Intercostals, transversus thoracis

Question 1

Innervation of intercostals?

Answer 1

1st to 11th intercostal n.

Question 2

Action of external intercostals?

Answer 2

Raises ribs (inspiration)
Supports intercostal space, stabilizes chest wall

Question 3

Origin/insertion of Internal & Innermost intercostals?

Answer 3

Lower margin of rib to upper margin of next inferior rib (courses obliquely forward and upward from costal angle to sternum

Question 4

Action of internal & Innermost intercostals?

Answer 4

Lowers ribs (expiration)

Supports intercostal spaces, stabilizes chest wall

Question 5

Origin/insertion of External intercostals?

Answer 5

Lower margin of rib to upper margin of the next inferior rib

Courses obliquely forward and upward from costal angle to sternum

Question 6

Origin of Transversus thoracis?

Answer 6

sternum and xiphoid process (inner surface)

Question 7

Insertion of transversus thoracis?

Answer 7

2nd to 6th ribs (costal cartilage, inner surface)

Question 8

Innervation of transversus thoracis?

Answer 8

2nd to 6th intercostal n.

Question 9

Action of transversus thoracis?

Answer 9

Weakly lowers ribs (expiration)