Anatomy of the thorax

Question 1

Why is a thoracocentesis done? Where is the needle inserted and why?

Answer 1

Take samples of pleural fluid
Needle is inserted into 9th intercostal space mid-axillary line during expiration
Intercostal space to avoid intercostal nerve damage
during expiration to avoid the inferior border of the lung

Question 2

Where is a chest drain usually done?

Answer 2

5th intercostal space, mid-axillary line

Question 3

What are the borders for the ‘safe triangle’ (not really a triangle) for chest drain?

Answer 3

1. apex below axilla
2. lateral border of pec major
3. a line superior to the horizontal level of the nipple
4. anterior border of latissimus dorsi

Question 4

When will the pleura of the lungs be visible on CXR?

Answer 4

If there is a pneumothorax
- costophrenic angle is usually distinct and sharp, but becomes blunt when there is a build up of fluid in the pleural space

Question 5

What happens to the structure and function of the lungs in emphysema?

Answer 5

There is destruction of alveolar walls –> permanent enlargement of air spaces
Surface area is reduced = less gas exchange
Loss of elastic tissue = less recoil
Bronchioles are narrowed = air becomes trapped