I received the following to day. It is an extract from a fuller
article.

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The eighth cranial nerve, the acoustic nerve, is a purely sensory
nerve. It goes from the hearing organ into the brain for
interpretation. But the hearing organ is made up of an eardrum; it is
made up of three little bones, the ossicles; it's made up of muscles
that activate those; it's made up of the organ of corti, a very, very
intricate and exquisitely arranged system of neurons which, of course,
are all human body tissues; and all of them require an ability to take
on food stuff and give off waste products in order for themselves to
be healthy. Those are called trophic functions.

That nerve supply starts in the nuclei of the brainstem. The brain
stem goes down the tracks of the cord at least as low as what we refer
to as a stellate ganglion, which is a sympathetic ganglion opposite
the transversus of the seven cervical  first thoracic spinal nerves.
From there, those impulses recur out into the sympathy trunks.

The sympathy trunks then recur back up the neck, middle cervical
ganglion, superior cervical ganglion and prolongations of which go
back through the cranial floor by the internal carotid canal, and by
way of the internal carotid and cavernous plexus, connect with all the
cranial nerves including the hearing organ.

Those structures of hearing gain their trophic nerve supply by what we
call a motor supply, not through the eighth cranial nerve.
…………..

Once an impulse gets into the sympathetic trunk, it recurs up and down
the pre-ganglionic and post-ganglionic fibers, and it's easy for us to
understand and research how those trophic impulses come from the
spinal cord into all of the cranial nerves.
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