ICL 4.3: Upper Extremity Vasculature

Question 1

which arteries does the aorta give rise to?

Answer 1

on the left side, the aorta gives rise to the left subclavian artery and the left common carotid artery

on the ride side, the ascending aorta gives rise to the brachiocephalic trunk –> the brachiocephalic trunk then divides into the right common carotid artery and the right subclavian artery

Question 2

what is the major artery that supplies the upper extremities?

Answer 2

right subclavian artery

Question 3

what does the subclavian artery travel along side of?

Answer 3

the subclavian artery travels with the brachial plexus posterior to the anterior scalene muscle and anterior to the middle and posterior scalene muscles

they then enter the cervical axillary passageway to get to the upper extremity

so it travels between the anterior and middle scalene muscles which both attach to rib 1

Question 4

what are the 3 parts of the subclavian artery?

Answer 4

these were all named in relationship to the anterior scalene muscle

1. medial section

the medial section branches off into the vertebral artery, thyrocervical trunk, internal thoracic artery and costocervical trunk

2. posterior section
3. lateral section

Question 5

what are the branches of the thyrocervical trunk?

Answer 5

they thyrocervical trunk is a branch of the medial portion of the subclavian artery; then the thyrocervical trunk branches into:

1. supra scapular artery
2. transverse cervical artery

then the transverse cervical artery branches into the dorsal scapular artery and the superficial cervical artery

Question 6

what is the pathway of the suprascapular artery? what does it travel along side of?

Answer 6

it travels along with the suprascapular nerve which originates from C5 and C6 = superior trunk of the brachial plexus

the suprascapular nerve travels to the supraspinatus and infraspinatus through the scapular notch = entrapment location

but the supra scapular artery travels over the scapular notch to supply blood to the supraspinatus and infraspinatus

“airforce goes over while navy goes under”

Question 7

what is the course of the transverse cervical artery?

Answer 7

it travels right over, anterior to the anterior scalene

this then branches into the superficial cervical artery and dorsal scapular artery

Question 8

where do you find the dorsal scapular artery?

Answer 8

medial segment of the subclavian artery –> thyrocervical trunk –> dorsal scapular artery

however, 75% of the time, the dorsal scapular artery can come off of the lateral segment of the subclavian artery –> it then goes between the superior and middle trunks of the brachial plexus**

Question 9

what is the relationship between the axillary artery and the subclavian artery?

Answer 9

the subclavian artery BECOMES the axillary artery

once subclavian hits the lateral border of rib 1 it becomes the axillary artery

Question 10

what are the segments of the axillary artery?

Answer 10

it’s divided into thirds by the pectoralis minor muscle at its attachment to the coracoid process

pec minor attaches to ribs 3-5 and attaches to coracoid process so if you peel it back you’ll see all 3 segments of the axillary artery! the pec minor is your landmark!

Question 11

what is anastomosis?

Answer 11

a connection of two arteries

Question 12

what is one of the most clinically important anastomosis in the body?

Answer 12

the scapular arterial anastomosis

this is important because lets say there’s damage to the 2nd region of the axillary artery, then you can bypass this damage through collateral circulation!

the arterial anastomosis provides increased protection for circulation around the shoulder to supply the arm, forearm and hand – the collateral circulation allows supply of the 3rd part of the axillary artery in the event of occlusion of the 2nd part

so the 3rd segment of the axillary artery (subscapular artery) is communicating with the 1st segment of the subclavian (dorsal scapular artery)

in the event of a slowly occurring occlusion, blood flow of the subscapular artery reverses direction, providing circulation to the third part

but if there’s rapidly occurring occlusion like with trauma, blood flow through that collateral pathway might not be enough to sustain viability of the limb

Question 13

what are the branches of arteries coming of the 2nd region of the axillary artery?

Answer 13

1. thoracoacromial artery

the thoracoacromial artery then has a bunch of little branches coming off of it that supply the bones and muscles in the area (calcite, acromion, deltoid, pectoral)

2. lateral thoracic artery

runs right down the ribcage on the serratus anterior muscle – the long thoracic nerve also runs down the ribcage and innervates the serrates anterior!

Question 14

what’s the function of the superior thoracic artery?

Answer 14

it’s a branch of the first region of the axillary artery

it supplies the 1st and 2nd intercostal spaces and part of the upper breast

Question 15

what are the branches of arteries coming of the 3rd region of the axillary artery?

Answer 15

1. subscapular artery

it bifurcates and gives rise to the circumflex scapular artery which wraps around the lateral border of the scapula to the back of the scapula – it also gives rise to the thoracodorsal artery

2. anterior circumflex humeral artery (tiny)
3. posterior circumflex humeral artery (huge**)

the anterior and posterior circumflex humeral arteries wrap around the surgical neck of the humerus and anastomose

Question 16

how can you differentiate between the posterior and anterior circumflex humeral arteries?

Answer 16

the posterior circumflex humeral artery is way larger

it becomes posterior by traveling with the axillary nerve through the quadrangular space

Question 17

what are the borders of the quadrangular space?

Answer 17

teres major and minor, long head of the tricep, and the humerus

boundaries include the teres minor superiorly, the long head of the triceps medially, the teres major inferiorly, and the surgical neck of the humerus laterally

Question 18

what is the relationship between the brachial and axillary artery?

Answer 18

the brachial artery is the continuation of the axillary artery

it starts at the inferior border of teres major

it will travel with the median and ulnar nerve through the arm

Question 19

what is the first branch of the brachial artery?

Answer 19

the profounda (deep) brachial artery

its goal is to get into the posterior compartment of the arm where are the extensors are so it actually wraps around and goes through the radial groove along with the radial nerve!

Question 20

what does the brachial artery bifurcate into?

Answer 20

once the brachial artery gets to the cubital fossa at the elbow under the distal biceps muscle ligament, it branches into the ulnar and radial arteries

Question 21

what is the course of the radial artery in the forearm?

Answer 21

it travels with the superficial radial nerve
deep to the brachioradialis muscle

it moves to the posterior hand by crossing the “anatomical snuff box” on the dorsum of the hand

on the anterior wrist, this artery is a common place to draw arterial blood or place a blood pressure catheter

Question 22

what is the course of the ulnar artery in the forearm?

Answer 22

the ulnar artery supplies most of the intermuscular branches and compartments of the anterior forearm

in the distal 2/3 of the forearm it travels with the ulnar nerve and crosses the wrist just lateral to the ulnar nerve superficial to the flexor retinaculum in Guyon’s canal

the ulnar artery meets up with the ulnar nerve after the ulnar nerve passes through the ulnar groove at the medial epicondyle (elbow, funny bone)

Question 23

what are the branches of the ulnar artery?

Answer 23

so the main branch of the ulnar artery distal to the cubital fossa is the common interosseous artery

the common interosseous artery then branches into the anterior and posterior interosseous arteries

they’re called this because they are anterior and posterior to the interosseous membrane between the radius and ulna, respectively

then the anterior interosseous artery pierces the interosseous membrane at the pronator quadratus muscle and forms an anastomosis with the posterior interosseous artery which then supply the median nerve!

Question 24

what are the borders of Guyon’s canal?

Answer 24

the roof is the volar carpal ligament

the floor is the flexor retinaculum (transverse carpal ligament)

Question 25

what does the ulnar artery become once it crosses into the wrist?

Answer 25

the ulnar artery becomes the superficial palmar arch, completed by the superficial palmar branch of the radial artery (anastomosis)

the supply the superficial and deep tissue of the hand

this arch is located just proximal to the distal palm crease, and is separated from the deep arch by the digital flexor tendons and the lumbrical muscles

Question 26

what does the radial artery become once it crosses into the wrist?

Answer 26

deep palmar arch

the radial artery lateral to FCR tendon, passes from anterior to posterior by circling around distal radius, crosses anatomical snuffbox and pierces 1st dorsal interosseous muscle to enter the anterior palm

it becomes the deep palmar arch (which is closed by the deep branch of the ulnar artery), which is located just proximal to the middle palmar crease

Question 27

what is the pathway of the digital arteries?

Answer 27

the common digital arteries branch off of the superficial palmar arch and travel towards the fingers

once the common digital arteries get to the metacarpal-phalangeal joint, they branch off and become the proper digital arteries

HOWEVER, the proper digital arteries do NOT anastomose, the are end arteries!!! so if there is a proximal laceration on the finger, the distal part of the finger won’t get any blood flow from collateral arteries

Question 28

what artery specifically supplies the pointer finger?

Answer 28

radialis indicis

Question 29

what artery specifically supplies the thumb?

Answer 29

1. princeps pollicis

2. dorsalis pollicis

Question 30

what is the Allen’s test?

Answer 30

it’s to verify that the radial and ulnar arteries anastomose in the deep and superficial arches of the hand

1. Occlude both the radial and ulnar arteries at the wrist
2. Have “patient” open and close the hand to drain blood
3. Release the ulnar artery while keeping pressure on the radial artery.
4. Immediate return to normal coloration implies that the ulnar artery is supplying the hand. In this case, the radial artery may be cannulated safely.
5. The test may be repeated with the radial artery released with pressure maintained over the ulnar artery. This implies that the radial artery is supplying the hand

Question 31

what is the venous drainage of the upper limb?

Answer 31

venous drainage occurs in two parallel arranged systems of veins

1. Deep System = deep to circumferential deep fascia (“sausage skin fascia”); capable of handling ALL the venous drainage alone (so you could get rid of the superficial system and you’d still get blood return to the heart)
2. Superficial System =
   within superficial fascia; physiologically, operates to maintain skin temperature; can be eliminated entirely without any adverse effects to the patient, including swelling

Question 32

what is the venae comitantes?

Answer 32

deep veins in all but the most proximal regions of the limbs are arranged intimately around the arteries with two or 2 or 3 linear veins which have frequent anastomoses with each other

when we talk about deep veins, it’s when there are 3 or 4 deep veins wrapping around an artery and there’s tons of little venous connections that loop them together

so sometimes when you can’t find an artery in lab, it might be because it’s covered by the venae comitantes

Question 33

where is the cephalic vein found?

Answer 33

it’s a superficial vein on the lateral side of the arm that does NOT run with an artery

it’s located in the delt-pectoral groove

it needs to be protected in cases of axillary trauma so if you compromise the axillary vein you need a plan B which is actually your cephalic vein!

Question 34

where is the basilic vein found?

Answer 34

it’s a superficial vein that runs down the medial side of the arm

it eventually drains into the axillary vein just like the cephalic vein!!

the axillary vein is actually formed by the basilic and brachial veins coming together –> the axillary vein continues proximally and becomes the subclavian vein at the lateral border of the first rib

Question 35

what is the function if the median cubital vein?

Answer 35

it connects the cephalic and basilica veins!

this is where you draw blood!!!!

Question 36

what are the 3 main superficial veins?

Answer 36

1. cephalic (lateral)
2. basilic (medial)
3. median cubital vein