Читать книгу The Esophagus - Группа авторов - Страница 16

The esophagus is a highly distensible muscular tube that moves food from the pharynx to the stomach. The upper esophageal sphincter (UES) opens for 1.5–2 seconds, allowing food to enter the esophagus, where esophageal body peristalsis propels the food downward. The lower esophageal sphincter (LES) then opens, allowing the food to move into the stomach. This occurs at the esophageal hiatus, the margin of which is formed by the right and left diaphragmatic crura, and which is located approximately 2–4 cm below the diaphragm. While essentially a midline structure, the esophagus is not quite a straight organ, and its upper portion is positioned to the left of midline, the mid portion to the right of midline, and the lower portion back to the left of midline. There are also four potential areas of normal constriction, two of which are due to its proximity to adjacent organs: the cricopharyngeus, aortic arch, left main bronchus, and LES [2]. The esophagus is fixed only at two locations, on its proximal and distal edges. The upper esophagus is attached to the cricoid cartilage, and the lower esophagus is attached via the phrenoesophageal ligaments. This distal attachment point allows for the formation of a tight seal between the abdominal and thoracic cavities, and the lack of fixation along the length of the esophagus allows the organ to possess both transverse and longitudinal mobility.