The esophagus is the muscular tube derived from the foregut that carries food and liquid from the oropharynx to the stomach. It crosses the diaphragm at the esophageal hiatus, which is located at the level of the tenth thoracic vertebra (T10). The esophagus has an upper sphincter, which prevents the entry of air, and a lower sphincter, which prevents the reflux of gastric acid. Food is transported by peristaltic movements of the esophageal muscles. The esophagus is supplied by the esophageal branches of the inferior thyroid artery, the thoracic aorta, and the left gastric arteries. The veins of the esophagus drain into the systemic circulation via the azygos and the hemiazygos veins and into the portal circulation via the left gastric veins. Portal hypertension results in esophageal varices, which are supplied by the left gastric veins. The esophageal wall consists of four concentric layers: mucosal, submucosal, muscular, and adventitia. The mucosa is lined by nonkeratinizing stratified squamous epithelium that transitions to columnar epithelium at the gastroesophageal junction. In gastroesophageal reflux disease (GERD), chronic acid exposure induces metaplasia of the lower esophageal squamous epithelium to gastric columnar epithelium (Barrett esophagus). Other diseases that may affect the esophagus include esophageal stricture, esophageal atresia, achalasia, and esophageal cancer.
- Tube that connects the pharynx (at the level of C6) to the stomach (at the level of T11)
- Length: ∼ 25 cm
- Located between trachea and spine
- Crosses the diaphragm at T10 through the esophageal hiatus
- The thoracic esophagus is extraperitoneal.
- The abdominal part is intraperitoneal.
- Constrictions of esophagus
- Passage for food and liquids between the oropharynx and stomach
- Peristaltic contractions of the esophageal muscles assist in moving food downwards.
|Cervical portion|| |
|Thoracic portion|| || |
|Abdominal portion|| || |
- Gross sensation of esophagus
- Innervates esophageal muscles and glands: Responsible for initiation of peristalsis and glandular activity.
- Cervical and thoracic sympathetic trunk
- Enteric nervous system: Auerbach plexus and Meissner plexus
Four concentric layers
- Mucosal (innermost)
- Adventitia (outermost)