As a medical student, my prof could spend a hour explaining this and yet I still don't understand it. Dr. Lee can do it in 4. No BS straight to the point. Love it.
It is ridiculous how easy you made this concept. TWO LONG WEEKS trying to get my head around this, and it only took me 3 minutes to completely understand this. I cannot be more THANKFUL Dr. Lee you're an amazing human being. ❤ May God continue to bless you always!!!!!!!
I love how Dr Lee smirks, turns and walks away from the board at the end of most videos - like an action hero walking away from an explosion behind him! No doubt, Neuro-op is kickass enough to warrant that.
My sister and I met you at the Ophthalmology Conference in South Africa and you encouraged us to watch your videos and drop you a comment... So here I am.. saying that Dr Lee, you are amazing!
Dr.Lee your residents and students are so lucky to have such an amazing professor like you, sir. I wish I could have a professor like you, I wouldn't have to quit ophthalmology residency in my home country. It's a pleasure to listening valuable concepts from you.
Just perfect! I saw my first case of INO in a patient and I couldn't really grasp the concept. Everything was so clearly explained in only a four minute video. Thank you!
I was convinced that convergence was always spared with INO, so I was confused when I had a patient who could not converge. Now I know the problem was located in the thalamo-mesencephalic junction! Thank you !
In case someone has the same difficulty; there's this point that confused me and still does because of the inconsistency of anatomical labeling (if want to call it that) which seems random and arbitrary in medical teaching, where they just say right and left (in some cases to be fair) when it does not make any sense.. Left and right, in neuro-anatomy at least, is always concerned with the side that the structure starts in (as far as I remember! please correct me if I'm wrong), but here in this example, the "RIGHT" MLF is meant to be : The MLF that "GOES" to the right side, although it's the one that was sent by the "LEFT" PPRF or "LEFT" VI Abducent nerve. The anatomical labeling of it is "RIGHT" and does not respect the fact that it started in the "LEFT" side and is meant to help the "LEFT" eye bring the opposite eye to do the same movement (conjugate), it is not in respect to that but rather to where it's going. Is this due to the fact that most lesions occur in the portion after it "decussates" to the contra lateral side (the eye which it is supposed to innervate) or in other words is it because the MLF was reduced to just the "longitudinal" part which happens to be on the contra lateral side? This means that when a lesion in the so-called "RIGHT" MLF (the one coming from LEFT CN-VI) is gonna fall short of accomplishing its mission of (conjugating the RIGHT eye's movement with LEFT eye which is intending to ABDUCT [ look laterally or left in this case ] ) i.e. failure of "ADDUCTING" the "RIGHT" eye. PHEWww... Now I get it! lol!
Thank you, I've been rewatching this video for the last 30 mins, trying to understand why Dr. Lee is seemingly contradicting himself in his clinical conclusion, despite initially giving the correct explanation.
Thanks Dr Lee, this video was very helpful! Also don't forget that anterior and posterior INOs can also have bilateral lesions, giving slightly extra symptoms :)
It seems that most sources say that in an MLF lesion, there will be ipsilateral loss of adduction, but ChatGPT suggests that there will be contralateral loss of adduction in MLF lesions. For me, logically, it doesn't make sense that in an MLF lesion, there would be ipsilateral loss of adduction. When we need to look to the left or right, the lateral rectus of one eye and the medial rectus of the other eye must coordinate so that both eyes move in sync. This is exactly the purpose of the MLF. The MLF coordinates the abduction of one eye with the adduction of the other. The key point to note is that the primary event is abduction, not adduction, as even Sir has used the arrows in this way. The good thing is that neither the third nor the sixth nerve crosses. Maybe we just got lucky, or perhaps scientists who study these things wanted us to study somewhat simpler concepts at the MBBS level. The point is that the sixth nerve originates from a more caudal part of the brain than the third nerve. The more caudal the nucleus, the less conscious we are of it, and the more ancient that part of the brain is. When we need to look left, the signal to look left will originate in the left sixth nerve nucleus, not the right third nerve nucleus. This means the primary event is abduction, followed by adduction. By this logic, if I want to look left, my left lateral rectus will move my left eye to the left. However, to also move the right eye to the left, the right medial rectus must contract (adduct). If the MLF is damaged, the right eye will not be able to adduct. The primary signal for abduction of the left eye remains intact, so ipsilateral abduction is spared. However, if the MLF is damaged, the secondary signal for adduction of the contralateral eye does not occur. Therefore, in an MLF lesion, the contralateral medial rectus cannot function. If anybody has any insights, please enlighten me.
1:18 If by the right MLF lesion, you mean left MLF lesion, then yes. Damage to the right MLF (i.e., the MLF originating in the right CN VI) would result in failure to adduct the contralateral (left) eye. If I'm wrong, please someone explain how.
thank you for the brilliant explanation.. but i was wondering if what will happen if we cover the better side and check uniocular movement in the lesion side????
Thats an interesting question! Maybe the right eye upon adduction it will have slight horizontal nystagmus compensating for the left eye maybe? I hope they answer your doubt!
Dr. Lee is legitimately so talented to make me feel I understand something in 4 minutes.
As a medical student, my prof could spend a hour explaining this and yet I still don't understand it. Dr. Lee can do it in 4. No BS straight to the point. Love it.
Now INO how INO works. Thank you!
Something like the thinman am I right!?
😂u sure do
It is ridiculous how easy you made this concept. TWO LONG WEEKS trying to get my head around this, and it only took me 3 minutes to completely understand this. I cannot be more THANKFUL Dr. Lee you're an amazing human being. ❤ May God continue to bless you always!!!!!!!
I love how Dr Lee smirks, turns and walks away from the board at the end of most videos - like an action hero walking away from an explosion behind him! No doubt, Neuro-op is kickass enough to warrant that.
It is totally a well-earned “mic-drop boss” moment.. thank you Dr Lee, you are transforming Neuro-ophthalmology a fascinating area of study for me
Dr.Lee I see passion in you
You are my inspiration
My sister and I met you at the Ophthalmology Conference in South Africa and you encouraged us to watch your videos and drop you a comment... So here I am.. saying that Dr Lee, you are amazing!
Dr.Lee your residents and students are so lucky to have such an amazing professor like you, sir. I wish I could have a professor like you, I wouldn't have to quit ophthalmology residency in my home country. It's a pleasure to listening valuable concepts from you.
Hocam sizi ne bıktırdı hastalar mı hastane mi hocalar mı
How and where I can see Dr.Lee?
For the longest time in internal medicine I was trying to figure this out. This was so simply explained and to the point, loved it. Thank you!
Just perfect! I saw my first case of INO in a patient and I couldn't really grasp the concept. Everything was so clearly explained in only a four minute video. Thank you!
I was convinced that convergence was always spared with INO, so I was confused when I had a patient who could not converge. Now I know the problem was located in the thalamo-mesencephalic junction! Thank you !
I could understand INO in comprehensive way only after watching this video 5yrs back..
Thank you so much sir🙏
Now I'm sharing this with my juniors
That INO breakdown was legit
Literally the best!! Thank you doctor Andrew
That was truly a mic drop moment at the end of this vid. Well taught
Studying for Step 1 and I just couldn’t figure this out. Thank you!
OH MY GOODNESS!!. DR LEE IS LEGIT. how easily are you explaining this. Subscribed!
Dr. Lee thank you for an incredible and clear explanation.
Studying for my medical school neuro exam and this video was SO helpful -- Thank you!!!
In case someone has the same difficulty; there's this point that confused me and still does because of the inconsistency of anatomical labeling (if want to call it that) which seems random and arbitrary in medical teaching, where they just say right and left (in some cases to be fair) when it does not make any sense..
Left and right, in neuro-anatomy at least, is always concerned with the side that the structure starts in (as far as I remember! please correct me if I'm wrong), but here in this example, the "RIGHT" MLF is meant to be : The MLF that "GOES" to the right side, although it's the one that was sent by the "LEFT" PPRF or "LEFT" VI Abducent nerve. The anatomical labeling of it is "RIGHT" and does not respect the fact that it started in the "LEFT" side and is meant to help the "LEFT" eye bring the opposite eye to do the same movement (conjugate), it is not in respect to that but rather to where it's going. Is this due to the fact that most lesions occur in the portion after it "decussates" to the contra lateral side (the eye which it is supposed to innervate) or in other words is it because the MLF was reduced to just the "longitudinal" part which happens to be on the contra lateral side?
This means that when a lesion in the so-called "RIGHT" MLF (the one coming from LEFT CN-VI) is gonna fall short of accomplishing its mission of (conjugating the RIGHT eye's movement with LEFT eye which is intending to ABDUCT [ look laterally or left in this case ] ) i.e. failure of "ADDUCTING" the "RIGHT" eye.
PHEWww... Now I get it! lol!
Thank you, I've been rewatching this video for the last 30 mins, trying to understand why Dr. Lee is seemingly contradicting himself in his clinical conclusion, despite initially giving the correct explanation.
This man is so addictive
You can’t stop watching
The best explanation of INO out there. Thanks
Dr. Lee, thank you so much.
Thanks Dr Lee, this video was very helpful! Also don't forget that anterior and posterior INOs can also have bilateral lesions, giving slightly extra symptoms :)
You're a great teacher. Thank you!
The best explanation ever! So simple. Thank you!
Wonderfull, differentiating between the midbrain and pons is an excellent pointer , never thought about it. Thank you
Amazing video that simplifies a difficult topic. Thank you doctor!
You have made it a lot easier to understand. Thanks for the informative videos
Bless you, sir, for your thoroughness.
I am at the end of my neurology studies. Dear D.r Lee you help me so much Thank you very much.
So fast, so good. Thank you!
Dr. Lee is so enthusiastic!
Excellent presentation doctor thanks a lot god bless you best wishes
Excellent explanation.
Fantastic teaching video , thank you Dr. Lee
no one can teach better than this,thank u
Great work sir
Beautiful explaination!
What an absolute baller, I like his excitement too! 1 day before step 1 but im getting sucked into his youtube wormhole...
Many thanks Dr. Lee
Incredible, such a good explanation.
These videos are gold, thank you!
Paresis = weakness (Partial Paralysis)
Plegia = Total Paralysis
GENIUS THANK YOU DOCTOR
You’re so good at explaining
Thank you Doctor Lee!!
Wow u explained it so well in 3 mins
thanks Dr. Lee you're such a great help! your vids are amazing!
Excellent!
It seems that most sources say that in an MLF lesion, there will be ipsilateral loss of adduction, but ChatGPT suggests that there will be contralateral loss of adduction in MLF lesions.
For me, logically, it doesn't make sense that in an MLF lesion, there would be ipsilateral loss of adduction.
When we need to look to the left or right, the lateral rectus of one eye and the medial rectus of the other eye must coordinate so that both eyes move in sync. This is exactly the purpose of the MLF. The MLF coordinates the abduction of one eye with the adduction of the other. The key point to note is that the primary event is abduction, not adduction, as even Sir has used the arrows in this way.
The good thing is that neither the third nor the sixth nerve crosses. Maybe we just got lucky, or perhaps scientists who study these things wanted us to study somewhat simpler concepts at the MBBS level.
The point is that the sixth nerve originates from a more caudal part of the brain than the third nerve. The more caudal the nucleus, the less conscious we are of it, and the more ancient that part of the brain is. When we need to look left, the signal to look left will originate in the left sixth nerve nucleus, not the right third nerve nucleus. This means the primary event is abduction, followed by adduction.
By this logic, if I want to look left, my left lateral rectus will move my left eye to the left. However, to also move the right eye to the left, the right medial rectus must contract (adduct). If the MLF is damaged, the right eye will not be able to adduct. The primary signal for abduction of the left eye remains intact, so ipsilateral abduction is spared. However, if the MLF is damaged, the secondary signal for adduction of the contralateral eye does not occur. Therefore, in an MLF lesion, the contralateral medial rectus cannot function.
If anybody has any insights, please enlighten me.
Fantastic explanation!! Thank you!
Doc is an excellent teacher
Simplified explanation. Thank you so much!
Oh my God. Wonderful
THIS IS LEGENDARY
big fan sir. love from india.
Dr lee thank you! You are amazing
Thank you Dr. Lee
YOU ARE AMAZING! THANK YOU
Impossible says I am possible ... Thanks to Dr Lee
Incredible
You are AMAZING
Super easy explanation, thanks a bunch Dr
Indeed
really thanks Prof Andy
Dr lee thank you
So "febrile" - very nice - thank you
1:18 If by the right MLF lesion, you mean left MLF lesion, then yes. Damage to the right MLF (i.e., the MLF originating in the right CN VI) would result in failure to adduct the contralateral (left) eye. If I'm wrong, please someone explain how.
It's a great explanation!Thank you so much!
amazing
thank you
best explanation ever
Amazing explanation thank you so much 👏
great Sir, thank you
THANK YOU SO MUCH!!!!
ماشاء الله 🙏
That's great. Still don't understand the direction of the nystagmus. Can anyone help?
AMAZING
wow. you made it so simple'
Thank you
Thank you very much
This is How to give explanation 🔥😍
Genius 😳
Thank u 😃 from iraq
How is your Iraq Saradocter
Are you taking new patients? I would be curious about treatment solutions?
thank you very much
Thank you!
you are a legend
Thank you Lee
V good explanation
thanks doc
Thanks ..so perfect❤
So amazing
thank you for the brilliant explanation.. but i was wondering if what will happen if we cover the better side and check uniocular movement in the lesion side????
Thats an interesting question! Maybe the right eye upon adduction it will have slight horizontal nystagmus compensating for the left eye maybe? I hope they answer your doubt!
Uniocular movts will be normal ...as the 3rd nerve nuclues as well as nerve is intact
Only binocular movt is affected in INO
what is the treatment doc asking from kenya
Can you explain to us please how we can differentiate between anterior Vs posterior INO
I've been suffering of this type of sickness since 2005.. Pls tell me how can avoid this.
I love watching this shit when I'm stoned and wearing 3d glasses 👓
it is truly helpful!! awesome!! Thanks a lot.
Thank you so much Dr. Lee. Your explanation is always clear and easy to comprehend.
Thank youu