Level 3 Muscles Overview - Breathing Actions

Question 1

Internal Intercostals

Answer 1

Location:
In between each of the ribs

Action:
- draws the ribs downwards, decreasing the volume of the thoracic cavity when breathing out (expiration)

Origin:
Superior border of each rib

Insertion:
Inferior border of the rib above

Question 2

External Intercostals

Answer 2

Location:
In between each of the ribs

Action:
- lifts the ribs upwards, increasing the volume of the thoracic cavity when breathing in (inspiration)

Origin:
Superior border of each rib

Insertion:
Inferior border of the rib above

Question 3

Diaphragm

Answer 3

Location:
Internal muscle at the bottom of the ribcage, separating the thoracic cavity from the abdominal cavity

Action:
- draws the central tendon down, increasing the volume of the thoracic cavity during inspiration

Origin:
Inner surface of the lower ribs and L1, L2 and L3

Insertion:
Central tendon