Interactive Transcript
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I'd like to scroll in the axial and coronal projection.
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And my first projection will be an axial diagram at the level of the PCL
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insertion on this tibial notch depression,
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which lies below the tibial plateau.
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The PCL, as mentioned, is about 38 mm in length and it has an anterior,
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a middle, and then posterior and posterior oblique fibers.
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The anterior and middle make up about 85% of the PCL.
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So let's scroll in the axial projection.
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We're down low in the tibial notch.
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It's round, it's fat. There's an anterolateral and a posteromedial bundle.
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We see them a little bit better right here.
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Anterolateral and posteromedial lying directly
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underneath the oblique popliteal ligament.
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Now the anterolateral bundle will tighten in flexion
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the posteromedial bundle will tighten in extension,
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one sees their very close position to the medial and the lateral meniscus.
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The PCL is arching up and anterior,
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and so it's starting to move anterior.
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Here's a nice separation between the anteromedial and posterior
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lateral bundle right here. So anteromedial, posterolateral.
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And the ACL has a much more linear configuration in cross-section,
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whereas the PCL is either circular or oblong.
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Let's keep scrolling, shall we?
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We're going to follow the PCL as it moves anterior and snuggles
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up against the inner aspect of the medial femoral condyle.
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And finally, we see its footprint snuggled up against
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the medial femoral condyle, with the more lateral ACL
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on the lateral side against the inner aspect of the lateral femoral notch.
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The coronal projection.
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We see the insertion of the PCL on the tibia.
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It's got a broad footprint.
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And now we're going to follow it as it arcs up and anterior towards you.
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And here it comes.
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There is a structure that is coursing behind it that arises from the
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supra posterior tip of the lateral meniscus and helps stabilize
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it called the meniscofemoral ligament of wrisberg.
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In front, there'll be a meniscofemoral ligament of Humphrey.
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These structures may tighten in flexion and also with tibial internal
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and external rotation, they are secondary stabilizers.
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Our PCL, because of its arc towards you, it's rising up from the tibia,
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may have a somewhat linear configuration and occasionally is confused
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with the ACL, which is itself a more linear structure.
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The ACL has now come into view as a linear structure compared with the
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insert on the inner aspect of the medial femoral condyle.
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And there it is. More round PCL, more linear ACL.
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Let's keep coming forward. Now, here's our more round PCL.
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Now, in a subset of individuals,
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either the meniscofemoral ligament of Humphrey
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or a separate fascicle called
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the distal anterior bundle of the PCL may have its own sort of separate
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insertion right here next to the highland cartilage of
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the medial compartment.
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If one images this on MRI coronally,
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it may look like a separate structure and is sometimes confused with a
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And this is a potential pitfall, the pseudo bucket handle tear.
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