Posterior mediastinum

Question 1

what is the lateral border of the posterior mediastinum?

Answer 1

Mediastinal pleura (part of the parietal pleural membrane)

Question 2

what is the anterior border of the posterior mediastinum?

Answer 2

pericardium

Question 3

what is the posterior border of the posterior mediastinum?

Answer 3

T5-T12 vertebrae

Question 4

what is the roof of the posterior mediastinum?

Answer 4

Imaginary line extending between the sternal angle (the angle formed by the junction of the sternal body and manubrium) and the T4 vertebrae

Question 5

what is the floor of the posterior mediastinum?

Answer 5

Diaphragm

Question 6

what does the posterior mediastinum contain?

Answer 6

a number of major organs, blood vessels and nerves:
Thoracic Aorta
Oesophagus
Thoracic Duct
Azygos System of Veins
Sympathetic Trunks

Question 7

what is the thoracic (descending) aorta a continuation of?

Answer 7

the arch of the aorta

Question 8

where does the thoracic (descending) aorta begin?

Answer 8

at the lower edge of the T4 vertebra

Question 9

where does the thoracic (descending) aorta descend through? (course of travel)

Answer 9

the posterior mediastinum to the left of the vertebrae, becoming more medially located as it moves

Question 10

where does the thoracic aorta end? where does it pass through?

Answer 10

At the inferior border of T12, the thoracic aorta becomes the abdominal aorta, and passes through the aortic hiatus of the diaphragm

Question 11

what arises from the thoracic aorta in the posterior mediastinum?

Answer 11

A number of branches arise from the thoracic aorta in the posterior mediastinum. . The major branches are

Question 12

how do the branches of the thoracic aorta tend to arise in the posterior mediastinum?

Answer 12

These tend to arise in three vascular planes

Question 13

where do the unpaired branches of the thoracic aorta extend?

Answer 13

unpaired branches to viscera extend anteriorly

Question 14

where do the paired branches of the thoracic aorta extend?

Answer 14

paired branches to viscera extend laterally

Question 15

where do the paired segmental parietal branches of the thoracic aorta extend?

Answer 15

paired segmental parietal branches extend mostly posterolaterally

Question 16

what are the major branches of the thoracic aorta?

Answer 16

Posterior intercostal arteries
Bronchial arteries
Oesophageal arteries
Superior phrenic arteries

Question 17

what type of branches are the posterior intercostal arteries of the thoracic aorta?

Answer 17

Paired parietal branches

Question 18

how many paired parietal branches of posterior intercostal arteries arise from the thoracic aorta?

Answer 18

Nine such pairs branch from the posterior aspect of the aorta

Question 19

what do the 9 pairs of parietal branches of posterior intercostal arteries supply? except what?

Answer 19

supplying the intercostal spaces (except the first two)

Question 20

where do the 9 pairs of parietal branches of posterior intercostal arteries pass?

Answer 20

Pass laterally and laterally, in parallel with the ribs

Question 21

what type of branches of the thoracic aorta are bronchial arteries?

Answer 21

Paired visceral branches, usually one or two

Question 22

where does the left bronchial artery always arise from?

Answer 22

always arise directly from the thoracic aorta

Question 23

where do the right bronchial arteries arise from?

Answer 23

usually branch indirectly from a right posterior intercostal artery

Question 24

what do the left and right bronchial arteries normally go onto supply?

Answer 24

They go on to supply the tracheobronchial tree

Question 25

what type of branches are the oesophageal arteries?

Answer 25

Unpaired visceral branches

Question 26

where do the oesophageal arteries arise?

Answer 26

from the anterior aspect of the aorta

Question 27

how many oesophageal arteries are there in most individuals?

Answer 27

In most individuals there are two, but there can up to five

Question 28

what do the oesophageal arteries go onto supply?

Answer 28

the oesophagus

Question 29

where do the superior phrenic arteries arise from?

Answer 29

the anterior aspect of the thoracic aorta at the aortic hiatus, varying in number

Question 30

how many superior phrenic arteries are there?

Answer 30

varying in number

Question 31

what do the superior phrenic arteries supply?

Answer 31

the superior aspect of the diaphragm

Question 32

what is the oesophagus?

Answer 32

The oesophagus is a muscular tube

Question 33

what does the oesophagus connect?

Answer 33

the pharynx to the stomach

Question 34

what does the oesophagus allow?

Answer 34

allowing swallowed food to pass into the digestive system

Question 35

where does the oesophagus pass into? where from?

Answer 35

It passes into the posterior mediastinum from the superior mediastinum, descending posteriorly to the arch of the aorta and the heart

Question 36

where does the oesophagus descend to?

Answer 36

descending posteriorly to the arch of the aorta and the heart

Question 37

where is the oesophagus originally positioned? where does it deviate to? when?

Answer 37

Whilst initially positioned to the right, the oesophagus deviates to the left as it moves downwards

Question 38

via what does the oesophagus leave the mediastinum?

Answer 38

It leaves the mediastinum via the oesophageal hiatus of the diaphra

Question 39

what is the oesophageal plexus?

Answer 39

a network of nerves surrounding the oesophagus as it descends

Question 40

what does the oesophageal plexus comprise of?

Answer 40

branches from the left and right vagus nerves

Question 41

what happens immediately above the diaphragm to the oesophageal plexus?

Answer 41

the fibres of the plexus converge to form the anterior vagal trunk and posterior vagal trunk

Question 42

where do the anterior and posterior vagal trunk travel along?

Answer 42

the surface of the oesophagus as it exits the thorax

Question 43

what is the thoracic duct?

Answer 43

The thoracic duct is the largest lymphatic vessel in the body

Question 44

what does the thoracic duct allow?

Answer 44

allowing return of lymph from most of the body (all but the right superior quadrant) into the venous system

Question 45

where does the thoracic duct originate from?

Answer 45

the cisterna chyli in the abdomen

Question 46

where does the thoracic duct enter the mediastinum through?

Answer 46

the aortic hiatus

Question 47

where does the thoracic duct ascend to lie?

Answer 47

It ascends to lie directly anterior to the T6-T12 vertebrae

Question 48

what happens after the thoracic duct has ascended to lie directly anterior to the T6-T12 vertebrae?

Answer 48

before deviating left as it ascends into the superior mediastinum

Question 49

whilst located in the posterior mediastinum, where does the thoracic duct receives its lymphatic drainage from?

Answer 49

the intercostal spaces and neighbouring anatomical structures through a number of branches

Question 50

what is the Azygos System of Veins?

Answer 50

This venous network drains blood from the body walls and mediastinal viscera

Question 51

where do the Azygos System of Veins empty into?

Answer 51

superior vena cava

Question 52

what does the Azygos System of Veins consist of?

Answer 52

3 major veins: Azygos vein Hemiazygos vein Accessory hemiazygos vein

Question 53

what is the azygos vein formed by?

Answer 53

the union of the right lumbar vein and the right subcostal vein

Question 54

what does the azygos vein enter the mediastinum via?

Answer 54

the aortic hiatus

Question 55

where does the azygos vein drain into?

Answer 55

superior vena cava

Question 56

what is the hemiazygos vein formed by?

Answer 56

Formed by the union of the left lumbar vein and left subcostal vein

Question 57

where does the hemiazygos vein enter the mediastinum through? where does it ascend?

Answer 57

through the left crus of the diaphragm, ascending on the left side

Question 58

what does the hemiazygos vein combine with? where?

Answer 58

At the level of T8, it turns to the right and combines with the azygos vein

Question 59

what is the accessory hemiazygos vein formed by?

Answer 59

the union of the fourth to eighth intercostal veins

Question 60

where does the accessory hemiazygos vein drain into?

Answer 60

the azygos vein at T7

Question 61

what are the sympathetic trunks?

Answer 61

paired bundles of nerves

Question 62

where do the sympathetic trunks extend from to?

Answer 62

extend from the base of the skull to the coccyx

Question 63

what are the sympathetic nerve bundles in the thoracic region known as?

Answer 63

In the thoracic region, these nerve bundles are known as the thoracic sympathetic trunks

Question 64

what happens as the sympathetic nerve bundle descend through the thorax?

Answer 64

they lie within the posterior mediastinum

Question 65

what arises from the sympathetic trunks?

Answer 65

the lower thoracic splanchnic nerves

Question 66

where do the lower thoracic splanchnic nerves continue? what do they supply?

Answer 66

they continue inferiorly to supply the viscera of the abdomen