Anatomy and Histology of the Esophagus

Anatomy of the Esophagus

• The esophagus is a muscular tube extending from the epiglottis to the gastroesophageal junction (GEJ).
• It is lined by stratified squamous epithelium.

Diseases Affecting the Esophagus

Mechanical Obstruction

• Causes: Congenital or Acquired, Atresia, Fistulas, Duplications, Agenesis (very rare), Stenosis
• Atresia: characterized by a thin, non-canalized cord replacing a segment of the esophagus, typically near the tracheal bifurcation
• Esophageal Stenosis: results from fibrous thickening of the submucosa and atrophy of the muscularis propria due to inflammation and scarring
• Clinical Presentation of Atresia: regurgitation during feeding shortly after birth, requires prompt surgical correction
• Complications of Atresia: aspiration, suffocation, pneumonia, and severe fluid and electrolyte imbalances
• Clinical Presentation of Esophageal Stenosis: progressive dysphagia, initially affecting solids and later liquids

Functional Obstruction

• Characterized by esophageal dysmotility, with discoordinated peristalsis or muscular spasms
• Achalasia: most significant cause, characterized by a triad of incomplete LES relaxation, increased LES tone, and esophageal aperistalsis
• Primary Achalasia: often idiopathic, involving degeneration of distal esophageal inhibitory neurons
• Secondary Achalasia: results from damage to the esophagus, vagus nerve, or dorsal motor nucleus of the vagus
• Clinical Presentation of Achalasia: difficulty swallowing (dysphagia), regurgitation, occasionally chest pain

Vascular Diseases

Esophageal Varices

• Tortuous dilated veins within the submucosa of the distal esophagus and proximal stomach
• Pathogenesis: portal hypertension leads to the development of collateral channels in the distal esophagus, creating varices
• Causes of Portal Hypertension: cirrhosis, hepatic schistosomiasis
• Clinical Features: often asymptomatic until rupture, massive hematemesis and death, first bleed has a 20% mortality rate, rebleeding occurs in 60% of cases

Esophagitis

• Types: Esophageal Lacerations (Mallory-Weiss tears), Chemical Esophagitis, Infectious Esophagitis
• Clinical Features and Morphology: ulceration and acute inflammation, symptoms include pain, odynophagia (painful swallowing), hemorrhage, stricture, or perforation in severe cases

Learn about the structure and diseases of the esophagus, including mechanical obstruction, atresia, and more. Understand the normal anatomy and abnormalities of the esophagus.