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Thoracic Esophagus
The thoracic esophagus is the portion of the esophagus that descends through the thorax from the superior thoracic aperture to the esophageal hiatus of the diaphragm. It passes through the superior and posterior mediastina and has important relationships with the trachea, aortic arch, thoracic aorta, left main bronchus, pericardium, left atrium, vagus nerves, and thoracic duct.
RegionThorax
SystemDigestive System
The thoracic esophagus is the portion of the esophagus that passes through the thoracic cavity. It begins where the cervical esophagus enters the thorax through the superior thoracic aperture and continues inferiorly through the mediastinum until it reaches the esophageal hiatus of the diaphragm.
Within the thorax, the esophagus descends first through the superior mediastinum and then through the posterior mediastinum. Its course brings it into close relationship with several major structures, including the trachea, aortic arch, descending thoracic aorta, left main bronchus, pericardium, left atrium, thoracic duct, azygos system, and vagus nerves.
The thoracic esophagus is a muscular tube specialized for transporting swallowed material from the pharynx toward the stomach. Coordinated peristaltic contractions propel the bolus inferiorly while the esophageal wall accommodates considerable changes in luminal diameter.
Extent
The thoracic esophagus extends from the superior thoracic aperture to the esophageal hiatus of the diaphragm.
It is continuous superiorly with the cervical esophagus and inferiorly with the short abdominal portion of the esophagus.
Superior Thoracic Aperture
The esophagus enters the thorax through the superior thoracic aperture, commonly called the thoracic inlet.
At this level it remains closely related to the trachea anteriorly and the vertebral column posteriorly.
Esophageal Hiatus
The thoracic esophagus leaves the thorax by passing through the esophageal hiatus in the diaphragm.
The hiatus is located at approximately the T10 vertebral level.
Course Through the Mediastinum
The thoracic esophagus descends through two major mediastinal compartments:
- Superior mediastinum
- Posterior mediastinum
Its anatomical relationships change considerably as it descends.
Superior Mediastinal Portion
Within the superior mediastinum, the esophagus lies posterior to the trachea.
It is also related to the aortic arch and its branches, the thoracic duct, vagus nerves, and vertebral column.
Posterior Mediastinal Portion
Below the transverse thoracic plane, the esophagus enters the posterior mediastinum.
Here it is related to the descending thoracic aorta, pericardium, left atrium, thoracic duct, azygos and hemiazygos venous systems, vagal trunks, and vertebral bodies.
General Direction
The thoracic esophagus does not descend as a perfectly straight midline tube.
It undergoes gentle deviations as it passes around neighboring structures and approaches the diaphragm.
Relationship to the Trachea
In the superior thorax, the trachea lies directly anterior to the esophagus.
This relationship continues from the cervical region until the trachea bifurcates into the main bronchi.
Tracheal Bifurcation
The trachea bifurcates into the right and left main bronchi near the level of the sternal angle.
The esophagus continues posterior to the tracheobronchial region.
Relationship to the Left Main Bronchus
The left main bronchus crosses anterior to the esophagus.
This relationship produces one of the normal external impressions or constrictions of the thoracic esophagus.
Relationship to the Aortic Arch
The aortic arch passes superiorly, posteriorly, and toward the left in relation to the upper thoracic esophagus.
Its close relationship creates another normal impression on the esophageal wall.
Relationship to the Descending Thoracic Aorta
The descending thoracic aorta initially lies to the left of the esophagus in the posterior mediastinum.
As the esophagus descends, their relative positions change, and the esophagus approaches the anterior aspect of the aorta near the diaphragm.
Relationship to the Pericardium
The esophagus lies posterior to the pericardium through much of the lower thorax.
This relationship places the esophagus immediately behind the posterior aspect of the heart.
Relationship to the Left Atrium
The left atrium lies anterior to the lower thoracic esophagus, with the pericardium intervening.
This close anatomical relationship is clinically important in cardiac imaging and procedures involving the posterior wall of the left atrium.
Relationship to the Vertebral Column
The thoracic vertebral bodies lie posterior to the esophagus.
Intervening structures vary by level and include the thoracic duct, vessels, connective tissue, and portions of the descending thoracic aorta.
Relationship to the Thoracic Duct
The thoracic duct ascends through the posterior mediastinum in close relationship to the esophagus.
It typically begins on the right side of the vertebral column and crosses toward the left at approximately the mid-thoracic level.
Relationship to the Azygos Vein
The azygos vein ascends on the right side of the vertebral column, generally to the right of the thoracic esophagus.
It forms part of the important venous network surrounding the posterior mediastinum.
Relationship to the Hemiazygos System
The hemiazygos and accessory hemiazygos veins lie predominantly on the left side of the vertebral column and cross toward the azygos vein.
Their transverse tributaries may pass posterior to the esophagus.
Relations of the Thoracic Esophagus
| Direction | Important Relations |
|---|---|
| Anterior | Trachea, left main bronchus, pericardium and left atrium |
| Posterior | Vertebral column, thoracic duct and posterior mediastinal structures |
| Left | Aortic arch, descending thoracic aorta and left mediastinal pleura |
| Right | Azygos vein and right mediastinal pleura |
Esophageal Constrictions
The esophagus has several normal anatomical constrictions along its course.
Some of these occur within the thorax because neighboring structures externally indent the esophageal wall.
Aortic Constriction
The passage of the aortic arch adjacent to the esophagus produces the aortic constriction.
This is a normal narrowing visible during contrast studies and endoscopic examination.
Bronchial Constriction
The crossing of the left main bronchus anterior to the esophagus produces another normal narrowing known as the bronchial constriction.
Diaphragmatic Constriction
A further constriction occurs where the esophagus passes through the esophageal hiatus of the diaphragm.
This is the most inferior normal thoracic narrowing.
Major Esophageal Constrictions
| Constriction | Cause |
|---|---|
| Pharyngoesophageal | Upper esophageal sphincter and cricopharyngeal region |
| Aortic | Aortic arch |
| Bronchial | Left main bronchus |
| Diaphragmatic | Esophageal hiatus |
Clinical Importance of the Constrictions
Esophageal constrictions are important because swallowed foreign bodies may become lodged at these sites.
They are also landmarks encountered during endoscopy and contrast imaging.
Wall of the Thoracic Esophagus
The thoracic esophageal wall consists of the typical esophageal layers:
- Mucosa
- Submucosa
- Muscularis externa
- Adventitia
Mucosa
The mucosa is lined by nonkeratinized stratified squamous epithelium.
This epithelium protects the esophageal wall from mechanical abrasion caused by swallowed material.
Mucosal Folds
When the esophagus is empty, its mucosa and submucosa form longitudinal folds.
These folds flatten as the lumen expands during passage of a bolus.
Submucosa
The submucosa contains connective tissue, blood vessels, lymphatics, nerves, and mucous esophageal glands.
Its elastic properties permit considerable distension of the esophageal lumen.
Esophageal Glands
Submucosal esophageal glands produce mucus that lubricates the esophageal surface.
This secretion assists the passage of swallowed material toward the stomach.
Muscularis Externa
The muscularis externa contains an inner circular layer and an outer longitudinal layer.
Coordinated contraction of these layers produces esophageal peristalsis.
Muscle Composition
The type of muscle in the esophageal wall changes progressively from superior to inferior.
The upper third is predominantly skeletal muscle, the middle third contains a mixture of skeletal and smooth muscle, and the lower third is predominantly smooth muscle.
Muscle Composition of the Esophagus
| Region | Muscle Type |
|---|---|
| Upper third | Predominantly skeletal muscle |
| Middle third | Mixed skeletal and smooth muscle |
| Lower third | Predominantly smooth muscle |
Adventitia
Most of the thoracic esophagus is surrounded by adventitia rather than serosa.
The adventitia consists of connective tissue that blends with surrounding mediastinal structures.
Absence of a Complete Serosal Covering
The absence of a complete serosal covering is an important anatomical feature of the thoracic esophagus.
It allows the esophagus to remain mobile within the mediastinum but also influences the potential spread of inflammation and malignancy into surrounding tissues.
Peristalsis
The principal function of the thoracic esophagus is to transport swallowed material toward the stomach through coordinated peristaltic contractions.
Primary Peristalsis
Primary peristalsis is the continuation of the swallowing wave initiated in the pharynx.
The contraction progresses inferiorly along the esophageal wall and propels the swallowed bolus toward the stomach.
Secondary Peristalsis
Secondary peristalsis can occur in response to distension of the esophagus by retained material.
It helps clear residual contents without requiring initiation of another pharyngeal swallow.
Esophageal Plexus
The thoracic esophagus is surrounded by an esophageal nerve plexus formed primarily by branches of the right and left vagus nerves, with sympathetic contributions.
The vagal fibers redistribute around the esophagus before reorganizing into vagal trunks near the diaphragm.
Right Vagus Nerve
The right vagus nerve passes posterior to the root of the right lung and contributes extensively to the esophageal plexus.
Its fibers tend to contribute more prominently to the posterior vagal trunk inferiorly.
Left Vagus Nerve
The left vagus nerve passes posterior to the root of the left lung and contributes to the esophageal plexus.
Its fibers tend to contribute more prominently to the anterior vagal trunk near the diaphragm.
Anterior Vagal Trunk
As the esophageal plexus approaches the diaphragm, vagal fibers regroup into the anterior vagal trunk.
This trunk is derived predominantly from the left vagus nerve.
Posterior Vagal Trunk
The posterior vagal trunk forms on the posterior surface of the lower esophagus.
It is derived predominantly from the right vagus nerve.
Vagal Arrangement
| Structure | Predominant Origin |
|---|---|
| Anterior vagal trunk | Left vagus nerve |
| Posterior vagal trunk | Right vagus nerve |
Parasympathetic Innervation
Parasympathetic innervation of the thoracic esophagus is supplied by the vagus nerves through the esophageal plexus.
These fibers participate in regulation of esophageal motility and glandular activity.
Sympathetic Innervation
Sympathetic fibers reach the thoracic esophagus from the sympathetic trunks through thoracic visceral branches.
They contribute to vascular regulation and visceral sensory pathways.
Enteric Nervous System
The esophageal wall contains intrinsic enteric neural networks, including the myenteric and submucosal plexuses.
These networks participate in coordination of smooth muscle activity, secretion, and local vascular function.
Myenteric Plexus
The myenteric plexus lies between the circular and longitudinal layers of the muscularis externa.
It has an important role in coordinating peristaltic activity.
Submucosal Plexus
The submucosal plexus lies within the submucosal region.
It contributes to regulation of glandular secretion and local mucosal function.
Arterial Supply
The thoracic esophagus receives blood from multiple segmental arterial sources.
The principal supply is provided by esophageal branches of the descending thoracic aorta, supplemented by branches from neighboring arteries.
Esophageal Branches of the Thoracic Aorta
Several small esophageal arteries arise directly from the descending thoracic aorta.
These vessels form longitudinal anastomoses along the esophageal wall.
Bronchial Artery Contributions
Branches of the bronchial arteries may contribute to the arterial supply of the thoracic esophagus, particularly in its upper and middle portions.
Inferior Thyroid Artery Contributions
Superiorly, arterial branches supplying the cervical esophagus from the inferior thyroid arteries communicate with thoracic esophageal vessels.
Inferior Arterial Anastomoses
Near the diaphragm, thoracic esophageal arteries communicate with vessels supplying the abdominal esophagus, particularly branches associated with the left gastric and inferior phrenic arteries.
Arterial Supply Summary
| Region | Important Arterial Sources |
|---|---|
| Upper thoracic esophagus | Esophageal branches with contributions from inferior thyroid and bronchial arteries |
| Middle thoracic esophagus | Esophageal branches of thoracic aorta and bronchial arteries |
| Lower thoracic esophagus | Thoracic aortic branches communicating with left gastric and inferior phrenic branches |
Venous Drainage
The thoracic esophagus contains an extensive venous plexus within and around its wall.
Venous blood drains principally toward the azygos and hemiazygos systems.
Azygos System
Veins from the right side of the thoracic esophagus commonly drain toward the azygos vein.
The azygos system provides an important pathway between the superior and inferior vena caval circulations.
Hemiazygos System
Venous drainage from the left side of the thoracic esophagus can enter the hemiazygos and accessory hemiazygos veins.
These veins ultimately communicate with the azygos vein.
Esophageal Venous Plexus
The esophageal venous plexus extends longitudinally along the esophagus and communicates between cervical, thoracic, and abdominal venous territories.
Portosystemic Communication
At the distal esophagus, veins draining toward the left gastric vein of the portal system communicate with veins draining toward the azygos system of the systemic circulation.
This forms an important portosystemic anastomosis.
Esophageal Varices
Increased pressure within the portal venous system can enlarge submucosal veins in the distal esophagus, producing esophageal varices.
These thin-walled dilated veins can be clinically important because rupture may result in severe gastrointestinal hemorrhage.
Lymphatic Drainage
The thoracic esophagus has an extensive longitudinal lymphatic network.
Lymphatic drainage varies by level and communicates broadly with cervical, mediastinal, and upper abdominal lymphatic pathways.
Upper Thoracic Lymphatic Drainage
The upper thoracic esophagus drains toward paratracheal and related superior mediastinal lymph nodes.
Middle Thoracic Lymphatic Drainage
The middle thoracic esophagus drains toward posterior mediastinal and neighboring mediastinal lymph nodes.
Lower Thoracic Lymphatic Drainage
The lower thoracic esophagus communicates with lymphatic pathways toward the left gastric and celiac lymph node groups.
Longitudinal Lymphatic Channels
Longitudinal lymphatic vessels within the esophageal wall permit lymph to travel considerable distances before reaching regional nodes.
This feature is important in understanding patterns of lymphatic spread from esophageal malignancies.
Neurovascular Supply Summary
| Feature | Principal Structures |
|---|---|
| Arterial supply | Esophageal branches of thoracic aorta with bronchial and other contributions |
| Venous drainage | Azygos and hemiazygos systems |
| Parasympathetic supply | Vagus nerves through esophageal plexus |
| Sympathetic supply | Thoracic sympathetic pathways |
| Lymphatic drainage | Paratracheal, mediastinal, left gastric and celiac pathways depending on level |
Esophageal Hiatus Anatomy
The esophageal hiatus is an opening in the muscular diaphragm through which the esophagus passes from the thorax into the abdomen.
It is formed predominantly by fibers of the right crus of the diaphragm.
Structures Passing Through the Esophageal Hiatus
Structures associated with the esophageal hiatus include:
- Esophagus
- Anterior vagal trunk
- Posterior vagal trunk
- Esophageal vessels and lymphatics
Diaphragmatic Contribution to Esophageal Closure
Fibers of the diaphragm surrounding the esophageal hiatus contribute to the antireflux barrier at the gastroesophageal junction.
Contraction of the crural diaphragm can exert an external sphincter-like effect around the distal esophagus.
Thoracic Esophagus on CT
On CT, the thoracic esophagus can be followed from the thoracic inlet through the mediastinum toward the esophageal hiatus.
Its relationship with the trachea, left main bronchus, aorta, left atrium, vertebral column, and surrounding mediastinal fat provides important landmarks.
Thoracic Esophagus on MRI
MRI can demonstrate the esophageal wall and its relationship with mediastinal soft tissues, heart, vessels, vertebral column, and diaphragm.
It may be particularly useful when detailed soft tissue characterization is required.
Contrast Esophagography
A contrast swallow can demonstrate the course, caliber, motility, and normal impressions of the thoracic esophagus.
Normal impressions related to the aortic arch and left main bronchus can be recognized during examination.
Endoscopy
Upper gastrointestinal endoscopy permits direct visualization of the thoracic esophageal mucosa.
The normal constrictions and the transition toward the gastroesophageal junction are important endoscopic landmarks.
Esophageal Foreign Bodies
Foreign bodies may become impacted at normal esophageal constrictions.
Within the thorax, the aortic, bronchial, and diaphragmatic constrictions are important potential sites of impaction.
Esophageal Perforation
Esophageal perforation allows luminal contents to enter the mediastinum.
Because most of the thoracic esophagus lacks a serosal covering, contamination can spread into surrounding mediastinal tissues.
Mediastinitis
Leakage from a thoracic esophageal perforation can cause severe inflammation and infection within the mediastinum.
The fascial and connective tissue planes of the thorax allow contamination to spread beyond the immediate site of injury.
Esophageal Carcinoma
Malignant tumors of the thoracic esophagus may extend locally into surrounding mediastinal structures and spread through the extensive lymphatic network.
The absence of a complete serosal layer facilitates direct extension beyond the muscular wall.
Local Tumor Relationships
Depending on its level, a thoracic esophageal tumor may approach or involve the trachea, bronchi, aorta, pericardium, left atrium, pleura, vertebral structures, or neighboring mediastinal tissues.
Lymphatic Spread of Esophageal Tumors
The longitudinal lymphatic network allows tumor cells to reach lymph nodes located some distance from the primary lesion.
This anatomical feature contributes to complex patterns of nodal spread.
Esophageal Stricture
An esophageal stricture is a pathological narrowing of the lumen.
Strictures may result from inflammation, scarring, malignancy, injury, or other processes and can interfere with passage of swallowed material.
Hiatal Hernia
A hiatal hernia occurs when part of the stomach passes through the esophageal hiatus into the thoracic cavity.
The anatomy of the distal thoracic esophagus, diaphragmatic crura, and gastroesophageal junction is central to understanding this condition.
Sliding Hiatal Hernia
In a sliding hiatal hernia, the gastroesophageal junction and proximal stomach move superiorly through the esophageal hiatus.
Paraesophageal Hernia
In a paraesophageal hernia, part of the stomach herniates through the hiatus alongside the esophagus while the gastroesophageal junction may remain relatively near its normal position.
Achalasia
Achalasia is an esophageal motility disorder associated with impaired relaxation of the lower esophageal sphincter and abnormal esophageal peristalsis.
Loss of inhibitory neurons within the myenteric plexus plays an important role in its pathophysiology.
Esophageal Dilatation in Achalasia
Persistent resistance at the distal esophagus can lead to progressive dilatation of the thoracic esophagus proximal to the gastroesophageal junction.
Contrast studies may demonstrate characteristic narrowing distally with proximal enlargement.
Gastroesophageal Reflux
Retrograde movement of gastric contents into the distal esophagus exposes the squamous mucosa to acid and other gastric contents.
The antireflux mechanism depends on several structures, including the lower esophageal sphincteric region, diaphragmatic crura, and anatomy of the gastroesophageal junction.
Left Atrium and Esophageal Procedures
The close relationship between the left atrium and thoracic esophagus is clinically important during procedures involving the posterior left atrial wall.
The distance between the two structures can be very small because only the pericardium and intervening connective tissues separate them.
Transesophageal Echocardiography
Transesophageal echocardiography takes advantage of the close relationship between the esophagus and heart.
An ultrasound transducer positioned within the esophagus can obtain detailed images of cardiac structures without the interference of the anterior chest wall and lungs.
Aortic Enlargement and the Esophagus
Because the thoracic esophagus is closely related to the aortic arch and descending thoracic aorta, enlargement of the aorta can alter or compress the esophageal lumen.
Thoracic Esophagus Versus Cervical Esophagus
| Feature | Thoracic Esophagus | Cervical Esophagus |
|---|---|---|
| Location | Superior and posterior mediastina | Neck |
| Superior boundary | Superior thoracic aperture | Pharyngoesophageal junction |
| Inferior boundary | Esophageal hiatus | Superior thoracic aperture |
| Major anterior relations | Trachea, left main bronchus, pericardium and left atrium | Trachea |
| Major arterial source | Esophageal branches of thoracic aorta | Inferior thyroid artery branches |
| Major venous drainage | Azygos and hemiazygos systems | Inferior thyroid veins |
Key Anatomical Relationships
| Structure | Relationship to Thoracic Esophagus |
|---|---|
| Trachea | Anterior in superior mediastinum |
| Aortic arch | Left-sided relationship producing esophageal impression |
| Left main bronchus | Crosses anteriorly and produces constriction |
| Descending thoracic aorta | Closely related on left and posterior aspects |
| Left atrium | Anterior, separated by pericardium |
| Thoracic duct | Closely related posteriorly |
| Azygos vein | Generally to right |
| Vagus nerves | Form esophageal plexus on surface |
| Diaphragm | Esophagus passes through hiatus near T10 |
Key Features of the Thoracic Esophagus
| Feature | Key Point |
|---|---|
| Extent | Superior thoracic aperture to esophageal hiatus |
| Mediastinal course | Superior and posterior mediastina |
| Diaphragmatic passage | Esophageal hiatus near T10 |
| Major anterior relations | Trachea, left main bronchus, pericardium and left atrium |
| Major arterial supply | Esophageal branches of descending thoracic aorta |
| Major venous drainage | Azygos and hemiazygos systems |
| Parasympathetic supply | Vagus nerves |
| Vagal organization | Esophageal plexus reorganizes into anterior and posterior vagal trunks |
| Outer covering | Predominantly adventitia |
| Major thoracic constrictions | Aortic, bronchial and diaphragmatic |
Anatomical and Clinical Importance
The thoracic esophagus is a central visceral structure of the mediastinum that connects the cervical and abdominal portions of the esophagus. Its course through the superior and posterior mediastina brings it into close relationship with the trachea, aortic arch, left main bronchus, descending thoracic aorta, left atrium, thoracic duct, azygos system, vagus nerves, and diaphragm.
The aortic arch, left main bronchus, and esophageal hiatus create important normal constrictions along the thoracic esophagus. Its arterial supply is predominantly derived from esophageal branches of the thoracic aorta, while venous drainage communicates with the azygos and hemiazygos systems. The vagus nerves form an esophageal plexus around the organ before reorganizing into anterior and posterior vagal trunks near the diaphragm.
These anatomical relationships are important in understanding esophageal foreign-body impaction, perforation, mediastinitis, hiatal hernia, achalasia, esophageal varices, esophageal carcinoma, transesophageal echocardiography, and surgical or endoscopic procedures involving the mediastinum and upper gastrointestinal tract.
Published on September 30, 2026
Last updated on September 30, 2026
Last updated on September 30, 2026