Muscle Chart: Intercostal Musculature

Question 1

External Intercostal (11 paired muscles)

Origin, Insertion, Innervation, Blood Supply

Answer 1

Superior: Inferior border of rib above at the tubercle of rib

Inferior: To superior border of rib below at the costal cartilage

Fibers follow same orientation as oblique muscles

Innervation: Intercostal nerve for corresponding level

Blood Supply: Intercostal artery

Question 2

External Intercostal Movements

Answer 2

Elevates ribs during forceful inhalation

Question 3

Internal Intercostal (11 paired muscles)

Origin, Insertion, Innervation, Blood Supply

Answer 3

Superior: Inferior border of rib above at the cartilage between the ventral side of ribs

Inferior: To angle of the rib below

Fibers follow same orientation as internal oblique muscle

Innervation: Intercostal nerve of corresponding level

Blood Supply: Intercostal artery

Question 4

Internal Intercostal Movements

Answer 4

Depress ribs during exhalation

Question 5

Innermost Intercostal (11 paired muscles)

Origin, Insertion, Innervation, Blood Supply

Answer 5

Superior: Inferior border of rib above at the cartilage between the ventral side of ribs

Inferior: To angle of the rib below

Innervation: Intercostal nerve of corresponding level

Blood Supply: Intercostal artery

Same as internal intercostal!

Question 6

Innermost Intercostal Movements

Answer 6

Maintains tension on the parietal pleura during respiration

Question 7

Levator Costarum

Origin, Insertion, Innervation, Blood Supply

Answer 7

Origin: Transverse processes of C7-T11

Insertion: Sub adjacent ribs between tubercle and angles

Innervation: Intercostal nerve of corresponding levels

Blood Supply: Intercostal artery

Question 8

Levator Costarum Movements

Answer 8

Elevate ribs during forceful inhalation

Question 9

Transversus Thoracis

Origin, Insertion, Innervation, Blood Supply

Answer 9

Origin: Posterior surface of lower sternum

Insertion: Internal surface of costal cartilages 2-6

Innervation: Intercostal nerve of corresponding level

Blood Supply: Intercostal artery

Question 10

Transversus Thoracis Movements

Answer 10

Depress ribs during exhalation