Blood Supply of the Esophagus
Arterial Supply (Segmental)
- Cervical (Upper 1/3): Inferior thyroid artery (a branch of the thyrocervical trunk).
- Thoracic (Middle 1/3): Esophageal branches directly from the thoracic aorta and bronchial arteries.
- Abdominal (Lower 1/3): Left gastric artery (a branch of the celiac trunk) and left inferior phrenic artery.
Venous Drainage (Segmental)
- Cervical (Upper 1/3): Inferior thyroid vein, which drains into the brachiocephalic vein (systemic circulation).
- Thoracic (Middle 1/3): Azygos and hemiazygos veins, which drain into the superior vena cava (systemic circulation).
- Abdominal (Lower 1/3): Left gastric vein, which drains into the portal vein (portal circulation).
Key Associations/Complications
- Esophageal Varices: A critical porto-caval (or porto-systemic) anastomosis exists in the submucosa of the lower esophagus. The left gastric vein (portal system) anastomoses with the azygos vein (systemic system).
- Pathophysiology: In portal hypertension (e.g., due to cirrhosis), blood shunts from the high-pressure portal system to the low-pressure systemic system. This causes the submucosal veins in the lower esophagus to become engorged and dilated, forming varices.
- Clinical Significance: These varices are prone to rupture, leading to life-threatening upper GI hemorrhage (hematemesis). This is a major cause of mortality in patients with advanced liver disease.