By MRCSA in MRCS Part A — 04 Jul 2026

43 OESOPHAGUS

# 44 OESOPHAGUS

Detailed notes

The oesophagus is a 25 cm muscular tube that conducts food from the pharynx to the stomach. It begins at the cricopharyngeus (C6) as the continuation of the laryngopharynx and ends at the cardia of the stomach (T11) after piercing the diaphragm at T10. It is the only part of the GI tract entirely lined by stratified squamous epithelium — a clue to its function: protection against abrasion, not absorption.

For MRCS purposes the oesophagus sits at the intersection of anatomy, histology and pathology — every topic from foreign body impaction to varices, Barrett's and adenocarcinoma can be traced back to its segmental anatomy and embryological transitions.

Three anatomical parts

➡ Cervical (C6 to T1, ~5 cm) — posterior to trachea, anterior to vertebral column, related to recurrent laryngeal nerves in the tracheo-oesophageal groove.

➡ Thoracic (T1 to T10, ~18 cm) — in the posterior mediastinum, crossed anteriorly by the aortic arch, left main bronchus and left atrium.

➡ Abdominal (T10 to T11, ~2 cm) — short intra-peritoneal segment from the diaphragmatic hiatus to the cardia.

Three anatomical constrictions

These are the classic "narrowings" — sites of foreign body impaction, stricture formation and the trickiest part of OGD navigation. Examiners love them.

Constriction	Level	Distance from incisors
Cricopharyngeus (UOS)	C6	15 cm
Aortic arch / left main bronchus	T4	22 cm
Diaphragmatic hiatus / LOS	T10–T11	40 cm

👩‍⚕️ If you remember one thing: "Cricopharyngeus at C6, Arch at T4, Diaphragm at T10." The cricopharyngeus is the narrowest — the most common site of impaction overall.

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Histology — a three-layer rule

The oesophagus follows an elegant upper-to-lower transition that mirrors its embryology and innervation:

Third	Muscle type	Innervation
Upper 1/3	Skeletal (striated)	Somatic — vagus via recurrent laryngeal
Middle 1/3	Mixed	Mixed
Lower 1/3	Smooth	Autonomic — vagus + sympathetic

The mucosa is non-keratinised stratified squamous epithelium throughout — until the Z-line (GOJ), where it transitions abruptly to gastric simple columnar epithelium. The Z-line is where Barrett's metaplasia begins.

Blood supply — segmental, like the trachea

Segment	Artery	Venous drainage
Cervical	Inferior thyroid artery	Inferior thyroid → brachiocephalic vein
Thoracic	Oesophageal branches of thoracic aorta + bronchial arteries	Azygos / hemiazygos
Abdominal	Left gastric + left inferior phrenic	Left gastric vein → portal vein

The crucial point for exams is the portosystemic anastomosis at the lower end: the left gastric vein (portal) anastomoses with oesophageal tributaries of the azygos (systemic). In portal hypertension, blood reverses through the left gastric vein, distending the submucosal plexus and producing oesophageal varices.

Lymphatic drainage

Lymphatics drain to the nearest nodes for each segment — important for cancer staging.

➡ Cervical oesophagus → deep cervical nodes

➡ Thoracic oesophagus → mediastinal (paratracheal, tracheobronchial, posterior mediastinal) nodes

➡ Abdominal oesophagus → left gastric and coeliac nodes

Nerve supply

Vagus nerves form the oesophageal plexus around the lower oesophagus. The left vagus rotates anteriorly and the right vagus rotates posteriorly as they enter the abdomen — "LARP" (Left Anterior, Right Posterior). Recurrent laryngeal nerves supply the upper oesophagus and lie in the tracheo-oesophageal groove — at risk during thyroidectomy and cervical oesophagectomy.

GORD and hiatus hernia

GORD results from incompetence of the lower oesophageal sphincter (LOS) — a functional rather than anatomical sphincter, maintained by intrinsic muscle tone, the diaphragmatic crura, the acute angle of His and the intra-abdominal segment of oesophagus.

Hiatus hernia disrupts these mechanisms:

Type	Frequency	Anatomy	Risk
Sliding	95%	GOJ slides up into thorax	Reflux
Rolling (paraoesophageal)	5%	GOJ remains in place; fundus herniates alongside	Strangulation/volvulus — surgical

Management ladder: lifestyle (weight loss, head-of-bed elevation, avoid late meals) → PPI → Nissen fundoplication (360° wrap of fundus around lower oesophagus, indicated in refractory cases or rolling hernias).

Barrett's oesophagus

Metaplasia of the lower oesophageal mucosa from squamous to intestinal-type columnar epithelium with goblet cells, driven by chronic acid exposure. Endoscopically: salmon-pink mucosa extending proximal to the GOJ.

➡ Premalignant — risk of adenocarcinoma ~0.5%/year.

➡ Surveillance OGD with biopsies; intervals depend on dysplasia grade.

➡ High-grade dysplasia → endoscopic mucosal resection or radiofrequency ablation.

👩‍⚕️ Metaplasia is reversible in principle because the driver (acid) is external. In practice, established Barrett's rarely regresses fully even on PPIs.

Oesophageal cancer

The two histological types behave like different diseases:

Feature	Squamous cell carcinoma	Adenocarcinoma
Location	Upper / middle 2/3	Lower 1/3 + GOJ
Risk factors	Smoking, alcohol, achalasia, hot drinks, HPV	Barrett's, GORD, obesity, hiatus hernia, male sex
Incidence (West)	Declining	Rising — now commonest
Cell of origin	Squamous epithelium	Columnar metaplastic mucosa

Presentation: progressive dysphagia (solids first, then liquids), weight loss, odynophagia, retrosternal pain, hoarseness (RLN involvement).

Investigations: OGD + biopsy (diagnostic) → CT chest/abdomen + EUS (local T and N staging) + PET-CT (distant disease) ± staging laparoscopy for lower-third tumours.

Siewert classification of GOJ tumours:

➡ Type I — 1–5 cm above GOJ (treated as oesophageal)

➡ Type II — within 1 cm above to 2 cm below (true junctional)

➡ Type III — 2–5 cm below GOJ (treated as gastric)

Achalasia

Failure of LOS relaxation due to loss of inhibitory myenteric (Auerbach's) plexus neurones. Dysphagia to solids AND liquids from the outset (contrast with cancer).

➡ Barium swallow: "bird's beak" tapering with dilated proximal oesophagus.

➡ Manometry: diagnostic — absent peristalsis + failure of LOS relaxation.

➡ Treatment: pneumatic dilatation, Heller's myotomy, POEM, or botulinum injection.

Mallory-Weiss tear vs Boerhaave's

	Mallory-Weiss	Boerhaave's
Lesion	Mucosal tear at GOJ	Full-thickness rupture (left posterolateral, distal)
Trigger	Retching, often alcohol	Forceful vomiting
Presentation	Haematemesis, stable	Chest pain, surgical emphysema, mediastinitis
Imaging	Often diagnosed at OGD	CT with water-soluble contrast
Management	Self-limiting in 90%	Emergency surgical repair

Pharyngeal pouch (Zenker's diverticulum)

A pulsion diverticulum through Killian's dehiscence — the area of weakness between the oblique fibres of thyropharyngeus and the transverse fibres of cricopharyngeus. Strictly a false diverticulum (mucosa + submucosa only).

➡ Elderly patients; regurgitation of undigested food, halitosis, gurgling neck mass, aspiration pneumonia.

➡ Treatment: endoscopic stapling or open diverticulectomy with cricopharyngeal myotomy.

[Image: MCQs banner]

Test yourself

Following an oesophagectomy, which artery provides the arterial supply to the upper oesophagus?

((Bronchial::Supplies the middle third, not the cervical/upper oesophagus.))
((Inferior thyroid::☑️ Principal supply to the cervical and upper thoracic oesophagus.))
((Left gastric::Supplies the abdominal/lower oesophagus and proximal stomach.))
((Left inferior phrenic::Supplies the lower oesophagus near the hiatus.))
((Superior thyroid::Supplies the larynx and upper thyroid, not the oesophagus.))

👩‍⚕️ Segmental rule: inferior thyroid (upper), aortic branches (middle), left gastric + inferior phrenic (lower).

A 70-year-old undergoes oesophagectomy with an oesophagogastric anastomosis. The arterial supply to the gastric component is mainly provided by which vessel?

((Left gastric artery::☑️ Principal supply to the proximal stomach, critical for the anastomosis.))
((Right gastric artery::Smaller branch to the lesser curve; not the dominant supply.))
((Right gastroepiploic artery::Supplies the conduit in gastric pull-up but not the proximal stomach itself.))
((Short gastric arteries::Branches of the splenic artery supplying the fundus only.))
((Splenic artery::Indirect supply via short gastrics; not the main vessel here.))

A man with portal hypertension suffers recurrent haematemesis. What is the most likely source of bleeding?

((Right gastric vein::Drains the lesser curve; minor portosystemic role.))
((Left gastric vein::☑️ Reverses flow in portal hypertension, distending oesophageal varices.))
((Gastroduodenal vein::Drains duodenum/pancreatic head — not a variceal site.))
((Left gastroepiploic vein::Drains the greater curve; not a variceal site.))
((Superior mesenteric vein::Midgut drainage — unrelated to oesophageal varices.))

👩‍⚕️ The portosystemic anastomosis is between the left gastric vein (portal) and oesophageal veins (azygos/systemic).

What is the normal epithelial lining of the oesophagus?

((Keratinised stratified squamous::Found in skin and hard palate.))
((Non-keratinised stratified squamous::☑️ Protective against abrasive food bolus.))
((Simple columnar::Found in stomach and intestines — and in Barrett's metaplasia.))
((Transitional::Found in the urinary tract.))
((Pseudostratified ciliated columnar::Respiratory epithelium.))

An oesophageal biopsy shows columnar epithelium with goblet cells. What process has occurred?

((Aplasia::Failure of development — not applicable to adult tissue change.))
((Atrophy::Reduction in cell size/number — does not change cell type.))
((Hyperplasia::Increase in cell number — same cell type.))
((Hypertrophy::Increase in cell size — same cell type.))
((Metaplasia::☑️ Reversible change from one differentiated cell type to another.))

What are the expected biopsy findings in Barrett's oesophagus?

((Columnar epithelium with goblet cells::☑️ Intestinal-type metaplasia is required for the diagnosis.))
((Stratified squamous with dysplasia::Suggests squamous carcinoma in situ.))
((Gastric columnar without goblet cells::Gastric metaplasia — not diagnostic of Barrett's.))
((Pseudostratified columnar::Respiratory epithelium — not found here.))
((Granulomatous inflammation::Suggests Crohn's or TB.))

👩‍⚕️ No goblet cells = no Barrett's (UK definition).

Barrett's oesophagus is potentially reversible because the underlying cause is what type of pathology?

((Localised pathology::Implies an intrinsic tissue defect — would not regress.))
((External pathology::☑️ Chronic acid exposure is the driver; removing it allows re-epithelialisation.))
((Genetic pathology::Genetic disease is not typically reversible.))
((Autoimmune pathology::No autoimmune mechanism in Barrett's.))
((Infectious pathology::Not infective in origin.))

What is the investigation of choice in Barrett's oesophagus?

((OGD and biopsy::☑️ Direct visualisation of salmon mucosa + histological confirmation.))
((Barium swallow::Shows mucosal irregularity but no histology.))
((CT chest/abdomen::For staging malignancy, not diagnosing Barrett's.))
((Oesophageal pH monitoring::Confirms GORD, not metaplasia.))
((Serum tumour markers::No reliable marker exists.))

A patient with Barrett's now presents with a 2-month history of dysphagia and weight loss. What will biopsy reveal?

((Adenocarcinoma::☑️ Barrett's is the precursor; dysphagia + weight loss = malignant progression.))
((Squamous cell carcinoma::Arises from squamous epithelium in upper/middle thirds — not from Barrett's.))
((High-grade dysplasia only::Possible but does not usually cause weight loss.))
((Intestinal metaplasia without dysplasia::Asymptomatic — would not explain dysphagia.))
((Benign stricture::Causes dysphagia but rarely weight loss.))

A patient is diagnosed with a tumour in the upper third of the oesophagus. What is the most likely histological type?

((Squamous cell carcinoma::☑️ Predominates in upper/middle thirds; smoking, alcohol, achalasia.))
((Adenocarcinoma::Lower third, arising from Barrett's.))
((Small cell carcinoma::Rare in oesophagus.))
((GIST::Mesenchymal tumour; very rare oesophageal site.))
((Lymphoma::Rare primary oesophageal tumour.))

👩‍⚕️ SCC = upper/middle (smoking, alcohol, achalasia). Adenocarcinoma = lower (Barrett's, GORD, obesity).

A patient on long-term broad-spectrum antibiotics presents with dysphagia. Most likely diagnosis?

((Candida oesophagitis::☑️ Antibiotic-induced flora disruption; white plaques on OGD.))
((Achalasia::Motility disorder, unrelated to antibiotics.))
((Oesophageal carcinoma::Progressive dysphagia + weight loss, not antibiotic-related.))
((Herpes oesophagitis::Discrete shallow ulcers in immunocompromised patients.))
((Pill oesophagitis::Direct injury from specific drugs (bisphosphonates, doxycycline).))

A child has swallowed a coin. At which level is it most likely lodged?

((Thyroid prominence::Not an oesophageal narrowing.))
((Cricoid cartilage::Surface landmark — vertebral level is the better answer.))
((C6 (cricopharyngeus)::☑️ Narrowest point of the oesophagus and commonest impaction site.))
((T10 (hiatus)::A narrowing but rarely the site of coin impaction.))
((T1::Not an anatomical narrowing.))

A coin is seen on chest X-ray after ingestion. Where is it most likely lodged?

((At thyroid level::Above the oesophagus.))
((At hyoid level::Above the upper oesophageal sphincter.))
((At cricopharyngeal level::☑️ Narrowest part of the oesophagus (C6).))
((At the carina::Bronchial foreign bodies lodge here, not oesophageal coins.))
((At the GOJ::A narrowing but uncommon for coins.))

A 3-year-old swallows a coin which lodges at the GOJ. How far from the incisors?

((22 cm::☑️ Average paediatric distance to the GOJ in a 3-year-old.))
((25 cm::Approximate distance at ~5 years.))
((30 cm::Older children.))
((40 cm::Adult distance to the GOJ.))
((15 cm::Adult cricopharyngeus distance.))

A male undergoing OGD for GORD — how far is the GOJ from the incisors?

((15 cm::Cricopharyngeus.))
((20 cm::Approximate aortic arch level.))
((25 cm::Left main bronchus.))
((40 cm::☑️ Adult GOJ distance (38–42 cm).))
((45 cm::Beyond the GOJ — into the stomach.))

👩‍⚕️ Memorise 15 – 22 – 40 (cricopharyngeus – arch – GOJ). These appear constantly.

An alcoholic man drank heavily last night and now presents with 200 mL of fresh haematemesis. Most probable diagnosis?

((Candida oesophagitis::White plaques, odynophagia — not acute haematemesis.))
((Oesophageal carcinoma::Causes chronic occult bleeding, not acute haematemesis.))
((Mallory-Weiss tear::☑️ Mucosal tear at GOJ after retching; classic in alcohol binge.))
((Oesophageal rupture::Boerhaave's — shock, mediastinitis, surgical emphysema.))
((Peptic stricture::Causes dysphagia, not acute bleeding.))

A 35-year-old develops haematemesis after prolonged vomiting with sudden pain. He is haemodynamically stable. Diagnosis?

((Mallory-Weiss tear::☑️ Mucosal tear at GOJ after retching; self-limiting in 90%.))
((Boerhaave syndrome::Full-thickness rupture with mediastinal emphysema and shock.))
((Oesophageal varices::Require chronic liver disease/portal hypertension.))
((Peptic ulcer::Not typically triggered by forceful vomiting.))
((Aorto-oesophageal fistula::Rare; catastrophic bleeding with thoracic aneurysm.))

A 39-year-old has sudden chest pain and haematemesis after forceful vomiting. Subcutaneous crepitus is noted over his chest. Diagnosis?

((Mallory-Weiss::Mucosal only — no mediastinal air or crepitus.))
((Boerhaave syndrome::☑️ Full-thickness rupture allows air into mediastinum and subcutaneous tissues.))
((Zenker's diverticulum rupture::Cervical lesion — does not cause thoracic crepitus.))
((Ruptured pulmonary bleb::Causes pneumothorax without haematemesis.))
((Tension pneumothorax::Hypotension and tracheal deviation, no haematemesis.))

👩‍⚕️ Mackler's triad of Boerhaave's: vomiting + chest pain + subcutaneous emphysema.

A 43-year-old with suspected Boerhaave syndrome. Most appropriate investigation?

((Chest X-ray::May show pneumomediastinum but is not definitive.))
((Barium swallow::Risks barium leak → chemical mediastinitis.))
((Endoscopy::Air insufflation can worsen the perforation.))
((CT with oral water-soluble contrast::☑️ Gold standard — shows leak, pneumomediastinum, effusions.))
((Manometry::Tests motility, not perforation.))

Five days after iatrogenic perforation during OGD, the patient is stable. Most appropriate investigation to assess healing?

((Barium swallow::Persistent contamination if it leaks — barium is not reabsorbed.))
((Water-soluble contrast swallow::☑️ Gastrografin is safely absorbed if it leaks; ideal for follow-up.))
((CT abdomen::Less sensitive for mucosal integrity.))
((Upper GI endoscopy::Risk of re-perforation during healing.))
((MRI chest::Not first-line.))

👩‍⚕️ Acute perforation → CT with water-soluble contrast. Follow-up of healing → water-soluble contrast swallow.

A 74-year-old with progressive heartburn and food sticking in the throat. Most likely diagnosis?

((Benign peptic stricture::☑️ Chronic reflux causes fibrotic narrowing — dysphagia without weight loss.))
((Oesophageal carcinoma::Typically rapid progression with weight loss.))
((Achalasia::Dysphagia to solids AND liquids from the outset.))
((Pharyngeal pouch::Regurgitation of undigested food, halitosis, neck lump.))
((Globus pharyngeus::Lump sensation without true dysphagia or heartburn.))

A 35-year-old with previous TOF repair has dysphagia. Barium shows a 3 cm mid-oesophageal stenosis. Best intervention?

((Surgical resection::Reserved for malignancy or failed conservative management.))
((Balloon dilatation::☑️ First-line for benign, short-segment strictures.))
((Botulinum injection::Used in achalasia, not structural strictures.))
((Medical treatment::Ineffective for established fibrotic strictures.))
((Oesophageal stenting::Reserved for malignant or palliative cases.))

Revision summary

➡ Length 25 cm; C6 → T11; pierces diaphragm at T10.

➡ Three constrictions — cricopharyngeus (C6, 15 cm), aortic arch (T4, 22 cm), LOS/hiatus (T10, 40 cm).

➡ Histology — non-keratinised stratified squamous; upper 1/3 skeletal, lower 1/3 smooth muscle. Z-line at GOJ.

➡ Arterial supply — inferior thyroid (upper), aortic branches (middle), left gastric + inferior phrenic (lower).

➡ Varices — left gastric vein (portal) ↔ oesophageal veins (azygos).

➡ Vagus rule — LARP: Left Anterior, Right Posterior at the hiatus.

➡ Hiatus hernia — sliding (95%, reflux) vs rolling (5%, surgical — strangulation risk).

➡ Barrett's — squamous → intestinal columnar with goblet cells; premalignant for adenocarcinoma.

➡ Cancer — SCC upper/middle (smoking, alcohol, achalasia); adenocarcinoma lower (Barrett's, GORD, obesity). Solids → liquids dysphagia.

➡ Investigation — OGD + biopsy; staging with CT, EUS, PET. Siewert I–III for GOJ tumours.

➡ Achalasia — solids AND liquids from outset; bird's beak on barium; manometry diagnostic.

➡ Mallory-Weiss — mucosal, self-limiting. Boerhaave's — full-thickness, surgical emergency, CT with water-soluble contrast.

➡ Pharyngeal pouch — false diverticulum through Killian's dehiscence; regurgitation, halitosis, neck lump.