Interactive Transcript
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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.
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