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So in this talk, we're gonna talk about an introduction

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to the normal anatomy of the oropharynx.

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There are four separate components to the oral

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pharynx: the tongue base, the tonsil, the soft

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palate, and the posterior pharyngeal wall.

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And we're gonna go through each specific level

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and focus on the applied anatomy that you'll

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need to know when you're evaluating patients

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that have imaging performed of the oropharynx.

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So the first area that we'll

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talk about is the tongue base.

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So when we look at the normal anatomy of the

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oral cavity and the oropharynx, we can see

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the chevron-shaped papillae, which are located

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in the posterior aspect of your tongue.

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The tongue that's anterior to the circumvallate

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papillae is referred to as the oral tongue, or the

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mobile tongue, and that's part of the oral cavity.

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And we'll cover that in the next lecture.

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But the area of the tongue that's

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located behind the circumvallate papillae

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is referred to as the tongue base.

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It has a separate embryologic origin and has a

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separate lymphatic supply compared to the oral tongue.

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So here's a schematic illustration of a tongue base

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carcinoma, and I wanna point out the applied anatomy.

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Notice the muscles that go from the

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genial tubercle to the tongue base.

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These are the genioglossus muscles, and notice

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the transverse fibers of the tongue base.

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When we look on the right-hand side, we see a CT

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of a patient that has a tongue base carcinoma.

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Here are the vertically oriented muscles that

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go from the genial tubercle to the tongue base.

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Notice the transverse fibers here.

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And on the patient's right side, we can see

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a very large right tongue base carcinoma.

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But this nicely illustrates a difference

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between the tumor, the floor of the mouth,

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which is from the genial tubercle to the tongue

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base, and the tongue base transverse fibers.

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Another example here.

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This is an example of a lateralized,

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right tongue base carcinoma.

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I wanna point your attention to the normal

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appearance of the tongue base, which

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contains fat and the transverse fibers.

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This tumor does not go to midline, but in this

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particular case, we can see that this tumor

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crosses the midline, and we have just a little bit.

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Of the remaining fat within a

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normally appearing tongue base.

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The next area is the tonsil, and the

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tonsil actually has three components to it.

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The main part of the tonsil is this area here, which

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is referred to as the faucial or the palatine tonsil.

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So if you've ever had your tonsils taken out,

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this is the part of the tonsil that's resected.

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The other part of the tonsil

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is this little area anteriorly,

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which extends from the palate to the

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lateral aspect of the tongue base.

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And this muscle is a palatoglossus muscle.

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It's also known as the anterior tonsillar pillar.

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If you look posteriorly, there's another muscle

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here, and that goes to the palate, to the pharyngeal

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wall, and that's the palatopharyngeus muscle.

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And this is known as the posterior tonsillar pillar.

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So the three components of the tonsil are the

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faucial/palatine tonsil, the anterior tonsillar

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pillar, and then the posterior tonsillar pillar.

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So this is what our referring physician sees.

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This is a patient that has a carcinoma involving

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the left tonsil, and here's a schematic illustration

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of a palatine or faucial tonsil carcinoma.

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And again, the key thing is are these

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various types of spread patterns.

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So here's just a nice little case that

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highlights the anatomy and the power of imaging.

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This is that schematic

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illustration of a tonsillar carcinoma.

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This patient has a tonsillar carcinoma involving

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the lower pole of the tonsil, but in this case,

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it's exophytic, extending out into the airway.

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This, on the other hand, is another tonsillar carcinoma.

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Our referring physician can see this, but

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they really can't see what's happening deeply.

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So if you look at the normal side, this

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triangular fat is the parapharyngeal space.

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Lateral to the parapharyngeal space is this

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muscle, which is the medial pterygoid muscle.

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If you look closely, there's

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a little muscle right here.

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This is the superior constrictor muscle.

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This is what we see deeply.

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When the referring physician sees

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this, they just see the cancer.

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What they don't see is a deep extension

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to involve the parapharyngeal space.

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Notice how it's compressed.

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It just looks like a little sliver here

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compared to what it should, like a big

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triangle, and we see tumor growing laterally.

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Notice how it's abutting the medial pterygoid muscle and

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it's growing along the superior constrictor muscle.

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Those are all deep extents of tumor that our referring

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physicians can't see, and if they do see this, these

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patients will probably not be treated with some

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type of robotic surgery, and this does turn out

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to be squamous cell carcinoma, especially in HPV.

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These patients will likely be treated with

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non-surgical organ preservation therapy.

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The next area is the soft palate.

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So here's a schematic illustration of a soft

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palate cancer, and this is what it looks like on

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MR. The imaging appearance is nonspecific, but

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the location is located right at the roof, if you

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will, of the oral tongue and the oropharynx.

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So here's the sagittal image of a

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cancer that involves the soft palate.

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Notice it's very large and very bulky,

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so this is a classical appearance

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of a soft palate cancer.

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Now, when we look at cross-sectional

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imaging, the soft palate cancers tend to be

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circumferential and sometimes narrow the airway.

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And the reason that's the case is that when we

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perform cross-sectional imaging through this soft

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palate cancer, you can see how this can have a

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circumferential appearance and narrow the airway.

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So if you look at this, you may not really

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get a full extent of the anatomic extent of

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the disease, but when you take this case and

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you perform the sagittal reconstructions,

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you can see this large mass that's involving the

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soft palate with the anterior extent extending just

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at the junction of the hard and the soft palate.

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When we look at the soft palate, we always

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consider, if you will, the palatal arch.

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So here's the arch of the soft palate,

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and there are two muscles that tether

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the soft palate to the skull base.

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And those are the muscles that we learned

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in medical school as the Italian muscles.

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There's a tensor palatini and a levator

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veli palatini. Anytime that you

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evaluate the soft palate, you have to

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perform some type of coronal imaging.

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This was a reconstructed imaging, nicely

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demonstrating squamous cell carcinoma, and on

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the coronal images on the contrast-enhanced

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T1-weighted image with fat suppression.

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Again, another example of squamous cell

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carcinoma involving the soft palate.

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In this particular case, we have a soft

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palate carcinoma that's growing superiorly.

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Now look at the normal anatomy of the nasopharynx.

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This is the torus tubarius.

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This is the opening of the Eustachian tube,

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and this is the fossa of Rosenmüller.

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In this particular case, this soft

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palate carcinoma is growing superiorly.

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We can see that it's enlarging the torus tubarius.

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It's extending into the fossa of Rosenmüller.

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But when you look at the contrast-enhanced T

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1-weighted images, you can also see this tumor

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growing along the surface of the torus tubarius.

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And there's a little muscle

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right here that we forget about.

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It's called the salpingopharyngeus

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muscle, and that literally acts to close

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the opening of the Eustachian tubes.

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So this is that tumor growing along

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that subtle salpingopharyngeus muscle.

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In this particular case, the soft palate carcinoma

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extended all the way into the skull base.

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So here's replacement of the normal fat involving

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the skull base compared to the opposite side.

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All of this was clinically occult, and when

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we showed this to our referring physicians,

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they opted not to treat this with surgery,

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and this patient was treated non-surgically.

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The last area that we'll talk about of

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the last component of the oropharynx

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is the posterior pharyngeal wall.

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There are not a lot of tumors that

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involve the posterior pharyngeal wall.

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The majority of the tumors involve the tongue base,

7:31

the soft palate, and the tonsil. The anatomy of the

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posterior pharyngeal wall is that it is formed by

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this muscle, which is the superior constrictor muscle.

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So the posterior pharyngeal wall is

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formed by the superior constrictor muscle.

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Here's a schematic illustration of a posterior

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pharyngeal wall squamous cell carcinoma, and

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this was a patient on sagittal reconstructions

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demonstrating a squamous cell carcinoma

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involving the posterior pharyngeal wall.

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When we look at the axial images, again,

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here's our standard schematic illustration.

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This muscle is the superior constrictor muscle.

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We can see this tumor involving the posterior

8:07

pharyngeal wall, and this was a case of

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a squamous cell carcinoma involving the

8:12

posterior pharyngeal wall and extending

8:14

laterally to involve that lateral aspect of it.

8:18

So in summary, when we talk about the subsites

8:21

of the oropharynx — the tongue base, the

8:23

tonsil, the soft palate, and the posterior

8:25

pharyngeal wall — hopefully this will give

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you the background information needed as you

8:31

look at the other vignettes in the section

8:33

on the oral cavity and the oropharynx.