Picture of Esophagus
The esophagus is the tube that connects the mouth and throat (pharynx) to the stomach. The esophagus is muscular, pink in color, and approximately 8 inches long. The inner lining of the esophagus is called the mucosa. The esophagus is situated in front of the spine and behind the heart and trachea (windpipe). It passes through the diaphragm before emptying into the stomach.
The upper and lower parts of the esophagus contain muscular sphincters. The upper esophageal sphincter (UES) lies at the top of the esophagus. When the UES closes, food and liquids are unable to travel down the windpipe. This sphincter is under conscious control. It is used to protect the windpipe when eating, vomiting, breathing, and belching.
The lower esophageal sphincter (LES) lies at the lower end of the esophagus. The LES closes to prevent acid and stomach contents from backing up (refluxing) into the esophagus. The LES sphincter cannot be controlled voluntarily.
Text Reference: American Cancer Society: "What Is Cancer of the Esophagus?"