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Dr. P here, this is a 48-year-old woman who

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3 00:00:03,979 --> 00:00:05,630 had a fracture 10 years ago, and now

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she's in a walking boot for lateral pain.

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You know, anytime I hear the term or word lateral

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pain as part of a history, it's not a word,

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it's two words, um, I start thinking about,

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especially in the absence of an ankle sprain,

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I start thinking about the lateral tendon group.

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Of course, there are other structures

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over there, like the sural nerve and the

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cuboid and the short plantar ligaments

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and portions of the Chopart joint.

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But I really do drill into

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the peroneus tendons first.

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And as I do that, I try and separate

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them out, peroneus longus and brevis.

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And there is the peroneus longus.

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You can identify it because it has

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more of a plantar course to it.

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So once you find the plantar course,

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you just follow it backwards.

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There is a little fluid hanging around with it.

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And then you get back to it, and it looks peachy.

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But the peroneus brevis, which is directly

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in front of it, it does not look so peachy.

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It has this large, confluent,

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high signal intensity within it.

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And on the sagittal view, let's scroll

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the sagittal view, and I'll demystify

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it by making it a little less magnified.

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There's your peroneus brevis, which

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goes to the base of the fifth.

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It has this weird-looking high signal

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intensity, round to oval mass inside.

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And the reason I wanted to share this case

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with you is this is an example of a

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mucoid or myxoid degeneration of a tendon.

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Now how and why this occurs, perhaps there's

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an injury or break between the periphery of the

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tendon itself and the sheath that surrounds it

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that allows the fluid that normally bathes the

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peroneus brevis to imbibe into a small crack or

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tear in the tendon and that gradually expands.

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This is not a common phenomenon

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at all but it is not uncommon

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with the peroneus longus.

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So the peroneus longus tends to be a hypertrophic

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type of tear whereas the peroneus brevis

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tends to be an atrophic split type tear.

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So frequently what you're going to see

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is the longus look something like this.

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And then you'll see the brevis over top

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of it, with a split, almost looks like an

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arrow that's been separated in the middle.

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Here's the separation right down the center there.

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So you will see that in the retro and

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intramalleolar region, not infrequently, and

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sometimes that is accompanied by a cyst that's

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occurring in the hypertrophic peroneus longus.

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But having an isolated cyst in the

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brevis, especially distally like

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this, is an uncommon phenomenon.

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So that concludes this case. Dr. P out.