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.
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.
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.
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! 😉
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!
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!
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.
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!
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.
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!
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.”
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
14/So now you know your mandibular fractures & you have a plan even when the patient gets punched!
• • •
Missing some Tweet in this thread? You can try to
force a refresh
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.
3/To remember what features make an aneurysm more likely to rupture, think what makes that guy at the bar that you angered more likely to rupture & start a fight.
What makes him more likely to rupture are the same things that make aneurysms more likely to rupture
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!
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
3/B is for bones.
On CT, the most important thing to look for w/bones is fractures. You may see focal bony lesions, but you may not
On MR, it is the opposite—you can see marrow lesions easily but you may or may not see edema associated w/fractures if the fracture is subtle
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
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.