0:01

Let's talk about the structures that may give radiologists

0:04

fits that have a band-like or linear configuration.

0:10

Let's start down low, and we've got a T1

0:13

gadolinium-augmented MR on the left, and a

0:16

gadolinium-water-augmented MR on the right.

0:20

This one water-emphasized, this one fat-emphasized.

0:24

Uh, but it's no matter.

0:25

Now this one was obtained in neutral positioning.

0:27

This one in external rotation.

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So the structures may look a little bit different.

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But look at the bifurcation of

0:35

the anterior band of the IGHL.

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There are two structures here.

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And yet it's, it's allegedly one band.

0:43

Now one of these bands can fold up on itself

0:47

and knuckle into the glenohumeral articulation.

0:50

In other words, it may raise up

0:52

superiorly or migrate superiorly.

0:54

And get entrapped, or curl into

0:57

the inferior aspect of the joint.

0:59

In fact, that's not uncommon, and occasionally that can be a

1:02

cause of clicking, or functional instability, or hesitation.

1:07

Let's keep rolling superiorly, and there are innumerable

1:11

little senechiae in the lateral aspect of the joint

1:15

capsule and then look at all these small areas of

1:18

capsular condensation and what I call micro-ligamentous

1:22

structures that sit behind the main portion of the MGHL.

1:27

Now the MGHL is extremely variable in terms of the

1:30

number of layers and the number of accessory ligaments.

1:34

It's also commonly perforated and it's

1:36

also variable in terms of its course.

1:39

If we were looking at it coronally, it may go this way.

1:42

Or it may go this way.

1:44

And so sometimes if you have the SGHL going that way, and

1:48

the MGHL going this way, and the IGHL going this way, it

1:52

makes the letter Z in one shoulder, and it'll make a reverse

1:56

Z, you know, going this way, in the opposite shoulder.

2:01

So this Z configuration in the coronal projection

2:04

is the classic configuration, but it's not

2:07

present in everybody because the MGHL may be very

2:10

horizontal and create a series of linear structures.

2:15

Because they sit in very close proximity.

2:18

In fact, look at this one right here.

2:20

I'm going to make it just a little bit

2:21

bigger so you can see a little better.

2:23

Watch what this one does.

2:24

It comes right onto, it disappears into the labrum.

2:29

Now when that structure separates from

2:30

the labrum, so let's draw the labrum.

2:32

Got a big triangular labrum, and then just in front of

2:36

it, You've got this structure that's attaching to it.

2:38

It's very thin and delicate.

2:40

It's gonna come right onto it.

2:41

When these two separate right there, you've got an injury.

2:46

But that's not all.

2:48

That might not be the only area of separation.

2:51

You could separate over here, too.

2:54

Between the labrum and the glenoid.

2:57

In that case, you'd have a two-part or double lesion.

3:01

The capsule coming off the labrum,

3:03

and the labrum coming off the glenoid.

3:06

And if you had periosteum, which is a linear structure that

3:09

you can't see very well over here, but you can see it over

3:13

here, combining with the cortex, you can't separate them,

3:16

this black area right here, but sometimes the periosteum

3:19

will come off, and then under that periosteum you'll see

3:22

a little bit of blood, let's see if I can get a different

3:25

color there, there's my blood for red, blood red, and now

3:29

you have periosteal stripping, now you have a triple lesion.

3:32

The periosteum is separated from the glenoid,

3:37

The labrum is separated from the glenoid,

3:40

and the capsule is separated from the labrum.

3:43

That would be a triple lesion.

3:47

So these linear structures can have

3:50

consequences in terms of interpretation.

3:53

Now let's go up a little higher, and we see

3:57

continuation of the capsular condensation,

4:00

or the glenohumeral ligament complex.

4:03

Some of these are more condensed as ligaments, some of them

4:06

are simply thin, wispy senechiae, like these right here.

4:14

curvilinear structure, the SGHL, a broad linear

4:18

structure, the superior aspect of the CHL, intra

4:22

articular portion, the coracohumeral ligament.

4:25

And then finally, we run into this big band-like

4:27

structure, which is arcing over the humeral head.

4:30

There it is right there.

4:31

This one inserting on the anterior tubercle of the

4:33

glenoid, the intra-articular arcuate segment of the

4:37

biceps, which can insert here, or here, or here.

4:42

It's got quite a variable insertion.

4:45

So those are some potential pitfalls in terms

4:49

of interpretation of linear structures in

4:52

the shoulder that may give radiologists fits.

4:55

Their clinical importance and implication are emphasized

4:58

in the demonstration of double and triple lesions.

5:02

And in a separate setting, we're going to talk about

5:04

some of the variations that can occur with these,

5:07

one of them known as the Buford Complex.