Lea Alhilali, MD Profile picture
Jun 12 18 tweets 9 min read Twitter logo Read on Twitter
1/Does PTERYGOPALATINE FOSSA anatomy feel as confusing as its spelling? Does it seem to have as many openings as letters in its name?

Let this #tweetorial on PPF #anatomy help you out

#meded #medtwitter #FOAMed #FOAMrad #neurosurgery #neurology #neurorad #neurotwitter #radres Image
2/The PPF is a crossroads between the skullbase & the extracranial head and neck. There are 4 main regions that meet here. The skullbase itself posteriorly, the nasal cavity medially, the infratemporal fossa laterally, and the 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
4/You can intuitively remember where each of these doors lead by thinking about what lies around the PPF. Brain is posterior, so post door opens to cranial nerves. Medially is the nose, so med door opens to nasal cavity. Anteriorly is the eye, so ant door goes to orbit & so forth Image
5/Name of each door/opening also tells where they go. SPHENOpalatine foramen goes medially towards the SPHENOID sinus. Inferior ORBITAL fissure is to the ORBIT. PterygoMAXILLARY fissure goes laterally like the MAXILLARY sinus. ROTUNDUM is for a cranial nerve, so goes to the brain Image
6/Let’s start w/the medial & lat openings. Sphenopalatine foramen (SPF) & pterygomaxillary fissure (PMF) can be seen when the walls of the post max sinus & pterygoid plate are parallel. They look like the two round openings of a cylinder—with the cylinder being the PPF itself. Image
7/Their names tell you which side of the cylinder they are on. SPF opens to the sphenoid body/sinus, so it's the medial opening, since these structures are medial. PMF opens towards the maxillary sinus, which goes out laterally towards the zygoma—so PMF is the lateral opening Image
8/There is also an easy mnemonic. In old naval times, the Port side of the ship was the side that docked along the port, so it was the side that dealt w/the outside world. PMF starts w/P, so it is the port side, the side that is towards the world outside the patient (lateral). Image
9/Posterior door has 2 parts. More superior part is foramen rotundum. It looks like a cylinder going straight back. I remember Rotundum is the post door bc both Rotundum & Rear start w/R. You can also remember that Rears are Round, if you want to be a little cheeky—literally Image
10/The lower half of the posterior door is the pterygoid or vidian canal. I remember that Vidian is the lower opening in the posterior door bc the V almost looks like an arrow pointing down. Image
11/Unlike rotundum that looks like a straight cylinder, Vidian has a bit of a curve to it, looking a little bit like the letter L. This helps me to remember that Vidian connects to Foramen Lacerum, bc Vidian looks a little like an L & Lacerum starts w/an L. Image
12/Anterior door is the inferior orbital fissure (IOF). You can remember this bc the eye is anterior to the PPF. You can also remember its name (IOF) with the little mnemonic that “I (eye) Opening is Forward.” Image
13/But it’s a little bit more complicated than that. While the IOF is anterior, it also superior, more like an anterior skylight than a door. So if you look through the rotundum/vidian door, you will see the SPF medially, the PMF laterally & the IOF in front of you on the ceiling Image
14/But it’s even a little more complicated than that! Turns out there’s a trap door in the floor as well—the palatine canals. You can remember this bc the mouth/palate is below the PPF so you need a hole going down. You can also remember this b/c both Palatine & Pothole start w/P Image
15/So looking from above, you will the Rotundum/Vidian rear door, w/the SPF door medially & the PMF door laterally. Up on the anterior ceiling is the IOF skylight, and down on the floor is the trapdoor to the palatine canals. Image
16/Here is a view from the side. You can better see how the IOF is like a skylight, rotundum is a rear door, and the palatine canals are the trap door with a ladder leading down to the mouth. Image
17/So let’s pretend we are intracranial & peering through the round hole of foramen rotundum. We will see what looks like a loft w/a ladder. The ladder is the palatine canals leading down. The loft itself has a skylight (IOF) & 2 windows—medial window is the SPF & lateral is PMF. Image
18/So now you know the basic anatomy of the PPF. As Elizabeth Taylor once said, “There are many doors in this world, don’t be afraid to look through them.” Don’t be afraid of the doors of the PPF—they can open the world of anatomy to you! Image

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2/First, a rule of thumb—or rather a rule of elbow! You have 10 fingers. If you divide that in half, you get 5.

If you divide your arm in half, that's at the elbow, you'll also get 5--C5 that is! C5 radiates to the elbow. So if it radiates below this, it's > C5 & above is < C5 Image
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May 31
1/ “Say Aaaaaaah!” I was explaining to my resident how I remember tongue anatomy on imaging & he said, “You have to put it on Twitter!”

So here's a #tweetorial about how to remember tongue anatomy on imaging.

#medtwitter #radres #medstudent #FOAMed #FOAMrad #neurorad #meded Image
2/ When you look on the coronal plane at the tongue, the first thing you notice are two column like structures that look like a pair of jeans—genioglossus—or as I like to say “jean-ee-o-glossus.” Genioglossus is latin for jeans of the tongue, right?  Image
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May 26
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3/Infarct appearance depends on timing. In first 12 hrs, the most common imaging finding is…a normal head CT. However, in some, you see a hyperdense artery or basal ganglia obscuration. Later in the acute period, you see loss of gray white differentiation & sulcal effacement Image
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1/”Tell me where it hurts.” How back pain radiates can tell you where the lesion is—if you know where to look!

A #tweetorial about how to remember lumbar radicular pain distributions.

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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
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