Hypaxial muscles of the thoracic body wall

Question 1

External Intercostal: origin/insertion

Answer 1

lower margin of rib to upper margin of lower rib (obliquely forward and downward

Question 2

Internal/innermost Intercostal: origin/insertion

Answer 2

lower margin of rib to upper margin of lower rib (obliquely forward and upward)

Question 3

External intercostal: action

Answer 3

elevates ribs during inspiration stabilizes thoracic wall

Question 4

internal/innermost intercostal: action

Answer 4

depresses ribs during expiration stabilizes thoracic wall

Question 5

Transversus thoracis: origin

Answer 5

body and xiphoid process of sternum

Question 6

Transversus thoracis: insertion

Answer 6

costal cartilages 2-6 (inner surface)

Question 7

Transversus throacis: action

Answer 7

depresses ribs during expiration

Question 8

innervation of all hypaxial muscles of the thoracic body wall

Answer 8

Intercostal nn. (thoracic ventral rami)