The Oesophagus - Anatomy

Question 1

Where does the oesophagus begin?

Answer 1

In the neck at the level of C6

Question 2

What is the oesophagus continuous with superiorly?

Answer 2

The laryngopharynx

Question 3

Does the oesophagus sit in front of or behind the trachea?

Answer 3

Behind the trachea

Question 4

Where does the oesophagus enter the abdomen?

Answer 4

Via the oesophageal hiatus at T10

Question 5

Where does the oesophagus terminate?

Answer 5

By joining the cardiac orifice of the stomach at T11

Question 6

What are the 4 layers of the oesophagus?

Answer 6

1. Adventitia
2. Muscle layer
3. Submucosa
4. Mucosa

Question 7

What is the adventitia?

Answer 7

Outer layer of connective tissue (the very distal and intraperitoneal portion of the oesophagus has an outer covering of serosa, instead of adventitia)

Question 8

Describe the muscle layer?

Answer 8

External layer of longitudinal muscle and inner layer of circular muscle

Question 9

Describe the mucosa?

Answer 9

Non-keratinised stratified squamous epithelium (continuous with columnar epithelium of the stomach).

Question 10

How is food transported through the oesophagus?

Answer 10

By peristalsis

Question 11

What is dysphagia?

Answer 11

Difficulty swallowing

Question 12

What are the 2 sphincters present in the oesophagus?

Answer 12

Upper and lower oesophageal sphincters

Question 13

Describe the upper oesophageal sphincter?

Answer 13

An anatomical, striated muscle sphincter at the junction between the pharynx and oesophagus. It is produced by the cricopharyngeus muscle.

Question 14

Function of the upper oesophageal sphincter?

Answer 14

Normally, it is constricted to prevent the entrance of air into the oesophagus

Question 15

Describe the lower oesophageal sphincter?

Answer 15

A physiological sphincter located in the gastro-oesophageal junction (junction between the stomach and oesophagus). The gastro-oesophageal junction is situated to the left of the T11 vertebra

Question 16

What is the lower oesophageal sphincter marked by?

Answer 16

arked by the change from oesophageal to gastric mucosa.

Question 17

Why is the lower oesophageal sphincter physiological?

Answer 17

It does not have any specific sphincteric muscle

Question 18

What is the function of the lower oesophageal sphincter?

Answer 18

During oesophageal peristalsis, the sphincter is relaxed to allow food to enter the stomach. Otherwise at rest, the function is to prevent the reflux of acidic gastric contents into the oesophagus.

Question 19

What are the physiological constrictions of the oesophagus? What is likely to happen here?

Answer 19

Where food/foreign objects are most likely to become stuck

A - Arch of aorta
B - Bronchus (left main stem)
C - Cricoid cartilage
D - Diaphragmatic hiatus

Question 20

Where does the thoracic part of the oesophagus receive its arterial supply from?

Answer 20

The branches of the thoracic aorta and the inferior thyroid artery (a branch of the thyrocervical trunk)

Question 21

What does venous drainage of the thoracic part of the oesophagus occur via?

Answer 21

Branches of the azygous veins and the inferior thyroid vein

Question 22

What is the abdominal oesophagus supplied by?

Answer 22

The left gastric artery (a branch of the coeliac trunk) and left inferior phrenic artery

Question 23

What is the abdominal oesophagus drained by?

Answer 23

2 routes:

• To the portal circulation via left gastric vein
• To the systemic circulation via the azygous vein

These two routes form a porto-systemic anastomosis, a connection between the portal and systemic venous systems.

Question 24

What is the oesophagus innervated by?

Answer 24

The oesophageal plexus

Question 25

What is the oesophageal plexus formed by?

Answer 25

A combination of the parasympathetic vagal trunks and sympathetic fibres from the cervical and thoracic sympathetic trunks.

Question 26

What is Barrett's oesophagus?

Answer 26

Metaplasia (reversible change from one differentiated cell type to another) of lower oesophageal squamous epithelium to gastric columnar epithelium

Question 27

What is Barrett's oesophagus usually caused by?

Answer 27

It is usually caused by chronic acid exposure as a result of a malfunctioning lower oesophageal sphincter. The acid irritates the oesophageal epithelium, leading to a metaplastic change.

Question 28

What is the most common symptom of Barrett's oesophagus?

Answer 28

A long-term burning sensation of indigestion.

Question 29

What are the clinical features of oesophageal carcinomas?

Answer 29

1. Dysphagia | 2. Weight loss

Question 30

What are the 2 major types of oesophageal carcinomas?

Answer 30

1. Squamous cell carcinoma | 2. Adenocarcinoma

Question 31

Where can squamous cell carcinoma occur?

Answer 31

The most common subtype of oesophagus cancer. It can occur at any level of the oesophagus.

Question 32

Where can adenocarcinoma occur?

Answer 32

Only occurs in the inferior third of the oesophagus and is associated with Barrett’s oesophagus. It usually originates in the metaplastic epithelium of Barrett’s oesophagus.

Question 33

What are oesophageal varices?

Answer 33

Abnormally dilated submucosal veins that lie within the anastomosis (between portal and systemic circulation)

Question 34

What are oesophageal varices predisposed to?

Answer 34

Predisposed to bleeding, with most patients presenting with haematemesis (vomiting of blood). Alcoholics are at a high risk of developing oesophageal varices.