2/ICA is like a staircase—winding up through important anatomic regions like a staircase winding up to each floor
Lobby is the neck. First floor is skullbase/carotid canal. Next it stops at the cavernous sinus, before finally reaching the rooftop balcony of the intradural space
3/ICA is divided into numbered segments based on landmarks that denote transitions on its way up the floors.
C1 is in the lobby or neck.
You can remember this b/c the number 1 looks elongated & straight like a neck
4/C2 is the petrous or horizontal segment. This is where the ICA gets to the next floor, the skullbase
I remember this b/c the ICA makes a curve forward here, like a swan’s neck--and number 2 has a forward, swan like curve that looks just like the curve of the petrous segment
5/C3 is the lacerum segment—from above foramen lacerum to petrolingual ligament.
It’s easy to remember b/c lacerum comes from the latin word for torn (b/c foramen lacerum is irregular like a tear or laceration)
Number 3 zig zags like a laceration or torn edge, so C3 = lacerum
6/C4 is the cavernous segment
Cavernous segment has the anterior genu. Here, the ICA makes a curve back, so it looks like a knee (genu is latin for knee)
You can remember C4 is cavernous bc the number 4 has a curve back like the anterior genu of the cavernous ICA, like a knee
7/C5 is the clinoid segment—at the ant. clinoid process
Clinoid process gets its name from its sloped shape. It’s from the same latin root as recline (CLIN)
And we all take a break (take five some might say😉) by sitting back or reclining
Take FIVE & reCLINE. C5 is CLINoid
8/C6 is the ophthalmic segment.
I remember this b/c the circle of the number 6 looks like eyes and its curve looks like eyebrows.
So 6 is an eye = ophthalmic
9/C7 is the communicating or terminal segment
You can remember this bc the number 7 looks like the ICA ending & giving off the PCOMM
The number 7 has the shape of a turn off right before the road ends—& the ICA gives off the PCOMM in its C7 segment right before terminating
10/Now you can remember all the segments of the ICA!
Hopefully this will help you to be precise in your localization and siphon away the term “carotid siphon”!!
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1/Having trouble remembering what you should look for in vascular dementia on imaging?
Almost everyone worked up for dementia has infarcts. Which ones are important?
Here’s a thread on the key findings in vascular dementia!
2/Vascular cognitive impairment, or its most serious form, vascular dementia, used to be called multi-infarct dementia.
It was thought dementia directly resulted from brain volume loss from infarcts, w/the thought that 50-100cc of infarcted related volume loss caused dementia
3/But that’s now outdated. We now know vascular dementia results from diverse pathologies that all share a common vascular origin.
It’s possible to lose little volume from infarct & still result in dementia.
So if infarcts are common—which contribute to vascular dementia?