Superior and Posterior Mediastina

Question 1

Be able to list/identify the various components of each region of the superior mediastinum.

Answer 1

Retrosternal region: thymus, left brachiocephalic v., superior portion of the superior vena cava; Intermediate reion: aortic arch, brachiovcephalic trunk, left common carotid artetry, left subclavian artery; Prevertebral region: trachea, esophagus, thoracic duct, left recurrent laryngeal nerve.

Question 2

What is the boundary between the superior and inferior mediastina?

Answer 2

The sternal angle.

Question 3

Why is the sternal angle important clinically?

Answer 3

It represents the level at which the trachea bifurcates as well as the level at which the great vessels leave the heart.

Question 4

Between what two vertebrae does a line drawn horizontally from the sternal angle posteriorly pass?

Answer 4

T4, T5

Question 5

What organ is found in the anterior mediastinum- in childhood?

Answer 5

the thymus

Question 6

What replaces this organ in the adult?

Answer 6

Fat and connective tissue.

Question 7

What structures are found only in the right aspect of the posterior mediastinum?

Answer 7

Azygous vein.

Question 8

What are found only in the left posterior mediastinum?

Answer 8

Hemiazygous and accessory hemiazygous veins, aorta.

Question 9

Which structures would be found on both sides of the posterior mediastinum?

Answer 9

Posterior intercostal aa., intercostal nn., intercostal vv., sympathetic trunk, paravertebral ganglia, rami communicans, splancnic nn., and vagus nn.

Question 10

Which specific vessels drain the intercostal spaces of the posterior thoracic wall?

Answer 10

intercostal veins

Question 11

What system do they form?

Answer 11

The azygous system.

Question 12

What is the typical pattern of this system?

Answer 12

Broken H.

Question 13

How is the superior vena cava formed?

Answer 13

The union of the left and right brachiocephalic vv.

Question 14

What vessels form the brachiocephalic veins?

Answer 14

The union of the internal jugular vv. with the subclavian vv. on the left and right sides.

Question 15

Be able to label a diagram of the venous components found in the superior mediastinum and the associated lymphatic trunks.

Answer 15

The diagrams on pages 186/187 are important. This is often on the exam as the venous system (which differs from the arterial system in this region) and the lymphatic system (and facts/information about it) can be tested simultaneously.

Question 16

Be able to label a diagram of the arterial bifurcation pattern in this region.

Answer 16

The diagram of the aortic arch as on page 184, or those on the heart diagrams as well!

Question 17

In which thoracic division(s) is the thoracic duct located?

Answer 17

The posterior (on it’s the way from the abdomen) AND superior (as it termninates) mediastina.

Question 18

Where does the thoracic duct begin?

Answer 18

At the cysterna chyli in the upper region of the abdomen.

Question 19

Where does the thoracic duct terminate?

Answer 19

At the junction of the left internal jugular and left subclavian vv.

Question 20

Be sure can label a diagram of the termination of both lymphatic vessels into the venous system at the root of the neck.

Answer 20

This is that diagram on page 187. It’s important!