What Is Esophageal Sphincter?
The esophageal sphincter is a bundle of muscles in the esophagus, including the lower and the upper esophageal sphincter, or LES and UES.
Locations of LES and UES
The LES is located at the lower end of the esophagus, where it connects the stomach. When the LES is closed, it prevents acid and other stomach contents coming backwords from the stomach.
The UES, located at the lower end of the pharynx, is also know as inferior pharyngeal sphincter. It guards the entrance into the esophagus. You can identify them from the picture below.
Keywords: esophageal sphincter