Anatomy and Art

a blog by Sara Egner

Blood Flow Out Into The Arm

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Blood gets pumped from the left ventricle, out into the aorta, where it goes either into the brachiocephalic trunk to get to the subclavian artery if it’s going to the right limb, or directly into the subclavian artery if it’s going to the left limb.

From the subclavian artery there is a branch to the vertebral artery, the internal thoracic artery, and the thyrocervical trunk, which has several branches including the suprascapular artery (which gets seen in an axillary dissection at the point where it courses under the suprascapular ligament and goes through the suprascapular notch) and also the transverse cervical artery (which supplies trapezius with it’s superficial branch, and if it splits into a deep branch supplies latissimus dorsi, levalor scapulae, the rhomboids, and more of trapezius).

Then costocervical trunk comes off of what is known as the second part of the subclavian artery.  It branches into a Deep cervical artery, and a supreme intercostal artery.

The third part of the subclavian artery usually has no branches.  But in people who’s transverse cervical arteries don’t split into a superficial and deep branch, you will find the replacement for that deep branch here.  In which case it will be called the dorsal scapular artery and do all the things described above as the deep branch of the transverse cervical artery.

Then once you’ve passed by the first rib, the subclavian artery becomes known as the axillary artery.  There is a popular mnemonic for this part, and it goes Suzi Taylor likes pot and sex (or sex and pot, those last few don’t always line up just perfectly).  So that all goes…
Suzi – Superior (or Supreme) thoracic artery, which supplies the upper thoracic wall
Taylor – Thoracoacromial artery, which branches into an acromial, clavicular, deltoid, and two pectoral branches (you can spot it ‘cuz it looks like a little tuft of arteries bursting out there)
Likes – Lateral thoracic artery, which supplies the lateral thoracic wall
Pot – Posterior circumflex humeral artery (which then travels with the axillary nerve through the quadrangular space – I like to think of Ax smoking pot while he goes through a square environment)
And – Anterior circumflex humeral artery (which is smaller that the posterior one)
Sex – Subscapular artery, which immediately divides into the circumflex scapular artery and thoracodorsal artery.  I’ve labeled this one lastly here, mostly to match the drawing above, but it often comes out before the humeral ones.  you’ll know it by being the one in that last bundle before getting to Teres Minor where there is an immediate branch, and also because it will come off medially toward the scapula as opposed to the circumflex humeral arteries which both go wrapping around the humerus.

After the border of Teres Minor, the major artery becomes known as the brachial artery.  I haven’t drawn that part here, but it will give off the profunda brachii, superior and posterior collateral arteries, and then break into a radial artery and an ulnar artery somewhere around the cubital fossa.

Written by Sara

September 12th, 2009 at 6:31 pm

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