Thoracic Wall Muscles

Question 1

Sternocleidomastoid Origin

Answer 1

lateral surface of mastoid process of temporal bone and lateral half of superior nuchal line

Question 2

Sternocleidomastoid Insertion

Answer 2

Sternal head: anterior surface of manubrium of sternum
Clavicular head: superior surface of medial third of clavicle

Question 3

Sternocleidomastoid Innervation

Answer 3

spinal accessory nerve (CN XI; motor), C2 and C3 nerves (pain and proprioception)

Question 4

Sternocleidomastoid Action

Answer 4

Unilateral – laterally flexes neck and rotates if so face is turned superiorly toward opposite side
Bilateral – extend neck at atlantooccipital joint; flexes cervical vertebrae; extend superior cervical vertebrae while flexing inferior vertebrae; may elevate manubrium

Question 5

Sternocleidomastoid Arterial Supply

Answer 5

Occipital, posterior auricular (ear), superior thyroid, and suprascapular arteries

Question 6

Serratus Posterior Superior Origin

Answer 6

Nuchal ligament, spinous processes of C7 to T3 vertebrae

Question 7

Serratus Posterior Superior Insertion

Answer 7

Superior borders of 2nd to 4th ribs

Question 8

Serratus Posterior Superior Innervation

Answer 8

2nd to 5th intercostal nerves

Question 9

Serratus Posterior Superior Action

Answer 9

Proprioception (elevate ribs)

Question 10

Serratus Posterior Superior Arterial Supply

Answer 10

upper posterior intercostal arteries

Question 11

Serratus Posterior Inferior Origin

Answer 11

Spinous processes of T11 to L2 vertebrae

Question 12

Serratus Posterior Inferior Insertion

Answer 12

Inferior borders of 8th to 12th ribs near their angles

Question 13

Serratus Posterior Inferior Innervation

Answer 13

Anterior rami to T9 to T12 thoracic spinal nerves

Question 14

Serratus Posterior Inferior Action

Answer 14

Proprioception (depress ribs- forced expiration)

Question 15

Serratus Posterior Inferior Arterial Supply

Answer 15

lower posterior intercostal arteries and subcostal artery

Question 16

Levatores costarum Origin

Answer 16

Transverse processes of C7-T11

Question 17

Levatores Costarum Insertion

Answer 17

Subjacent ribs between tubercle and angle

Question 18

Levatores Costarum Innervation

Answer 18

Posterior primary rami of C8-T11 nerves

Question 19

Levatores Costarum Action

Answer 19

Elevate ribs

Question 20

Levatores Costarum Arterial Supply

Answer 20

posterior intercostal arteries

Question 21

External Intercostal Origin

Answer 21

Inferior border of ribs

Question 22

External Intercostal Insertion

Answer 22

Superior border of ribs below

Question 23

External Intercostal Innervation

Answer 23

Intercostal nerve

Question 24

External Intercostal Action

Answer 24

Elevate ribs during forced inspiration

Question 25

External Intercostal Arterial Supply

Answer 25

posterior intercostal arteries , internal thoracic artery and musculophrenic artery

Question 26

Internal Intercostal Origin

Answer 26

Inferior border of ribs

Question 27

Internal Intercostal Insertion

Answer 27

Superior border of ribs below

Question 28

Internal Intercostal Innervation

Answer 28

Intercostal nerve

Question 29

Internal Intercostal Action

Answer 29

Interosseous part: depresses ribs during active (forced) respiration

Question 30

Internal Intercostal Arterial Supply

Answer 30

posterior intercostal arteries, internal thoracic artery and musculophrenic artery

Question 31

Innermost Intercostal Origin

Answer 31

Inferior border of ribs

Question 32

Innermost Intercostal Insertion

Answer 32

Superior border of ribs below

Question 33

Innermost Intercostal Innervation

Answer 33

Intercostal Nerve

Question 34

Innermost Intercostal Action

Answer 34

lnterchondral part: elevates ribs during active (forced) respiration

Question 35

Innermost Intercostal Arterial Supply

Answer 35

posterior intercostal arteries, internal thoracic artery and musculophrenic artery

Question 36

Subcostal Origin

Answer 36

Internal surface of lower ribs near their angles

Question 37

Subcostal Insertion

Answer 37

Superior borders of 2nd or 3rd ribs below

Question 38

Subcostal Innervation

Answer 38

Intercostal nerve

Question 39

Subcostal Action

Answer 39

Probably act in same manner as internal intercostal muscles (depresses ribs during active respiration

Question 40

Subcostal Arterial Supply

Answer 40

posterior intercostal arteries

Question 41

Transverse Thoracic Origin

Answer 41

Posterior surface of lower sternum

Question 42

Transverse Thoracic Insertion

Answer 42

Internal surface of costal cartilages 2-6

Question 43

Transverse Thoracic Innervation

Answer 43

Intercostal nerve

Question 44

Transverse Thoracic Action

Answer 44

Weakly depress ribs

Question 45

Transverse Thoracic Arterial Supply

Answer 45

internal thoracic artery

Question 45

Diaphragm Origin

Answer 45

L1- L3 vertebral bodies, inner surface of ribs 7- 12, xiphoid process

Question 46

Diaphragm Insertion

Answer 46

Central tendon

Question 47

Diaphragm Innervation

Answer 47

Phrenic nerve C3, C4, C5

Question 48

Diaphragm Action

Answer 48

Upon contraction, the diaphragm descends & increases the height of the thoracic wall

Question 49

Diaphragm Arterial Supply

Answer 49

musculophrenic artery and subcostal arteries and intercostal artery