showing a dilated esophageal body bird beak-like narrowing of lower esophageal sphincter (see Video 1). b; Vigorous achalasia showing diffuse spasm-like contractions in the esophageal body with ...

The bolus enters the stomach through a ring-like muscle called the lower esophageal sphincter. This sphincter relaxes, allowing the bolus to enter the stomach. In the stomach, the following ...