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.
3/Let’s skip to L3 for a second. I remember L3 is to the knee—easy, it rhymes!
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.
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!
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.
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!
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Here's a little help on how to do it yourself w/a thread on how to read a head CT!
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!
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
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!
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
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.