Mediastinum

Question 1

Where is the mediastinum found?

Answer 1

In the midline of the thoracic cavity, that is surrounded by the left and right pleural sacs.

Question 2

What is the mediastinum divided into?

Answer 2

Superior and inferior

Question 3

What is the inferior mediastinum further divided into?

Answer 3

Anterior mediastinum
Middle mediastinum
Posterior mediastinum

Question 4

What are the borders of the superior mediastinum?

Answer 4

First Rib (S)
T4 Vertebra (I)

Question 5

What are the contents of the superior mediastinum?

Answer 5

Thymus
Trachea
Oesophagus
Thoracic duct
Aortic arch
Veins (superior vena cava, brachiocephalic, left superior intercostal)
Nerves (vagus, phrenic, left recurrent laryngeal)
Lymphatics
Other small arteries and veins

Mnemonic: Try To Eat Toast And Vitamins Now Little Oliver

Question 6

What are the borders of the anterior inferior mediastinum?

Answer 6

T4 (S)
T9 (I)

Sternum (A)
Pericardium (P)

Question 7

What are the conetnts of the anterior inferior mediastinum?

Answer 7

Remnants of the thymus, lymph nodes

Question 8

What are the borders of the middle inferior mediastinum?

Answer 8

T4 (S)
T9 (I)

Anterior aspect of pericardium (A)
Posterior aspect of pericardium (P)

Question 9

What are the contents of the anterior inferior mediastinum?

Answer 9

Phrenic nerve, heart, pericardium, ascending aorta, pulmonary trunk, superior vena cava, pericardiacophrenic artery

Question 10

What are the borders of the posterior inferior mediastinum?

Answer 10

T4 (S)
T9 (I)

Posterior aspect of pericardium (A)
Spine (P)

Question 11

What are the contents of the posterior inferior mediastinum?

Answer 11

Descending thoracic aorta, azygos veins, hemiazygos veins, accessory hemiazygos veins, thoracic duct, cisterna chyli, esophagus, esophageal plexus, vagus nerve, greater, lesser and least splanchnic nerves, lymphatics

Mnemonic: on the DATE Vivian Slapped Larry

Question 12

What divides in mediastinum?

Answer 12

A transverse plane that extends from the sternal angle (manubriosternal junction), to the intervertebral disc between T4 and T5 vertebrae.

Question 13

Discuss lymphatics

Answer 13

Most of the mediastinal organs drain into the thoracic duct.

The interesting exception is the right side of the heart, which together with the right lung, right sides of head, neck and thorax, drains into the right lymphatic trunk.