2/When I look at the skullbase veins, I see an angry Santa yelling at me. His eyebrows are raised, his mouth is open, & he has a mustache w/a big beard hanging down.
Each I look at the skullbase, I look for this Santa—bc each part of him is an important venous structure.
3/So let’s start w/Santa’s eyes. The eyes are actually not a venous structure, but an important landmark—foramen ovale, where the V3 trigeminal nerve exit.
I remember ovale is Santa's eyes bc eyes are OVAL, so his eyes are OVALE
4/Next are Santa’s angry raised eyebrows. These are the sphenoparietal sinuses.
I remember these are the eyebrows bc I call them “seen”-oparietal sinuses & you see w/your eyes.
These have this “eyebrow” shape bc they are following the curve of the greater sphenoid wing
5/Sphenoparietal sinuses meet in the middle at the cavernous sinus—like your eyebrows meet in the middle at your nose.
I remember the cavernous sinus & intracavernous sinuses are Santa’s nose bc you dig in a cavern. And where do all kids like to go digging? Their nose! 🤢
6/Right below Santa’s nose is his mustache & this is the basilar plexus, right below the cavernous sinus.
You can remember this bc mustaches are made of a base & handlebars—and the BASE of Santa’s mustache is the BASilar plexus
7/Extending from Santa’s mustache is his beard. These are the petrosal sinuses (inferior & superior), important in many neurosurgical approaches.
You can remember that the PETROsal sinuses make up sides of the beard bc you use PETROleum to smooth the sides of your beard
8/Finally, Santa’s mouth is the marginal sinus. I remember this bc the word marginal sounds like “Aaaargh”—the sound pirates make from their mouth. I call it the Maaaargh—inal sinus
So hopefully this thread has given you some ELF-confidence when it comes to skullbase anatomy!
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@TheAJNR 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
@TheAJNR 3/But that’s now outdated.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?
@TheAJNR 2/In the lumbar spine, it is all about the degree of canal narrowing & room for nerve roots.
In the cervical spine, we have another factor to think about—the cord.
Cord integrity is key. No matter the degree of stenosis, if the cord isn’t happy, the patient won’t be either
@TheAJNR 3/Cord flattening, even w/o canal stenosis, can cause myelopathy.
No one is quite sure why.
Some say it’s b/c mass effect on static imaging may be much worse dynamically, some say repetitive microtrauma, & some say micro-ischemia from compression of perforators
1/Do radiologists sound like they are speaking a different language when they talk about MRI?
T1 shortening what? T2 prolongation who?
Here’s a translation w/an introductory thread to MRI.
2/Let’s start w/T1—it is #1 after all! T1 is for anatomy
Since it’s anatomic, brain structures will reflect the same color as real life
So gray matter is gray on T1 & white matter is white on T1
So if you see an image where gray is gray & white is white—you know it’s a T1
3/T1 is also for contrast
Contrast material helps us to see masses
Contrast can’t get into normal brain & spine bc of the blood brain barrier—but masses don’t have a blood brain barrier, so when you give contrast, masses will take it up & light up, making them easier to see.
1/Asking “How old are you?” can be dicey—both in real life & on MRI! Do you know how to tell the age of blood on MRI?
Here’s a thread on how to date blood on MRI so that the next time you see a hemorrhage, your guess on when it happened will always be in the right vein!
2/If you ask someone how to date blood on MRI, they’ll spit out a crazy mnemonic about babies that tells you what signal blood should be on T1 & T2 imaging by age.
But mnemonics are crutch—they help you memorize, but not understand. If you understand, you don’t need to memorize
3/If you look at the mnemonic, you will notice one thing—the T1 signal is all you need to tell if blood is acute, subacute or chronic.
T2 signal will tell if it is early or late in each of those time periods—but that type of detail isn’t needed in real life