Mediastinum and contents

Question 1

What are the four main sub-divisions of the mediastinum

Answer 1

Superior
Anterior
Middle
Posterior

Question 2

What is the mediastinum? How may structures in the mediastinum be broadly categorised?

Answer 2

= the area in the middle of the chest between the pleural spaces on each side. Contains all of the thoracic organs except the lungs.

Structures can be divided into those that:
* Arise and remain in the mediastinum: heart, thymus
* ** Traverse the mediastinum: oesophagus, thoracic duct, phrenic nerves, vagus nerve**
* Arise in the mediastinum: aorta, aortic arch vessels, bronchial tree, pulmonary arteries
* End in the mediastinum: trachea, IVC, venous drainage of the head and neck, pulmonary veins

Key nerves: vagus nerves, phrenic nerves

Question 3

What are the boundaries of the mediastinum?

Answer 3

Anterior: sternum
Posterior: vertebral column
Superior: thoracic inlet/ root of the neck
Inferior: diaphragm
Lateral: pleurae and lungs

Question 4

Contents of the middle medastinum

Answer 4

• Heart, pericardium
• Roots of aorta, pulmonary artery, IVC and SVC and 4 pulmonary veins

Question 5

Contents of the superior mediastinum

Answer 5

• Arterial supply and venous drainage of the upper body
• Trachea
• Thymus
• All structures transversing the mediastinum between neck and abdomen (phrenic nerves, vagus nerves, oesophagus, thoracic duct)

Question 6

Contents of posterior mediastinum

Answer 6

• Lower oesophagus
• Descending aorta
• Lower thoracic duct and vagus nerves