Thoracic Wall Muscles

Question 1

Origin and insertion of internal intercostalis

Answer 1

Origin: lower border of ribs
Insertion: upper border of rib below

Question 2

Origin and insertion of Innermost intercostalis

Answer 2

Origin: lower border of ribs
Insertion: upper border of rib below

Question 3

Origin and insertion of Transversus thoracis

Answer 3

Origin: posterior surface of lower sternum and xiphoid
Insertion: inner surface of costal cartilages 2-6

Question 4

Origin and insertion of levator costarum

Answer 4

Origin: transverse processes of T7-T11
Insertion: subjacent ribs between tubercle and angle

Question 5

Action of external intercostals

Answer 5

Elevates ribs in inspiration

Question 6

Action of internal intercostalis

Answer 6

Depress ribs in costal part and elevate ribs in interchondral part

Question 7

Innermost intercostals

Answer 7

Elevate ribs

Question 8

Transversus thoracis action

Answer 8

Depress ribs

Question 9

Subcostalis action

Answer 9

Elevated ribs

Question 10

Levator costarum

Answer 10

Elevated ribs

Question 11

Diaphragm origin and attachment

Answer 11

Origin: xiphoid process, lower 6 costal cartilages, L1-L3 vertebrae

Attachment: converge into central tendon

Question 12

Innervation of diaphragm

Answer 12

Phrenic nerve

Question 13

Action of diaphragm

Answer 13

Draws central tendon down and forward during inspiration

Question 14

Blood supply for diaphragm

Answer 14

Pericardiophrenic, musculophrenic, superior and inferior phrenic arteries

Question 15

Thoracic wall muscles

Answer 15

1. External intercostal
2. Innermost intercostal
3. Internal intercostal
4. Levator costarum
5. Subcostal
6. Transversus thoracis

Question 16

Origin and insertion of External intercostalis

Answer 16

Origin: lower border of ribs
Insertion: upper border of rib below