Esophagus

Lore & Background

The esophagus begins at the back of the mouth, passing downward through the rear part of the mediastinum, through the diaphragm, and into the stomach. It has four points of constriction: at its start behind the cricoid cartilage, where crossed by the aortic arch, where compressed by the left main bronchus, and at the esophageal hiatus. The wall from the lumen outwards consists of mucosa (stratified squamous epithelium), submucosa, layers of muscle fibers between fibrous tissue, and an outer connective tissue layer. Most muscle is smooth, though striated muscle predominates in the upper third.

Reader's Guide

The esophagus is significant as a critical conduit in the digestive system, facilitating the passage of food through peristaltic contractions. Its structure includes two sphincters—the upper anatomical sphincter and the lower functional sphincter—that prevent reflux and regulate swallowing. The esophagus may be affected by gastric reflux, cancer, varices, tears, constrictions, and motility disorders, leading to symptoms such as dysphagia or chest pain. Clinical investigations include X-rays with barium sulfate, endoscopy, and CT scans. Surgically, the esophagus is difficult to access due to its position between critical organs and directly between the sternum and spinal column. Its rich blood supply and venous drainage vary along its course, and its lymphatic drainage mirrors that of foregut-derived abdominal structures.

Did You Know?

• The word esophagus is from Ancient Greek οἰσοφάγος (oisophágos), from οἴσω (oísō), future form of φέρω (phérō, 'I carry') + ἔφαγον (éphagon, 'I ate').
• The lower esophageal sphincter is a functional sphincter, not an anatomical one, and helps prevent reflux of acidic stomach content.
• The esophagus has four points of constriction where swallowed corrosive substances or solid objects are most likely to lodge.
• The mucosa of the esophagus is a stratified squamous epithelium, contrasting with the single layer of columnar cells of the stomach.