0:00

In the last couple of minutes, we'll just talk about some

0:03

of the diseases that involve the muscle wrappers.

0:06

And by wrappers I mean the fascia

0:08

that surrounds the muscle, uh, compartments.

0:11

This is an example of a muscle hernia,

0:14

quite an easy diagnosis.

0:16

Uh, in this example where there's a frank defect in the

0:20

fascia, and we have this muscle signal material

0:23

that is extending, um, out through the defect.

0:27

But these can be very subtle.

0:29

Uh, this was one of our fellows

0:31

who had a very subtle muscle hernia, much more evident

0:34

on ultrasound than on Mr,

0:37

because you don't see the fascial defect

0:39

and the bulge is subtle.

0:41

So when there is concern for a muscle hernia,

0:45

I think ultrasound is a much better technique.

0:48

It's dynamic, and you can do the patient standing up,

0:52

which will bring out the hernia.

0:54

So, uh, really it's a much, much better, uh, modality

0:58

'cause these are easily overlooked.

1:00

This is a picture, uh, of the hernia that much more obvious,

1:04

uh, clinically, uh, than it is on the, um, mr.

1:08

Uh, examination. Uh, in terms of the wrappers,

1:11

the other thing we wanna consider is compartment syndrome.

1:15

Now, there is no role for MR in acute compartment syndrome.

1:19

It delays treatment.

1:20

So this is suspected based on clinical features

1:24

listed to your left.

1:25

We go straight to pressure measurements,

1:28

but every once in a while we will see, uh, compartment

1:32

syndrome and secondary my necrosis that wasn't suspected.

1:37

Uh, this was a young, uh, male, uh,

1:40

who developed extensive rhabdomyolysis involving his

1:44

buttock and his thigh.

1:46

Uh, he don't, I,

1:47

we did not have a clear etiology in this particular patient,

1:51

but most of the cases that I see are either postoperative,

1:54

where they've been recumbent for a long time,

1:57

or in, uh, drug users, uh, particularly in cocaine users,

2:01

uh, which has a vasal spasm, uh, effect on top

2:05

of the patient, uh, perhaps being out of it

2:07

and not moving for many hours.

2:10

So anything that causes prolonged pressure can progress

2:14

onto, uh, my necrosis.

2:16

If you have my necrosis, this is a rare entity,

2:19

but something that you should be aware of is

2:22

that it can develop this calcific form where you get a shell

2:26

of cal calcifications, not true bone, uh, no marrow

2:30

inside the lesion, uh, around an area

2:33

where the muscle has undergone.

2:35

Uh, my calcific or my, uh, necrosis.

2:40

There's, uh, an exertional compartment syndrome

2:42

that's described.

2:44

Uh, fortunately, this is rather vague,

2:46

and many recent reviews have indicated there's a lack

2:50

of validity of this diagnosis using, um,

2:54

various diagnostic uh, tools.

2:56

So I know some people believe in it, but this

2:59

Is a, an example of a pressure change, uh,

3:03

or a signal change, at least in the anterior compartment

3:06

after exercise in somebody who was having symptoms.

3:10

But I would really exercise caution in interpreting this

3:14

because this is an asymptomatic volunteer.

3:17

These are taken from a beautiful paper

3:19

by Larry White's group in Toronto where they, uh, studied,

3:24

uh, perfusion, and they found no difference

3:27

between the patients

3:28

that had clinical exertional compartments syndrome

3:31

and normal volunteers

3:32

that many normal volunteers showed signal changes

3:36

and volume increases in their compartment.

3:39

So, I, I don't really know exactly how to, uh, interpret,

3:43

uh, these, uh, examinations.

3:46

So in the last, uh, 40, uh, 45 minutes, uh, I've gone

3:50

through the main, uh, findings that we see, uh,

3:53

with the muscle trauma.

3:54

And again, I thank you for your attention

3:57

and thank you to Don and to modality

3:59

and the organizers, uh, for allowing me to participate.