Thoracic Vasculature

Question 1

What is the initial source of blood supply to the thorax?

Answer 1

Aorta and subclavian arteries

Question 2

What parts of the thorax does the aorta supply?

Answer 2

-posterior intercostal arteries
-bronchial arteries

Question 3

What parts of the thorax do the subclavian arteries supply?

Answer 3

the internal thoracic artery (which goes on to supply anterior intercostal arteries!)

The subclavian artery drops off a branch (before it heads out and supplies the upper extremities) this branch is the internal thoracic artery
-The branch supplies the intercostal arteries

Question 4

What does the internal thoracic (mammary) artery emerge from?

Answer 4

subclavian artery

Question 5

Where does the internal thoracic (mammary) artery descend?

Answer 5

along the anterior thoracic wall

Question 6

What branches off of the internal thoracic artery? What do the branches supply?

Answer 6

-anterior intercostal arteries will branch off of the internal thoracic artery
-these anterior intercostal arteries supply each intercostal space

Question 7

What is the internal thoracic (mammary) artery renamed once is descends to the abdominal region?

Answer 7

Superior epigastric artery

Question 8

What artery ascends forms an anastomosis with the superior epigastric artery? What is the branch of the artery named which forms the anastomosis?

Answer 8

The external iliac artery ascends to form the anastomosis
The name of the branch that comes off the iliac artery and will form this anastomosis is called the inferior epigastric artery

**Mother Nature’s Plan B for blood flow to get to the iliac system/lower extremities/pelvis:
-Blood can flow from the subclavian artery and through the superior epigastric in order to supply the iliac system through this anastomosis

Question 9

What do intercostal arteries supply?

Answer 9

The rib cage through the intercostal arteries

Question 10

What does the posterior intercostal artery emerge from?

Answer 10

thoracic aorta

Question 11

What does the anterior intercostal artery emerge from?

Answer 11

internal thoracic artery

Question 12

Where does the anterior intercostal artery enter once it emerges from the internal thoracic artery?

Answer 12

the anterior intercostal space

Question 13

Where does the posterior intercostal artery enter once it emerges from the thoracic aorta?

Answer 13

the posterior intercostal space

Question 14

What do the anterior and posterior intercostal arteries operate as?

Answer 14

One continuous loop to supply blood to the intercostal space

Question 15

Which artery is sometimes used as a graft for a coronary artery bypass graft (CABG)?

Answer 15

The internal thoracic (mammary) artery

Question 16

How does a CABG work?

Answer 16

Plaque build up will block blood flow in coronary artery
-the internal thoracic (mammary) artery will be cut and reattached to the coronary artery just distal to the point of occlusion
-this will re-route bloodflow (blood will come from the subclavian and then flow through the internal thoracic artery and allow blood to get back into coronary circulation)

Question 17

What supplies the airways/lungs (trachea, bronchi, bronchioles, etc.)?

Answer 17

Bronchial arteries

Question 18

What do the right and left bronchial arteries emerge from?

Answer 18

The upper thoracic aorta, these right and left bronchial arteries will then make their way along the airways/bronchioles!

Question 19

What do intercostal veins (in intercostal spaces) drain into?

Answer 19

The azygos system

Question 20

What are the three veins of the azygos system?

Answer 20

-Azygos vein
-Hemi-azygos vein
-Accessory hemi-azygos vein

Question 21

Where is the azygos vein loacted?

Answer 21

Right side of vertebral column, it will head up and plug into to the SVC and drain/return blood back to the heart

Question 22

What does the azygos vein directly drain blood from?

Answer 22

All intercostal veins on the RIGHT side of the rib cage

Question 23

What does the azygos vein indirectly drain blood from?

Answer 23

Intercostal spaces on the LEFT side of the rib cage (via the hemiazygos and accessory hemiazygos veins)

Question 24

What does the azygos vein drain into?

Answer 24

SVC (superior vena cava) which will return blood to the heart

Question 25

What drains the blood from the LEFT side 1st-4th (top) intercostal veins?

Answer 25

The left brachiocephalic vein

Question 26

Where is the accessory hemi-azygos vein located?

Answer 26

LEFT side of the vertebral column (above hemi-azygos)

Question 27

What LEFT side intercostal veins does the accessory hemi-azygos vein drain blood from?

Answer 27

LEFT side 5th-8th intercostal veins

Question 28

Where is the hemi-azygos vein located?

Answer 28

LEFT side of vertebral column (below accessory hemi-azygos)

Question 29

What LEFT side intercostal veins does the hemi-azygos vein drain blood from?

Answer 29

LEFT side 9th-11th intercostal veins

Question 30

Which vein crosses the midline and drains into the azygos vein?

Answer 30

BOTH the accessory hemi-azygos vein and the hemi-azygos vein

Question 31

What other parts of the body does the azygos system drain blood from (other than intercostal)?

Answer 31

Lower trunk, pelvis, lower extremeties

Question 32

What pathway does the azygos system act as if needed?

Answer 32

Acts as a collateral pathway to bypass the IVC (inferior vena cava) if necessary
The IVC will drain veins from the iliac system (veins of lower extremities/pelvis)
Yet if it is compromised, the azygos system is also attached to the iliac system by the lumbar veins
SO, the azygos system can drain the lower extremities and pelvis if necessary/return the blood to the heart!