[1] It is created by the collar sling fibres and the circular muscles around this gastroesophageal junction.

[2] The angle of His is normally undeveloped in infants, with the esophagus making a vertical junction with the stomach.

[3] As a result, reflux of stomach contents is common.

This prevents the reflux of stomach acid, digestive enzymes, and duodenal bile from entering the esophagus.

[4][5] This is important in preventing gastroesophageal reflux disease and inflammation of the esophagus.