Thoracic Wall

Question 1

External Intercostals

Answer 1

O: Inferior margin of rib above
I: Superior margin of rib below
N: Intercostal nerves
A: most active during inspiration; supports intercostal space; moves ribs superiorly

Question 2

Internal Intercostals

Answer 2

O: Lateral edge of costal groove of rib above
I: Superior margin of rib below
N: Intercostal nerves
A: move active during expiration; supports intercostal space; moves ribs inferiorly

Question 3

Innermost intercostals

Answer 3

O: Medial edge of costal groove of rib above
I: Internal aspect of superior margin of rib below
N: Intercostal nerves
A: Acts with internal intercostal muscles

Question 4

Subcostal

Answer 4

O: Internal surface (near angle) of lower ribs
I: Internal surface of second or third rib below
N: Related intercostal nerves
A: Depress ribs

Question 5

Transversus thoracis

Answer 5

O: Inferior margins and internal surfaces of costal cartilages of second to sixth ribs
I: Inferior aspect of deep surface of body of sternum, xiphoid process & costal cartilage ribs 4-7
N: Related intercostal nerves
A: Depresses costal cartilages