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Topic

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Esophagus

The esophagus is a 25–30 cm long muscular tube that connects the pharynx to the stomach, serving as the main conduit for food and liquid. It begins at the lower border of the cricoid cartilage (C6 vertebra), descends through the posterior mediastinum, and passes through the esophageal hiatus of the diaphragm (T10 vertebra) before joining the stomach at the cardiac orifice (T11). Structurally, it has an inner circular and outer longitudinal muscle layer with upper one-third skeletal muscle, middle one-third mixed, and lower one-third smooth muscle. It is lined by non-keratinized stratified squamous epithelium, adapted for resisting mechanical stress. The esophagus has three natural constrictions:

  1. Cervical constriction – at the cricopharyngeus (C6)

  2. Thoracic constriction – at the aortic arch and left main bronchus (T4–T5)

  3. Diaphragmatic constriction – at the esophageal hiatus (T10)

Synonyms

  • Gullet

  • Oesophagus (British spelling)

  • Food pipe

Function

  • Conducts food and liquid from the pharynx to the stomach via coordinated peristalsis

  • Prevents reflux through upper and lower esophageal sphincters

  • Provides a flexible, collapsible tube that adapts to swallowing and respiration

  • Protects mucosa with mucous secretion

Arterial Supply

  • Cervical esophagus: branches of the inferior thyroid artery

  • Thoracic esophagus: branches from the bronchial arteries and thoracic aorta

  • Abdominal esophagus: branches from the left gastric artery and left inferior phrenic artery

Venous Drainage

  • Cervical esophagus: inferior thyroid vein

  • Thoracic esophagus: azygos and hemiazygos veins

  • Abdominal esophagus: left gastric vein (drains into portal vein)

  • Clinical importance: forms portosystemic anastomoses → site of esophageal varices in portal hypertension

Nerve Supply

  • Parasympathetic: vagus nerve (CN X) via the esophageal plexus → motor to smooth muscle, secretomotor to glands

  • Sympathetic: thoracic sympathetic trunk → regulates vascular tone and pain sensation

MRI Appearance

T1-weighted images:

  • Lumen contains air (signal void, black) or fluid (variable low signal)

  • Wall shows intermediate signal intensity

  • Periesophageal fat is hyperintense, providing contrast

T2-weighted images:

  • Wall shows intermediate signal, while edema or inflammation is hyperintense

  • Fluid-filled lumen appears bright; air remains dark (signal void)

  • Useful for detecting tumors, strictures, or esophagitis

STIR (Short Tau Inversion Recovery):

  • Suppresses fat, improving contrast for edema, inflammation, or mediastinal spread of pathology

  • Normal wall remains low signal; pathology appears bright hyperintense

T1 Post-Contrast (Gadolinium-enhanced):

  • Normal wall enhances homogeneously

  • Pathology (tumors, inflammation, ulcers) enhances heterogeneously or asymmetrically

CT Appearance

Non-contrast CT:

  • Appears as a collapsed tubular soft tissue structure posterior to the trachea and anterior to the vertebral column

  • Lumen may contain air (black) or fluid (soft tissue density)

  • Wall thickening, masses, or foreign bodies are identifiable

Contrast-enhanced CT (CECT):

  • Wall enhances, making lesions more conspicuous

  • Detects tumors, varices, strictures, perforations, diverticula, and trauma

  • Defines relation of esophagus to aorta, heart, trachea, and diaphragm

MRI images

Esophagus anatomy MRI coronal image -img-00000-00000

MRI images

Esophagus anatomy MRIaxial image -img-00000-00000

CT image

Esophagus anatomy CT axial image -img-00000-00000