Oesophagus

Question 1

Oesophagus overview

Answer 1

• Muscular tube, 25cm long
• Extend from pharyngoesophageal junction (C6) to cardiac orifice of stomach (T11)
• Passes through oesophageal hiatus of diaphragm at T10
• Travels in the posterior mediastinum
• 2 sphincters present:
  1) Upper oesophageal sphincter (formed by inferior constrictor muscle)
  2) Lower oesophageal sphincter (formed by thickening of oesophageal wall) – not a ‘true’ sphincter

Question 2

Constrictions of oesophagus

Answer 2

1) Arch of Aorta
2) Bronchus (left, main)
3) Cricoid cartilage
4) Diaphragm (oesophageal hiatus)

Question 3

Hiatal Hernia

Answer 3

-A protrusion of part of stomach into mediastinum via oesophageal hiatus of diaphragm

Can be classified into:

1) Sliding hiatal hernia – abdominal part of oesophagus, cardia and fundus of stomach herniates through oesophageal hiatus into thorax (can cause regurgitation of stomach contents into oesophagus)
2) Rolling hiatal hernia – cardia remain in place while fundus of stomach herniates through oesophageal hiatus (no regurgitation)

Question 4

GORD (gastro-oesophageal reflux disorder)

Answer 4

• Acid reflux from stomach into oesophagus, causing irritation of epithelial lining of oesophagus wall and inflammation
• Usually caused by weakening of lower oesophageal sphincter

Question 5

Barrett’s oesophagus

Answer 5

-Epithelial lining of oesophagus badly damaged, causing lining to thicken and become inflamed and red
-Cell dysplasia occur:
Non-keratinised squamous epithelial cells –> Columnar epithelial cells
-Increases risk of oesophageal cancer

Question 6

Oesophageal layers

Answer 6

1) Mucosa:
-Lined by non-keratinised squamous epithelial cells
-Secretes mucous to reduce friction + prevent wear and tear
2) Submucosa
-Made of connective tissues
-Blood vessels present
3) Muscularis externa
-Made up of inner oblique muscle, middle circular muscle, outer longitudinal muscle
-Composed of different type of muscles in each third:
Superior 1/3 – skeletal muscles
Middle 1/3 – skeletal + smooth muscles
Inferior 1/3 – smooth muscles
4) Adventitia
-Made up of connective tissues

Question 7

Arterial supply

Answer 7

1) Upper 1/3 – Inferior thyroid artery (from thyrocervical trunk, branch of subclavian artery)
2) Middle 1/3 – Thoracic aorta
3) Lower 1/3 – Left gastric artery

Question 8

Venous supply

Answer 8

1) Left gastric vein to portal circulation
2) Azgous vein to systemic circulation
(porto-systemic anastomosis)

Question 9

Innervation

Answer 9

Oesophageal plexus consists of:

1) Vagus nerve (parasympathetic) – general sensation fibres
2) Cervical and thoracic sympathetic – detects pain

Question 10

Lymphatics

Answer 10

1) Deep cervical nodes (upwards) (lies along internal jugular vein)
2) Juxta-oesophageal nodes (downwards) (anterior to oesophagus in posterior mediastinum)