Posterior mediastinum

Question 1

How do vagi in the posterior and anterior mediastinum differ

Answer 1

In the posterior part of the oesophagus, you form the posterior oesophageal nerve which mainly takes right vagal fibres through the diaphragm to the abdominal viscera.
The left vagus provides fibres to the oesophageal plexus and then continutes as the anterior oesophageal nerve.

Question 2

What are the contents of the posterior mediastinum?

Answer 2

• Oesophagus
• Descending aorta
• Thoracic duct
• Azygos venous system
• Posterior mediastinal lymph nodes
• Thoracic sympathetic trunks
• Splanchnic nerves

Question 3

What are the boundaries of the posterior mediastinum?

Answer 3

superior: transverse plane from sternal angle to disk between T4-5
inferior: diaphragm
lateral: mediastinal parietal pleura

Question 4

Where does the oesophagus begin and end?

Answer 4

• Begins at level of C7 vertebra

* Ends at stomach, level of T11 vertebra

Question 5

Where are the constrictions of the oesophagus?

Answer 5

1. Junction with pharynx
2. Crossed by arch of oarta
3. Compressed by left main bronchus
4. Oesphageal hiatus

Question 6

What is the course of the oesophagus?

Answer 6

• Bends more anteriorly at T7
• Is right of aorta above T7
• Deviates to left at T7
• Progressively anterior to aorta below T7
• Passes through diaphragm at T10

Question 7

What are the arteries of the osephagus?

Answer 7

• Right bronchial
• Superior left bronchial
• Posterior intercostal
• Esophageal
• Mediastinal branches

Question 8

What are the veins of the osephagus?

Answer 8

• Azygous
• Accessory hemiazygous
• Hemiazygous

Question 9

What is the innervation of the oesophagus?

Answer 9

• After passing posteriorly to the root of the lungs, the right and left vagus nerves approach the oesophagus
• each nerve divides into several branches that spread forming a plexus
• plexus continues inferiorly on the oesophagus toward the diaphragm. Just over the diaphragm,
  fibres of the plexus converge to form two trunks:

o The anterior vagal trunk – mainly from fibres originally in the left vagus nerve
o The posterior vagal trunk – mainly from fibres originally in the right vagus nerve

Question 10

What is the lymphatic drainage of the oesophagus?

Answer 10

posterior mediastinal and left gastric lymph nodes

Question 11

What happens to the oesophagus at T7?

Answer 11

The oesophagus is to the right of the aorta above T7
Beyond T7 the oesophagus starts moving towards the left
The oesophagus also starts to bend more anteriorly