Ipsilateral Puns

Hello. Would anyone be willing to provide a list of sorts for what sensory info is processed contralateral and what is ipsilateral? Any bilateral ones that are important?

I know hearing and vision are contralateral. Other processes are a little fuzzy.

Hello! My boyfriend is hesitant about getting his third dose due to what happened after his first two doses. I'm only a second-year medical student so hoping to get some expert opinions.

HPI - acute onset numbness and tingling on ipsilateral side of body (including face) for 12-24 hrs after Covid vaccines

Demographic - 26M, East Asian

Height - 6 ft/183cm

Weight - 145 lb/66 kg

PMHx - none

PSHx - none

FHx - maternal HTN, cardiovascular issues (unclear on details)

Essentially, the numbness began immediately after the shots both times and lasted for less than a day. Some tingling as well, but motor functions were normal. (This is all from his own history, not a PE.) He also had other expected side effects like muscle weakness/mild fatigue.

He's very worried because he doesn't think sensory loss is a "normal" side effects so now he doesn't want to get his third dose. He wants to know if this is a concerning finding, and, even if it's not, he wants to understand the pathophysiology behind why he experienced this, so we would appreciate any explanation, thank you!

By face weakness, i mean the muscles under CN7 innervation. Not the other cranial nerves.

I understand that the corticobulbar and corticospinal tracts are still close to each other and neither have decussated at the cerebral peduncles at the midbrain, so midbrain strokes affecting the pyramidal tract(both corticobulbar and corticospinal) tend to cause face,arm,leg weakness all on the same side, i.e produce a subcortical stroke type of weakness pattern.

My question is which level, exactly, do the CN7 distribution UMN nerves decussate to produce crossed signs? Do they decussate right at the junction between the midbrain and the pons, and therefore every pontine stroke must invariably lead to crossed signs? Or do they decussate at the middle part of the pons such that those pontine strokes that occur at a level above the level of decussation mimic a subcortical stroke type of weakness pattern, whereas those below would produce crossed signs?

Im asking this because, hypothetically, suppose i have a patient with arm and leg weakness on one side + UMN CN7 weakness sparing forehead on the same side. At this point of the physical exam, should i include pontine lesions in my differential, in addition to cortical, subcortical, and midbrain lesions? Or should i exclude pontine lesions just based on the fact that the face weakness was not crossed?

I understand that other signs need to be taken into account e.g other cranial nerve deficits, cortical signs etc before a proper diagnosis should be made. However, i am trying to make every second of the physical exam process a reasoning exercise, instead of only starting to reason after every single step is performed.

I also tried reading books like Bradley's but they usually just describe the weaknesses in any syndrome as "hemiparesis", without specifying whether face is included, and whether the facial weakness is ipsilateral or contralateral to body weakness.

Thank you!

I do know that the corticospinal tract decussates at the pyramids / medulla. If the left part of the cortex controls the right side of the body, why does a lesion on the right side if the spinal cord lead to ipsilateral loss of UMN?

Has anybody found a diagram or something that simplifies this? I always get confused on when is the lesion ipsilateral or not.

Dosent frontal eye feild just control the ipsilateral eye adduction during lateral gaze ?

Basic labs all normal, CSF normal except minimally elevated protein. CT, CTA, MRI, MRA of head and neck all normal. Just got MRA of t-spine and L-spine. Radiologist gave very vague reading on t-spine “anterior displacement of cord with mild flattening at t-2 through t-8. Gave a very detailed reading of l-spine describing normal findings and normal cord signal at each level. Symptoms progressing rapidly and no one has a clue. At one point a psych evaluation was ordered. Anyone have any ideas?

.

I know touch, sight and hearing are contralateral and taste and smell are ipsilateral. I understand the concept of crossing over of nerves at the chiasma but I get confused when there's crossing over beyond that.

For example I got a question that asked about where sound in the left ear ends up and I figured ok it crossed over so its in the right hemisphere but the answer was that it crossed over to the right auditory cortex before being transmitted to the left hemisphere for language processing so it ends up on the left, the same side it arrived on. would a sound to the right ear do the same? cross to the left auditory cortex and then cross back or would it stay at the left for language processing?

edit: thanks for the correct, smell is the only ipsilateral sense

Is it by compressing the pyramidal tracts?

https://preview.redd.it/aw64h6cw8g041.png?width=554&format=png&auto=webp&s=c1c2789fdc9cdd06d825f87f197a1df17ed826c9

Anybody have a cheat sheet for this???

Can someone explain to me how the nerve fiber pathways are affected in each of the above case?

Im using 300 pg KA Notes, and ive been noticing sometimes stuff is added that is not in the video. The note in title is on of these. What does that mean?

So what is it, for reals?

Do auditory signals (say verbal speech) from the left ear cross over to the right hemisphere? But then they come back to the left hemisphere to Wernicke's area?

There was a section bank question about this but AAMC's explanations are trash

So let's suppose that the mandible for whatever reason (dental malocclusion) shifts from its centered position under the cranium, to a laterally displaced one. For the example I will say that the lower jaw displaced to the left side of the cranium.

Does this displacement creates a torque on the cranio-cervical articulation (Atlanto occipital joint) that would at time tend to produce a tilting of the skull to the same side of the jaw displacement -in this case the left? Of course this would be in the frontal plane about a sagittal axis.

Is this correct to assume that, taking in consideration that the mandible hangs from the skull? Or not?

Thanks in advance.

I understand how strokes affect the body, and I understand CN7 specifically. My trouble is with the other cranial nerves. For example, would a brain stem stroke affecting the right CNV nucleus cause sensory loss to the ipsilateral or contralateral face?