Oesophagus

Question 1

Describe the oesophagus

Answer 1

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

Question 2

Describe the course of the oesophagus

Answer 2

The oesophagus begins in the neck, at the level of C6. Here, it is continuous superiorly with the laryngeal part of the pharynx (the laryngopharynx).

It descends downward into the superior mediastinum of the thorax, positioned between the trachea and the vertebral bodies of T1 to T4. It then enters the abdomen via the oesophageal hiatus (an opening in the right crus of the diaphragm) at T10.

It terminates by joining the cardiac orifice of the stomach at level of T11.

Question 3

How long is the oesophagus

Answer 3

25cm

Question 4

Describe the structure of the oesophagus

Answer 4

It is made up of 4 layers and they include:
Adventitia- Outer layer of connective tissue.

Muscular layer-external layer of longitudinal muscle and inner layer of circular muscle.

Submucosa-

Mucosa- non-keratinised stratified squamous epithelium.

Question 5

Food is transported through the oesophagus by

Answer 5

Peristalsis.

Question 6

How many sphincters does the oesophagus have

Answer 6

2- Upper and lower oesophageal sphincters.

Question 7

Upper oesophageal sphincter is located where

Answer 7

Junction between pharynx and oesophagus.
Produced by cricopharyngeus.

Question 8

Lower oesophageal sphincter is located where

Answer 8

Gastro-esophageal junction-between stomach and esophagus.
It is a physiological sphincter.

Question 9

Function of cricopharyngeus

Answer 9

It constricts to prevent the entrance of air into the oesophagus.

Question 10

Discuss anatomical relations

Answer 10

Anatoical relations can be discussed bases on the segments of the oesophagus.They include the cervical and thoracic segment and the abdominal segment.

Question 11

Cervical and thoracic segment relations.

Answer 11

Anterior-Trachea.
Left recurrent laryngeal
nerve
Pericardium

Posterior-Thoracic vertebral
bodies
Thoracic duct
Azygous veins
Descending aorta

Left- Subclavian artery
Aortic arch
Thoracic duct
Pleura

Right-Pleura
Terminal part of azygous
vein

Question 12

Abdominal segment relations

Answer 12

Anterior- Left vagus nerve
Posterior surface of the
heart

Posterior- Right vagus nerve.
Left crus of
diaphragm.

Question 13

Arterial supply

Answer 13

Cervical and thoracic part-Branches of thoracic aorta.
Inferior thyroid artery.

Abdominal part-Left gastric artery.
Left phrenic artery.

The abdominal part of oesophagus has a mixed venous drainage via two 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.

Question 14

Innervation

Answer 14

The oesophagus is innervated by the oesophageal plexus.

It is formed by a combination of the parasympathetic vagal trunks and sympathetic fibres from the cervical and thoracic sympathetic trunks.

Question 15

Venous drainage

Answer 15

Upper part of the oesophagus drains
into the brachiocephalic veins.

Middle part drains into the azygos veins

Lower part drains into the left gastric vein and azygos vein.

Question 16

Lypmhatics

Answer 16

Superior third – deep cervical lymph nodes.

Middle third – superior and posterior mediastinal nodes.

Lower third – left gastric and celiac nodes.

Question 17

Clinical correlates

Answer 17

Barretts oesophagus
Oesophageal varices.
Achalasia cardia
Dysphagia

Question 18

Barretts oesophagus

Answer 18

It refers to the metaplasia of lower oesophageal squamous epithelium to gastric columnar epithelium.

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 19

Dysphagia(Difficulty in Swallowing).

Answer 19

It is caused by hardening of the muscular layers of the oesophagus. It interferes with peristalsis and cause difficulty in swallowing.

Question 20

Constrictions of the oesophagus

Answer 20

The oesophagus shows four constrictions.

1.At the start of the esophagus, where the laryngopharynx joins the esophagus, behind the cricoid cartilage.
2.Where it is crossed on the front by the aortic arch in the superior mediastinum.
3.Where the esophagus is compressed by the left main bronchus in the posterior mediastinum.
4.The esophageal hiatus, where it passes through the diaphragm in the posterior mediastinum.

Question 21

Oesophageal varices

Answer 21

In portal hypertension, the communications
between the portal and systemic veins draining
the lower end of the oesophagus dilate( left gastric vein and azygos vein).

These dilatations are called oesophageal varices. Rupture
of these varices can cause serious haematemesis
or vomiting of blood. The oesophageal varices can
be visualised radiographically by barium swallow.

Question 22

Achalasia cardia

Answer 22

The condition
of neuromuscular incoordination characterised by inability of the oesophagus to dilate is known
as ‘achalasia cardia’. It may be due to congenital
absence of nerve cells in wall of oesophagus.
Due to failure of oesophagus to dilate, food accumulates.