Thoracic Cavity 1

Question 1

What is contained in the thoracic cavity?

Answer 1

lungs and chest wall lined by pleura

heart covered with pericardium

Question 2

What lines body cavities?

Answer 2

serous membrane

Question 3

What is the function of serous membrane?

Answer 3

• allows movement, expansion and contraction of organs
• compartmentalisation
• layer of fluid to allow frictionless movement

Question 4

Where is the superior mediastinum found?

Answer 4

behind the manubrium, between the thoracic inlet and the plane through the sternal angle (T4/5 intervertebral disc level)

Question 5

Where is the inferior mediastinum found?

Answer 5

inferior to the transverse plane through the sternal angle and the diaphragm

subdivided into anterior, middle and posterior mediastinum

Question 6

Relations of the right side of the mediastinum

Answer 6

• right atrium and veins
• superior vena cava
• arch of the azygos
• inferior vena cava

Question 7

Relations of the left side of the mediastinum

Answer 7

• left ventricle and arteries
• left common carotid artery
• left subclavian artery
• arch of aorta
• thoracic aorta

Question 8

What is contained in the middle mediastinum?

Answer 8

• heart
• pericardium
• origins of great vessels (aorta pulmonary trunk)
• terminal parts of IVC and SVC
• phrenic nerves
• branches of vagus

Question 9

What are the functions and the different layers of the pericardium?

Answer 9

• anchors the heart and prevents overexpansion of the heart
• 2 layers:
• fibrous pericardium externally
• serous pericardium internally

Question 10

Relations and attachments of the fibrous pericardium

Answer 10

• anteriorly related and attached by the sterno-pericardial ligament to the body of sternum and 3rd-6th CC
• posteriorly related and attached by the pericardiovertebral ligaments to 5th-8th thoracic vertebrae
• inferiorly blends with the central tendon of the diaphragm by the pericardiophrenic ligament

Question 11

What does the attachment of fibrous pericardium to the diaphragm do?

Answer 11

Stops the diaphragm from everting the ribs medially reducing the pressure on them

Question 12

Explain the composition of serous pericardium

Answer 12

• 2 layers, parietal and visceral
• parietal: lines inner aspect of fibrous pericardium and reflects on itself around roots of great vessels to continue as the visceral layer
• visceral layer: epicardium

Question 13

Where is the pericardial cavity found?

Answer 13

between parietal and visceral layers of serous pericardium

Question 14

What is the purpose of the transverse pericardial sinus?

Answer 14

to separate the arterial and venous ends of the heart tube

Question 15

Describe the position and relations of the transverse pericardial sinus

Answer 15

posterior to the ascending aorta and pulmonary trunk, anterior to the superior vena cava
superior to the left atrium and pulmonary veins

Question 16

What is the importance of the transverse pericardial sinus?

Answer 16

Important in cardiac surgery. A finger can make a ligature through the sinus to stop circulation

Question 17

Other name for transverse pericardial sinus

Answer 17

sinus of Theile

Question 18

Other name for oblique pericardial sinus

Answer 18

Haller’s cul-de-sac

Question 19

Describe the relations of the oblique pericardial sinus

Answer 19

surrounded by the reflection of the serous pericardium around the right and left pulmonary veins and the IVC

Question 20

What is the nerve supply to the pericardium?

Answer 20

• sensory fibres from phrenic nerve
• parasympathetic vasomotor fibres from the vagus nerve
• sympathetic cardiopulmonary vasomotor fibres from cardiopulmonary splanchnic nerves

Question 21

Describe the journey of the phrenic nerve

Answer 21

Arises from ventral rami of C3,4,5 (mainly 4) and travels over the scalenus anterior muscle and enters mediastinum between venous and arterial planes (subclavian artery and vein) between the fibrous pericardium and parietal pleura

Question 22

What is an identifiable feature of the phrenic nerve?

Answer 22

It passes anterior to the root of the lung

Question 23

Where does the right phrenic nerve pass?

Answer 23

adjacent to the SVC then IVC and through the caval opening to enter the diaphragm

Question 24

Where does the left phrenic nerve pass?

Answer 24

crosses the aortic arch and over the left ventricle and pierces diaphragm

Question 25

What nerve is the sole motor supply to the diaphragm?

Answer 25

phrenic nerve

Question 26

Where can pericardial pain be referred to?

Answer 26

• C4 dermatome

- back of the neck, supraclavicular region, shoulder tip

Question 27

What are the boundaries of the anterior mediastinum?

Answer 27

• sternal body and xiphoid process
• pericardium
• lungs with pleura

Question 28

What are the contents of the anterior mediastinum?

Answer 28

• thymus (or its remnants in adults)
• internal mammary vessels
• lymph nodes
• connective tissue
• fat tissue
• lower pole of thyroid

Question 29

What are the possible pathologies for the anterior mediastinum?

Answer 29

4 tumours

• thymoma (thymus)
• thyroid tumour
• lymphoma
• teratoma

Question 30

Explain the position and relations of the thymus

Answer 30

• between manubrium, sternum and pericardium
• related to pericardium, SVC, left and right brachiocephalic veins, pleura, phrenic nerves, trachea
• from jugular notch to 4 CC

Question 31

What forms the brachiocephalic veins?

Answer 31

internal jugular and subclavian veins

Question 32

What froms the SVC?

Answer 32

left and right brachiocephalic veins

Question 33

What are the 3 branches of the aortic arch?

Answer 33

• brachiocephalic trunk
• left common carotid artery
• left subclavian artery

Question 34

What position of the mediastinum is the pulmonary arteries found?

Answer 34

Within the pericardium so in the middle mediastinum