Upper Esophageal Sphincter Function and Acid Reflux Pain

The upper esophageal sphincter is a muscular valve that is located at the upper portion of the esophagus, which is typically about 8 inches long.

Unlike the lower esophageal sphincter (LES), which opens and closes without our conscious effort, the upper esophageal sphincter is under our conscious control. We can control when it opens. For example, we can open the upper esophageal sphincter by swallowing foods or liquids.​

Illustration of the mouth and top of the esophagus

How the Upper Esophageal Sphincter Works

During swallowing, the upper esophageal sphincter opens to allow food and liquids to pass into the esophagus. It can also reduce the backflow of food and liquids from the esophagus into the pharynx.

In addition to eating, we use this part of the esophagus while simply breathing. It also comes into play during unpleasant bodily functions, such as burping or throwing up, that serve to expel gas or harmful materials from the body.

The cluster of muscles that make up the upper esophageal sphincter prevents food from traveling down the trachea, or windpipe. This is known as aspiration and refers to foreign materials in the airway. Aspiration can lead to choking or even pneumonia if food journeys to the lungs. When food goes down the "wrong pipe," the best advice is to cough, which helps the food go down the esophagus instead.

Also Known As: The upper esophageal sphincter is abbreviated as UES. It is also known as the inferior pharyngeal sphincter since it's positioned at the lower end of the pharynx and protects the opening into the esophagus.

Upper Esophageal Sphincter Malfunction

If the upper esophageal sphincter doesn't function properly, an acid that has flowed back into the esophagus is allowed into the throat.

This can lead to painful medical conditions, such as heartburn or gastroesophageal reflux disease (GERD), the term used to describe repeated cases of heartburn.

Why the Upper Esophageal Sphincter Is Unique

The UES plays a special role in regulating the passage of food and liquid down the throat, but it and the LES are not the only sphincters in the body. There's also the anal sphincter, the muscle group near the anus that regulates the passage of stool out of the body. Then, there's the sphincter of Oddi, which regulates the passage of bile and pancreatic secretions into the small intestine.

While sphincters appear in different areas of the body, they all function to control the flow of substances through organs and to open and shut different body parts. Sphincters play an important role in keeping the body sound and healthy.

The Bottom Line

While learning about the body parts that play key roles in the development of acid reflux won't make your discomfort disappear, it can turn you into an informed patient, knowledgeable enough to pursue a variety of options to find the right treatment.

Chronic heartburn or GERD can seriously affect one's quality of life. If you're having repeated episodes of acid reflux, consult your healthcare provider about how to remedy the problem. Antacids, surgery or even home remedies and lifestyle changes can alleviate your symptoms.

Frequently Asked Questions

  • What causes upper esophageal sphincter dysfunction?

    Upper esophageal sphincter (UES) dysfunction can be caused by a number of neurological and neuromuscular diseases, or it may not have an exact identifiable cause. The UES is affected by esophageal dysmotility, which refers to irregular or inconsistent contractions in the esophagus.

  • How do you prevent acid reflux?

    You can prevent acid reflux by eating high-fiber and alkaline foods. It's also important to avoid foods that trigger acid reflux, such as fatty meats. If you continually experience heartburn despite a change in diet, a healthcare provider can offer further treatment. Some people may take medication to help prevent heartburn.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Sivarao DV, Goyal RK. Functional anatomy and physiology of the upper esophageal sphincter. Am J Med. 2000;108 Suppl 4a:27S-37S. doi:10.1016/s0002-9343(99)00337-x

  2. Torrico S, Kern M, Aslam M, et al. Upper esophageal sphincter function during gastroesophageal reflux events revisited. Am J Physiol Gastrointest Liver Physiol. 2000;279(2):G262-7. doi:10.1152/ajpgi.2000.279.2.G262

  3. Johns Hopkins Medicine. FAQs About Swallowing Disorders.

  4. Johns Hopkins Medicine. GERD Diet: Foods That Help with Acid Reflux (Heartburn).

Additional Reading
  • Carol Ann Rinzler, Ken DeVault, MD. Heartburn & Reflux for Dummies. Wiley Publishing, Inc., 2004.

By Sharon Gillson
 Sharon Gillson is a writer living with and covering GERD and other digestive issues.