Lea Alhilali, MD Profile picture
Jun 8, 2022 14 tweets 7 min read Read on X
1/Mike Tyson once said, “Everyone has a plan until they get punched.”
In honor of all the great hooks and crosses—here is a #tweetorial about mandibular fxs! #FOAMed #medtwitter #Meded #neurorad #HNrad #FOAMrad #Medstudenttwitter @MedTweetorials Image
2/A key concept in these fxs is dental occlusion. The jaw is meant to chew. To crush food, teeth need to come as close together as possible—occlusion. Each tooth needs to meet up with its counterpart that fits with it, so no room is left for food—and food will be crushed. Image
3/Occlusion can be lost w/a fx. The importance of dental occlusion makes mandibular fxs different from other fxs. Usually, we want to fix a bone so that it lines up again. But for the mandible, we want to fix it so the TEETH line up again—so chewing will work. Image
4/Another important concept is multiplicity. It used to be taught that the mandible was a ring w/the skullbase—& you can’t break a ring in one place, so every mandible fx had to have a 2nd one. But this is only true ~50% of time—but it is still worth it to look for the 2nd fx. Image
5/Because of the shape of the mandible and the typical forces applied to it, mandibular fractures usually occur at the same few locations. But the names of these fxs are not always intuitive—at least not without a tweetorial to help explain them! 😉 Image
6/Well, perhaps I lied a little. The most common fx does have an intuitive name. An angle fx starts at…wait for it…the angle and extends into socket of the 3rd molar. If you can’t remember an angle fx starts at the mandibular angle, then not even this tweetorial can help you! Image
7/A subcondylar fracture starts from the notch between the condyle and coronoid process, called the sigmoid notch and extends into the posterior ramus. Don’t call this a ramus fx bc a ramus fx goes straight horizontally through the ramus! Image
8/Here are examples of subcondylar fxs. A key finding in subcondylar fxs is that it separates the condyle from the rest of the mandible. It can be difficult to see the fx running through the sigmoid notch & ramus on 2D images—3D images can be helpful to see the fx anatomy. Image
9/I remember subcondylar fxs bc they separate the condyle from the rest of the mandible. If you isolate someone, you make them feel SUBpar—so SUBcondylar fxs make the condyle feel subpar bc they separate it from the rest of the mandible! Image
10/Condylar head/neck fxs are easy to remember—they are through, well, the condylar head or neck. These are fx/dislocations. Pterygoid muscles attach to the head & pull medially. So when the head is no longer attached to the mandible, pterygoids are unopposed & pull it medially. Image
11/So if you ever see a condylar head displaced medially, you know it is a condylar head or neck fracture bc this is where the pterygoids are unopposed and pull medially! Image
12/Body fxs are through the body of the mandible and are named for the tooth socket that they involve. So you would say “A mandibular body fx through the FILL IN THE BLANK TOOTH socket.” Image
13/Body fxs through the canine are given the special name “parasymphaseal” or “mental” fx bc they are near the mental foramen where the inferior alveolar nerve exits. Menton means “chin” in French, so if they are a body fx anteriorly near the chin, they are “mental” fxs Image
14/So now you know your mandibular fractures & you have a plan even when the patient gets punched! Image

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Nov 20
1/Time to rupture all your misconceptions about aneurysms!

When you see an aneurysm on imaging, do you know if it’s at high risk of rupture?

This month’s @theAJNR SCANtastic shows you which aneurysms are bursting w/risk!

ajnr.org/content/45/11/…Image
2/Aneurysm rupture is a devastating even, as it results in subarachnoid hemorrhage & complications such as hydrocephalus, vasospasm, infarcts, & death.

Preventing it by treating aneurysms before they rupture is key. But you also don’t want to overtreat. Image
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What makes him more likely to rupture are the same things that make aneurysms more likely to rupture Image
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Nov 11
1/Need help reading spine imaging? I’ve got your back!

It’s as easy as ABC!

A thread about an easy mnemonic you can use on every single spine study you see to increase your speed & make sure you never miss a thing! Image
2/A is for alignment

Look for:
(1) Unstable injuries

(2) Malalignment that causes early degenerative change. Abnormal motion causes spinal elements to abnormally move against each other, like grinding teeth wears down teeth—this wears down the spine Image
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On CT, the most important thing to look for w/bones is fractures. You may see focal bony lesions, but you may not

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Nov 8
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I could never seem to remember or understand it—but now I do & I’ll show you how!

A thread so you will never fear brachial plexus anatomy again! Image
2/Everyone has a mnemonic to remember brachial plexus anatomy.

I’m a radiologist, so I remember one about Rad Techs.

But just remembering the names & their order isn’t enough.

That is just the starting point--let’s really understand it Image
3/From the mnemonic, we start with the roots—the cervical nerve roots.

I remember which roots make up the brachial plexus by remembering that it supplies the hand.

You have 5 fingers on your hand so we start with C5 & we take 5 nerve roots (C5-T1). Image
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Nov 6
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! Image
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 memorizeImage
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

So let’s look at T1Image
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Oct 29
1/To call it or not to call it? That is the question!

Feeling wacky & wobbly when it comes to normal pressure hydrocephalus?

Don’t want to overcall it, but don’t want to miss it either!

Check out the latest in NPH w/this month’s @theAJNR SCANtastic!

ajnr.org/content/45/10/…Image
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This begs the question—when do you stop looking & call it idiopathic? When do you suggest it on imaging? Image
3/There’s an iNPH Radscale, which scores 7 different imaging features.

Score above 8 is very sensitive for iNPH.

But who’s going to take out calipers & evaluate SEVEN different imaging findings on every dementia MR?

Also this scale doesn’t predict who will respond to shunting Image
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Oct 18
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. Image
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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 Image
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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. Image
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