Thread by @EricLawson90

In honor of nearly 1000 followers and my first official week as #ChiefNeurologyResident, a brief #Tweetorial! Picking a simple topic I found extremely confusing as a #medstudent and #NeurologyIntern “CNS Anatomical Orientation”
@MedTweetorials
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Dorsal, rostrum, anterior, inferior.... why can’t we just say front, back, bottom, and top?!

This actually goes back to embryology. So a brief tangent...
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As an embryo we can divide the CNS into 5 main parts:
1. Telencephalon
2. Diancephalon
3. Mesencephalon
4. Rhknbencephalon
5. Spinal cord
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Those 5 parts are arranged with certain curves/junctions built in.
-midbrain/diencephalic junction
-pontomesencephalic junction
-Cephalic flexure
-pontomedullary junction
-Cervical flexure
-cervicomedullary junction
4/

These embryologic terms/orientation set the basis for how we discuss CNS orientation on imaging and in practice!

Animals have much simpler orientation cause they are on all fours. Humans decided to make it difficult by standing on our hind legs!
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So let’s simplify it and picture humans as if we were on all fours too!
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So now that you are walking around on all 4 limbs what does this have to do with CNS orientation?!

The four main terms we use are:
1- dorsal
2- rostral
3- caudal
4- ventral

The orientation rotates at the midbrain/diencephalic junction!
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So, above the midbrain-diancephalic junction and below it, our orientation compass rotates!
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BUT remember our human is all fours! So we only need one orientation set!

Dorsal- top/toward the sky
Ventral- bottom/toward the ground
Rostral-forward/toward the head
Caudal- back/toward the tailbone
(Excuse my poor 🎨 skills)
Pink line=midbrain/diencephalic junction
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To make it more complicated our #radiology and pathology colleagues like @RyanBPetersonMD and @StewartGNeill added another set of terms to describe neuroimages and neuropathology sections.
1- Axial/horizontal
2- Coronal
3- Sagittal
10/

Fortunately these have a simple way to remember them:
Axial/horizontal-parallel to the floor
Coronal- cutting through like a crown on a queens head
Sagittal- plane of an archer like Sagittarius
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Thanks for reading! Comments, corrections, and teaching is welcome! @MedTweetorials @AaronLBerkowitz @Tracey1milligan @BryanCUlrich @SitaraKoneru @EmoryNeurology @NMatch2021 @VizcarraJA @sallywilliamsmd @Oga_DoctorBlue @gradydoctor @WNGtweets @SharashidzeVera @MonicaDhakar

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