Sinonasal Anatomy
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Hello everyone, Dr. Sidney Levy here.
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3 00:00:04,390 --> 00:00:06,780 Today I would like to talk about the anatomy
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of the sinonasal cavity or sinonasal region as
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a prelude to a discussion of the diagnosis and
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staging of sinonasal squamous cell malignancy.
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So firstly, what are the boundaries and
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relationships of the sinonasal cavity?
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And I would like to draw these for you.
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I have here an example case of a large
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sinonasal squamous cell carcinoma on the right.
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But I would actually like to concentrate
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on the left-hand side in order to demonstrate
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some normal anatomy to you so that we are better
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oriented when we start addressing the tumor.
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On the axial projection, we have a T2-weighted sequence.
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I can show you the left nasal cavity with its mucosa
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communicating with the maxillary sinus and its mucosa.
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And the posterior boundary is the choana,
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beyond which we have the nasopharynx.
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Thank you very much.
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And I'll just round it off by outlining
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the mucosa of the nasal septum.
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On the coronal projection, we have
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mucosa outlining the maxillary sinus.
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We also have mucosa outlining the left nasal cavity
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and the superior boundary at the superior margin
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of the ethmoidal air cells is the cribriform plate.
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And we have mucosa outlining the ethmoidal
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air cells, lateral to which lies the orbit.
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In the sagittal projection, forget the tumor,
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we have the cribriform plate, we have mucosa
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of the nasal cavity, and we keep tracing
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that back as far as the posterior choanae.
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Don't forget the sphenoidal sinus as well.
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So what are the compartments?
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bounding the sinonasal cavity.
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Laterally, we have the orbits.
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Superiorly, we have the anterior cranial fossa.
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Laterally, we have the infratemporal
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fossa and masticator space.
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And posteriorly, we have the nasopharynx,
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as well as the pterygopalatine fossae,
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which are not on this direct slice.
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So in summary, the sinonasal cavity is an irregularly
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shaped region with multiple subsites, which we will
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cover in our next vignette, but the compartments that
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bound it are the anterior cranial fossa superiorly,
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the orbit superolaterally, the nasopharynx posteriorly,
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the hard palate and oral cavity inferiorly, and
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the masticator space and infratemporal fossa posterolaterally.
Sidney Levy, PhD, MBBS
Radiologist and Nuclear Medicine Specialist
I-MED
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