Anatomy & embryology

Topic Completed: 1 August 2012

Minor changes: 17 December 2020

Copyright: 2003-2021,, Inc.

PubMed Search: Esophagus[TI] anatomy[TI]

Elliot Weisenberg, M.D.
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Cite this page: Weisenberg E. Anatomy & embryology. website. Accessed October 22nd, 2021.
Definition / general
  • Also called gullet
  • Muscular tubular structure 25 cm long in adults, 10 - 11 cm in newborns; develops from cranial portion of the foregut; connects pharynx and stomach; has cervical, thoracic and abdominal segments
  • Main purpose is to propel food from pharynx to stomach via peristalsis; secretes mucin for lubrication and to minimize reflux of gastric contents but has no other significant secretory or absorptive functions
  • Extends from cricopharyngeus muscle in pharynx (level of C6) to lower esophageal sphinchter at gastroesophageal junction (T11 / T12)
  • Notocord induces formation of foregut from endoderm
  • At day 21 (end of week 3), lateral walls of foregut develop septa that fuse and divide foregut into esophagus and trachea
  • At week 4, myenteric plexus develops
  • At weeks 5 - 6, septation of walls ends; initial lining is stratified columnar epithelium, which proliferates and almost occludes the lumen
  • At weeks 6 - 7, submucosal plexus develops, circular muscular layer develops
  • At weeks 6 - 7, epithelial vacuolization appears, vacuoles coalesce to form a single esophageal lumen
  • At week 8, ciliated cells appear and extend to almost entire columnar epithelium
  • At week 9, longitudinal muscle layer develops; interstitial cells of Cajal appear
  • At week 10, a single layer of columnar cells covers entire esophagus
  • At month 4, submucosal glands appear due to downward growth of columnar cells, extend distally to cardiac mucosa
  • At month 5, stratified squamous epithelium initially appears in midesophagus and replaces ciliated epithelium cephalad and caudally; proximal esophagus may retain ciliated epithelium at birth
  • At month 5, upper esophagus has both striated and smooth muscle
Regions (AJCC)
  • Cervical (lower border of cricoid cartilage to suprasternal notch / thoracic inlet, 5 cm long, begins 15 cm from incisors); contains striated muscle
  • Upper thoracic (suprasternal notch to tracheal bifurcation, 5 cm long, begins 20 cm from incisors); has striated and smooth muscle
  • Midthoracic (tracheal bifurcation to diaphragmatic hiatus, 5 cm long, begins 24 cm from incisors); has striated and smooth muscle
  • Lower thoracic and abdominal (10 cm long, begins 30 cm from incisors); extends past diaphragm to its junction with stomach; has smooth muscle only

  • Usual points of narrowing (possible sites of food / pill lodging): cricoid cartilage (due to cricopharyngeus muscle), aortic arch, anterior crossing of left main bronchus and left atrium, where it passes through diaphragm
  • Gastroesophageal junction: traditionally defined as macroscopic point of flaring of tubular esophagus or proximal limit of gastric rugal folds; endoscopic definition is Z ("zigzag") line at irregular boundary of squamous and columnar mucosa in distal esophagus, which is usually 2 - 3 cm proximal to macroscopic GE junction; histologic definition is proximal limit of gastric oxyntic (fundic) mucosa (Hum Pathol 2006;37:40)
  • Distal 1 - 2 cm of esophagus is often composed of cardiac or cardiac - oxyntic type of mucosa; there is no consensus if this is normal or due to reflux esophagitis
  • Esophageal sphincters: two areas of high pressure at rest (physiologic, not anatomic sphincters); upper esophageal sphincter is at cricopharyngeus and inferior pharyngeal constrictor muscles; lower esophageal sphincter is 2 - 4 cm proximal to esophagogastric junction at level of diaphragm (composed of intrinsic esophageal muscles, sling fibers of proximal stomach and crural diaphragm)
  • Vagotomy does NOT affect tone of lower esophageal sphincter; tone is affected by gastrin, acetylcholine and serotonin
Vessels and nerves
  • Arterial blood supply: cervical region - inferior thyroid artery; upper thoracic - bronchial and intercostal arteries; lower thoracic - aortic branches; abdominal - left gastric and inferior phrenic arteries; infarction is rare due to numerous anastomoses
  • Venous drainage: extensive submucosal venous plexus communicates with periesophageal veins; flows into inferior thyroid (upper 1/3), azygous (middle 1/3) and gastric veins (lower 1/3); azygous vein empties into superior vena cava and gastric veins into portal system; this connection between caval and portal venous systems explains esophageal varices due to portal hypertension
  • Nerves: left and right vagus nerves run lateral to esophagus, form plexi along anterior and posterior surfaces, then reunite to form anterior and posterior vagal trunks to stomach; have parasympathetic and sympathetic innervation
  • Lymphatic drainage: freely anastomosing networks in submucosa, muscularis propria and occasionally lamina propria; facilitate lengthwise tumor dissemination; upper third drains into paratracheal and internal jugular nodes, middle third to mediastinal nodes, lower third to nodes around aorta and celiac axis
  • Adjacent structures: cervical esophagus lies in posterior mediastinum, posterior to trachea and thyroid gland; is bounded by left and right recurrent laryngeal nerves and carotid sheaths; distal esophagus is posterior to left atrium and bounded by azygous veins; passes through opening in diaphragm called the hiatus
  • Incisura / angle of His: left side of esophagus forms sharp angle where it joins the stomach
Diagrams / tables

Images hosted on other servers:

4 weeks - relation of gut to yolk sac

Diaphragmatic crura

Arterial blood supply

Venous drainage


Lymphatic drainage

Cervical region

Clinical images

AFIP images

Z line - endoscopic appearance

Gross images

Images hosted on other servers:

Gastroesophageal junction

Microscopic (histologic) images
Contributed by Dr. Grigory Demyashkin, I. M. Sechenov First Moscow State Medical University (Russia)

6 - 8 week embryo

Upper left: small intestine
bottom left: esophagus
center: stomach
top right: pancreas; right: liver

Top: spine
lower left: trachea amd esophagus
center: lung, glandular stage

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Image 01 Image 02