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Dr. P here with the 7th or facial nerve.

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Got a beautiful little diagram here that shows the

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intramedullary or real origin of the 7th nerve,

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which is located in the pons.

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But then we have exit at the pontobulbar sulcus.

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And that origin is going to come out in an anterolateral

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orientation with its chubby little neighbor,

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the 8th nerve.

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Now, my goal here is to talk about the apparent origin,

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which you see right here on this diagram,

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but also the segments of the facial nerve.

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So now, let's utilize an MRI

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to look at the apparent origin of the 7th nerve

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anterolaterally in the pontobulbar sulcus,

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and then look at the appearance of the 7th nerve

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and its relationship to some of the other structures

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around it, as we decide on the individual segments

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of the 7th nerve.

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So, I am going to look in the sagittal projection,

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pretty much orthogonally like this.

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And when I do that in the sagittal projection,

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I end up with four dots.

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One, two, three and four.

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Let's take a look at those four dots.

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We've got seven up,

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like the soda,

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and coke down,

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like the soda.

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Seven up, right there.

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So, I'm going to put a dot over that

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7th nerve.

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Coke down,

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I'm going to put a dot over that.

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Then in the back,

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I've got the superior vestibular nerve

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and the inferior vestibular nerve.

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Now, those are divided by some septa,

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never mind if they're bony or fibrous for right now.

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And I'm going to make those septa in blue.

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Dividing the top group from the bottom

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group is the crista falciformis,

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and then incompletely dividing from the top down,

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but particularly the cochlear nerve,

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sorry, the 7th nerve and the superior vestibular nerve

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is Bill's bar,

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or Bill bar.

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So, we've got this almost T-shaped configuration.

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Some people actually draw Bill's bar all the way through,

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but it only goes about halfway through.

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So, let's just review.

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Seven up, coke down,

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superior vestibular, inferior vestibular.

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So now, in the next vignette,

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let's drive home the individual segments of the 7th nerve.