Part I. M + NAV Of Thoracic Wall

Question 1

4 muscles of thoracic wall:

Answer 1

External and internal intercostal m
Innermost intercostal m
Subcostal m
Transversus throacis m

Question 2

How many pair of external intercostal m?

Answer 2

11 pair

Question 3

Where is the location of external intercostal m?

Answer 3

Fill space from tubercles of ribs (posterior) to costochondral joints (anterior)

Most superficial in intercostal space

Question 4

Fiber direction of external intercostal m?

Answer 4

Inferoanterior between 1 rib and the next one inferior to it

Fingers in front pockets

Question 5

Action of external intercostal m?

Answer 5

Elevates ribs in forced inspiration

Maintain tonus in normal respiration

Question 6

External intercostal membrane extends from?

Answer 6

Costochondral joint to sternum

Question 7

How many pair of internal intercostal m?

Answer 7

11 pair

Question 8

Location of internal intercostal m?

Answer 8

Fill space from sternum (anterior) to costal angle (posterolateral)

Middle layer in intercostal space

Question 9

Fiber direction internal intercostal m

Answer 9

Inferoposterior between 1 rib and the next one inferior to it

(Opposite external)

Question 10

Action of internal intercostal m

Answer 10

Depress ribs in forced expiration

Maintain tonus in normal respiration

Question 11

internal intercostal membrane extends from

Answer 11

Costal angle to TPs of vertebrae

Question 12

How many pair innermost intercostal m?

Answer 12

11

Question 13

Location of innermost intercostal m

Answer 13

Fill lateral portion of intercostal space only

Inner layer in intercostal space

Question 14

Fiber direction of innermost intercostal m

Answer 14

Similar to internal — inferoposterior

Question 15

innermost intercostal m is separated from internal intercostal m by

Answer 15

Intercostal NAV

Question 16

Action of innermost intercostal m

Answer 16

Depress ribs in forced expiration

Maintain tonus in normal respiration

Question 17

Location of subcostal m

Answer 17

Internal surface of lower ribs near their angle

Question 18

Fiber angle subcostal m

Answer 18

Very similar to internal intercostal m — inferoposterior

Question 19

Which muscle crosses at least 1 rib to span 2+ intercostal spaces?

Answer 19

subcostal m

Question 20

Action of subcostal m

Answer 20

Weekly depress ribs

Question 21

Location of transversus throacis m?

Answer 21

Inner surface of anterior thoracic wall

Question 22

transversus throacis m spans:

Answer 22

Superolaterally from inferior sternum to 2-6th costal cartilages

Question 23

Action of transversus throacis m

Answer 23

Weakly depress ribs

May function in proprioception

Question 24

Where are typical intercostal nerves?

Answer 24

3rd through 6th

Question 25

Where are the 12 pair of thoracic spinal nerves? And what do they become?

Answer 25

Ventral rami fo T1-T11 spinal nerves become Intercostal N Ventral rami T12 spinal nerves become Subcostal N

Question 26

Dorsal rami pass posteriorly to innervate:

Answer 26

Vertebrae, joints, muscles and skin

Question 27

What is the motor innervation of typical intercostal n?

Answer 27

Intrinsic muscle of thoracic wall

Question 28

What is the sensory innervation of typical intercostal n?

Answer 28

To dermatome skin regions

Question 29

5 branches of typical intercostal n

Answer 29

``` Collateral branch Lateral cutaneous branch Anterior cutaneous branch Muscular branch Rami communicantes ```

Question 30

Where is the collateral branch of typical intercostal n?

Answer 30

Starts near angle of rib and passes along superior margin of lower rib

Question 31

What does collateral branch of typical intercostal n innervate?

Answer 31

Intercostal muscles and parietal pleura

Question 32

Where is lateral cutaneous branch of typical intercostal n?

Answer 32

Enters superficial fascia in midaxillary line

Question 33

What does the lateral cutaneous branch of typical intercostal n innervate?

Answer 33

Sensory - skin in lateral thoracic region

Question 34

Where is the anterior cutaneous branch of typical intercostal n?

Answer 34

Enters superficial fascia in parasternal line

Question 35

Where does the anterior cutaneous branch of typical intercostal n innervate?

Answer 35

Sensory — skin in anterior thoracic region

Question 36

What does the muscular branch of typical intercostal n innervate?

Answer 36

Motor — intrinsic muscle of thoracic wall

Question 37

What is the rami communicantes of typical intercostal n?

Answer 37

Sympathetic connections between intercostal nerve and sympathetic trunk

Question 38

What does the white ramus of the rami communicantes of typical intercostal n contain?

Answer 38

Presynaptic fibers leaving nerve to enter ganglion

Question 39

What does the gray ramus of the rami communicantes of typical intercostal n contain?

Answer 39

Postsynaptic fibers leaving ganglion to enter nerve

Question 40

Where are thoracoabdominal nerves?

Answer 40

7th-11th intercostal nerves

Question 41

What do thoracoabdominal nerves do?

Answer 41

Cross costal margin passing from thorax to abdomen

Question 42

What do thoracoabdominal nerves innervate?

Answer 42

Abdominal skin and musculature

Question 43

Is it intercostal nerves or arteries that can be posterior or anterior?

Answer 43

Arteries (the nerve is simply Intercostal n.)

Question 44

Where does the internal thoracic artery branch from and where does it bifurcate?

Answer 44

Subclavian A; Superior Epigastric & Musculophrenic A

Question 45

What space does the internal thoracic artery bifurcate?

Answer 45

6th intercostal space

Question 46

The ___th pair of Anterior Intercostal Arteries branch from_________________ artery while the ___th pair branch from _____________ artery.

Answer 46

1-6th pair branch from Internal Thoracic A | 7-9th pair branch from Musculophrenic A

Question 47

The ___ (number) pair of Posterior Intercostal Arteries branch from_________________ artery while the ___ (number) pair branch from _____________ artery.

Answer 47

1 and 2nd pair branch from Superior Intercostal A (from Costocervical Trunk) 3-11th pair (and Subcostal A) branch RIGHT from Descending Thoracic Aorta

Question 48

The return system is called:

Answer 48

Azygos system

Question 49

What does azygos mean?

Answer 49

Unpaired or single

Question 50

What does the azygos system do overall?

Answer 50

Drains back, thoracoabdominal walls and mediastinal viscera Provides alternate route for venous return from lower body (if needed)

Question 51

The azygos v ascends at what location:

Answer 51

Posterior mediastinum on right side of T4-T12

Question 52

Where does the azygos v drain?

Answer 52

Superior Vena Cava

Question 53

Where does azygos v receive blood

Answer 53

Right 4th-11th posterior intercostal veins

Question 54

Where is the hemiazygos v located?

Answer 54

It ascends posterior mediastinum on left side of T9-T12

Question 55

At T9 what happens to Hemiazygos v?

Answer 55

Crosses vertebral bodies to drain into azygos v

Question 56

Where does the hemiazygos v receive blood from?

Answer 56

9th-11th posterior intercostal vv

Question 57

Accessory hemiazygos v is located where?

Answer 57

Descends posterior mediastinum on left side of T5-T8

Question 58

At about T8 what happens to the Accessory Hemiazygos v?

Answer 58

Crosses vertebral body to drain into Azygos V. | Sometimes joins Hemiazygos V

Question 59

Accessory hemiazygos v receives blood from

Answer 59

Left 4th-8th posterior intercostal vv

Question 60

Where does the Superior Intercostal V receive blood from?

Answer 60

1-3rd Posterior Intercostal Vv

Question 62

What does the Superior Intercostal V drain into on the Right?

Answer 62

Azygos V

Question 63

The breast is innervated by

Answer 63

Anterior and lateral cutaneous branches of 2-6th Intercostal N

Question 64

What does the Superior Intercostal V drain into on the Left?

Answer 64

Accessory Hemiazygos V or L Brachiocephalic V

Question 65

The dorsal branches of the posterior intercostal arteries, supply what?

Answer 65

vertebral column, back muscles and skin