Lea Alhilali, MD Profile picture
Mar 15, 2023 8 tweets 5 min read Read on X
1/I call the skullbase “homebase” bc you can’t make an anatomy homerun without it!

Most know the arteries of the skullbase, but few know the veins. Do you?

Here’s a🧵to help you remember #skullbase venous #anatomy!
#medtwitter #meded #neurorad #radtwitter #neurosurgery #radres Image
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. Image
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 Image
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 Image
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! 🤢 Image
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 Image
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 Image
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! Image

• • •

Missing some Tweet in this thread? You can try to force a refresh
 

Keep Current with Lea Alhilali, MD

Lea Alhilali, MD Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!

PDF

Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @teachplaygrub

Mar 3
1/Does PTERYGOPALATINE FOSSA anatomy feel as confusing as its spelling?

Does it seem to have as many openings as letters in its name?

Are you pterrified of the pterygopalatine fossa (PPF)?

Let this thread on PPF anatomy help you out. Image
2/The PPF is a crossroads between the skullbase & the extracranial head and neck

There are 4 main regions that meet here:

(1) Skullbase itself posteriorly, (2) nasal cavity medially, (3) infratemporal fossa laterally, and (4) orbit anteriorly. Image
3/At its most basic, you can think of the PPF as a room with 4 doors opening to each of these regions: one posteriorly to the skullbase, one medially to the nasal cavity, one laterally to the infratemporal fossa, and one anteriorly to the orbit Image
Read 18 tweets
Feb 28
1/Feel like a fish out of water when it comes to water on the brain?

Read on for this month’s @Radiographics summary of what you need to know about hydrocephalus!!



@cookyscan1 @RadG_editor #RGphx doi.org/10.1148/rg.240…Image
2/To understand hydrocephalus, think of CSF like the flow of traffic

3 main ways traffic backs up:

(1) Obstruction on the road:
For hydrocephalus, this is an obstruction along CSF in the ventricle Image
3/

(2) Obstruction of an off ramp
For hydrocephalus=obstruction at its off ramp into the venous system

(3) Rush hour
For hydrocephalus=over production Image
Read 8 tweets
Feb 27
1/Do scans for dizziness make your head spin?

Need to know what to look for?

Just hear me out!

This month’s @theAJNR SCANtastic will show what to look for:

ajnr.org/content/46/2/3…Image
2/I always remember the rhyme of the big three for dizz-ee!

First, are vestibular schwannomas

These give an ice cream cone shape in the internal auditory canal! So scoop up that finding! Image
3/Next is labyrinthitis

Labyrinthitis can look like night & day, depending on the timing

Late labyrinthitis is dark—loss of bright fluid signal on FIESTA

Early labyrinthitis is bright—enhances on post-contrast Image
Read 12 tweets
Feb 26
1/Time is brain! But what time is it?

If you don’t know the time of stroke onset, are you able to deduce it from imaging?

Here’s a thread to help you date a stroke on MRI! Image
2/Strokes evolve, or grow old, the same way people evolve or grow old

The appearance of stroke on imaging mirrors the life stages of a person—you just have to change days for a stroke into years for a person

So 15 day old stroke has features of a 15 year old person, etc. Image
3/Initially (less than 4-6 hrs), the only finding is restriction (brightness) on diffusion imaging (DWI)

You can remember this bc in the first few months, a baby does nothing but be swaddled or restricted

So early/newly born stroke is like a baby, only restricted Image
Read 10 tweets
Feb 25
1/My hardest thread yet! Are you up for the challenge?

How stroke perfusion imaging works!

Ever wonder why it’s Tmax & not Tmin?

Do you not question & let RAPID read the perfusion for you? Not anymore! Image
2/Perfusion imaging is based on one principle: When you inject CT or MR intravenous contrast, the contrast flows w/blood & so contrast can be a surrogate marker for blood.

This is key, b/c we can track contrast—it changes CT density or MR signal so we can see where it goes. Image
3/So if we can track how contrast gets to the tissue (by changes in CT density or MR signal), then we can approximate how BLOOD is getting to the tissue.

And how much blood is getting to the tissue is what perfusion imaging is all about. Image
Read 18 tweets
Feb 24
1/”That’s a ninja turtle looking at me!” I exclaimed. My fellow rolled his eyes at me, “Why do I feel I’m going to see this a thread on this soon…”

He was right! A thread about one of my favorite imaging findings & pathology behind it Image
2/Now the ninja turtle isn’t an actual sign—yet!

But I am hoping to make it go viral as one. To understand what this ninja turtle is, you have to know the anatomy.

I have always thought the medulla looks like a 3 leaf clover in this region.

The most medial bump of the clover is the medullary pyramid (motor fibers).

Next to it is the inferior olivary nucleus (ION), & finally, the last largest leaf is the inferior cerebellar peduncle.

Now you can see that the ninja turtle eyes correspond to the ION.Image
3/But why are IONs large & bright in our ninja turtle?

This is hypertrophic olivary degeneration.

It is how ION degenerates when input to it is disrupted. Input to ION comes from a circuit called the triangle of Guillain & Mollaret—which sounds like a fine French wine label! Image
Read 9 tweets

Did Thread Reader help you today?

Support us! We are indie developers!


This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Don't want to be a Premium member but still want to support us?

Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal

Or Donate anonymously using crypto!

Ethereum

0xfe58350B80634f60Fa6Dc149a72b4DFbc17D341E copy

Bitcoin

3ATGMxNzCUFzxpMCHL5sWSt4DVtS8UqXpi copy

Thank you for your support!

Follow Us!

:(