Neuro question

[viper]

---

Members don't see this ad.

Do the sensations (touch) from face go ipsilateral or contralateral? HY neuro (p. 78) says ipsilateral. Kaplan says contralateral - I think contralateral. But which is it?

Also what do people think of HY neuro. After reading it a bit, I am not liking it. It is filled with errors and kinda sucks. What are your thoughts on it?

Thanks,

 

[JMD]

I came across this and dropped an e-mail to my neuro professor (awesome teacher, by the way) because I had 3 different sources saying 3 different things (it always frustrates me to come across discrepancies in different sources). Here is his reply:

"The details on CN5 are a bit tricky, as you have determined by
consulting multiple sources. The reality of the anatomy is: the
principal sensory nucleus of 5 has both a contralateral (VTT) and
ipsilateral (DTT) projection to VPM. The ipsilateral projection is minor
and transmits sensory info arising apparently only from the oral cavity
to the ipsi VPM. Half of the texts don't even mention it. The major
projection is the contralateral VTT, which transmits all other sensory
info from each portion of CNV (V1,V2,V3) to the contralateral VPM. It is
the only one I mentioned and the one you need to know for lesion localizing."

 

[idq1i]

Also what do people think of HY neuro. After reading it a bit, I am not liking it. It is filled with errors and kinda sucks. What are your thoughts on it?

Thanks,

I recommend Lange Clinical Neuro

 

[viper]

Sounds good to me. In reality, obviously these pathways are much more complex than we learn. However, in a basic text and especially one for USMLE, the contralateral should be mentioned first (and then if the author feels like it, the other should be noted) - this would avoid confusing the hell out of us. I think Fix (author of HY) made an error on this one and should have said contralateral. This book has too many errors - and for a book in third edition, they should have fixed these things.
Thanks for the response, but what is VTT and DTT referring to?

 

[Ramoray]

That is correct about the major being contralateral but as far as lesions go you have to think of levels. Dont quote me on exact levels cause i havent reviewed neuro yet but for example a lesion of the medulla will knock out the CN V nucleus v. a lesion of the upper pons in the same position will breach the ascending fibres that crossed from below, from the contralateral side and since the nucleus was at a lower level you are not impinging on it anymore. So anyway lower lesions cause impsi sensation loss since you take out the nucleus on the same side before any of its fibres cross, and higher ones cause contra sensation loss since you simply take out the fibres ascending that have long since crossed and you dont touch the nuclues since it is not present at the higher levels.. Correct me if im wrong i very well could have this backwwards or straight out wrong since my memory is poor but i believe this to be correct.

 

[JMD]

Thanks for the response, but what is VTT and DTT referring to?

I actually am not totally sure... I think it's Ventral and Dorsal Trigeminothalamic tract or something like that. I agree that Fix goofed on that and the book's not great for being a 3rd edition.

About to do one last quick review of neuroanatomy for my exam in 4 days. Probably just use FA and my annotations though. I think I'm through with HY at this point.

 

[viper]

Couple of others to chew-on.

1. if you turn chin to right side - there is intorsion of left eye and extorsion of right eye (p. 92 HY neuro). Can someone explain this - I don't get it.

2. I get the difference between visceral and somatic - so visceral afferent, visceral efferent, somatic afferent, etc. But Fix also uses general and special in front of these (without any explanation of what they mean). Can someone explain the difference between say general visceral efferent and special visceral efferent please?

Thanks,

ps. and if i run into one more thing that he doesn't explain and decides to put in here, I am chucking this book out the window. The Kaplan neuro was actually so much better than this.

 

[RLMD]

I dont know what yall are talking about. HY Neuro does a good job explaining this. Pgs. 77-79 in the third edition, it breaks down the ventral trigeminal thalamic tract (pain and temperature - contralateral) and dorsal trigeminal thalamic tract (tactile descrimination, pressure - ipsilateral). It even has a picture on pg. 79. what more could you want?

 

[idq1i]

Couple of others to chew-on.

1. if you turn chin to right side - there is intorsion of left eye and extorsion of right eye (p. 92 HY neuro). Can someone explain this - I don't get it.

2. I get the difference between visceral and somatic - so visceral afferent, visceral efferent, somatic afferent, etc. But Fix also uses general and special in front of these (without any explanation of what they mean). Can someone explain the difference between say general visceral efferent and special visceral efferent please?

Thanks,

ps. and if i run into one more thing that he doesn't explain and decides to put in here, I am chucking this book out the window. The Kaplan neuro was actually so much better than this.

1 - same crap in the BRS 😡
If you tilt your head to the right, the right eye will intort, and the left will extort. Vice versa when you tilt your hear to the left. The idea here is to keep the vertical orientation of the eyes unchanged

2 - special viscerals are your senses - like taste. General viscerals are everything else

 

[viper]

I dont know what yall are talking about. HY Neuro does a good job explaining this. Pgs. 77-79 in the third edition, it breaks down the ventral trigeminal thalamic tract (pain and temperature - contralateral) and dorsal trigeminal thalamic tract (tactile descrimination, pressure - ipsilateral). It even has a picture on pg. 79. what more could you want?

Damn, only if you would read our posts as carefully as you read HY. We were wondering if in the dorsal TTT the tactile discrimination is ipsilateral - as is stated on p. 78, and as the pic says on p. 79. We think it should say contralateral, that was what the discussion was about, not about if he explained it or not.

 

[viper]

1 - same crap in the BRS 😡
If you tilt your head to the right, the right eye will intort, and the left will extort. Vice versa when you tilt your hear to the left. The idea here is to keep the vertical orientation of the eyes unchanged

2 - special viscerals are your senses - like taste. General viscerals are everything else

alright i think i figured it out (I'm guessing). As you turn chin to right, both eyes will rotate left to compensate. For the left eye this will be extortion as it moves away from the center (nose). For the right eye, it also rotates left, but towards the center (nose) and will be intorted. One of those relative-thingymajiggys, me thinks.

 

[lattimer13]

First Aid was more than enough for the neuroanatomy that was on my exam on tuesday.

 

[Pox in a box]

First Aid was more than enough for the neuroanatomy that was on my exam on tuesday.

Then you were extremely lucky.

 

[lattimer13]

Then you were extremely lucky.

we also had nolte, the guy who wrote the textbook "the human brain" teach us neuroanatomy in our first year. he used to write questions for step 1 but not anymore...step 1 questions seemed WAY easier than his exam questions for his class. but you're right i was probably lucky on my exam with neuro.

 

[viper]

we also had nolte, the guy who wrote the textbook "the human brain" teach us neuroanatomy in our first year. he used to write questions for step 1 but not anymore...step 1 questions seemed WAY easier than his exam questions for his class. but you're right i was probably lucky on my exam with neuro.

did you get any neuro CT's or angiograms. Some friends who took it recently said they got coronary artery angiograms and another got some gross CTs.

 

[HiddenTruth]

Ok, visceral afferents are fibers that supply your vessels and sm mm. While, special are for special senses (taste, etc).

This is the way I understand the TG p/w. That p/w is mad confusing. But, basically you have to divide it up into 3 stimuli.

1. Pain and temperature. So, the TG gangl sends its peripheral processes to all the areas of the face wherever it supplies. THe central processes come back and synapse in the lower 2/3 spinal TG nucleus in the pons. Ok, so I'll come back to what happens to these fibers.

2. Discrminitive touch. Likewise, the TG nucleus sends its central processes to the brain stem, and these synapse in the principle TG nucleus and the upper 1/3 of the spinal TG nucleus (probably don't have to know the latter). Now, both the principal TG nucleus and spinal TG nucleus decussate and send their axons to the contralateral side via dorso and ventral trigeminothalamic tracts (Dorsal is carrying information from D iscriminative touch, while ventral is carrying pain and temp.

3. Proprioception and motor. THis is kinda wierd. But, the ganglia for this, mesocephalic TG nucleus, is in the CNS, but it is analogous to the TG ganglia, and so it's peripheral processes are supplying the mm spindles and GTO in the mm of mastication, while its central processes are synapsing on ipsilateral TG motor nucleus,which is also in the pons. And, somehow they also synapse on the principal TG nucleus (but this may be a minor part). And, then the motor nucl sends efferents out to the respective mm where the proprioceptive stimuli is comming from. Oh, and the mesocephalic TG nucleus extends up to the MB. SO, the point is that a lesion above the pons, will give u contralateral loss of pain, temp, and touch to the face, while it should give u ipsilateral loss of the muscles (depending on where the lesion is, because the mesocephalic nucl extends from pons up to the midbrain). But, i think that is key.

Anyways, hopefully this made some sense.

 

[lattimer13]

did you get any neuro CT's or angiograms. Some friends who took it recently said they got coronary artery angiograms and another got some gross CTs.

yes, quite a few, but very straightforward. ie, gave a common clinical presentation and asked to identify where the lesion was (got CTs, angiograms, and a few very poor quality drawings; one looked like a kindergartener had drawn it)