Anatomy and Ventilation

Question 1

Can we palpate the first rib?

Answer 1

No

Question 2

What part of the anatomy allows us to do chest compressions?

Answer 2

Costal cartilages (allow some give)

Question 3

How many ribs on each side of direct connections to the sternum?

Answer 3

7 ribs

Question 4

How many ‘false’ ribs do we have on each side?

Answer 4

3

Question 5

How many floating ribs are there on each side?

Answer 5

2 (ribs 11 and 12)

Question 6

How far does the diaphragm move in breathing?

Answer 6

Can move one and a half intercostal spaces

Question 7

Describe the diaphragm

Answer 7

Fibromuscular membrane separating the abdomen from the thorax
Neurovascular structures pass through the central part
The heart sits on the central tendon of the diaphragm

Question 8

Describe the external intercostal muscles

Answer 8

Fibres run in the direction of putting hands in pockets
Same direction as external obliques in abdomen
Pull the ribs up when they contract
(First rib is tethered by other muscles therefore acts as an anchor point)

Question 9

Describe the internal intercostals

Answer 9

Fibres run perpendicular to external intercostals

Pull the ribs down on contraction

Question 10

Describe the innermost intercostal

Answer 10

Thin, weak, hard to see
Mostly found laterally on the thorax
Fibres run parallel to internal intercostals therefore actions are the same - pull ribs down on contraction
Exercise increases the amount of intercostals you need

Question 11

Where do the structures cross the diaphragm?

Answer 11

Vena cava = T8
Oesophagus = T10
Aorta = T12 (aortic hiatus)

Question 12

Where are the neurovascular bundles in the ICSs?

Answer 12

Thick bundles at the top of ICS

Therefore insert needles into the bottom of ICS

Question 13

What do the thick bundles in the ICSs usually contain?

Answer 13

Posterior intercostal artery
Posterior intercostal vein
Intercostal nerve

Question 14

Describe the venous drainage of the thoracic cavity

Answer 14

Posterior of thoracic cavity we have the azygous venous system
Main azygous vein found to right of vertebral bodies
Collects blood from ICSs via hemiazygous and accessory hemiazygous veins
Drains into SVC

Question 15

Describe the phrenic nerves

Answer 15

C3, 4 and 5
Control the diaphragm
Motor nerves but also sensory (caused of referred pain)
Run anterior to hilum of the heart

Question 16

Foreign bodies tend to go in which direction when inhaled and why?

Answer 16

Right lung

Right main bronchus is at a much less acute angle than the left main bronchus

Question 17

What provides the dual blood supply to the lungs?

Answer 17

Pulmonary arteries

Bronchial arteries

Question 18

How does the diaphragm move in ventilation?

Answer 18

Contracts (moves down) in inspiration

Relaxes in expiration

Question 19

Describe the process for how the air enters the lungs

Answer 19

Inspiratory muscles contract
Thoracic cavity expands
Pleural pressure becomes more negative
Lungs inflate
Alveolar pressure becomes subatmospheric
Air flows into the lungs until they equal atmospheric pressure

Question 20

If everything wasn’t stuck together well, where would the lungs, thoracic cage and diaphragm move?

Answer 20

Lungs - in and up
Thoracic cage - out
Diaphragm - down

Question 21

What are the stages of the respiratory cycle?

Answer 21

1. Inspiration
2. Rest
3. Expiration
4. Pause

Question 22

What is the average tidal volume?

Answer 22

0.5L (500ml)

Question 23

The intrapleural pressure is always …

Answer 23

Negative

Question 24

What is the average air flow?

Answer 24

1 litre per second (decreases with age)

Question 25

Describe forced expiration

Answer 25

Beyond the resting expiratory level
Use of the abdominal muscles and the internal intercostal
Occurs during exercise, respiratory obstruction and some disease states

Question 26

Define the residual volume

Answer 26

Amount of air that can never be expelled from the lungs

Question 27

What percentage of the oxygen you breathe in each breath gets to the alveoli?

Answer 27

20%

Question 28

Define the inspiratory capacity

Answer 28

Inspiratory reserve volume + tidal volume

Question 29

Give some reasons why the diaphragm may not be able to move into the abdomen as easily

Answer 29

Pregnancy
Obesity (fat is not compressible)
Corsets

Question 30

Which muscles are used in forced inspiration?

Answer 30

Diaphragm 
External intercostals
Sternocleidomastoid 
Scalene 
Serratus anterior 
Pectoralis major

Question 31

What muscles are used in forced expiration?

Answer 31

Internal intercostals
External oblique
Internal oblique
Rectus abdominus