Superior and Posterior Mediastinum

Question 1

Where does the transverse thoracic plane run from to

Answer 1

The sternal angle to the intervertebral space between T4 and T5

Question 2

What are the 5 boundaries of the superior mediastinum

Answer 2

1. Manubrium
2. Bodies of T1-T4
3. Thoracic inlet
4. Parietal pleura
5. Transverse thoracic plane

Question 3

What are the 7 contents of the superior mediastinum (starting with the most anterior)

Answer 3

1. Thymus
2. Brachiocephalic veins and SVC
3. Arch of aorta
4. Trachea
5. Oesophagus
6. Phrenic and vagus nerves
7. Lymphatics

Question 4

What drains into the great vessels of the superior mediastinum

Answer 4

Head, neck and the upper limb; empties into the SVC

Question 5

What 3 branches come off the arch of the aorta

Answer 5

1. Brachiocephalic trunk
2. Left common carotid artery
3. Left subclavian artery

Question 6

What nerve branches from the vagus nerves

Answer 6

The left and right recurrent laryngeal

Question 7

Where does the right vagus nerve run in the superior mediastinum

Answer 7

It runs anterior to the right subclavian artery

Question 8

Where does the right recurrent laryngeal nerve run in the superior mediastinum

Answer 8

It loops under the subclavian artery

Question 9

Where does the left vagus nerve run in the superior mediastinum

Answer 9

It runs between the left common carotid and left subclavian arteries

Question 10

Where does the left recurrent laryngeal nerve run in the superior mediastinum

Answer 10

It loops under the arch of the aorta; posterior to the ligamentum arteriosum

Question 11

Is the vagus nerve part of the sympathetic or the parasympathetic nervous system

Answer 11

Parasympathetic

Question 12

What plexus’ branch from the vagus nerve and where are they located

Answer 12

1. Cardiac plexus; deep to aortic arch
2. Right pulmonary plexus; right bronchi
3. Left pulmonary plexus; left bronchi
4. Oesophageal plexus; surface of the oesophagus

Question 13

What vagal trunk arises from the left and right vagal nerves

Answer 13

1. Left vagal nerve forms the anterior vagal trunk

2. Right vagal nerve forms the posterior vagal trunk

Question 14

What is the root value of the phrenic nerve

Answer 14

Anterior rami C3, C4, and C5

Question 15

Where does the right phrenic nerve run in the superior mediastinum

Answer 15

Alongside the right brachiocephalic vein, the SVC and the pericardium over the right atrium

Question 16

Where does the right phrenic nerve pierce the diaphragm

Answer 16

Near the caval opening

Question 17

Where does the left phrenic nerve run in the superior mediastinum

Answer 17

In between the left subclavian artery and vein, to the left of the aortic arch and onto the surface of the pericardium over the left atrium

Question 18

Where does the left phrenic nerve pierce the diaphragm

Answer 18

To the left of the pericardium

Question 19

What information and innervation does the phrenic nerve provide to the superior mediastinum

Answer 19

1. Motor innervation to the diaphragm

2. Sensory information to the fibrous pericardium

Question 20

Where does the trachea run from to

Answer 20

Begins at C6/7 and runs to the carina at T4/5

Question 21

What muscle is in the posterior section of the trachea

Answer 21

Trachealis muscle

Question 22

What is the oesophagus a continuation of and where does it begin

Answer 22

The pharynx and at C6

Question 23

Describe the positioning and route of the oesophagus

Answer 23

Initially it lies to the right of the aorta, then it crosses anteriorly prior to piercing the diaphragm at T10

Question 24

Where are the 3 constrictions of the oesophagus

Answer 24

1. Arch of aorta
2. Left bronchus
3. Diaphragm

Question 25

What are the 4 boundaries of the posterior mediastinum

Answer 25

1. Transverse thoracic plane 2. Bodies of T5-T12 3. Pericardium and diaphragm 4. Parietal pleura

Question 26

Where does the descending aorta become the thoracic aorta

Answer 26

At T4/5

Question 27

Where does the thoracic aorta become the abdominal aorta

Answer 27

After piercing the diaphragm through the aortic hiatus

Question 28

What do the anterior branches of the thoracic aorta supply

Answer 28

The organs and tissues within the thoracic cavity (oesophagus, pericardium & bronchi)

Question 29

What do the posterolateral branches of the thoracic aorta supply

Answer 29

The thoracic wall (posterior intercostal arteries)

Question 30

What are the 5 main branches of the thoracic aorta

Answer 30

1. Oesophagus 2. Pericardium 3. Bronchi 4. Thoracic wall 5. Diaphragm

Question 31

What does the azygous venous system drain

Answer 31

The posterior abdominal wall and the thoracic wall

Question 32

What thoracic wall veins drain directly into the azygous vein

Answer 32

1. Right posterior intercostal veins 2-11 | 2. Right subcostal vein

Question 33

Where does the 1st right posterior intercostal vein drain

Answer 33

Directly into the right brachiocephalic vein

Question 34

What thoracic wall veins drain directly into the left brachiocephalic vein

Answer 34

Left posterior intercostal veins 1-4

Question 35

What veins drain into the accessory hemiazygous vein

Answer 35

The left posterior intercostal veins 5-8; and then into the azygous vein

Question 36

What veins drain into the hemiazygous vein

Answer 36

The left posterior intercostal veins 9-11 plus the left subcostal vein; and then into the azygous vein

Question 37

Describe the pathway of the thoracic duct

Answer 37

Ascends up the right hand side of the vertebral column and wraps around the left internal jugular vein

Question 38

Where does the thoracic duct empty into the venous system

Answer 38

At the junction of the left internal jugular and left subclavian veins; called the left venous angle

Question 39

What are splanchnic nerves

Answer 39

Nerves coming from the sympathetic chain providing innervation to the abdominal viscera

Question 40

What is the root value of the greater splanchic nerve

Answer 40

T5-T9 ganglia

Question 41

What is the root value of the lesser splanchnic nerve

Answer 41

T10-T11 ganglia

Question 42

What is the root value of the least splanchnic nerve

Answer 42

T12 ganglion

Question 43

What ganglia does the greater splanchnic nerve supply

Answer 43

1. Coeliac | 2. Superior mesenteric

Question 44

What ganglia does the lesser splanchnic nerve supply

Answer 44

1. Superior mesenteric | 2. Aorticorenal

Question 45

What ganglia does the least splanchnic nerve supply

Answer 45

Aorticorenal

Question 46

At what vertebra does the IVC pierce the diaphragm and what is the opening called

Answer 46

T8 and the caval opening

Question 47

At what vertebra does the oesophagus and vagal trunk pierce the diaphragm, and what is the opening called

Answer 47

T10 and the oesophageal hiatus

Question 48

At what vertebra does the aorta, thoracic duct and azygous vein pierce the diaphragm, and what is the opening called

Answer 48

T12 and the aortic hiatus

Question 49

At what vertebra do the greater and lesser splanchnic nerves pierce the diaphragm, and where do they pierce it

Answer 49

T12 and through openings in the crura

Question 50

At what vertebra does the least splanchnic nerve and the sympathetic trunk pierce the diaphragm, and where do they pierce it

Answer 50

T12 and behind the medial acruate ligament