0:00

I'm back with some more distal branches

0:02

of the 7th or facial nerve.

0:05

I've got a sagittal T1 and an axial T1.

0:08

Now, my sagittal T1 is taken all the way out here,

0:11

and these two dots right here represent

0:14

the 7th nerve, up.

0:16

Cochlear nerve, down.

0:18

I'm going to ignore the cochlear nerve right now,

0:21

and we're right at the locus of the geniculate ganglion.

0:23

So, we're right over here in the axial projection.

0:27

Now, I'm going to follow the 7th nerve.

0:30

And right around the geniculate ganglion,

0:32

we have the genu or the knee,

0:34

or one of the curves of the 7th nerve.

0:37

I can follow it forward, and now I can follow it back.

0:41

It travels with the petrosal plexus of veins,

0:44

so it's a little bit brighter, normally.

0:46

You don't want to confuse that with enhancement.

0:48

It's just flow phenomenon.

0:50

And now as we follow it back,

0:51

we see our second curve right here.

0:53

And it curves down into the vertical

0:57

segment of the 7th nerve,

0:59

which corresponds axially to

1:01

this structure right here.

1:04

So, what branches come out at this locus?

1:07

The posterior auricular branch in the descending

1:10

portion before it exits the cranial vault or cavity,

1:14

and then passes through the parotid gland.

1:17

Now, it doesn't innervate the parotid gland,

1:20

but it does form a parotid plexus,

1:22

which splits into five branches,

1:25

innervating the muscles of facial expression.

1:28

And these can be remembered with the cute mnemonic,

1:31

'"Two Zebras Bit My Cow."

1:33

T for temporal,

1:34

Z for zygomatic,

1:35

B for buccal,

1:36

M for mandibular,

1:37

and C for cervical.

1:39

Let's move on, shall we?

Distal Branches of the Facial Nerve

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