Thoracic Cavity & Breathing

Question 1

Name the five structures of the sternum

Answer 1

Jugular notch, manubrium, sternal angle, body, xiphoid process

Question 2

How many true ribs are there?

Answer 2

7

Question 3

Which are the floating ribs?

Answer 3

11-12

Question 4

Which are the false ribs?

Answer 4

8-10

Question 5

Between what vertebral levels would you describe the thoracic cavity as being?

Answer 5

T1-T12

Question 6

What are the major structures that exit the superior thoracic aperature?

Answer 6

Left and right carotid, left and right subclavian, left and right internal and external jugular veins, oesophagus, trachea, recurrent laryngeal nerves, left and right vagus and phrenic nerves.

Question 7

What perforates the diaphragm at T8 vertebral level, leaving the inferior thoracic aperature?

Answer 7

IVC

Question 8

What vertebral level does the oesophagus perforate the diaphragm?

Answer 8

T10

Question 9

What structures make up the scapula?

Answer 9

Acromion, coracoid process, glenoid fossa, subscapular fossa

Question 10

How many lobes does the right lung have?

Answer 10

3

Question 11

Which lung has two lobes?

Answer 11

Left

Question 12

How many fissures does the left lung have?

Answer 12

1

Question 13

How many fissures does the right lung have?

Answer 13

2

Question 14

What are the two types of pleura that surround the lungs?

Answer 14

Visceral and parietal

Question 15

Which pleura adheres tightly to the surface of the lungs?

Answer 15

Visceral

Question 16

What two structures lie directly posterior and anterior to the thoracic plane?

Answer 16

Disc between T4-T5 and the sternal angle

Question 17

What landmarks might you find in the thoracic plane?

Answer 17

Carina, start and end of aortic arch, perforation of the SVC into the heart, terminal end of pulmonary trunk

Question 18

Between which vertebral levels would you describe the superior mediastinum?

Answer 18

T1-T4

Question 19

The inferior mediastinum consists of what three sections?

Answer 19

Anterior, middle, posterior

Question 20

What structures may be mentioned to describe the position of the Hilum in the lungs?

Answer 20

Posterior to the cardiac impression, vertebral level T5-T7

Question 21

Name the main structures that are found in the posterior mediastinum

Answer 21

Oesophagus, IVC, descending thoracic aorta, thoracic duct, azygous veins, thoracic splanchnic nerves.

Question 22

What vertebral level is the xiphoid process?

Answer 22

T10

Question 23

The typical ribs have what parts?

Answer 23

Head with two facets, neck, tubercle, costal angle, costal groove.

Question 24

Which ribs only articulate with one vertebrae?

Answer 24

1, 10, 11, 12

Question 25

The 1st rib is what shape?

Answer 25

Sickle shaped and flat

Question 26

Which ribs have no costal cartilages?

Answer 26

11 and 12

Question 27

The costal margin is shared cartilage among which ribs?

Answer 27

8-10

Question 28

What marks the boundaries of the inferior thoracic aperture?

Answer 28

T12, costal margin and xiphoid process

Question 29

Name the three layers of intercostal muscle

Answer 29

External, internal, innermost

Question 30

What nerves innervate the intercostal muscles?

Answer 30

Ventral rami of the thoracic spinal nerves

Question 31

Where does the neurovascular bundle of each intercostal space run?

Answer 31

In the costal groove of each rib

Question 32

What are the functions of the three layers of intercostal muscle?

Answer 32

External- elevate during forced inspiration. Internal and innermost- depression during forced expiration

Question 33

What happens to the diameter of the thorax during elevation of the upper ribs?

Answer 33

Increase in anterior-posterior diameter, known as the "pump-handle" movement

Question 34

What happens to the diameter of the thorax during elevation of the low ribs?

Answer 34

Increase in transverse diameter, known as the "bucket-handle" movement

Question 35

What are the accessory inspiratory muscles?

Answer 35

sternocleidomastoid, scalenus anterior/medius/posterior, pectoralis major/minor, serratus anterior and latissimus dorsi

Question 36

What are the accessory expiratory muscles?

Answer 36

rectus abdominis, external/internal oblique and transversus abdominus

Question 37

What part of the pleura can sense pain?

Answer 37

Parietal

Question 38

What part of the pleura does the phrenic nerve innervate?

Answer 38

Mediastinal and diaphragmatic parietal pleura

Question 39

Which nerve supply the apical and costal parietal pleura?

Answer 39

Intercostal nerves

Question 40

What arteries supply the parietal pleura?

Answer 40

Intercostal arteries

Question 41

What arteries supply the visceral pleura?

Answer 41

Bronchial arteries

Question 42

Where do pleural effusions collect?

Answer 42

Costo-diaphragmatic recess

Question 43

On a plain x-ray, how would you discern a pleural effusion?

Answer 43

"blunting" or decrease of the costophrenic angle

Question 44

What is thoracocentesis?

Answer 44

Pleural tap, a procedure performed to drain the excess fluid in the costo-diaphragmatic recess

Question 45

What part of the pulmonary plexus innervates 75% of the lungs?

Answer 45

Posterior

Question 46

How does a pneumothorax occur?

Answer 46

Air or gas within the pleural space removes the surface tension of the serous fluid and results in the collapse of the lung.

Question 47

What is a tension pneumothorax?

Answer 47

Air enters the pleural cavity and cannot escape. The pressure causes a mediastinal shift which impairs venous return to the heart and cause haemodynamic compromise, as well as flattening the diaphragm, deviating the trachea to the contralateral side and reducing the function of the contralateral lung.

Question 48

Where is a chest drain inserted in a pneumothorax or pleural effusion?

Answer 48

5th or 6th intercostal space, mid-axillary line

Question 49

Which costal cartilage aligns with the xiphisternal joint?

Answer 49

6th

Question 50

Where is the cardiac notch of the pleura?

Answer 50

4th-6th costal cartilage

Question 51

What costal cartilage does the sternal angle align with?

Answer 51

2nd

Question 52

What ribs does the costo-diaphramatic recess sit between?

Answer 52

10th and 12th

Question 53

Which costal cartilage will you find the horizontal fissure on the right side?

Answer 53

4th

Question 54

What is the angle of the right main bronchus?

Answer 54

25 degrees

Question 55

What is the angle of the left main bronchus?

Answer 55

45 degrees

Question 56

Name the layers of tissue, from external to internal, you would encounter during a standard chest drain insertion for pneumothorax?

Answer 56

Skin, superficial fascia, external intercostal muscle, internal intercostal muscle, innermost intercostal muscle, endothoracic fascia, parietal pleura, visceral pleura, lung

Question 57

Where would a chest drain usually be inserted?

Answer 57

5th intercostal space, midaxillary line.

Question 58

Describe what happens during the inspiratory phase of the cough reflex

Answer 58

Irritation of cough receptors cause vocal cords to abduct, external intercostals and diaphragm contract, thoracic cavity size increases, decreasing pressure, air moves into thorax.

Question 59

The epiglottis and vocal cords close, trapping air within the lungs. What stage of the cough reflex is this?

Answer 59

Compression

Question 60

What muscles are involved in the expiratory phase of the cough reflex?

Answer 60

Internal intercostals and abdominal muscles

Question 61

What affect on the cough reflex can ACE inhibitors have?

Answer 61

Side effect of persistent dry cough. Caused by the accumulation of bradykinin which releases pro-inflammatory peptides that irritate the c-fibres, resulting in hyperstimulation of the cough reflex.

Question 62

Irritation of what nerve causes sneezing?

Answer 62

Trigeminal (V)

Question 63

How are larger particles prevented from entering the respiratory system?

Answer 63

Trapped in the mucus secretion in conducting zone and swept upwards towards the nose and mouth via the mucociliary escalator

Question 64

What partial pressure of oxygen would you find in venous blood?

Answer 64

~40mmHg

Question 65

What partial pressure of C02 would you find in arterial blood?

Answer 65

~40mmHg

Question 66

The partial pressure gradient between the air and the tissues is smaller in CO2, what ensures that equal amounts of exchange happen?

Answer 66

CO2 is 20x more soluble that O2.

Question 67

Explain Fick's law.

Answer 67

Rate of diffusion is proportional to the surface area of the tissue, the pressure gradient and the gas constant. It is inversely proportional to tissue thickness.

Question 68

What is the gas constant?

Answer 68

Gas solubility / sqrt(gas molecular weight)

Question 69

Use Fick's law to describe why gas exchange is reduced in pathological disease, such as pneumonia.

Answer 69

Alveolar air is blocked by infectious fluid, creating a thicker diffusion pathway, increasing rate of diffusion across the membrane. The surface area is also reduced due to inflammatory consolidation, reducing the rate of diffusion across the membrane.

Question 70

What is VQ matching?

Answer 70

the changes in bronchiolar constriction/dilation (V) and arteriolar constriction/dilation (Q) happening at each gas exchange surface in the lungs to maximise coupling.

Question 71

What do the V and Q stand for in VQ?

Answer 71

Ventilation and perfusion

Question 72

What is the ideal VQ ratio?

Answer 72

0.8-1

Question 73

What happens in the arterioles in the lungs when there is a low PaO2 (hypoxia)?

Answer 73

Vasoconstriction, decreasing blood flow and redirecting it to better perfused areas

Question 74

A high VQ ratio would indicate what cause of respiratory distress?

Answer 74

High VQ=Low Q= Low perfusion= Reduced blood flow/blocked vessel (i.e. pulmonary embolism)