Exit of the Glossopharyngeal Nerve
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Dr. P here talking about the glossopharyngeal
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or 9th cranial nerve,
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arising from the medulla oblongata.
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Here's 9, 10, and 11 right here.
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And the nerve passes anterolaterally.
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So, let's go down.
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Now, it courses right next to the flocculus,
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part of the flocculo nodular lobe of the cerebellum.
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Here's the flocculus.
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So, you can see the close proximity
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of the glossopharyngeal nerve to the flocculus.
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Here's the glossopharyngeal nerve.
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There's the flocculus right next to it.
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And then we follow it into the region of the jugular fossa,
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which is going to be right here.
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Now, it's difficult to follow contiguously,
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but you see part of it right there.
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And again,
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we're going to talk about nerves 9, 10, and 11 together.
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They're all going into the jugular foramen through
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the central part of the jugular foramen.
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Not as easily seen on this T1-weighted image,
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but it is seen, as it is on this T2-weighted
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cisternographic image.
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Now, as the nerve hits the jugular foramen,
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I want to talk about what happens in here,
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which is very difficult to see anatomically.
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But you've got superior and inferior ganglia in the jugular foramen,
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and they have their own sheath of dura mater.
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The inferior ganglion sits on the inferior surface of the
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petrous part of the temporal bone and is
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related with a triangular depression into which
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the aqueduct of the cochlea actually opens.
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Let's have a look at that anatomic information on CT.
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So on this accompanying CT image,
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you see a triangular shaped space in the region of the
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jugular fossa with the jugular tympanic spine.
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And this is known as the petrosal fossula
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and contains the inferior ganglion of nine.
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Dr. P out.
Stephen J Pomeranz, MD
Chief Medical Officer, ProScan Imaging. Founder, MRI Online
ProScan Imaging
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