Thoracic Cavity 1

Question 1

What is the function of serous membrane?

Answer 1

Allows movement, expansion and contraction of organs, Compartmentalise, lubricate potential spaces to prevent friction.

Question 2

what do body cavities consist of?

Answer 2

• confine organs and systems that have related functions
• lined by sous membranes

Question 3

Where will you find the viceral and parietal pleura layer?

Answer 3

Viceral is the serous membrane incontact with the lungs whereas the parietal layer is incontact with the thoracic wall and superior diaphragm.

Question 4

1) what are abdominal and pelvic cavities lined by?
2) what is the thoracic cavity lined with?
3) what is the heart covered by?

Answer 4

1) peritoneum
2) pleura
3) pericardium

Question 5

what makes up the thoracic cage?

Answer 5

• sternum
• 12 pars of ribs
• costal cartilage
• 12 thoracic vertebrae and intervertebral discs

Question 6

what is the thoracic cavity divided into?

Answer 6

1- right pleural cavity
2- left pleural cavity
3- mediastinum

Question 7

describe true ribs

Answer 7

• ribs 1-7
• attach sternum directly through their own costal cartilage

Question 8

where does pleura cover?

Answer 8

lungs
root of lung
the diaphragm
thoracic wall

Question 9

what makes up the thoracic wall

Answer 9

• thoracic cage
• skin and subcutaneous tissue
• thoracic muscles and fascia
• intercostal muscles
• mammary glands and breast tissue

Question 10

What is the parietal pleura attached to?

Answer 10

Thorax wall
the fascia at the thoracic inlet
1st rib and T1
Fibrous pericardium and other mediastinal structures and the Diaphragm

Question 11

What is the mediastinum?

Answer 11

The space between the two pleural sacs, sternum and the costal cartilage, thoracic vertebrae and diaphragm.
It is mobile region to accommodate volume and pressure changes

Question 12

Name the different areas the mediastinum is broken up into?

Answer 12

Superior mediastinum, middle and the Inferior mediastinum (which further gets subdivided into the anterior, middle and postierior mediastinum)

Question 13

Describe the location of superior mediastinum

Answer 13

It is behind the maubrium, between the inlet and the sternal angle.

Question 14

Describe the location of inferior mediastinum

Answer 14

Inferior to transverse plane through the sternal angel and the diaphragm.

Question 15

What are the structres on the right side of the mediastinum?

Answer 15

These related to the right atrium and veins: SVC, arch of azygos and IVC

Question 16

What are the structres on the left side of the mediastinum?

Answer 16

Relate to left ventricle and arteries: Left common carotid artery, left subclavian artery, arch of aorta and thoracic aorta.

Question 17

What are the contents of the middle mediastinum

Answer 17

Heart, Pericardium, Origins of great vessels, smaller vessels (pulmonary veins) phrenic nerves and branches of the vagus nerve.

Question 18

What is the pericardium and its functions

Answer 18

It is a fibro-serous sac that encloses the heart and the roots of the great vessels.
Its functions are anchoring the heart to surrounding tissue without compromising cardiac movement and prevent the overfilling of the heart.

Question 19

What are the layers the pericardium is comprised of?

Answer 19

Fibrous pericardium (external) and the serous pericardium (internal)

Question 20

What is the fibrous pericardium attached too?

Answer 20

• Apex is fused with tunica adventitia of great vessels
• anteriorly it is attached to sterno-pericardial ligament (to sternum and CC 3-6)
• posteriorly is attached to the pericardiovertebral ligaments (5-8)
• inferiorly it blends with the central tendon of the diaphragm

Question 21

What are the two layers of the serous pericardium?

Answer 21

Parietal - lines the inner aspect of the fibrous pericardium.
Visceral = epicardium.

Question 22

describe the parietal layer of the serous pericardium?

Answer 22

• lines the inner aspect of the fibrous pericardium
• reflects onto itself around the roots of the great vessels and continuous as the visceral layer

Question 23

Where is the pericardial cavity? and how much fluid sits here and it function.

Answer 23

Between parietal and visceral layers of serous pericardium.
10-15ml of fluid produced by serous pericardium. It reduces friction during contraction of the heart

Question 24

describe the fibrous pericardium and what its related to anteriorly and posteriorly?

Answer 24

• apex is fused with the adventitia of the great vessels
• anteriorly, related and attached by the sterno-pericardial ligament to the body of the sternum and 3rd-6th costal cartilages
• posteriorly, related and attached by the pericardiovertebral ligaments to 5th-8th thoracic vertebrae.

Question 25

what is the pericardium related to inferiorly?

Answer 25

blends with the central tendon of the diaphragm - this attachment of the diaphragm halts the descent of the diaphgram during inspiration.

Question 26

How are the transverse and oblique sinuses (pericardial sinuses) formed?

Answer 26

During embryological development the endocardial tube folds and invaginates into the serous pericardium.

Question 27

what does the transverse pericardial sinus do?

Answer 27

separates the arterial and venous ends of the heart tube.

Question 28

Where is the location of the Transverse pericardial sinus and when is it important?

Answer 28

- It is posterior to the ascending aorta and pulmonary trunk and anterior to the SVC. - Superior to left atrium and pulmonary veins. - It is important in cardiac surgery. It used to separated the arterial and venous ends of the heart tube.

Question 29

Where is the location of the Oblique pericardial sinus?

Answer 29

It is a recess on the posterior aspect of the left atrium, on either sides are the pulmonary veins.

Question 30

what is the oblique pericardial sinus surrounded by?

Answer 30

surrounded by the reflection of the serous pericardium around the right and left pulmonary veins and the inferior vena cava.

Question 31

What are the nerve supplies for the pericardium?

Answer 31

Sensory fibres from the phrenic nerve, vasomotor from the vagus nerve and the cardiopulmonary splanchnic nerves.

Question 32

what ns controls heart beat?

Answer 32

autonomic nervous system = unconscious sensation

Question 33

What are the roots of the phrenic nerve and its journey?

Answer 33

Arises from C3,4,5 (keeps the diaphragm alive). It descends over scalenus anterior muscle and then enters the mediastinum between the subclavian vein and artery. It then passes anterior to root of lung, lies between fibrous pericardium and parietal pluera. It runs along SVC IVC and crosses the aortic arch over left ventrical

Question 34

What does the phrenic nerve supply?

Answer 34

sole Motor supply to the diaphragm and sensory supply to the mediastinal pariertal pleura, peritoneum and pleura related to central tendon of diaphragm and the parietal pericardium

Question 35

examples of how the phrenic nerve can become injured?

Answer 35

- radial incision on the diaphragm - lung tumours - polio - cardiac surgery

Question 36

Where is the refereed pain for the phrenic nerve?

Answer 36

Back of neck, supraclavicular region and shoulder tip.

Question 37

describe the route of the phrenic nerve?

Answer 37

- passes anterior to the root of the lung - lies between fibrous pericardium and parital pleura - right phrenic nerve passes through the canal hiatus

Question 38

describe the phrenic nerve

Answer 38

- arises from the ventral rami of C3, C4, C5 - sits on top of selenium anterior - enters the mediastinum between the venous and arterial planes, subclavian artery and vein.

Question 39

What are the bounderies of the anterior medistinum?

Answer 39

Sternal body and xiphoid, pericardium and lungs with pleura

Question 40

What are the contents of the anterior mediasternum?

Answer 40

Thymus(in kids), internal mammary vessels, Lymph nodes, CT, fat and lower pole of thyroid.

Question 41

What tumours can arise in the anterior medistinum

Answer 41

Terrible 4s. Thymus, Thyroid Terrible lymphoma and teratoma

Question 42

What is the thumus?

Answer 42

- Bilobed organ of lymphoid tissue, it is active until puberty and can extend from lower neck to 4th CC. - increasing fibro-fatty infiltration with age

Question 43

What are the 3 planes of the superior mediastinum and what lies between them?

Answer 43

Venous, arterial and the trachea and oesophagus. The vagus and phrenic nerve lies within these planes.

Question 44

where does the vagus and phrenic nerve lie between?

Answer 44

lies between the venous and arterial plane

Question 45

What are the contents of the venous plane? or what occurs here?

Answer 45

Brachiocephalic vein (BCV) formed by IJV and subclavian. The right and left BCV forms the SVC. The arch of azygos joins the SVC this will then enter the right atrium.

Question 46

where does the left brachiocephalic vein pass anterior too?

Answer 46

passes anterior to the arch of the aorta, posterior to the manubrium

Question 47

What occurs in the arterial plane?

Answer 47

The ascending aorta continuous as the aortic arch above the sternal angel. It curves up and backwards and then continues as the thoracic aorta in posterior mediastinum.

Question 48

What are the branches of the Aortic Arch?

Answer 48

- Brachiocephalic trunk (divided into right subclavian and right common carotid) - Left common carotid - the left subclavian (posterior and to the left of the trachea)

Question 49

At what level does the pulmonary trunk divide and what does it divide into?

Answer 49

Divides at T4/5 disc into Right and left pulmonary arteries. right pulmonary artery = posterior to the ascending aorta and superior vena cava left pulmonary artery= inferior to the arch of the aorta and anterior to the thoracic aorta.

Question 50

where does the pulmonary trunk lie?

Answer 50

- it lies within the pericardium to the left of the ascending aorta.