0:00

We're focusing on all six components

0:02

of the rotator cuff,

0:04

and we're moving now into the sagittal

0:06

projection and how to use it.

0:08

Let me do a little drawing for you first.

0:11

You know, as you move from medial to lateral,

0:14

and I'll make a...

0:17

I'll make a humeral head that's in pink.

0:20

And let's pretend we're about over here.

0:22

We're about at this location.

0:24

At that location,

0:25

you're going to see a fair amount of muscular tissue.

0:29

And the reason you don't see any muscular tissue

0:31

here is because the cuff is ruptured.

0:33

So, don't be worried that you don't see it coronally.

0:36

But in a normal shoulder,

0:37

you'll see some muscular tissue,

0:38

which I'll make orange.

0:40

And then within that muscular tissue,

0:43

which will include several different muscles,

0:46

the supraspinatus and infraspinatus,

0:49

you're going to see some individual tendon subunits.

0:54

Now as we get a little further over,

0:57

and I'll show you where we are.

1:00

We're going to pretend we're over here,

1:02

then things look a lot different.

1:04

So now we'll make a humeral head.

1:06

What does it look like now?

1:08

Now, things flatten out and they become much darker.

1:13

You may see multiple round spots near each other,

1:17

or they may be one contiguous black band.

1:21

And then you'll often see a little bit

1:24

of lighter signal right there.

1:25

Usually in the posterior one third or

1:28

middle third of the humeral head.

1:30

And that signifies that you're making the

1:33

leap or transition to the infraspinatus,

1:35

even though we all know now that there's quite a bit

1:39

of interweaving and interdigitation between

1:41

the fibers of these two structures.

1:44

So we'll make our infraspinatus in purple.

1:47

And because it has a steeper radius of curvature,

1:51

it often looks a little more like little

1:53

hairs coming in than the supraspinatus,

1:56

which looks more like a flat black structure.

2:01

And we have discussed this previously in some of our vignettes.

2:05

So now, let's go to our sagittal.

2:08

So, let's reinvent ourselves here.

2:11

And you can see from my line that this sagittal is

2:14

out near the periphery or a far

2:17

edge of the humeral head.

2:19

And to quote a famous author,

2:23

"Where is the beef?"

2:24

There is no beef.

2:26

There's no supraspinatus,

2:28

just a ragged fiber remnant that's lying in a hole.

2:33

There's no infraspinatus.

2:35

There is a sick, swollen teres

2:38

and there are some sick irregular

2:41

looking infraspinatus fibers.

2:43

We've got a bald humeral head.

2:45

And I've got on the right side,

2:47

the T1-weighted image to match it.

2:50

Now, one potential pitfall that you've got to be very

2:54

cognizant of

2:56

is the underbelly or undersurface of the deltoid.

3:00

Sometimes you'll see a little bit of coalescence

3:04

of the tendon. Not in this example,

3:07

but if the deltoid is sagging down or

3:10

sitting down on the humeral head,

3:13

you're actually looking at that tendon and

3:15

you will confuse it for an intact cuff.

3:17

It happens all the time,

3:19

so don't get fooled by that.

3:22

But let's continue scrolling now.

3:24

We'll go out to the side. We've got nothing.

3:28

A little bit of teres.

3:30

We start working our way medially,

3:32

we still got nothing.

3:33

We still got nothing.

3:35

And we should be running into the biceps about now,

3:37

and we do.

3:37

Right there.

3:39

There's our biceps. Let's follow our biceps in.

3:42

There goes our biceps. So our biceps is present.

3:46

It's accounted for.

3:47

But although you don't know this from this vignette,

3:50

it's also subluxed.

3:51

But that's a story for a different vignette.

3:55

There is the coracohumeral ligament,

3:57

one component of it.

4:00

The intraarticular component,

4:03

in another vignette,

4:05

you would have seen that the extraarticular

4:06

component is already ruptured.

4:08

But I'm showing it for the supraspinatus,

4:11

which is nowhere to be found.

4:13

The infraspinatus,

4:14

which is also nowhere to be found.

4:17

And finally, the subscapularis,

4:19

which is found.

4:20

There is the robust,

4:22

superficial portion of the subscap,

4:24

but the deeper fibers of the subscap.

4:27

Let me blow it up a little bit.

4:29

These deeper fibers here

4:31

and these deeper fibers right here,

4:35

which should be flush on the lesser tuberosity,

4:38

and they're not.

4:39

They're replaced by inflammatory

4:42

fibrous tissue and/or scar.

4:45

You see directly above it,

4:47

the position of the biceps.

4:49

So have firmly established that the supraspinatus

4:53

is ruptured all the way from front to back,

4:58

all the way from anterior to posterior.

5:00

See if I can blow it up for you rather quickly.

5:06

Well, there we go.

5:08

So all the way from anterior to posterior,

5:12

it's torn. So it's a complete tear.

5:15

Completeness is length.

5:17

The infraspinatus is torn.

5:18

All the way from anterior to posterior,

5:21

it's a complete tear.

5:22

And the subscapularis is demonstrating a

5:25

partial thickness under surface tear.

5:29

The sagittal invaluable in telling you the front

5:32

to back length of tears and in identifying

5:36

and qualifying subscapularis tears.