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Dr. P here, back with the parasympathetic ganglia

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and their relationship to cranial nerve five.

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There are four of them in the head and neck:

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the ciliary, the pterygopalatine,

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the submandibular, and the otic.

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I want to look at an axial T1 thin section,

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1 mm high-resolution MRI to show you the

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position of the two that are most important

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and intimate with the fifth nerve.

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I want to share with you the position of the

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submandibular ganglion and pterygopalatine

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ganglion. Let's start with the SMG first.

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We're just atop the region of

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the submandibular gland.

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It's pretty hard to see on this

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T1-weighted image,

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but let's scroll a little bit and we see this

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ill-defined sort of stellate round structure

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that lies just lateral to the hyoglossus or

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right near or on top of the hyoglossus,

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but along the posterior margin of the

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mylohyoid. That's an important landmark.

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Now, when we look at this ganglion sagittally,

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if we were looking from the side,

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we might see something like the lingual

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nerve coming down. And by the way,

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the lingual nerve often houses with its

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traveling partner, the corda tympani nerve,

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which is a branch of the seventh.

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So the lingual nerve from the mandibular division

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of five has the lingual nerve as its branch.

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And these two travel together in concert.

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The branch of the seventh nerve,

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namely the chorda tympani nerve,

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traveling within yellow. The lingual nerve.

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Now,

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hanging down from the lingual nerve

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is the submandibular ganglion. Sorry,

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is the submandibular ganglion,

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not the stellate ganglion.

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So there's your submandibular ganglion

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and there are actually two filaments.

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There's an anterior filament and a posterior

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filament that suspends this nerve.

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Now, let's talk a little bit more about

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the function of the nerve.

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Even though we're talking parasympathetic

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ganglia in the head, neck, ciliary,

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pterygopalatine, submandibular, and otic,

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this particular nerve has some sympathetic

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function from the external carotid plexus that

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travels there or gets there

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via the facial artery.

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We've got pre-ganglionic parasympathetics from

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the superior salivatory nucleus of the

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pons via the chorda tympani.

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So they get there via this traveling partner

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of the chorda tympani and the lingual nerve.

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You've also got some post-ganglionic

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sympathetics to the oral area and to the

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submandibular gland and sublingual gland where

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some secretory function is also provided.

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And there's some sympathetic function

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in this distribution as well.

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Now, I'd like to move on to an MRI,

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the pterygopalatine ganglion. Let's do that, shall we?

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Dr. P out.