The upper esophageal sphincter is called the cardiac sphincter because it is just posterior to the heart.

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The upper esophageal sphincter is also known as the pharyngoesophageal sphincter. It is located at the top of the esophagus and is responsible for regulating the passage of food, liquids, and air into the esophagus. It is not located near the heart. The cardiac sphincter is another name for the lower esophageal sphincter, which is located at the bottom of the esophagus and regulates passage of food and liquids into the stomach.

The Upper Esophageal Sphincter Is Called the Cardiac Sphincter Because