Oesophagus

The oesophagus is a muscular canal about 25 centimeters long in adults, connecting the oropharynx to the stomach. It transports food and liquids to the stomach through coordinated peristaltic waves and does not perform digestion or absorption.

It travels from the neck through the posterior mediastinum, passing behind the trachea and heart, and enters the abdomen through the diaphragmatic hiatus at the esophageal opening, meeting the stomach at the gastro-oesophageal junction. It is divided into cervical, thoracic, and abdominal parts and contains an upper oesophageal sphincter and a lower oesophageal sphincter that help regulate passage and prevent reflux.

The wall comprises mucosa with non-keratinized stratified squamous epithelium, submucosa, and muscularis propria with inner circular and outer longitudinal muscle layers. The outer layer is adventitia along most of its course, with a serosal covering near the stomach. The upper sphincter consists mainly of skeletal muscle, while the lower sphincter functions as a tonic smooth muscle zone at the gastro-oesophageal junction.

Blood supply derives from branches of the inferior thyroid arteries in the neck, thoracic aorta branches in the chest, and the left gastric artery in the abdomen. Venous drainage follows the azygos and hemiazygos systems in the thorax and the left gastric vein to the portal system. Lymphatics drain to mediastinal and celiac nodes. Innervation is provided by the vagus nerves (parasympathetic) and accompanying sympathetic fibers.

Clinically, the oesophagus can be affected by reflux disease, esophagitis, Barrett’s oesophagus, and cancers (squamous cell in the upper/middle regions and adenocarcinoma near the GE junction). Diagnostic tools include endoscopy, barium swallow, and esophageal manometry; treatments range from lifestyle changes and proton-pump inhibitors to dilation, stenting, and surgical fundoplication.