Cardial orifice

The cardiac orifice of the stomach (Cardial orifice) is where the esophagus opens into the stomach. This orifice is located at the junction between the esophagus and the stomach (cardiac part of stomach) and is surrounded by the lower esophageal sphincter, which helps regulate the passage of food and prevents reflux of gastric contents back into the esophagus.

In cats, the transition from the esophageal to the gastric mucosa is abrupt and corresponds to the point of insertion of the phreno-esophageal membrane at the diaphragm level, indicating the location of the cardiac orifice.[1] This region is characterized by a thickened circumferential smooth muscle layer, which correlates with the high-pressure zone of the caudal esophageal sphincter.[1]