Mediastinum

Question 1

What is the mediastinum

Answer 1

Part of the thoracic cavity which lies between the lungs

Question 2

What does the mediastinum contain

Answer 2

All thoracic viscera apart from the lungs

Heart and pericardium
Great vessels that enter and leave the heart
Veins that drain the chest wall
Trachea and main bronchi
Oesophagus
Nerves (somatic and autonomic)
Lymphatics
Thymus gland

Question 3

What is the pericardium

Answer 3

Fibrous sac around the heart

Question 4

What is the mediastinum divided into

Answer 4

Superior and inferior compartments

Question 5

Where does the line between the compartments of the mediastinum run

Answer 5

Sternal angle anteriorly to the T4/T5 junction posteriorly

Question 6

What is the inferior mediastinum divided into

Answer 6

Anterior compartments
Middle compartments
Posterior compartments

Question 7

Where is the anterior mediastinum

Answer 7

Lies between the posterior aspect of the sternum and the anterior aspect of the pericardial sac

Question 8

What is the anterior mediastinum

Answer 8

Narrow space that contains the thymus gland in children and remnant in adults

Question 9

What does the middle mediastinum contain

Answer 9

Heart inside the pericardial sac
The pulmonary trunk
Ascending aorta

Question 10

Where is the posterior mediastinum

Answer 10

Lies between the posterior aspect of the pericardial sac and the vertebrae

Question 11

What are the main components of the superior mediastinum

Answer 11

Arch of the aorta and its three branches
Superior vena cava and its tributaries - the left and right brachiocephalic veins
Trachea
Oesophagus
Phrenic nerves (left and right)
Vagus nerves (left and right)
Thoracic duct
Thymus gland

Question 12

What does the ascending aorta give rise to

Answer 12

Coronary arteries which supply the myocardium

Question 13

Where does the arch of the aorta lie

Answer 13

Superior mediastinum

Question 14

Where does the descending (thoracic) aorta descend

Answer 14

Posterior mediastinum
Into the abdomen posterior to diaphragm

Question 15

What does the right common carotid artery supply

Answer 15

Right side of the head and neck including the brain

Question 16

What does the right subclavian supply

Answer 16

Right upper limb

Question 17

What does the left common carotid artery supply

Answer 17

Left side of the head, neck and brain

Question 18

What does the left subclavian artery supply

Answer 18

Left upper limb

Question 19

What does the arch of the aorta contain

Answer 19

Aortic bodies where chemoreceptors are located

Question 20

What do chemoreceptors monitor

Answer 20

Arterial oxygen and carbon dioxide

Question 21

Where does chemoreceptors information travel

Answer 21

Visceral sensory information travels back to CNS along the path of the vagus nerve

Question 22

What is the ligamentum arteriosum

Answer 22

Fibrous, cord-like connection between the pulmonary trunk and the arch of the aorta

Question 23

In the placenta what does the ductus arteriosus do

Answer 23

Diverts most of the blood entering the pulmonary trunk directly to the aortic arch

Question 24

Where does the superior vena cava return blood from

Answer 24

From the neck, head, and upper limbs

Question 25

Where does the superior vena cava and its tributaries lie

Answer 25

Superior mediastinum

Question 26

What does the internal jugular vein drain

Answer 26

Head and neck

Question 27

What does the subclavian vein drain

Answer 27

Upper limb

Question 28

What forms each brachiocephalic vein

Answer 28

Internal jugular vein Subclavian vein

Question 29

Where does the inferior vena cava return blood from

Answer 29

All regions inferior to the diaphragm (abdomen, pelvis and lower limbs)

Question 30

How long is the thoracic part of the IVC

Answer 30

Very short

Question 31

What is the shape of the trachea

Answer 31

Semi-rigid due to C-shape incomplete rings of cartilage in its walls

Question 32

Where is the trachea palpable

Answer 32

Just superior to the suprasternal notch

Question 33

Where does the trachea extend

Answer 33

Larynx in the midline of the neck into the superior mediastinum

Question 34

Where does the trachea terminate

Answer 34

At the level of the sternal angle (and junction between T4 and T5 vertebrae) by bifurcating into the left and right main bronchi

Question 35

What is the oesophagus

Answer 35

Muscular tube

Question 36

Where is the oesophagus

Answer 36

Extends from the pharynx in the midline of the neck to the stomach

Question 37

How does the oesophagus work

Answer 37

Waves of contractions of smooth muscle in the oesophageal wall move swallowed food and fluid distally (peristalsis)

Question 38

Where does the oesophagus lie in the superior mediastinum

Answer 38

Lies in the midline of the thorax, posterior to the trachea

Question 39

What are the right and left phrenic nerves formed by

Answer 39

C3, C4, C5 spinal nerves

Question 40

What innervates the diaphragm

Answer 40

Right and left phrenic nerves

Question 41

What are the phrenic nerves

Answer 41

Somatic nerves Contain motor and sensory fibres

Question 42

Where do the left and right phrenic nerves descend

Answer 42

Descend through the neck

Question 43

Where do the left and right phrenic nerves enter the thorax

Answer 43

Through the superior thoracic aperture

Question 44

What is the thoracic duct

Answer 44

Major channel for lymphatic drainage from most regions of the body

Question 45

Where does the thoracic duct empty

Answer 45

Into the venous system at the union of the left internal jugular vein and left subclavian vein

Question 46

What type of organ is the thymus

Answer 46

Lymphoid organ

Question 47

Where does the thymus lie

Answer 47

Superior mediastinum

Question 48

What is the pericardium

Answer 48

Tough, fibrous sac that encloses the heart like a loose-fitting bag

Question 49

Why is the pericardium loose

Answer 49

Allow movement of the heart within it

Question 50

How many layers do the pericardium have and there names

Answer 50

2 Outer fibrous layer Inner serous layer

Question 51

Where is the tough, outer fibrous layer of the pericardium attach

Answer 51

Attached superiorly to the great vessels Inferiorly to the central tendon of the diaphragm

Question 52

What are the two parts of the thin, inner serous layer

Answer 52

Parietal layer Visceral layer

Question 53

What does the parietal layer of the inner serous layer line

Answer 53

Inner aspect of the fibrous pericardium

Question 54

What does the visceral layer of the inner serous layer line

Answer 54

Covers the surface of the heart

Question 55

What is the space between the two layers of the serous pericardium

Answer 55

Pericardial cavity

Question 56

What does the pericardial cavity contain

Answer 56

Small amount of pericardial fluid that lubricated the serous membranes Allows them to slide over each other with movements of the heart

Question 57

What innervates the fibrous pericardium

Answer 57

Right and left phrenic nerves give rise to sensory branches

Question 58

Where does the apex project

Answer 58

Left of the sternum towards the left lung

Question 59

Name the surfaces of the heart

Answer 59

Base Inferior surface Anterior surface Pulmonary surface

Question 60

Where does the base (surface of the heart) face

Answer 60

posteriorly

Question 61

What is another name for the base surface

Answer 61

Posterior surface

Question 62

Where is the inferior surface of the heart

Answer 62

Lies on the central tendon of the diaphragm

Question 63

What is another name for the inferior surface

Answer 63

Diaphragmatic surface

Question 64

What does the anterior surface face

Answer 64

The sternum and ribs

Question 65

What is another name for the anterior surface

Answer 65

Sternocostal surface

Question 66

What is the pulmonary surface

Answer 66

Left and right sides of the heart face the lungs

Question 67

What does the base/posterior surface of the the heart relate to

Answer 67

Left atrium Part of right atrium

Question 68

What does the inferior/diaphragmatic surface relate to

Answer 68

Left ventricle Part of the right ventricle

Question 69

What does the anterior/sternocostal surface relate to

Answer 69

Right ventricle

Question 70

What does the left pulmonary surface relate to

Answer 70

Left ventricle

Question 71

What does the right pulmonary surface relate to

Answer 71

Left atrium

Question 72

What is the apex formed by

Answer 72

Left ventricle

Question 73

Where does the apex lie

Answer 73

Lies at the left 5th intercostal space in the midclavicular line

Question 74

Where is the apex palpable

Answer 74

Left 5th intercostal space in the midclavicular line

Question 75

What does the right border correspond to

Answer 75

Right atrium

Question 76

What does the left border correspond to

Answer 76

Left ventricle

Question 77

What does the inferior border correspond to

Answer 77

Right ventricle and part of the left ventricle

Question 78

Where does the right border lie

Answer 78

Lateral to the right sternal angle From right 3rd to right 6th costal cartilage

Question 79

Where does the left border lie

Answer 79

Extends from left 2nd to left 5th intercostal space in the midclavicular lie

Question 80

Where does the superior border lie

Answer 80

Along the line connecting the superior extents of the right and left borders right 3rd costal cartilage to left 2nd intercostal space

Question 81

Where does the inferior border lie

Answer 81

Along the line connecting the inferior end of the right border with the apex

Question 82

What is an auricle

Answer 82

Outpouchings from the walls of the right and left atria