0:00

Let's focus on the lateral tendon anatomy,

0:02

beginning with the peroneus brevis.

0:05

Initially, very high up, the brevis is associated

0:10

with the adjacent muscular unit and sits a

0:13

little more posterior to the peroneus longus.

0:17

And as we start to move down, the brevis

0:20

is going to assume a deeper position

0:23

and then a more anterior position.

0:26

And as we get retromalleolar, the brevis is

0:29

going to flatten right up against the back of the

0:32

fibula, which should have a groove to house these

0:37

two structures, particularly the peroneus brevis.

0:40

So if that groove is too deep,

0:43

or if that groove is too shallow, or if that

0:45

groove has spurs, you've got a problem,

0:48

and now the peroneus complex,

0:51

and especially the brevis, is prone to injury.

0:54

So let's keep working our way down.

0:56

We see a little muscular slip right

0:58

here, and if that muscular slip continues

1:01

below the ankle joint and inserts on the

1:04

calcaneus, then we're gonna have a peroneus

1:06

quartius, or a peroneal calcaneal muscle.

1:10

So we don't have that here, the muscle is

1:12

dissipating, but in front we have the brevis.

1:15

So we've gone from a retromalleolar

1:18

position, we started out with a muscular and

1:21

supramalleolar position, muscular position.

1:24

Supramalleolar position.

1:26

Retromalleolar position.

1:28

And now, we're in an inframalleolar position.

1:31

Now that we're inframalleolar and

1:33

below the ankle joint, we have a

1:34

thin wispy, infralateral retinaculum.

1:39

Let's keep going downward.

1:40

There's the retinaculum again.

1:41

Shall we?

1:42

And as we go down further, now we're

1:44

at the level of the calcaneal tubercle,

1:47

or peroneal calcaneal tubercle.

1:49

So this is the tubercle

1:51

segment of the peroneus brevis.

1:53

Now, as we go down more inferiorly, now we're post-

1:56

tubercular or pre-insertional peroneus brevis.

2:00

And then finally, we make our way to the

2:02

insertion along the base of the fifth metatarsal.

2:07

Now, let's go back a little bit.

2:09

We've already said that the area where the

2:11

peroneus brevis is prone to injury is in

2:13

the retromalleolar region, especially if the

2:16

groove of the fibula is malformed, not smooth,

2:21

irregular, lumpy, bumpy, or too shallow.

2:24

Another area where the brevis may be prone

2:26

to injury is if you get spurs out here in

2:30

the region of the calcaneus where you have

2:32

an anomaly known as tuberculum bifidum,

2:36

where you have not one of these, but two of these.

2:39

And sometimes it can restrict the movement

2:42

of one or both of the peroneus tendons.

2:47

So we've got innumerable segments.

2:49

We've got different appearances of the tendon,

2:51

for instance, when we are retromalleolar,

2:54

the tendon is going to be flat, or a

2:56

little lower, it's going to be round.

2:58

As we get more distal, it becomes elongated,

3:01

and right as it inserts, it becomes extremely wispy.

3:06

It's allowed to have a little bit of fluid around it,

3:08

about a millimeter in thickness of fluid all

3:11

the way around, that is not necessarily abnormal.

3:15

And that concludes our discussion

3:18

in the main projection, the axial

3:20

projection of the peroneus brevis.

3:23

Yes, in the sagittal projection, we see it

3:25

nicely, coursing around the back of the fibula.

3:28

It's so flat, we have trouble seeing it in the

3:31

sagittal projection behind the lateral malleolus.

3:34

Then we're able to follow it down.

3:35

It looks a little bit more robust.

3:37

We're in the inframalleolar segment.

3:39

It's now in front of the longus.

3:42

And finally, we can track it down to

3:44

the base of the fifth metatarsal and

3:47

differentiate it clearly from the peroneus longus,

3:50

which is entering the cuboid tunnel.