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Esophagus

Oesophagus

For medical students2 min readUpdated 2026-10-10

The esophagus is an unpaired muscular tube that connects the pharynx to the stomach. Located primarily anterior to the vertebral column, this organ ensures reliable and rapid transit of the food bolus through a complex layered wall organization.

Total lengthApproximately 25 centimeters on average
SkeletotopyExtends from the 6th cervical (C6) to the 11th thoracic (T11) vertebra
ConstrictionsFeatures three physiological constrictions along its course
TunicsThe wall is formed by mucosal, muscular, and outer adventitial/serosal layers

Topography and Parts of the Esophagus

Anatomically, the esophagus begins where the pharynx ends. In adults, this transition projects at the level of the 6th cervical vertebra (C6). The organ ends at the junction with the stomach, corresponding to the level of the 11th thoracic vertebra (T11).

Throughout its length (about 25 cm), the tube is divided into three topographical parts:

Spatial Configuration: Curvatures and Constrictions

Although the esophagus is a tubular organ, its course is not strictly straight. It lies anterior to the vertebral column, following its curvature and adapting to neighboring structures. There are four curvatures overall:

Of major clinical significance are the three physiological constrictions along the organ's course. These are the zones where the lumen naturally narrows:

  1. Pharyngeal constriction — located at the very beginning, at the pharyngoesophageal junction.
  2. Aortic constriction — formed where the esophagus is crossed by the aortic arch.
  3. Diaphragmatic constriction — located where the tube passes through the esophageal hiatus of the diaphragm.

Histological Structure of the Wall

The organ wall is ideally adapted for propelling food and consists of three main layers.

The mucosa (tunica mucosa) is lined with non-keratinized stratified squamous epithelium, protecting tissues from mechanical trauma. A characteristic feature of the mucosa is the presence of prominent longitudinal folds that allow the lumen to dilate during the passage of a large food bolus. The submucosa contains proper esophageal glands (glandulae oesophageae), whose secretions further lubricate the walls.

The muscular layer (tunica muscularis) is responsible for peristalsis. It is formed by two layers: an inner circular layer and an outer longitudinal layer. The distribution of muscle tissue types along the organ's length is noteworthy:

The outer coat varies depending on the region. The cervical and thoracic parts are covered by connective tissue adventitia (tunica adventitia), which loosely attaches the esophagus to surrounding structures. The abdominal part, located within the peritoneal cavity, is covered by a serous membrane (tunica serosa).

Blood Supply, Innervation, and Lymphatic Drainage

The organ receives a rich blood supply from multiple sources due to its significant length. Blood is supplied by branches of the inferior thyroid artery (a. thyroidea inferior), the thoracic aorta (aorta thoracica), and the left gastric artery (a. gastrica sinistra).

Nerve regulation is provided by the esophageal plexus (plexus oesophageus), formed by branches of the vagus nerve (n. vagus) and the sympathetic trunk (truncus sympathicus).

Lymphatic drainage from various segments is directed to corresponding regional nodes: cervical, tracheobronchial, mediastinal, and gastric lymph nodes, ensuring robust immune protection throughout the organ's length.

Mnemonic

To quickly remember the three physiological constrictions of the esophagus, use the mnemonic PAD: Pharyngeal, Aortic, Diaphragmatic.

Frequently asked questions

What anatomical and physiological constrictions are distinguished in the esophagus?

The esophagus features both anatomical and physiological constrictions located at various levels.

Physiological constrictions:

  • Pharyngeal — transition of the pharynx into the esophagus.
  • Aortic — crossing with the aortic arch.
  • Diaphragmatic — esophageal hiatus of the diaphragm.

Anatomical constrictions:

  • Cricopharyngeal — at the pharyngoesophageal junction (level of the cricoid cartilage, cricopharyngeus muscle — m. cricopharyngeus).
  • Aortic — at the point of contact with the aortic arch.
  • Bronchial — at the point of contact with the left main bronchus.
  • Diaphragmatic — at the passage through the esophageal hiatus of the diaphragm.
Which organs are in contact with the thoracic part of the esophagus?

The thoracic part of the esophagus has syntopical relations with structures of the superior and posterior mediastinum.

Syntopy of the thoracic segment:

  • Trachea — the esophagus lies posterior to it, emerging from beneath its left margin.
  • Aortic arch (arcus aortae) — at the level of the tracheal bifurcation, the esophagus lies to the left of the posteroright surface of the aortic arch; this forms the aortic constriction.
  • Origin of the left common carotid and left subclavian arteries — the esophagus borders them.
  • Thoracic duct — passes between the left common carotid and left subclavian arteries.
  • Left recurrent laryngeal nerve (n. laryngeus recurrens sinister) — runs on the left, in the groove between the esophagus and trachea.
  • Vertebral column — the esophagus lies anterior to it; the sagittal curvature of the esophagus follows the spinal curve and is separated from it by prevertebral fascia and space.
Which arteries supply blood to the esophagus?

Blood supply to the esophagus is provided by branches of several arteries.

Arterial supply includes:

  • Inferior thyroid artery (a. thyroidea inferior) — its branches supply the cervical esophagus.
  • Thoracic aorta (aorta thoracica) — gives off esophageal branches (3–6 rr. esophagei) to the esophageal wall.
  • Left gastric artery (a. gastrica sinistra) — supplies the lower thoracic and abdominal parts of the esophagus.
Through which veins does venous drainage occur from the esophagus?

Venous drainage from the esophagus occurs via esophageal veins (vv. oesophageales) and associated venous pathways.

Drainage pathways include:

  • Unpaired thyroid plexus (plexus thyroideus impar) — collects blood, including from the esophagus, and drains it into the brachiocephalic veins.
  • Azygos venous system (v. azygos) — receives esophageal veins (vv. oesophageales) from the thoracic segment.
  • Left gastric vein — drains the lower thoracic and abdominal portions of the esophagus.

In the lower third of the esophagus and the cardias of the stomach, portosystemic anastomoses form, which are clinically significant in portal hypertension.

At the level of which vertebrae is the esophagus located?

In adults, it begins at the level of the 6th cervical vertebra (C6) and ends at the transition into the stomach at the 11th thoracic vertebra (T11) level.

How does the type of muscle tissue change within the esophageal wall?

In the upper third of the organ, the muscular coat consists of skeletal muscle. In the middle third, it is mixed, and in the lower third, it is represented solely by smooth myocytes.

What outer layer covers the esophagus?

The cervical and thoracic segments are covered by adventitia (tunica adventitia), while the short abdominal segment is covered by a serous membrane (tunica serosa).

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