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

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I want to make three points.

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First, The 7th nerve has two bends.

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One bend is known as the genu.

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It occurs in front,

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and this is also known as the geniculum

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of the facial nerve. Genu means knee,

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and it contains the geniculate ganglion.

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You can actually see the ganglion right here.

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It's this gray little blob that is covered by this whitish area,

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which represents the petrosal plexus of veins right next to it,

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coursing alongside portions of the

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horizontal tympanic facial nerve.

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And those will come back to the second curve in the nerve.

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So, we come back to the second curve.

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Now, we can't see that curve because that curve goes down

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into the screen as the vertical segment,

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and then exits from the stylomastoid foramen.

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So, we've established that there's two curves.

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One curve here at the genu with the geniculate ganglion

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and the other curve in the back.

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Now, if we try and cross-reference the geniculate ganglion,

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which is our second point of interest,

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the geniculate ganglion is right here in the sagittal projection.

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This is a magnified sagittal view.

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So, this would be anterior.

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This would be posterior.

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I'll minify it a little bit so you can see where you are.

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So, here's the cerebellum back here.

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Now, it's really hard to see the ganglion,

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but you can see what a challenging structure it is to see.

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And then, the next point I'd like to make is the first

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branches that come off from the facial nerve.

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Now, the reason I chose to show you the geniculate ganglion

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is that's a marker for where these branches come off,

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because you can't really see them.

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And these include the greater superficial petrosal nerve,

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which arises right there,

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and the greater petrosal nerve runs through

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the pterygoid canal,

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its synapses in the pterygopalatine ganglion

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and postsynaptic fibers of the greater petrosal

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nerve innervate the lacrimal

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and the tympanic segment.

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The facial nerve runs through the tympanic cavity,

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medial to the incus.

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We can't really see that here,

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but it's more of a horizontal component to it.

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And then, it reaches its second bend where

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it runs in a vertical orientation.

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So in the temporal part of the facial canal,

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the nerve gives rise to a few more branches

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to the stapedius and to the chorda tympani.

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And the chorda tympani

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supplies taste of fibers to the anterior

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two thirds of the tongue and also synapses

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with the submandibular ganglion.

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Now postsynaptic fibers from the submandibular ganglion supply,

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the sublingual and the submandibular glands.

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Let's move on.