Last revised by Jeremy Jones on 13 Mar 2024

The esophagus (plural: esophagi or esophaguses) is a muscular tube that conveys food and fluids from the pharynx to the stomach. It forms part of the upper gastrointestinal tract.

The esophagus is 23-37 cm long with a diameter of 1-2 cm and is divided into three parts:

The cervical esophagus begins at the upper esophageal sphincter, which is formed by the cricopharyngeus muscle 6.

The esophagus then descends to the left of the midline through the neck and superior mediastinum, returning to the midline at T5, before coursing to the left of the midline once more, in the posterior mediastinum. The distal thoracic esophagus then curves anteriorly to pass through the diaphragm into the abdominal cavity. 

The lower esophageal sphincter, a specialized region of the circular muscle of the distal esophagus, manifests itself radiographically as the phrenic ampulla (a.k.a. esophageal vestibule), a 2-4 cm long dilatation between the A-ring and B-ring 6.

There are three normal esophageal constrictions that should not be confused for pathological constrictions:

  • cervical constriction (narrowest point): due to the cricoid cartilage at the level of C5/6

  • thoracic constriction: due to the aortic arch at the level of T4/5

  • abdominal constriction: at the esophageal hiatus at the level of T10/11

Follows arterial supply:

  • upper third: deep cervical lymph nodes

  • middle third: posterior mediastinal lymph nodes

  • lower third: left gastric and celiac group lymph nodes

However it is important to note that within the esophageal walls, there are lymphatic channels which enable lymph to pass for long distances. Therefore, drainage may not necessarily follow any strict pattern.

The esophagus is made up of five layers, noting there is no serosal layer. From outer to inner, these are:

  • adventitia

  • muscularis propria

    • outer longitudinal muscularis propria

    • inner circular muscularis propria (in the upper one-third of the esophagus this layer is composed of striated (voluntary) muscle while the lower two-thirds is smooth muscle)

  • submucosa

  • mucosa

    • stratified squamous epithelium that abruptly changes to columnar epithelium in the lower esophagus

Majority of the anatomical variations of the esophagus are congenital, typically occurring at time of separation from the trachea (around third to seventh weeks intrauterine)

  • modified barium swallow is used to evaluate pharyngeal motility during swallowing; the procedure utilizes barium of varying consistencies given by mouth with video recording of swallowing

  • barium swallow is the main radiological method of assessing the esophagus; double contrast esophagogram using CO2 gas-forming crystals and barium contrast are used to distend the esophagus and coat the mucosa

Endoscopic ultrasonography is used for evaluation of the depth of the esophageal tumor.

  • 80% will contain gas allowing for appreciation of the wall if there is enough surrounding mediastinal fat

  • if collapsed will appear as round or ovoid

  • T1: isointense to muscle

  • T2: hyperintense to muscle

Useful for the staging of esophageal cancer.

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