Cardiac sphincter

Cardiac Sphincter

The cardiac sphincter, also known as the lower esophageal sphincter (LES), is a band of smooth muscle that is located at the junction of the esophagus and the stomach. This sphincter plays a crucial role in the digestive process by preventing the backflow of stomach contents into the esophagus.

Anatomy

The cardiac sphincter is located approximately 40 cm from the incisors at the junction of the esophagus and the stomach. It is not a distinct anatomical entity but rather a functional one, composed of a 3-4 cm segment of the lower esophagus that maintains a tonic contraction.

Function

The primary function of the cardiac sphincter is to prevent the reflux of gastric contents into the esophagus. It achieves this by maintaining a higher resting pressure than that of the stomach. The sphincter relaxes to allow the passage of swallowed food into the stomach and then contracts to prevent the backflow of gastric contents.

Clinical Significance

Dysfunction of the cardiac sphincter can lead to a condition known as gastroesophageal reflux disease (GERD). This condition is characterized by the chronic backflow of stomach acid into the esophagus, leading to symptoms such as heartburn and regurgitation. Treatment options for GERD include lifestyle modifications, medication, and in severe cases, surgery.

See Also

• Esophagus
• Stomach
• Gastroesophageal reflux disease