Applied Anatomy of the Thoracic Oesophagus
Carcinoma of the Oesophagus
Epidemiology:
- 6th most common cancer worldwide
- Males > females; peak 60–70 years
- Two main types: squamous cell carcinoma (middle third) and adenocarcinoma (lower third)
Anatomical distribution:
| Location | Type | Notes |
|---|---|---|
| Upper third | Squamous cell carcinoma | Rare |
| Middle third (commonest overall) | Squamous cell carcinoma | Most common overall; at bronchial constriction level |
| Lower third | Adenocarcinoma | Arising from Barrett’s oesophagus; increasing incidence |
Clinical features:
- Dysphagia — initially to solids, progressing to liquids (progressive dysphagia = hallmark)
- Weight loss, regurgitation, odynophagia
- Hoarseness (left recurrent laryngeal nerve invasion)
- Bovine cough (tracheo-oesophageal fistula, or recurrent laryngeal nerve palsy)
- Horner’s syndrome (sympathetic trunk invasion)
Spread:
- Longitudinal (submucosal lymphatics): extensive cranial and caudal spread before nodal involvement
- Local: direct invasion of trachea, bronchi, aorta, thoracic duct, recurrent laryngeal nerves
- Lymphatic: posterior mediastinal → tracheobronchial → coeliac nodes
- Haematogenous: liver (most common), lung, bone
Poor prognosis: most patients present with advanced disease due to the absence of a serosal layer on the oesophagus (facilitating early local spread).
Dysphagia — Anatomical Basis
Definition: Difficulty swallowing
Oesophageal causes:
- Carcinoma (progressive, painless initially)
- Benign strictures (peptic, post-corrosive, post-radiation)
- Achalasia
- Oesophageal spasm
Extrinsic compression causes (relevant to thoracic oesophagus):
| Structure | Cause |
|---|---|
| Aortic arch | Dysphagia lusoria (aberrant right subclavian artery) |
| Left atrium | Dysphagia from left atrial enlargement (visible on barium swallow) |
| Mediastinal lymph nodes | Malignancy, tuberculosis |
| Left principal bronchus | Bronchogenic carcinoma |
Achalasia of the Oesophagus
Definition: Failure of relaxation of the lower oesophageal sphincter due to degeneration of the myenteric plexus (Auerbach’s plexus) in the oesophageal wall.
Features:
- Dysphagia for both solids and liquids (from onset — unlike carcinoma which is initially for solids only)
- Regurgitation of undigested food
- Barium swallow: smooth tapering of the lower oesophagus — “rat-tail” or “bird’s beak” appearance; massive dilatation of the oesophagus above
Treatment: Heller’s cardiomyotomy (surgical or laparoscopic division of lower oesophageal sphincter muscle); pneumatic dilatation; botulinum toxin injection
Oesophageal Varices
Cause: Portal hypertension (most commonly cirrhosis of the liver)
Mechanism: Raised portal pressure → retrograde flow through left gastric vein → dilated submucosal veins in the lower oesophagus → varices
Risk: Spontaneous rupture → massive haematemesis — a life-threatening emergency
Treatment: Endoscopic banding or sclerotherapy; TIPSS (transjugular intrahepatic portosystemic shunt); surgical portosystemic shunts
Gastro-Oesophageal Reflux Disease (GORD)
Cause: Failure of the lower oesophageal sphincter (LOS) → acid reflux into oesophagus
Features: Heartburn, regurgitation, worsened by lying flat or bending forward, relieved by antacids
Complications:
- Barrett’s oesophagus: Metaplastic replacement of squamous epithelium of lower oesophagus by columnar epithelium — a premalignant condition for adenocarcinoma
- Peptic stricture
- Haemorrhage, anaemia
Oesophageal Perforation (Boerhaave Syndrome)
Cause: Spontaneous full-thickness rupture of the oesophagus due to sudden rise in intra-oesophageal pressure (severe vomiting — Boerhaave syndrome)
Most common site: Left posterolateral wall of the lower thoracic oesophagus (weakest point — lacks serosal layer)
Consequences:
- Mediastinitis (rapidly fatal if untreated)
- Right or bilateral pleural effusion (oesophageal contents enter pleural cavity)
- Surgical emergency — requires urgent drainage and repair
Barium Swallow — Normal Indentations
On a barium swallow, the following normal impressions are seen on the oesophagus:
| Indentation | Cause | Level |
|---|---|---|
| Left lateral oblique indent | Aortic arch | T4 |
| Anterior horizontal indent | Left principal bronchus | T4–T5 |
| Smooth posterior impression (abnormal if present) | Dilated left atrium | T5–T6 |
| Narrowing with smooth taper | Diaphragmatic hiatus | T10 |
Hiatus Hernia
Definition: Herniation of part of the stomach (and sometimes other abdominal contents) through the oesophageal hiatus into the thorax.
Types:
- Sliding (type I) — 80%: Gastro-oesophageal junction and part of stomach herniate into thorax; LOS is above diaphragm → GORD
- Rolling/Para-oesophageal (type II): Fundus of stomach herniates through hiatus alongside the oesophagus while GEJ remains below diaphragm; risk of strangulation
Surgical repair (Nissen fundoplication): Wraps the fundus of the stomach around the lower oesophagus to recreate the lower oesophageal sphincter mechanism.