Esophagus

It is a narrow muscular tube measuring about 25 cm in length and with an average diameter of 2 cm. The esophagus connects the pharynx to the stomach and helps in conveying the food from pharynx to the stomach. The esophagus is flattened posteriorly, keeping the lumen collapsed.

The esophagus begins at the lower border of the cricoid cartilage. It descends posterior to the trachea and anterior to the vertebral column. The esophagus lies in the posterior part of superior and inferior mediastinum. Only terminal half an inch enters the abdomen through the esophageal opening in the diaphragm at the level of 10th thoracic vertebra. It terminates by becoming continuous with the stomach at the cardiac orifice to left of midline at level of 11th thoracic vertebra.

Peritoneal relation: It is retroperitoneal organ but anterior and lateral surfaces re covered by visceral peritoneum.

Anatomical relationships in the thorax:

  • Anterior: Trachea, left recurrent laryngeal nerve, left principal bronchus and pericardium with the left atrium.
  • Posterior: Vertebral column, thoracic duct, throracic aorta and azygos vein.
  • Right side: The mediastinal pleura and the terminal part of the azygos vein.
  • Left side: The left subclavian artery, the aortic arch, the thoracic duct, and the mediastinal pleura.

Anatomical relationships in the abdomen.

  • Anterior: anterior vagal trunk (from left vagus) and posterior surface of left lobe of liver.
  • Posterior: posterior vagal trunk (from right vagus) and left crus of diaphragm

Constriction:
Esophagus has four normal constrictions. Knowing this helps in inserting the nasogastric tube.

  • 1st construction- 15 cm from the incisor teeth, at the level of pharyngoesophageal junction and caused by the cricopharyngeus muscle
  • 2nd and 3rd constriction(broncho-aortic)- 22.5 cm from the incisor teeth, caused by aortic arch, and 27.5 cm from the incisor teeth, caused byleft bronchus
  • 4th constriction: 40 cm from the incisor teeth, where it passes through the esophageal hiatus of the diaphragm.

Function
conducts food from pharynx to stomach via the wave-like contractions (peristalsis) of its muscular coat

Blood supply
Arteries

  • Upper third is supplied by inferior thyroid arteries.
  • Middle third is supplied by oesophageal branches of the left gastric artery.
  • Lower third is by branches of left gastric artery (from celiac trunk) and left inferior phrenic artery (from aorta).

Veins

  • Upper third- Brachiocephalic vein.
  • Middle third- azygos vein.
  • Lower one third drains to left gastric vein (portal venous system) and esophageal veins (to azygos vein- systemic vein). It forms porto-systemic anastomoses and is the site for esophageal varices.

Lymph drainage

  • Upper one third- deep cervical lymph nodes.
  • Middle one third- posterior mediastinal lymph nodes.
  • Lower one third- left gastric lymph nodes

Nerve supply

  • parasympathetic – vagus.
  • sympathetic – greater and lesser thoracic splanchnic nerves.

Clinical significance

  • Esophageal varices
  • Achalasia cardia
  • Gastroesophageal Reflux Disease