Lea Alhilali, MD Profile picture
Jun 3, 2022 7 tweets 5 min read Read on X
1/”Tell me where it hurts.” How back pain radiates can tell you where the lesion is—if you know where to look!
A 🧵about how to remember lumbar radicular pain distributions. #medstudenttwitter #medtwitter #radres #FOAMed #FOAMrad #neurorad #Meded #backpain #spine #Neurosurgery Image
2/Let’s start with L1. L1 radiates to the groin. I remember that b/c the number 1 is, well, um…phallic. So the phallic number 1 radiates to the groin. Image
3/Let’s skip to L3 for a second. I remember L3 is to the knee—easy, it rhymes! Image
4/Ok, back to L2. Two is the number between 1 and 3, so the distribution of L2 is between the distributions of L1 and L3—and between the groin and knee is the thigh. L2 radiates to the thigh. It’s not the catchiest way to remember it, but it works. Image
5/L4 radiates to the calf. I remember this bc the number 4 looks like the calf, with the top part of the 4 looking like a bulging gastroc & the bottom part of the four is the rest of the calf connecting to the ankle. Don’t we all wish we had bulging gastrocs like the number 4! Image
6/L5 radiates to the big toe. So I have the little rhyme “Five is to the big guy!” L5 is also foot drop. So I remember big guys are heavy, and heavy gravity = drop. If I hear the history “foot drop,” I never stop looking until I have traced out the entire L5 nerve root. Image
7/Finally, S1 radiates to the side of the foot. I remember this bc both S1 & Side start w/S.
So now you know where in the lumbar spine to look when a patient says the pain radiates down the leg & hopefully remembering the lumbar radicular distributions won’t cause you any pain! Image

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More from @teachplaygrub

Apr 25
1/Radiologist not answering the phone?

Just want a quick read on that stat head CT?

Here's a little help on how to do it yourself w/a thread on how to read a head CT! Image
2/In bread & butter neuroimaging—CT is the bread—maybe a little bland, not super exciting—but necessary & you can get a lot of nutrition out of it

MRI is like the butter—everyone loves it, it makes everything better, & it packs a lot of calories. Today, we start w/the bread! Image
3/The most important thing to look for on a head CT is blood.

Blood is Bright on a head CT—both start w/B.

Blood is bright bc for all it’s Nobel prizes, all CT is is a density measurement—and blood is denser (thicker) than water & denser things are brighter on CT Image
Read 20 tweets
Apr 23
1/Time to FESS up! Do you understand functional endoscopic sinus surgery (FESS)?

If you read sinus CTs, you better know what the surgeon is doing or you won’t know what you’re doing!

Here’s a thread to make sure you always make the important findings! Image
2/The first step is to insert the endoscope into the nasal cavity.

The first two structures encountered are the nasal septum and the inferior turbinate. Image
3/So on every sinus CT you read, the first question is whether there is enough room to insert the scope.

Will it go in smoothly or will it be a tight fit? Image
Read 19 tweets
Apr 21
1/Ready for a throw down?

MMA fights get a lot of attention, but MMA (middle meningeal art) & dural blood supply doesn’t get the attention it deserves.

A thread on dural vascular anatomy! Image
2/Everyone knows about the blood supply to the brain.

Circle of Willis anatomy is king and loved by everyone, while the vascular anatomy of the blood supply to the dura is the poor, wicked step child of vascular anatomy that is often forgotten Image
3/But dural vascular anatomy & supply are important, especially now that MMA embolizations are commonly for chronic recurrent subdurals.

It also important for understanding dural arteriovenous fistulas as well. Image
Read 17 tweets
Apr 16
1/ Need a global perspective on dementia?

Do you know the global cortical atrophy (GCA) score for evaluating dementia patients—or are you still gestalting volume loss???

Don’t estimate when you can calculate!

Here’s a thread of what you need to know about the GCA score! Image
2/The global cortical atrophy score calculates cortical volume loss on a scale of 0-3 in 13 different regions & ventricular dilatation

Gyri shrink down w/atrophy, the same way your cheeks shrink down with aging! Image
3/Gyri look like lips with around a mouth of sulcal space.

Without volume loss, the gyri look like big fat pursed model lips

But w/volume loss they open up like the scream w/thinning of the lips Image
Read 9 tweets
Apr 14
1/Wish that your knowledge of autoimmune encephalitis was automatic?

Do you feel in limbo about limbic encephalitis?

Do you know the patterns?

Read on for what you need to know in this month's @RadioGraphics review!



@cookyscan1 @RadG_Editor doi.org/10.1148/rg.240…Image
@RadioGraphics @cookyscan1 @RadG_Editor 2/Two pearls:
(1) Most common pattern is limbic encephalitis
(2) Small cell can cause any autoimmune pattern.

You can remember the causes by the demographic:
Young man: testicular
Older: Small cell
Woman with psychiatric symptoms (limbic): breast Image
@RadioGraphics @cookyscan1 @RadG_Editor 3/Limbic encephalitis is the most common pattern

But it has many, many different causes

Remember--limbic involvement is shaped like a question mark!

So for limbic encephalitis, the cause remains a question bc differential is so broad

Must question & clinically correlate! Image
Read 8 tweets
Apr 2
1/One important aspect to stroke care is well, ASPECTS.

It’s a simple score system—but it’s important to understand all aspects!

Read on for the latest research on ASPECTS in this month’s @theAJNR SCANtastic!

ajnr.org/content/46/3/5…Image
2/ASPECTS stands for “Alberta Stroke Program Early CT Score.”

It’s meant to replace gestalt-ing what percent of the MCA territory is infarcted.

Instead, it uses a 10-pt score to semi-quantitate the infarcted tissue in the MCA territory on non-contrast head CT Image
3/You can think of it as a score card for the MCA.

For each region of MCA territory NOT infarcted, the pt gets one point—for a highest score of 10, and lowest score of 0 Image
Read 18 tweets

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