Ösophagus

Ösophagus, or esophagus, is a muscular tube about 25 cm long in adults that transports swallowed food and liquids from the pharynx to the stomach. It extends from the cricoid cartilage (C6) to the gastroesophageal junction at approximately the level of T11, traversing the posterior mediastinum and passing through the diaphragm at the esophageal hiatus.

Structure: The Ösophagus comprises mucosa, submucosa, muscularis propria and adventitia. The mucosa is lined by non-keratinized stratified squamous epithelium. The muscularis propria contains inner circular and outer longitudinal layers; the upper third consists mainly of skeletal muscle, the lower third smooth muscle, with a mixed arrangement in the middle third. The lumen is maintained by the lower esophageal sphincter, a high-tonic zone at the gastroesophageal junction.

Function: It uses coordinated peristaltic waves to propel boluses toward the stomach. Primary peristalsis is initiated by swallowing; secondary peristalsis clears residual content. The upper esophageal sphincter prevents air entry; the lower esophageal sphincter prevents reflux.

Vascular supply and innervation: Blood supply derives from branches of the inferior thyroid artery (upper), thoracic aorta (middle), and left gastric/left inferior phrenic arteries (lower). Venous drainage mirrors this pattern to the azygos/hemiazygos systems and to the portal system via the left gastric vein. Innervation is provided by the vagus nerves (parasympathetic) and thoracic sympathetic trunks.

Clinical notes: Common disorders include gastroesophageal reflux disease and reflux esophagitis, Barrett’s esophagus, peptic stricture, and malignancy (squamous cell carcinoma proximal/mid esophagus; adenocarcinoma at the distal segment). Diagnostic tools include endoscopy with biopsy, barium swallow radiography, and esophageal manometry to assess motility.