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Do cranial nerves 5,6,8,10,12 end up being ipsilateral cranial nerves that do not decussate to innervate their end target organs,muscles,etc?
Thanks for the help
Thanks for the help
Do cranial nerves 5,6,8,10,12 end up being ipsilateral cranial nerves that do not decussate to innervate their end target organs,muscles,etc?
Thanks for the help
Not sure if I understood your question correctly, but all the CNs are peripheral nerves, so they are all ipsilateral
I thought all CN's decussate after leaving the brainstem...where only CN4 decussates immediately
I thought all CN's decussate after leaving the brainstem...where only CN4 decussates immediately
Not quite. The lower motor neuron exiting the brainstem for everything but CN IV is ipsilateral to its cranial nerve nucleus. The upper motor neuron for every single cranial nerve descussates in the brainstem just like any other upper motor neuron. CN IV is just more confusing in that the lower motor neurons cross over as they leave the brainstem. So the left CN IV nucleus controls the right superior oblique, and is also innervated by the right pre-central cerebral cortex. None of the others do that. In general a cranial nerve innervates muscles that are ipsilateral to its nucleus, and contralateral to the brain hemisphere that controls it. Of course, this is ignoring that a lot of the muscles in the head receive innervation from both sides of the brain.
Hmm that makes sense. And all nerves receive dual supply except for Nerve VII and XII? I had heard about VII but didnt know XII receives supply from only one hemisphere as well, can anyone confirm this
I'm scared. all this sounds like a lost ancient language to me.
Not quite. The lower motor neuron exiting the brainstem for everything but CN IV is ipsilateral to its cranial nerve nucleus. The upper motor neuron for every single cranial nerve descussates in the brainstem just like any other upper motor neuron. CN IV is just more confusing in that the lower motor neurons cross over as they leave the brainstem. So the left CN IV nucleus controls the right superior oblique, and is also innervated by the right pre-central cerebral cortex. None of the others do that. In general a cranial nerve innervates muscles that are ipsilateral to its nucleus, and contralateral to the brain hemisphere that controls it. Of course, this is ignoring that a lot of the muscles in the head receive innervation from both sides of the brain.