Superior Mediastinum and Posterior Mediastinum

Question 1

What are the boundaries for the superior mediastinum?

Answer 1

-Anterior: Manubrium
-Inferior: Line from the sternal angle to T4/T5 disc
-Posterior: T1-T4 vertebrae
-Superior: Thoracic inlet

Question 2

What are the contents of the superior mediastinum?

Answer 2

-Thymus
-Brachiocephalic veins (L/R), Superior Vena Cava
-Aorta (Btachiochephalic artery, left common carotid artery, left subclavian artery)
-Vagus and prenic nerves

Question 3

What is the location of the thymus?

Answer 3

Beneath sternum, in superior and anterior mediastinum

Question 4

What is the function of the thymus?

Answer 4

Children: Functional T cell immunity
Adults: Involution, replaced by fat

Question 5

What forms the Brachiocephalic Veins?

Answer 5

-union of internal jugular and subclavian veins
-Left and right brachiocephalic veins converse together to make the superior vena cava

Question 6

Left Brachiocephalic vein

Answer 6

Long horizontal course, posterior to the manubrium

Question 7

Tributary veins of the left brachiocephalic vein

Answer 7

Left internal jugular, left subclavian, internal thoracic, thoracic duct

Question 8

Right brachiocephalic vein

Answer 8

Short, vertical course, lateral to brachiocephalic artery

Question 9

Tributary veins of the right brachiocephalic vein

Answer 9

Right internal jugular, right internal thoracic, right lymphatic duct

Question 10

What is the relationships of the Superior Vena Cava?

Answer 10

-Anterior: of the right lung and associated pleural
-Posterior: right vagus nerve, right pulmonary artery, right main bronchus, azygous vein
-Medial: ascending aorta
-Lateral: Right phrenic nerve

Question 11

Azygous Vein

Answer 11

Collects the posterior VAN and empties in the posterior part of the Superior Vena Cava

Question 12

Superior Vena Cava Syndrome

Answer 12

Any disease the process that results in compression of the superior vena cava

Question 13

What happens in Superior Vena Cava Syndrome?

Answer 13

Increase in pressure in venous system draining into the SVC.
Fluid leaks out (hydrostatic) of venous system into interstitial tissues=swelling and edema

Question 14

What parts of the body does Superior Vena Cava syndrome affect?

Answer 14

Upper limbs, head, neck (including brain)

Question 15

What causes Superior Vena Cava Syndrome?

Answer 15

Lung cancer, enlarges lymph nodes, aortic aneurism

Question 16

What are the parts of the aorta?

Answer 16

Ascending, arch, descending thoracic, abdominal

Question 17

Where does the the ASCENDING part of the aorta begin, end, branches off of and the relationship?

Answer 17

Begin: at eh aortic valve (3rd left costal cartilage)
Ends: at the 2nd right costal cartilage
-Branches: off the ascending aorta, left and right coronary artery
-Relationship: lateral to SVC

Question 18

Where does the ARCH of the aorta begin, end, branches off of and the relationship?

Answer 18

Begins/ends: T4/T5 vertebral disc, arches posteriorly over pulmonary trunk and left main bronchus
Branches: off the arch, brachiocephalic artery, left common carotid artery left
Relationships:
-Anterior: left recurrent laryngeal nerve wraps under the aortic arch and back to innervate the voice box, left vagus nerve, left phrenic nerve
-Posterior: Trachea/bifurcation, esophagus

Question 19

What does the descending thoracic branch off of?

Answer 19

Posterior VAN arteries

Question 20

What is an aortic aneurysm?

Answer 20

dilation of the aorta. Often asymptomatic but if large enough may produce symptoms by affecting nearby structures

Question 21

Aortic Aneurysm: ascending

Answer 21

Compress SVS

Question 22

Aortic Aneurysm Arch

Answer 22

(A) Stretching of the left recurrent laryngeal nerve=horse voice
(B) Compress trachea/left bronchus = cough, wheezing
(C) Compress esophagus=dysphagia

Question 23

What are the Aortic Arch Branches?

Answer 23

-Brachiocephalic artery
-Left common carotid artery
-Left subclavian artery

Question 24

What does the Brachiocephalic artery become?

Answer 24

Right common carotid and right subclavian artery @ sternoclavicular joint; may give rise to accessory Thyroid ima artery

Question 25

What is the relationship of the Brachiocephalic artery?

Answer 25

Anterior: Brachiocephalic vein
Posterior: Trachea

Question 26

What is the relationship of the Left Common Carotid Artery?

Answer 26

-Anterior: brachiocephalic vein
-Posterior: trachea and left recurrent laryngeal nerve
-Lateral: vagus nerve, left phrenic nerve

Question 27

What is the relationship of the left subclavian artery?

Answer 27

Runs lateral to trachea and left common carotid and exits the mediastinum at the sternoclavicular joint

Question 28

What is the function of the Vagus Nerve?

Answer 28

In mediastinum innervates cardiac, pulmonary, esophageal plexus.