The Oesophagus

Question 1

Describe the oesophagus.

Answer 1

a fibromuscular tube, approximately 25cm in length, that transports food from the pharynx to the stomach.

Question 2

Where does the oesophagus originate from and extend to?

Answer 2

the inferior border of the cricoid cartilage (C6) and extends to the cardiac orifice of the stomach (T11).

Question 3

At what vertebral level does the oesophagus enter the abdomen via the oesophageal hiatus?

Answer 3

T10

Question 4

Describe the structural layers of the oesophaus from innermost to outermost.

Answer 4

Mucosa
Submucosa
Muscle layer
Adventitia (except when in the peritoneal cavity then its serosa).

Question 5

Describe the muscular layer of the oesophagus.

Answer 5

External layer of longitudinal muscle and inner layer of circular muscle.
The external layer is comprised of different muscle types in each third:
superior third - voluntary striated muscle.
middle third - voluntary striated and smooth muscle.
inferior third- smooth muscle.

Question 6

Describe the histology of the mucosa of the oesophagus.

Answer 6

non-keratanised stratified squamous epithelium.

Question 7

What process allows food to be transported through the oesophagus?

Answer 7

peristalsis

Question 8

what is the function of the upper oesophageal sphincter?

Answer 8

to prevent air entry into the oesophagus

Question 9

Describe the upper oesophageal sphincter

Answer 9

anatomical, striated muscle sphincter between the pharynx and oesophagus
it is normally constricted to prevent air entry

Question 10

what is the function of the lower oesophageal sphincter?

Answer 10

to prevent the reflux of gastric contents

Question 11

where is the lower oesophageal sphincter located?

Answer 11

at the gastro-oesophageal junction between the stomach and oesophagus. (to the left of T11 vertebra)

Question 12

why is the lower oesophageal sphincter classified as a physiological rather than anatomical sphincter?

Answer 12

It does not have any specific sphincteric muscle, instead it is maintained by mechanical factors e.g. angle, folds, diaphragm etc.

Question 13

What are the four physiological constrictions of the oesophagus?
USE ABCD
and what is the clinical significance of this?

Answer 13

Arch of aorta
Bronchus (left main stem)
Cricoid cartilage
Diaphragmatic hiatus

These areas where food/foreign objects are most likely to become impacted.

Question 14

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Answer 14

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Question 15

describe the venous drainage of the thoracic oesophagus

Answer 15

venous drainage into the systemic circulation occurs via branches of the azygous veins and the inferior thyroid vein.

Question 16

describe the arterial supply to the abdominal oesophagus

Answer 16

• left gastric artery (branch of coeliac trunk).
• left inferior phrenic artery.

Question 17

Describe the mixed venous drainage of the abdominal oesophagus

Answer 17

• to the portal circulation via the left gastric vein.
• to the systemic circulation via the azygous vein.
• these two routes form a porto-systemic anastomosis.

Question 18

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Answer 18

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Question 19

describe the lymphatic drainage of the oesophagus

Answer 19

superior third - deep cervical lymph nodes
middle third - superior and posterior mediastinal nodes.
lower third- left gastric and celiac nodes.