0:00

So the next case of an anatomic variant, we're going to be discussing the

0:03

persistent sciatic artery. This is a 66-year-old

0:07

male with an incidental finding that was seen on a CT abdomen that

0:11

led to a CT angio runoff order.

0:15

So as we're starting down, that's the aorta and its branches as we're taking

0:19

off. I like a wider window width than level as I'm approaching these

0:23

scans. And so as I'm scrolling down, the last inferior

0:27

mesenteric artery branch has just come off, and we will see that aorta

0:30

bifurcating into the two common iliac arteries.

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Focusing on the left side here, we can see that common iliac

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artery bifurcated into the external and internal

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iliac artery that then

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kind of proceeded, and the external iliac artery then

0:49

continues as the common femoral artery and then

0:53

bifurcates into a superficial and a deep femoral or a

0:56

profunda femoral artery, which are normal in caliber.

0:59

However, when we look at the contralateral side,

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this right common iliac artery, it bifurcated into an external and an

1:07

internal iliac artery.

1:10

This internal iliac artery is quite large in caliber,

1:14

especially when you compare it to that contralateral side right

1:17

here.

1:19

And it's seen coursing through that greater sciatic foramen,

1:22

exiting

1:24

that greater sciatic foramen and continuing in that gluteal space.

1:28

There's an enlargement of that artery right here with an aneurysmal

1:32

formation and a filling defect in that aneurysmal sac that's an

1:36

associated thrombus. And then this artery

1:39

continues down to the back of the thigh, going all the way down

1:43

along the thigh at the back.

1:45

And that's in the mid-thigh, and it is

1:49

going to go all the way down up until the knees, and then

1:53

at the level of the knee.

1:56

Under the level of the knee, it then bifurcates and gives rise to the anterior

1:59

tibial artery and then a short tibioperoneal trunk.

2:03

Going back up to see the branches of the external iliac

2:07

artery. So looking at that external iliac artery again,

2:11

the right external iliac artery

2:15

then bifurcated to give rise to a deep or a profunda femoral

2:19

artery and a superficial femoral artery.

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Now, you'll notice that the superficial femoral artery is much smaller in size

2:25

compared to the deep femoral artery, as well as compared to the contralateral

2:29

superficial femoral artery.

2:31

And so as we're going down, this superficial femoral

2:35

artery remains hypoplastic in its entirety.

2:38

And really the dominant outflow

2:41

vessel for that right lower extremity is this

2:45

persistent sciatic artery, which was a continuation of the internal

2:49

iliac artery. And this superficial femoral artery

2:52

never really formed the popliteal artery, and it just kind of peters out.

2:56

So the dominant supply in this person, even though it's rare, is

3:00

this persistent sciatic artery, which has a tortuous

3:03

course, and there's a hypoplastic superficial femoral artery.