Vestibulocochlear Nerve: Cochlea and Internal Auditory Canal
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I want to finish up our discussion of
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the cochlear vestibular, or 8th nerve,
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by starting with the cochlea.
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The nerve comes away from the cochlea.
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There's the modiolus of the cochlea,
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there's the spiral lamina.
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And the high signal intensity represents the components
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of endolymph and perilymph in the otic capsule.
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Now, the spiral ganglia are where the nerves start.
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Then it becomes a nerve and it travels through the
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internal auditory meatus and then enters
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the ponto midbrain sulcus,
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or just above the ponto midbrain sulcus
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at the cerebellopontine angle.
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Now, there's a nerve in front and a nerve in back
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when you're at the level of the cochlear nerve.
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Since it's seven, up,
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coke, down,
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you're at the level of the inferior vestibular nerve.
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When you're at the level of the facial nerve,
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you're at the level posteriorly of the superior
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vestibular nerve.
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Or set another way, let's draw.
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So if I were to produce a sagittal oblique,
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like this or this,
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and then I had you look at that sagittal oblique,
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you'd see four round structures,
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like this.
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So this would be anterior,
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this would be posterior,
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and high up front,
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you would see the facial nerve.
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So seven, up,
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coke, down.
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Here would be your cochlear nerve.
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And in the back,
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you'd have the superior vestibular nerve
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and the inferior vestibular nerve.
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And these would be separated by the crista falciformis
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and might be partially separated vertically
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by the structure known as Bill's bar.
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Let's move on, shall we?
Stephen J Pomeranz, MD
Chief Medical Officer, ProScan Imaging. Founder, MRI Online
ProScan Imaging
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