Muscles of the Thorax that Assist In Breathing

Question 1

Diaphragm

Answer 1

O-Costal attachment: inner surface of the lower six ribs
Lumbar attachment: upper two or three lumbar vertebrae
Sternal attachment: inner part of xiphoid process

I- Central tendon

A- Draw down the central tendon of the diaphragm
Increases the volume of the thoracic cavity during inhalation

N-Phrenic C3, 4, 5

Question 2

External intercostals

Answer 2

O-Inferior border of the rib above

I- Superior border of the rib below

A- Draw the ribs superiorly [increasing the space of the thoracic cavity] to assist with inhalation

N- Thoracic

Question 3

Internal intercostals

Answer 3

O-Inferior border of the rib above

I-Superior border of the rib below

A-Draw the ribs inferiorly [decreasing the space of the thoracic cavity] to assist with exhalation

N-Thoracic