
The anatomy and physiology of the gastroesophageal junction and of the esophageal hiatus is essential to the understanding of reflux mechanisms and antireflux procedures. In addition, several layers that separate the thoracic and the abdominal cavity support the esophageal hiatus. This membrane anchors the esophagus within the hiatus. In most individuals this membrane inserts 3.3 cm above the junction of the tubularesophagus with the stomach. Part of the problem of defining the gastroesophageal junction is the fact that the internal junction does not coincide with the external junction.