Session 2

Question 1

What are true ribs?

Answer 1

Ribs where costal cartilages connect each rib directly to the sternum: ribs 1-7.

Question 2

What are false ribs?

Answer 2

Ribs where the costal cartilages connect to the costal cartilage of the ribs above them instead of the sternum: ribs 8-10.

Question 3

What are floating ribs?

Answer 3

Ribs where the costal cartilages don’t connect them to any solid structures: ribs 11 and 12.

Question 4

Where are the articulate facets on a rib?

Answer 4

Connecting the rib to the superior and inferior costal facets, and transverse processes of the spinal vertebrae.

Question 5

How many lobes does the left lung have? Why?

Answer 5

2 lobes, the rest of the space is taken up by the heart.

Question 6

Where might ribs with 2 articulations with the spine be found?

Answer 6

At the top and bottom of the thorax.

Question 7

How does the chest wall move during breathing?

Answer 7

Like a bucket handle; ribs move upwards at the joints with the spine and sternum to increase lateral diameter.

Question 8

How does the sternum move during breathing?

Answer 8

Like a pump handle; moves antero-superiorly on the sternoclavicular joints to increase thoracic volume anteriorly.

Question 9

How can bending forwards assist breathing?

Answer 9

Allows recruitment of the pectoral muscles.

Question 10

When might patients be seen using neck muscles in breathing?

Answer 10

When very strained for breath, e.g. in emphysema.

Question 11

What direction do the external oblique intercostal muscles face?

Answer 11

Infero-medially (like hands in pockets).

Question 12

What is the function of the external oblique intercostal muscles?

Answer 12

Pull the ribs upwards.

Question 13

What direction do the internal oblique intercostal muscles face?

Answer 13

Superio-medially (perpendicular to the externals).

Question 14

What is the function of the internal oblique intercostal muscles?

Answer 14

Pull the ribs downwards.

Question 15

What direction do the innermost intercostal muscles face?

Answer 15

Superio-medially (similar to internal obliques).

Question 16

Where does the vena cava move through the diaphragm?

Answer 16

At the canal opening around the T8 vertebra level.

Question 17

WHere does the oesophagus move through the diaphragm?

Answer 17

Through the oesophageal hiatus around the T10 vertebral level.

Question 18

Where does the aorta move through the diaphragm?

Answer 18

At the aortic hiatus around the T12 vertebral level (actually behind the diaphragm).

Question 19

What structures can be found under the costal groove of each rib?

Answer 19

Intercostal vein, artery and nerve.

Question 20

What structures can be found above each rib?

Answer 20

Collateral branches of the intercostal nerve, artery and vein.

Question 21

Where would a needle be inserted into the thorax in relation to the ribs?

Answer 21

Just superior to the rib to minimise the damage to structures in the chest wall.

Question 22

What is the venous drainage of the chest wall?

Answer 22

Intercostal veins -> azygous and hemiazygous veins -> superior vena cava.

Question 23

What nerves supply the diaphragm; what are their roots?

Answer 23

Left and right phrenic nerves, roots C3,4,5.

Question 24

Where are objects entering the lung most likely to become lodged; why?

Answer 24

The right main bronchus, it forms a more acute angle of entry than the left main bronchus.

Question 25

What is the function of the costodiaphragmatic recesses?

Answer 25

Allow the lungs to expand downwards.

Question 26

Describe the forces acting on the lungs at resting expiratory level.

Answer 26

All forces are balanced so no net movement; if there are imbalances then they will spring the lungs back to resting expiratory level.

Question 27

Which process in ventilation is active and which is passive?

Answer 27

Inspiration is active, expiration is passive.

Question 28

Describe interpleural pressure in relation to atmospheric pressure.

Answer 28

Always lower to prevent the lungs from collapsing.

Question 29

What is the function of pleural fluid?

Answer 29

To ensure the lungs fill the thoracic cavity and change volume with the thorax via negative interpleural pressures.

Question 30

What is lung compliance?

Answer 30

The volume change per unit pressure of the lungs, i.e. stretchiness.

Question 31

How is lung compliance decreased pathologically?

Answer 31

Supine/prone position; laparoscopic surgical intervention; severe restrictive pathology; chronic restrictive pathology; hydrothorax (PE); pneumothorax; high standing diaphragm.

Question 32

What physiologically decreases lung compliance?

Answer 32

Surface tension in the fluid lining the airways.

Question 33

Describe the relationship of elastic recoil and compliance.

Answer 33

Elastic recoil is inversely proportional to compliance.

Question 34

How is surface tension in the lungs reduced?

Answer 34

Using surfactant.

Question 35

Describe the structure and molecular functions of surfactant.

Answer 35

Detergent mixture made up of phospholipid, phosphatidylcholine and proteins that disrupts hydrogen bonds between surface molecules.

Question 36

What happens in the lungs if surfactant is absent?

Answer 36

Bubbles form, smaller alveoli are absorbed by larger ones (Laplace’s law) and lung linings will collapse (atelectasis).

Question 37

Describe respiratory distress syndrome.

Answer 37

Babies born before 36 weeks have too little surfactant so their lungs are stiff with few alveoli so breathing is compromised. Adult RDS results from widespread inflammation to the lungs usually secondary to sepsis or trauma.

Question 38

How does decreasing airway diameter affect resistance?

Answer 38

Increases it by the 4th power.

Question 39

Which airways have the highest overall resistance?

Answer 39

Larger ones as there are fewer airways so larger summative resistance. Highest is int he medium-sized bronchi.

Question 40

How does obstructive airway disease affect breathing?

Answer 40

Airways are narrowed so inspiration is normal as airways can expand at lower resistances but expiration is more difficult as resistance is higher.