Skip to content

Relevant Anatomic Relations of the Esophagus

Author: Jules Lin

General Anatomy of the Esophagus

  • Primary Function: Transport food from the mouth to the stomach.
  • Structure:
    • Muscular tube starting at the inferior border of the cricoid cartilage (C6 vertebra).
    • Ends at the gastric orifice (T11 vertebra).
    • Length ranges from 22 to 28 cm; varies with patient height.
  • Anchoring Points:
    • Superiorly: Cricoid cartilage.
    • Inferiorly: Diaphragm.
  • Diameter: Approximately 2.5 cm.
  • Anatomic Narrowings:
    1. Cricopharyngeal constriction at the upper esophageal sphincter (1.5 cm diameter).
    2. Compression by aortic arch, left atrium, and left mainstem bronchus (~22 cm from incisors).
    3. Lower esophageal sphincter.

Esophageal Wall Layers

  1. Mucosa:
    • Squamous epithelium.
    • Lamina propria.
    • Muscularis mucosa.
  2. Submucosa.
  3. Muscularis propria:
    • Inner circular muscle layer.
    • Outer longitudinal muscle layer.
  4. Adventitia.
  5. Muscle Composition:
    • Upper 40%: Striated muscle.
    • Lower 60%: Smooth muscle.
  6. Clinical Relevance: Dysmotility disorders often affect the distal two-thirds involving smooth muscle.

Cervical Esophagus

Anatomy

  • Length: 5 cm.
  • Extends from cricoid cartilage (C6) to suprasternal notch anteriorly and T1-T2 interspace posteriorly.
  • Shifts to the left at the base of the neck.

Surgical Approach

  • Left neck incision is preferred (e.g., transhiatal esophagectomy, Zenker diverticulectomy).

Surrounding Structures

  • No serosal lining or mesentery.
  • Surrounded by loose fibroareolar tissue.
  • Paraesophageal space (anterior) and retroesophageal space (posterior) created by fascia and carotid sheaths.

Clinical Significance

  • Infections can spread from neck to mediastinum due to fascial connections, leading to necrotizing mediastinitis.
  • Iatrogenic perforations commonly occur above the cricopharyngeal muscle, causing posterior pharyngeal perforations.

Blood Supply

  • Arterial: Right and left superior and inferior thyroid arteries.
  • Venous: Inferior thyroid vein.
  • Middle thyroid vein may be divided for better exposure.

Innervation

  • Recurrent laryngeal nerves.
  • Sympathetic chains.

Upper Esophageal Sphincter (UES)

Components

  • Cricopharyngeus muscle.
  • Inferior pharyngeal constrictor muscles.
  • Cricoid cartilage and hyoid bone.

Function

  • Maintains a basal tone but allows rapid changes for swallowing.
  • Relaxes with increased intrapharyngeal pressure to allow food passage.

Killian Triangle

  • A weak area between the inferior constrictor and cricopharyngeal muscles.
  • Site for formation of Zenker diverticulum due to muscle hypertrophy or dysmotility.

Pathologies

Zenker Diverticulum

  • Occurs in the Killian triangle.
  • Results from hypertrophy of the cricopharyngeus muscle or underlying dysmotility.
  • Symptoms: Dysphagia, regurgitation, aspiration.
  • Treatment: Surgical resection or endoscopic stapling.

Necrotizing Mediastinitis

  • Life-threatening infection spreading from the neck to the mediastinum.
  • Requires early surgical drainage.
  • Often results from dental or tonsillar infections.

Trachea and Spine

Anatomical Relationships

  • Anterior: Membranous trachea.
  • Posterior: Vertebral bodies.

Clinical Significance

  • Injury to the trachea during esophageal surgery can cause tracheoesophageal fistula.
  • Spinal abscess can occur from cervical esophageal perforation or anastomotic leak.
  • Anterior spinal surgeries risk inadvertent esophageal injury.

Recurrent Laryngeal Nerves

Origin and Course

  • Branches of the vagus nerves.
  • Right nerve loops around the right subclavian artery.
  • Left nerve loops around the aortic arch.
  • Ascend in the tracheoesophageal groove.

Clinical Significance

  • Injury can cause hoarseness, impaired swallowing, and increased risk of aspiration.
  • Bilateral injury may lead to airway obstruction requiring tracheostomy.
  • Prevention: Careful dissection and avoidance of metal retractors on the nerve.

Thoracic Esophagus

Anatomy

  • Length: 20 cm.
  • Extends from the thoracic inlet to the diaphragmatic hiatus.
  • Shifts to the right at T7 vertebra.

Surgical Approach

  • Right thoracotomy or thoracoscopy is preferred for mid-esophageal access (e.g., Ivor-Lewis esophagectomy).

Blood Supply

  • Arterial: Bronchial arteries and esophageal branches from the descending aorta.
  • Venous: Drains into the azygos vein.

Surrounding Structures

  • Anterior: Trachea, pericardium, left atrium.
  • Posterior: Spine, descending aorta.
  • Lateral: Mediastinal pleura, lungs.

Clinical Significance

  • Tumor invasion into adjacent structures like the heart or aorta may be unresectable.
  • Aortoesophageal fistula can occur with direct invasion, leading to life-threatening hemorrhage.
  • Boerhaave syndrome: Spontaneous perforation usually on the left lateral distal esophagus.

Vagus Nerves

Course

  • Form pulmonary and esophageal plexuses around the esophagus.
  • Coalesce into anterior (left) and posterior (right) vagal trunks near the distal esophagus.

Function

  • Provide parasympathetic innervation to the esophagus.
  • Control esophageal motility via the myenteric (Auerbach) plexus.

Clinical Relevance

  • Injury can lead to gastroparesis or dysmotility disorders.
  • Achalasia: Degeneration of ganglion cells in Auerbach plexus causing aperistalsis and LES dysfunction.

Azygos Vein

Location

  • Adjacent to the right side of the upper thoracic esophagus.

Clinical Significance

  • May be involved by mid-esophageal tumors.
  • Care needed to avoid injury during esophageal surgery.

Lymphatic Drainage and Thoracic Duct

Lymphatic Network

  • Rich submucosal lymphatic plexus allows widespread tumor spread.
  • Direction of Drainage:
    • Above carina: Drains superiorly.
    • Below carina: Drains inferiorly to lower mediastinal and abdominal nodes.

Thoracic Duct

  • Main lymphatic vessel beginning at the cisterna chyli (T12).
  • Runs posterior to the esophagus between the azygos vein and aorta.
  • Empties into the junction of the left subclavian and jugular veins.

Clinical Relevance

  • Damage can cause chylothorax (leakage of lymph into the thoracic cavity).
  • Requires surgical ligation or interventional embolization if injured.

Abdominal Esophagus

Anatomy

  • Length: 3 to 6 cm.
  • Angulates to the left after passing through the esophageal hiatus.
  • Ends at the cardia along the lesser curvature of the stomach.

Blood Supply

  • Arterial: Branches from the left gastric artery and inferior phrenic artery.
  • Venous: Drains into the left gastric vein.

Gastroesophageal Junction (GEJ)

  • Location varies based on histological, endoscopic, or surgical criteria.
  • Important for surgeries like Nissen fundoplication and Heller myotomy.

Diaphragm and Esophageal Hiatus

Esophageal Hiatus

  • Located at the level of the T10 vertebra.
  • Formed mainly by the right crus of the diaphragm.

Phrenoesophageal Membrane

  • Attaches esophagus to diaphragm.
  • Composed of superior and inferior sheaths.
  • Degeneration may lead to hiatal hernia formation.

Lower Esophageal Sphincter (LES)

Structure

  • Not a true anatomical sphincter but a high-pressure zone.
  • Formed by thickened circular muscle fibers and gastric sling fibers.
  • Extends 3 to 4 cm above the gastroesophageal junction.

Function

  • Prevents gastroesophageal reflux.
  • Relaxes to allow food passage into the stomach.

Clinical Relevance

  • GERD results from LES dysfunction.
  • Achalasia involves impaired LES relaxation.
  • Surgical procedures (e.g., Heller myotomy) must consider LES anatomy to preserve function.

Pathologies

Achalasia

  • Loss of ganglion cells in the myenteric plexus.
  • Symptoms: Dysphagia, regurgitation, chest pain.
  • Treatment: Heller myotomy with or without fundoplication.

Hiatal Hernia

  • Protrusion of the stomach through the esophageal hiatus.
  • Types:
    • Sliding: GEJ and stomach slide into thorax.
    • Paraesophageal: Part of the stomach herniates alongside the esophagus.
  • Symptoms: GERD, chest pain, dysphagia.
  • Treatment: Surgical repair to restore anatomy and prevent complications.

Key Takeaways

  • Understanding esophageal anatomy is crucial for surgical planning and management of esophageal diseases.
  • Anatomic relationships to surrounding structures (trachea, aorta, vagus nerves) have significant clinical implications.
  • Esophageal pathologies often relate to specific anatomical features (e.g., Zenker diverticulum at Killian triangle).
  • Lymphatic drainage patterns influence the spread of esophageal cancer and guide oncologic surgery.

Note: All information is based on the provided context. Important keywords are highlighted in bold for emphasis.