Anterior and Middle Mediastinum

Question 1

What vertebra is the superior mediastinum between

Answer 1

T1 and T5

Question 2

What vertebra is the inferior mediastinum between

Answer 2

T5 and T9

Question 3

What vertebra is the sternal angle at

Answer 3

T5

Question 4

What are the 4 boundaries of the anterior mediastinum

Answer 4

1. Body of sternum (anteriorly)
2. Pericardium (posteriorly)
3. Transverse thoracic plane (superiorly)
4. Diaphragm (inferiorly)

Question 5

What are the 3 main contents of the anterior mediastinum

Answer 5

1. Loose connective tissue
2. Fat
3. Lymphatics

Question 6

What anterior mediastinal structure is much larger in children

Answer 6

Thymus; turns into fat as you reach adulthood

Question 7

What 3 structures are within the middle mediastinum

Answer 7

1. Heart
2. Pericardium
3. Roots of great vessels

Question 8

What 3 structures are adjacent to the middle mediastinum

Answer 8

1. Great vessels
2. Phrenic nerve
3. Lung root structures

Question 9

Where does the right phrenic nerve attach to the pericardium

Answer 9

Superficial to the right atrium

Question 10

Where does the left phrenic nerve attach to the pericardium

Answer 10

Superficial to the left atrium and ventricle

Question 11

What is the tunica adventitia of vessels

Answer 11

It is the outermost tunica of a blood vessel, surrounding the tunica media

Question 12

What does the fibrous pericardium blend with inferiorly

Answer 12

It is continuous with the central tendon of the diaphragm

Question 13

What does the fibrous pericardium blend with superiorly

Answer 13

Tunica adventitia of the great vessels

Question 14

Name the layers of the pericardium, starting with the outermost

Answer 14

1. Fibrous
2. Parietal (serous)
3. Visceral (serous)

Question 15

Name the space in between the parietal and visceral pericardium

Answer 15

The pericardial cavity

Question 16

Describe the location of the transverse pericardial sinus

Answer 16

Posterior to the pulmonary trunk, anterior to the SVC and superior to the atria

Question 17

What is the oblique pericardial sinus

Answer 17

This is the space behind the heart

Question 18

What are the 6 different sections of the heart

Answer 18

1. Base
2. Right border
3. Inferior border
4. Apex
5. Left border
6. Superior border

Question 19

Describe what portions of the heart are in each of the different sections

Answer 19

Base = mainly left atrium
Right border = right atrium
Inferior border = right ventricle
Apex = left ventricle
Left border = left ventricle and left auricle
Superior border = right and left atria, and auricles

Question 20

What runs through the coronary groove

Answer 20

Right coronary artery

Question 21

What overlies the interventricular septum on the surface of the heart

Answer 21

Anterior interventricular groove

Question 22

What 2 veins creates the SVC

Answer 22

Right and left brachiocephalic veins

Question 23

Where does the ligamentum arteriosum attach to

Answer 23

At the superior end, the aorta; at the inferior end, top of the left pulmonary artery

Question 24

What does the ligamentum arteriosum function as

Answer 24

Acts as the fibrous connection between the pulmonary trunk and the arch of the aorta

Question 25

What nerve runs posterior to the ligamentum arteriosum

Answer 25

Left recurrent laryngeal

Question 26

What are the 4 branches of the right coronary artery

Answer 26

1. SA nodal 2. AV nodal 3. Right marginal 4. Posterior interventricular

Question 27

What are the 2 branches of the left coronary artery

Answer 27

1. Circumflex (left marginal) | 2. Anterior interventricular (diagonal)

Question 28

What 4 sections of the heart does the right coronary artery supply

Answer 28

1. Right atrium and most of right ventricle 2. SA and AV nodes 3. Posterior 1/3 of the IV septum 4. Part of the left ventricle

Question 29

What 4 sections of the heart does the left coronary artery supply

Answer 29

1. Left atrium and most of left ventricle 2. AV bundle 3. Anterior 2/3 of the IV septum 4. Part of the right ventricle

Question 30

Describe where the cardiac veins drain to

Answer 30

All veins drain to the coronary sinus, except the anterior cardiac which drain directly into the right atrium

Question 31

What arteries do they great, middle and small cardiac veins run alongside

Answer 31

``` Great = anterior interventricular Middle = posterior interventricular Small = right marginal ```

Question 32

Describe the internal structure of the right atrium

Answer 32

One side is very muscular (musculi pectinati) and one side is very smooth (sinus venarum)

Question 33

Where is the SA node located

Answer 33

Crista terminalis

Question 34

What are the muscular ridges in the ventricular wall called

Answer 34

Trabeculae carneae

Question 35

What conducting shortcut is unique to the right ventricle

Answer 35

Moderator band

Question 36

Where do the chordae tendinae anchor at

Answer 36

The papillary muscles

Question 37

What valve is located between the right atrium and ventricle

Answer 37

Tricuspid valve

Question 38

Describe the internal structure of the left atrium and auricle

Answer 38

Very smooth and thin walled; auricle region has some muscular ridges

Question 39

What valve is located between the left atrium and ventricle

Answer 39

Mitral (bicuspid) valve

Question 40

How many pulmonary veins are flowing into the left atrium

Answer 40

Normally 4; 2 left and 2 right

Question 41

What valves are shut at low pressure

Answer 41

Semilunar

Question 42

What valves are shut at high pressure

Answer 42

Cuspid

Question 43

How are the coronary arteries filled with blood

Answer 43

Due to the backflow of blood after the end of systole, as the heart muscle relaxes

Question 44

What stops the cuspid valves from prolapsing

Answer 44

Papillary muscles contract as the ventricles do, so there is tension in the chordae tendinae (prevents prolapse)

Question 45

What are the 2 functions of the hearts non-conductive fibrous skeleton

Answer 45

1. Support for valves | 2. Electrical insulation between atria and ventricles

Question 46

Where does the SA node receive its innervation from

Answer 46

Autonomic innervation from the cardiac plexus (located between the arch of the aorta and the carina)

Question 47

What is the function of the SA node

Answer 47

It is the heart's pacemaker; it depolarises and sets the heart rate