2/Sphenopalatine ganglion (SPG) is the largest collection of neurons outside the brain—like a mini brain just for your face. It contains sensory, sympathetic, & parasympathetic nerve fibers. Given this, it’s not surprising that it’s felt to contribute to facial pain syndromes
3/SPG is a meeting point for the sensory nerves from V2 (thus related to trigeminal neuralgia) & the sympathetics and parasympathetics from the greater superficial and deep petrosal nerves, which have been implicated in cluster headache, migraine, & other facial pain syndromes.
4/We can see the SPG in the pterygopalatine fossa on MR neurography. We can see V2 in rotundum as well as the greater superficial petrosal (GSP) & deep petrosal nerves forming the vidian nerve right below rotundum in the vidian canal. These come together as the SPG in the PPF.
5/ SPG blocks are classically for cluster HA/trigeminal autonomic cephalgia (TAC) bc of its parasympathetic activation (lacrimation, rhinorrhea, etc) & sympathetic dysfunction (ptosis & miosis)—but it has been found to be effective in other HA and facial pain syndromes
6/The simplest SPG block method is the transnasal topical approach. A cotton swab applicator soaked w/local anesthetic is advanced posterior to the middle turbinate. It is then laid against the mucosa in that region & the anesthetic is absorbed through the mucosa to the SPG.
7/The next more invasive step is to add to the insertion of a curved catheter, to inject local anesthetic, rather than just laying a cotton soaked tip in that region. However, the injected anesthetic is still absorbed through the mucosa to the SPG.
8/A more direct route is to come to the SPG from below, inserting a syringe through the greater palatine foramen of the posterior hard palate & directly injecting upward into the PPF, where the SPG lives. However, there are many significant drawbacks to this method.
9/Finally, the most direct method is from an infrazygomatic approach to the PPF under image guidance to directly inject anesthetic & possibly steroid directly onto the SPG. This has the advantage of targeted & precise delivery. Only drawbacks are technical difficulty & radiation.
10/Which approach is the best? Intranasal is easier and less invasive, but infrazygomatic is more precise. Some studies have suggested precision matters. So don’t be afraid to put your needle where it needs to go to help relieve the patient’s pain.
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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!
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.
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
1/”I LOVE spinal cord syndromes!” is a phrase that has NEVER, EVER been said by anyone.
Do you become paralyzed when you see cord signal abnormality?
Never fear—here is a thread on all the incomplete spinal cord syndromes to get you moving again!
2/Spinal cord anatomy can be complex. On imaging, we can see the ant & post nerve roots. We can also see the gray & white matter. Hidden w/in the white matter, however, are numerous efferent & afferent tracts—enough to make your head spin.
3/Lucky for you, for the incomplete cord syndromes, all you need to know is gray matter & 3 main tracts. Anterolaterally, spinothalamic tract (pain & temp). Posteriorly, dorsal columns (vibration, proprioception, & light touch), & next to it, corticospinal tracts—providing motor
1/Do you get a Broca’s aphasia trying remember the location of Broca's area?
Does trying to remember inferior frontal gyrus anatomy leave you speechless?
Don't be at a loss for words when it comes to Broca's area
Here’s a 🧵to help you remember the anatomy of this key region!
2/Anatomy of the inferior frontal gyrus (IFG) is best seen on the sagittal images, where it looks like the McDonald’s arches.
So, to find this area on MR, I open the sagittal images & scroll until I see the arches. When it comes to this method of finding the IFG, i’m lovin it.
3/Inferior frontal gyrus also looks like a sideways 3, if you prefer. This 3 is helpful bc the inferior frontal gyrus has 3 parts—called pars
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