Session 2

Question 1

Describe where all the ribs end

Answer 1

Ribs 1 to 7 - connected to the sternum via costal cartilages
Ribs 8 to 10 - articulate with the costal cartilage above
Ribs 11 to 2 - end free in abdominal muscles

Question 2

Describe the parts of the typical ribs (3-9)

Answer 2

Head - articulates with vertebra
Tubercule - articulates with transverse process of corresponding thoracic vertebra
Shaft - has a costal groove to protect intercostal vessels and nerve
Neck

Question 3

What are the different intercostal muscle and what do they do?

Answer 3

External - fibres run down and anteriorly (hands in pockets). 30%chest expansion at rest (rest is diaphragm). Bucket handle movement.
Internal - fibres run down and Posteriorly. Active during forced expiration.
Innermost - similar to internal but less well developed

Question 4

What allows the ribs to move when the external intercostal muscles contract?

Answer 4

The first rib is tethered

Question 5

Where do the intercostal vein, artery and nerve lie and in what order?

Answer 5

VAN superior to inferior

In the intercostal groove between the internal and innermost intercostal muscles

Question 6

Where should a needle be inserted during a chest drain/pleural aspiration?

Answer 6

At the upper border of the rib

Question 7

What do the intercostal arteries supply?

Answer 7

Intercostal muscles, parietal pleura and overlying skin

Question 8

What supplies the visceral pleura?

Answer 8

Bronchial arteries

Question 9

What are the intercostal nerves?

Answer 9

The anterior rami of the spinal nerves T1-12

Question 10

What abdominal organs could penetrating chest injuries damage?

Answer 10

Liver, spleen, parts of the stomach and upper kidneys.

Question 11

What does the diaphragm consist of, what are its openings and what nerve innervates it?

Answer 11

A central tendon and peripheral muscular part.
Openings for IVC (T8), oesophagus (T10) and aorta (aortic hiatus - T12).
Phrenic nerve (C3,4,5)

Question 12

What does the thoracic cavity consist of?

Answer 12

Two lateral pulmonary cavities and a central mediastinum.

Question 13

Where are the visceral and parietal pleura continuous?

Answer 13

At the hilum of the lungs

Question 14

What is the name given to the angle between the right and left bronchi?

Answer 14

Carina

Question 15

What is a bronchopulmonary segment and what is the clinical relevance?

Answer 15

A pyramid shaped area of lung supplied by a single segmental bronchus and branch of the pulmonary artery and vein. Important surgically in case of removal.

Question 16

When are respiratory muscles at rest?

Answer 16

At the end of quiet respiration when the elastic forces of the lung and chest wall are balanced.

Question 17

What muscles are used for forced expiration/inspiration?

Answer 17

Expiration - abdominal and internal intercostal muscles

Inspiration - sternocleidomastoid, scalene, serratus anterior and pectoral muscles.

Question 18

Describe the pressure in the pleural space

Answer 18

Always negative (

Question 19

Give some of the terms used to describe lung volumes/capacities and their approximate values

Answer 19

Expiratory reserve volume (1.5L) + tidal volume (0.5L) + inspiratory reserve volume (3L) = vital capacity (5L)

Vital capacity (5L) + residual volume (1L) = total lung capacity (6L)

Functional residual capacity (2.5L) + inspiratory capacity (3.5L) = total lung capacity (6L)

Question 20

What is the compliance of the lungs?

Answer 20

The volume change per unit pressure change

Question 21

What factors can affect compliance?

Answer 21

Prone/supine positions
Pneumo/hydrothorax
High standing of diaphragm

Question 22

What is specific compliance?

Answer 22

Compliance depends on starting volume

=volume change per unit pressure change/starting volume of lung

Question 23

What are the roles of surfactant?

Answer 23

Increases compliance (especially in low lung volumes)
Stops alveoli collapsing into each other
Stops collapsing at the end of expiration

Question 24

Why does the surface tension of the fluid lining alveoli increase as the lungs expand?

Answer 24

Surfactant molecules are further apart

Question 25

Why could alveoli potentially collapse into each other and how does surfactant stop this?

Answer 25

Alveoli are in effect a series of interconnecting bubbles. Small bubbles have a higher pressure than bigger ones, so smallo ones could collapse into the big ones.
In practice, as the alveoli get bigger, because of surfactant the surface tension increases proportionally so they have the same pressure within them.

Question 26

Why can premature babies develop respiratory distress syndrome?

Answer 26

They have little surfactant