Hypopharynx - The Postcricoid Space Anatomy
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Hello everyone, this is
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Dr. Sidney Levy, continuing our discussion
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of the anatomy of the hypopharynx.
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I'd like to focus on the postcricoid region, which
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is one of the three subsites of the hypopharynx.
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I'd like to draw its boundaries for you first.
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The postcricoid region or space is the
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anterior wall of the lower hypopharynx.
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It extends from the level of the arytenoid cartilages
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to the inferior border of the cricoid cartilage.
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This here is the inferior border of the cricoid cartilage.
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This here is the level of the arytenoid cartilages,
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which are best demonstrated on the axial projection.
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Superior to the postcricoid space,
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we have the laryngeal inlet, which is here.
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Inferior to the postcricoid space,
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we have the cervical esophagus, here.
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Now, you may have noticed that the region
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of the postcricoid space is abnormally
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prominent on the sagittal projection.
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And the reason for this is that there
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is actually a malignancy in this region.
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And they can be often very difficult to spot.
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Often, all you will get is an abnormal thickening of the
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anterior wall of the hypopharynx, as you have in this case.
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But back to the anatomy.
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Anterior to the postcricoid space,
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we have the structures of the larynx.
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That includes the laryngeal cartilages, specifically the
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cricoid cartilage here, and the glottis, subglottis, and
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supraglottis, so essentially the soft tissues of the larynx.
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So the postcricoid space is small because
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remember it doesn't include the posterior
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wall of the hypopharynx at this level.
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The posterior wall of the hypopharynx is here.
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Therefore, the postcricoid space is actually a
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very thin area of soft tissue and really only
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constitutes this line of soft tissue here.
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So in summary, the postcricoid region is
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a small region which is easy to overlook.
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It's best to think of it as the
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anterior wall of the lower hypopharynx.
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It may be seen often most easily on the sagittal
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projection or the axial projection, but your key
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landmarks are the arytenoid cartilages, which are
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anterior to it, as part of the supraglottic larynx.
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This here is the postcricoid space.
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I will also draw the posterior hypopharyngeal wall.
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Because the lumen is collapsed at this level, they
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are often seen as a continuous soft tissue structure.
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And it's best to help orient yourself using a
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combination of the axial and the sagittal projections.
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And remember the larynx is anterior,
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the cervical esophagus is inferior, and the
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posterior hypopharyngeal wall is posterior.
Sidney Levy, PhD, MBBS
Radiologist and Nuclear Medicine Specialist
I-MED
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