I was so confused why sup oblique was depressing the eye in adducted position, when its function is to abduct the eye. This cleared my concept. Thank you so much.
If both the superior rectus and inferior oblique elevate the eyes, and the inferior oblique also abducts the eye, then why is it that when the eye is abducted, only the superior rectus is being used, and not the inferior oblique?
Ok so we r just dumb, i thought about it and realized the mistake me and u were making (i think) KEY POINT: there is a difference between muscle action depending on the STARTING POSITION of the eye. Example: RIGHT EYE: Look straight then look (in one motion) to the top right corner of your eye, that's inferior oblique doing the job (PLUS superior rectus because it also acts on the Y axis in bringing eyeball up) Now, RIGHT EYE: look alll the way to the right, you just ABducted using your lateral rectus, NOT your inferior oblique. Now, go look back at the vectors in his video for testing the superior rectus, you will see that because the eye is ALREADY ABducted using LATERAL RECTUS, the inferior oblique due to its positioning CANNOT elevate the eye along the Y-axis as it previously could when the eye started at NEUTRAL position (it can only rotate the eye which as he says in the video is hard to see). Effectively, the SUPERIOR RECTUS muscle is the only muscle left that could function in the ABducted position of your right eye for LOOKING UP along the Y-axis. Therefore if a person cannot raise their right eye from the ABducted position, it must be due to SUPERIOR RECTUS dysfunction because that's the only available muscle able to make the eye look up from the ABducted position given you ELIMINATED the function of the other muscle (inferior oblique) that can make the eye look up. Hope that helps all the other ppl who r dummies like me out there (or just have another way of thinking =))
Hello! Can someone please explain to me why the vector of the muscle must be parallel to the gaze of the orbit in order to isolate the muscle function. Or how those things being parallel can isolate one muscle’s function.
When 2 muscles are both responsible for elevating the eye clinicians figured how one muscle could be tested without recruiting the other muscle to elevate the eye. For example, both the SR and IO elevate the eye. when a patient abducts the gaze of the eye is parallel with the SR muscle. In this way when the patient looks up the only muscle elevating the eye is the SR. The IO muscles vector pull is perpendicular to the gaze of the eye and thus only acts on the z-axis to extort the eye.
@@TheNotedAnatomist so a better way of understanding it is to say that the gaze of eye is made PERPENDICULAR to the vector pull of the muscle(IO)that also causes the same action as muscle that we are testing(SR) instead if saying the gaze is made parallel to the muscle(SR) being tested .i know it sounds a little complicated but it clears the doubt. The focus of the test is to make the gaze perpendicular to the IR rather than Parallel to the SR. And in actual measurements those two vector axes are not perpendicular(SR vs IO on horizontal plane ) but for practical/clinical purposes making the gaze parallel to the muscle being tested( which is perpendicular to the mucle not being tested but produces the same action) gets the job done and is simpler to understand.
In more simple(but not simplest) terms , in case of SR muscle test , when the eye is in abducted position even if the IO gets the nerve signal and contracts it can't produce any movement in horizontal axis( elevation /depression) so the only muscle that can produce such action is SR.
+ohoney jones To test the lateral rectus muscle all that is required is for the patient to abduct the eye. To test the superior rectus muscle the patient must first abduct the eye then elevate it. In this way, the superior rectus muscle is isolated from the inferior oblique muscle (the other muscle that elevates the eye). Does that help?
Just an additional info, it could be the clinician also want to know the intorsion-extorsion movement of the eye while doing a certain eye movement that is why it need ti abduct it first.
+Supratim Karmakar Hi Supratim, yes the superior rectus does elevate the eye in the abducted position. As well, the inferior rectus depresses the eye in an abducted position. However, in the natural state, when the eye is looking forward (neutral position) the superior rectus muscle elevates and adducts the eye (look up and in). This video tutorial discusses the clinical testing of extraocular muscles and CN's. This video discusses the anatomical movements of the muscles (ruclips.net/video/u3BcgOIjbGA/видео.html)
1 diagram explained in 5 minutes= 1 hour of lecture. Thank you kind sir!
You are most welcome! I am happy it was helpful.
@@TheNotedAnatomist very helpful..God bless you
I've had this concept explained to me but this is the first time a diagram has made it make sense to me. Really well explained.
Thank you so so much! You’ve made such a complex concept to something so intuitive. We owe you big time!
1 youtube video beats 6 years of medical school.... I can't believe it took me this long to find your videos!
Never seen such a perfect video, thankyou for explaining what I had been trying to get for months🙏🏻
OMG I was so confused about the notion until I watched this tutorial. Huge thanks to you sir !
This is like the best explanation ever, thank you Dr.
It’s the best video for understanding ever 👏👏
man this diagram explains everything
You're one badass anatomist who's got his concepts spot on. Great video.. keep up the work
Perfect explanation. You the man!
Its best explanatory and conceptual video!! made it easy !
Glad it helped!
this topic was confusing until now. thank you so much!
I looked everywhere on the internet for a clear explanation of this but couldn't find it...you explained it so well thank you!
I was so confused why sup oblique was depressing the eye in adducted position, when its function is to abduct the eye. This cleared my concept. Thank you so much.
Simple, yet makes a lot of sense! Well explained!! Thanks a lot!!!
Glad it was helpful!
Thank you so much! I have misunderstood this topic for years.
You're very welcome!
This is exactly what I need! Thank you again!!
Thank you for this awesome video. The graphic illustrations are spot on. I now understand better. Thanks!
oh wow this is why you test in a H pattern. I finally get it. thank you so much.
Brilliantly explained, thank you so much! 🙏
i had a midterm exam yesterday, but i see this video now
OMG WHAT A LIFE SAVIOUR
Thanks I almost lost hope understanding this
😂
This is the best explanation so far! Thank you for this video. 😊
Thank you so much , I was so confused about SO isolation
Excellent ... well done ...
You're an amazing person, keep making videos. :)
Thank you sir very helpful you made thet very easy for us thanks again
You are welcome
This saved me tons of time, Thankssss.
Best explaination!! I understand it so much , thank you !!
thank you for your amazing work.
Thank you so much! Great video
best explained ever
Thank you. This is very helpful.
Best explanation ever
excellent. Tks You are the man
You're welcome!
Saved my life
You are always my favorite ❤
You amazing! What a smart guy!
Thank you ❤
amazing explanation, thank you!
Thank you, your explanation was great!
THIS IS VERY NICE!
0:59 there is a mistake, IR+SR are swapped with IO+SO, but the Video is very helpful, thank you!
THANK YOU SO MUCH!!!
Thank you so much! This is a very clear explanation
Thank you sir
@The Noted Anatomist how do you grade the amount of superior rectus elevation. what is considered a full gaze?
A big thanks! 💓👌
hmm, now I have another question, why don't we just get the patient to look down and out in one motion to test Superior Oblique?
thank you so much
I finally understand this!!!!!
Thank you 😀
Thank you so much 😊
Super helpful!!
What type of doctor would a person go to for these types of tests?
Any physical exam from a general practitioner or neurologist
Thank you!
I GET IT FINALLY THANK YOU SO MUCH ❤️❤️❤️
thank you thank you thank you finally i got it
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Wonderful!
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If both the superior rectus and inferior oblique elevate the eyes, and the inferior oblique also abducts the eye, then why is it that when the eye is abducted, only the superior rectus is being used, and not the inferior oblique?
yeah i have the same question... either we're dumb or ppl r just memorizing the rules and not understanding this point
Ok so we r just dumb, i thought about it and realized the mistake me and u were making (i think)
KEY POINT: there is a difference between muscle action depending on the STARTING POSITION of the eye.
Example: RIGHT EYE: Look straight then look (in one motion) to the top right corner of your eye, that's inferior oblique doing the job (PLUS superior rectus because it also acts on the Y axis in bringing eyeball up)
Now, RIGHT EYE: look alll the way to the right, you just ABducted using your lateral rectus, NOT your inferior oblique. Now, go look back at the vectors in his video for testing the superior rectus, you will see that because the eye is ALREADY ABducted using LATERAL RECTUS, the inferior oblique due to its positioning CANNOT elevate the eye along the Y-axis as it previously could when the eye started at NEUTRAL position (it can only rotate the eye which as he says in the video is hard to see).
Effectively, the SUPERIOR RECTUS muscle is the only muscle left that could function in the ABducted position of your right eye for LOOKING UP along the Y-axis. Therefore if a person cannot raise their right eye from the ABducted position, it must be due to SUPERIOR RECTUS dysfunction because that's the only available muscle able to make the eye look up from the ABducted position given you ELIMINATED the function of the other muscle (inferior oblique) that can make the eye look up.
Hope that helps all the other ppl who r dummies like me out there (or just have another way of thinking =))
Wow this is actually ground breaking explanation!!! thanks @@crymore7
Hello! Can someone please explain to me why the vector of the muscle must be parallel to the gaze of the orbit in order to isolate the muscle function. Or how those things being parallel can isolate one muscle’s function.
When 2 muscles are both responsible for elevating the eye clinicians figured how one muscle could be tested without recruiting the other muscle to elevate the eye. For example, both the SR and IO elevate the eye. when a patient abducts the gaze of the eye is parallel with the SR muscle. In this way when the patient looks up the only muscle elevating the eye is the SR. The IO muscles vector pull is perpendicular to the gaze of the eye and thus only acts on the z-axis to extort the eye.
@@TheNotedAnatomist so a better way of understanding it is to say that the gaze of eye is made PERPENDICULAR to the vector pull of the muscle(IO)that also causes the same action as muscle that we are testing(SR) instead if saying the gaze is made parallel to the muscle(SR) being tested .i know it sounds a little complicated but it clears the doubt.
The focus of the test is to make the gaze perpendicular to the IR rather than Parallel to the SR.
And in actual measurements those two vector axes are not perpendicular(SR vs IO on horizontal plane ) but for practical/clinical purposes making the gaze parallel to the muscle being tested( which is perpendicular to the mucle not being tested but produces the same action) gets the job done and is simpler to understand.
In more simple(but not simplest) terms , in case of SR muscle test , when the eye is in abducted position even if the IO gets the nerve signal and contracts it can't produce any movement in horizontal axis( elevation /depression) so the only muscle that can produce such action is SR.
Finalyyyy i understood 1
Thank u
I. LOVE. YOU.
why do you have to abduct it first to test it for superior and lateral rectus why cant you just adduct it?
+ohoney jones To test the lateral rectus muscle all that is required is for the patient to abduct the eye. To test the superior rectus muscle the patient must first abduct the eye then elevate it. In this way, the superior rectus muscle is isolated from the inferior oblique muscle (the other muscle that elevates the eye). Does that help?
Just an additional info, it could be the clinician also want to know the intorsion-extorsion movement of the eye while doing a certain eye movement that is why it need ti abduct it first.
Thanks ❤️❤️❤️😭😭
finally
hey man, sup recti and inf recti act in abducted position.. atleast i think so..
+Supratim Karmakar Hi Supratim, yes the superior rectus does elevate the eye in the abducted position. As well, the inferior rectus depresses the eye in an abducted position. However, in the natural state, when the eye is looking forward (neutral position) the superior rectus muscle elevates and adducts the eye (look up and in). This video tutorial discusses the clinical testing of extraocular muscles and CN's. This video discusses the anatomical movements of the muscles (ruclips.net/video/u3BcgOIjbGA/видео.html)
I dont like his eplanation. made it too complicated