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This case is an ankle injury case.

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And not only is it important to show you

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what particular ligament is involved or the

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area that's involved, but it also explains

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an overarching theme in pediatric imaging,

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which is that ligaments and tendons are

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a lot stronger than the actual bones that

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they're attached to, which is a completely

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different paradigm from what happens in the

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adult population where it's the ligaments and

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tendons that tear first or get injured first.

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And secondarily, the bone.

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That's because the composition of

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bone and cartilage in the pediatric

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population is much different.

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You know, kids are not just small adults.

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And this is a perfect example.

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Typically, adults, when they injure their

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lateral ankle, they tear this ligament

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right over here, which is the ATFL, also

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known as the anterior talofibular ligament.

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So, as I go through this, I'm going to go back

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and forth, and one way to realize that you're

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looking at the talofibular ligament is bring

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up a coronal image, as I do have over here, and

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then see what the cross-sectional imaging does.

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So, at this point, we know

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we're at, we're too high.

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So, any ligament you see at this level

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cannot be the talofibular because

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you're at the level of the tibia.

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So, you're at the high ankle.

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So, any ligament you see over here, for

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example, this one is the tibiofibular.

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As we go further down, now

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we're at the level of the talus.

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So, we know any ligament we see at this

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point, for example, this guy right

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here, it has to be the talofibular.

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And look at this, this is a beautiful

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example of an anterior talofibular ligament.

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Yet it's completely normal.

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However, look what's happening behind over here.

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This is a little piece of fibula

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that has been avulsed off of the

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bigger portion right over here.

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Okay?

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So, you can actually see the little

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fracture line going right through here.

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On the coronal images, I have both

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a coronal T1 and a coronal fat

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suppressed fluid sensitive sequence.

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And if you're ever confused whether it's

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a STIR or a T2 fat sat, if somebody's

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asking a question, you can avoid

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the issue altogether and just call it a

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fat suppressed fluid sensitive sequence.

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As I look at this, and you'll notice right

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here, there's a little piece of bone, a fleck

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of bone, that has been avulsed off of the

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inferior margin of the bigger fibular epiphysis.

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Okay?

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So, and we know from the mechanism that

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this is probably an inversion type of

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injury, such that now the sole of the foot

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is pointing medially or even towards the

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patient's head, in an inverted fashion.

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So, when that happens, three things can happen.

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First, you can injure the complex

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that we just showed, which is the

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anterior talofibular ligament.

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The next thing to go is the

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calcaneofibular ligament, which is

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best seen, I think, on the axials.

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As we come down here, we find where the

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calcaneus is, and there should be a nice

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structure over here that's nice and dark.

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We don't see it.

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It's sort of globular, hyperintense.

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There's fluid.

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In the associated peroneus

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longus and brevis tendons.

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So, we know there is some injury, at

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least a partial tear, of this ligament,

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which is the calcaneofibular ligament.

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Finally, the third thing to go is

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posteriorly, back over here, which

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is the posterior talofibular ligament.

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Again, you see it attaching to the fibula,

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part of the fibula that has been avulsed off,

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but the ligament itself is completely normal.

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So, great example.

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of an avulsed anterior talofibular ligament

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where a little piece or fleck of fibula has been

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taken off, but the ligament itself is intact.

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A very good look for the type of

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injuries kids get, and not adults.