0:01

The second concept that we will discuss is one

0:03

that I mentioned yesterday

0:05

and promised I would at least talk a little bit more about

0:08

today, and that is the concept

0:10

of post row superior internal impingement.

0:14

The importance is in fact that with excessive

0:17

and repetitive contact of the post row superior aspect

0:21

of the humeral head and glenoid rim in the abducted

0:25

externally rotated position, a number

0:28

of abnormalities could possibly occur.

0:31

Now, there is in fact a controversy or second controversy.

0:35

Some people is shown in the, the blue box on the left

0:40

say, well wait a minute.

0:41

That's a normal finding to get crowding

0:43

of posterior structures in abduction and external rotation.

0:48

And they will point out that it's seen both in non throwers

0:52

and throwers, and both in the dominant

0:54

and non-dominant shoulders of the throwers.

0:59

Others will counter,

1:00

and I believe this,

1:01

that it is a pathologic condition when extreme

1:05

that occurs mainly,

1:06

but not solely in the dominant shoulder of these throwers,

1:11

and is accentuated by that postero superior shift

1:15

of the humeral contact point

1:18

and the capsular laxity that we talked about.

1:22

So let's go back to this particular picture,

1:24

which I showed you yesterday, showing you in the abducted,

1:28

externally rotated position in a transverse image.

1:32

You can see where the greater

1:34

and lesser tuberosities are located,

1:38

and you can see that with posterior translation

1:41

of the contact point

1:42

and abduction, external rotation,

1:45

things are gonna get crowded here.

1:47

And I pointed out yesterday that the structures

1:50

that are typically affected that the superior aspect

1:55

of the labrum, the articular surface

1:59

of the in infraspinatus,

2:00

and to a lesser extent, the supraspinatus,

2:03

and then cystic changes

2:05

that may occur in the greater tuberosity

2:07

and in the humeral head.

2:10

And I showed you some examples.

2:12

I believe I may have shown you this example with Mr.

2:15

Arthrography showing you, by the way, some laxity

2:18

of the anterior capsule stripping of the periosteum.

2:22

But let's look back here.

2:24

Abnormality of the postal superior labrum,

2:27

a delaminated tear between the articular

2:31

and bursal side of sup and infraspinatus tendons

2:35

and contrast filled cysts in the greater tuberosity.

2:39

This is a classic example of what we look for

2:42

with posterior superior internal impingement.

2:46

Beyond that, there may be a posterior shift

2:49

of the humeral head with the respect to the glenoid.

2:53

Here's another example.

2:55

This one I didn't show you yesterday.

2:57

The white arrow pointing

2:58

In fact to post road superior labral irregularity.

3:03

The orange arrow pointing

3:05

to the delaminated tear involving the articular surface

3:10

of the, uh, this was kind of the, uh, junctional fibers

3:13

of super and infraspinatus.

3:15

And here's the deamination between the articular

3:19

and bursal side fibers.

3:21

And there may have been a fla, a labral flap

3:24

or fragment present anteriorly in this case.