What is the cardiac sphincter?

The cardiac sphincter, also known as the lower esophageal sphincter (LES), is a muscular ring located at the bottom of the esophagus. Its main function is to prevent stomach acid and food from flowing back into the esophagus and causing heartburn or acid reflux.

The cardiac sphincter typically remains contracted to keep the opening between the esophagus and stomach closed, only relaxing when food or liquid is swallowed. However, in some individuals, the cardiac sphincter may become weak or dysfunctional, leading to gastroesophageal reflux disease (GERD).

GERD is a condition in which stomach acid and food frequently flow back into the esophagus, causing symptoms such as heartburn, chest pain, and difficulty swallowing. Lifestyle changes and medications can often help manage GERD, but in severe cases, surgery may be necessary to strengthen the cardiac sphincter.