0:00

Okay, let's take a 53-year-old man who's in a motor vehicle

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accident in November, in fact, November 30th of 2017.

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The exam is performed about six weeks later,

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and he's got shoulder pain and spasms.

0:19

The shoulder locks whenever he reaches

0:22

behind his arm, and it pops in and out.

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In fact, it popped in and out four

0:26

times prior to this examination.

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And we've got, uh, three images in front of you right now.

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We're gonna add another one, namely the T1

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fat image, but these are all water-weighted.

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Gradient echo axial, a proton density fat

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suppression in the middle, and a T2 fat suppression.

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Sagittally, and this is kind of the line up that I

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like, along with a T1-weighted image in a projection.

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Usually I like my T1 in the coronal projection.

0:53

In the axial projection, you could, you could

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choose 3D gradient echo with fat suppression.

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You could choose T1, you could

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choose GRE, and this is a, a GRE.

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So as you know, GRE, good for cartilage, good for

1:06

articular, pretty good for tendons, not so good for both.

1:09

So this one shows a defect, a Hill-Sachs defect.

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Uh, but it doesn't really show

1:14

all the edema that goes with it.

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However, the coronal does.

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And so this is a pretty classic Hill Sachs in

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that it's not quite at the apex where you see the

1:23

slap lesion contusion from direct upward force.

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It's a little off to the side, usually about 5

1:29

millimeters or so, uh, more laterally positioned.

1:32

And, uh, there's some variability to it.

1:35

In fact, You know, the classic slap lesion, uh, can be

1:39

measured in the axial projection in terms of location.

1:42

So back here you see some Hyland cartilage.

1:44

Now, unfortunately, the Hyland cartilage isn't as

1:46

crisp as I work my way around as I I'd like it to be.

1:50

But it stops right about there.

1:52

And so if you take a line from the Hyland cartilage

1:55

where it ends, the articular cartilage ends, and you,

1:57

you, you go right to the center of the humerus and

2:00

then you go right to the center of your Hill-Sachs.

2:06

206 to 209 degrees, uh, with that angle.

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So, you know, you're not going to draw that angle,

2:13

but that just gives you an idea of what you're

2:15

looking for in the axial projection, as opposed

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to, say, the pseudo Hill-Sachs that you get from

2:21

repetitive micro impaction in the impinger.

2:24

It's going to be in a different, a different

2:26

place, uh, but it is going to have a trough.

2:29

So we have our, our typical Hill-Sachs.

2:31

We've shown you how to find it.

2:33

We've shown you its depth.

2:34

It means there's been a dislocation.

2:37

So as they say in the movies, pay no attention to this

2:39

gigantic, um, complete rotator cuff tear anteriorly.

2:45

We're missing the entire cuff.

2:46

The posterior cuff is swollen with a

2:48

little interstitial, uh, cyst inside it.

2:52

Um, if we pull down the axial and rotate

2:55

it, uh, sorry, scroll it up and down.

2:57

Um, pay no attention.

2:59

At least yet, to the subscapularis

3:02

detachment and the biceps absence.

3:05

Although, you should be aware that this injury

3:08

has a strong association with the family of angles.

3:13

The Haggles, the Behaggles, the Raggles, and the Igles.

3:18

So whenever you see this, You gotta look down low, and

3:22

whenever you see something down low, you gotta look here.

3:25

So they go together like soup and

3:27

sandwich, or like Vegemite and toast.

3:30

So, let's take a look at the axillary region.

3:34

We're gonna be appalled by what we see.

3:37

We see a detachment right there.

3:39

That's a little thread or string,

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but not a very robust attachment.

3:43

There it is, detached, and pulled

3:45

away from the neck of the humerus.

3:48

in the axillary region.

3:49

So we would say, okay, the humerus has

3:53

an avulsion of the glenohumeral ligament.

3:55

From it, a so-called haggle without bone.

3:59

But that's not all.

4:01

On the glenoid side, even though it's not very

4:03

detached, This entire structure has come off, and

4:07

there's a big space between it and the glenoid.

4:10

You see it again on the next slice, and the next slice.

4:13

Let's go the other way.

4:14

It doesn't look quite as bad as we go

4:16

posterior, but as we go anterior, it persists.

4:20

So we have basically a folded, floating IGHL,

4:25

or an anterior inferior glenohumeral ligament

4:28

attachment, otherwise known as a glenoid.

4:34

Now you can also see the patient's Hill-Sachs

4:36

impaction and the flattening that it generates

4:39

in the back in the sagittal projection.

4:41

You can measure the Hill-Sachs lesion.

4:44

You can give it a percent of the circumference of the

4:47

humeral head which we're going to do in separate vignettes

4:51

when we do measurements for on track and off track.

4:54

Uh, pathology, engagement and non-engagement, you're

4:57

wondering what that means, but that's in a separate

4:59

vignette, which we're going to call engagement.

5:01

So, you can go to that vignette, which

5:04

is more advanced, when you're ready.

5:06

Look at how the humeral head, due to a combination of

5:11

loss of the depressor mechanism, we have no rotator cuff

5:14

superiorly, here's the coronal to prove it, it's empty,

5:18

bone on bone, but we also have lost the inferior restraint.

5:24

I mean, normally this inferior restraint helps you

5:26

when you're in abduction and external rotation, but it

5:29

also provides some support to keep the humerus down.

5:34

And when you completely lose that and you

5:36

have what we call a floating IGHL or IGLE,

5:39

now you've lost the bottom minor restraint.

5:42

You've lost the depressor mechanism up top.

5:45

It's no wonder that the humerus is migrating all the way

5:49

up towards Alaska, towards the North Pole, towards Darwin.

5:53

It's going north, and it's abutting

5:55

the undersurface of the acromion.

6:01

ball, and the poor biceps is nowhere to be found.

6:05

Here is a thin piece of the middle glenohumeral ligament.

6:09

So this is an example of a patient with

6:13

a floating IGHL and an ice Hill-Sachs.

6:16

Uh, for those of you youngins that are taking boards,

6:20

to visualize the Hill-Sachs, uh, or the posterolateral

6:24

humeral head on radiographs, an anteroposterior

6:27

projection, uh, is obtained with the arm internally.

6:31

Uh, rotated, and then the typical view is a

6:34

dedicated Stryker notch view, which you should be

6:38

familiar with, especially if you're taking, uh,

6:40

basic boards or even more advanced MSK boards.

6:44

The Stryker notch view is obtained with the

6:45

patient's supine, uh, position with the palm of

6:49

the hand placed against the ear or behind the ear.

6:53

The head and the elbows should be pointing

6:55

forward to the tube angled at about a 45

6:58

degree cephalad orientation towards the axilla.

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So a Stryker view should be something familiar

7:05

to you musculoskeletal aficionados out there.

7:09

An example of a pretty catastrophic injury from a motor

7:13

vehicle accident with a large, full-thickness,

7:18

anterior supraspinatus rupture, subscapularis rupture.

7:23

Middle glenohumeral ligament, didn't show it, was ruptured.

7:26

The biceps is ruptured.

7:28

And the patient has the obligatory associated,

7:32

not obligatory, but commonly associated,

7:34

inferior labral ligamentous injury called IGL.