Movements of thoracic wall:

Question 1

Movements of thoracic wall:

Answer 1

Changes during inspiration and expiration: when intercostal muscles contract

Question 2

Question 3

Movement from front to back – Anterior posterior dimension

Answer 3

• Superior and anterior movement of the sternum- similar to a pump handle
• The angle increases in the Anterior posterior dimension
• This movement is mainly ribs 2-6 and the lower end of the sternum

Question 4

Movement in the Transverse dimension:

Answer 4

• Increases - elevation of lateral shaft of rib (like bucket handle movement)
• Raising lateral-most parts of ribs (especially lower ribs)

Question 5

Movement from front to back - Anterior posterior dimension

and Movement in the Transverse dimension:

Answer 5

These movements in these directions increases the vertical thoracic dimensions
= the height

Question 6

Contraction of diaphragm

Answer 6

• domes flatten
• Increases vertical thoracic dimension = height
• Compresses abdominal viscera

Question 7

Relaxation of diaphragm

Answer 7

• domes elevate
• vertical thoracic dimension return to neutral
• abdominal viscera no longer compressed

Question 8

The phrenic nerve

Answer 8

C3, C4, C5 keeps the diaphragm alive

Question 9

What happens if the phrenic nerve is damaged?

Answer 9

Remember:
There’s two muscular domes of the diaphragm (left and right)
and 2 phrenic nerves (one on left and one on right)
- If only one nerve is damaged - then the one dome of the
diaphragm wont work = will be paralysed
- If damaged, the dome will move UP (not sloped)
Because the abdominal organs are being pushed down by the other side (the working side/ dome) when it contracts (inspiration) = and when it pushes down, it pushes the organs up into the other side (paralyzed dome)
-The damaged lung will descend during expiration due to the positive pressure