0:00

Now there are names that the orthopedic surgeons apply

0:03

to a a variety of areas,

0:05

and there's several that occupy the shoulder region.

0:09

Let me talk about one here.

0:13

There is something known as the bare area.

0:18

I've made a drawing here showing you the posterior aspect

0:21

of the proximal humus.

0:23

I'm showing you the articular cartilage in dark blue

0:26

and the footprint of the supraspinatus

0:29

in infraspinatus and Terry's minor.

0:32

You will note that

0:34

although the supraspinatus, at least in young people,

0:37

attaches to the edge of articular cartilage,

0:40

the in infraspinatus tendon's footprint does not extend all

0:43

the way to that area.

0:46

This is known as the bear area.

0:49

Now, there's a larger bear area that is in fact medial

0:52

to the Terry's minor tendon attachment,

0:55

but the bear area, that term

0:58

describes this particular region.

1:01

So here's a section to prove that point.

1:04

You can see the bear area adjacent

1:06

to the articular cartilage between the end

1:09

of the articular cartilage

1:11

and the footprint of the terrace minor tendon.

1:15

As we get older, there is a normal peeling away

1:19

of many different tendons in the human body,

1:23

and indeed that can occur right here

1:26

at the footprint of the supraspinatus.

1:30

So a bear area in that region may occur in older people

1:34

and may be an asymptomatic finding.

1:38

I became aware of that when I did many,

1:40

many coronal sections in Cric shoulders,

1:44

and I'm showing you an example here.

1:47

The yellow arrow is pointing to a new bear area

1:50

that has developed in an older person

1:53

because of peeling away in a smooth fashion

1:56

of the deep fibers of the supraspinatus tendon.

2:00

This generally is not symptomatic. It is smooth.

2:04

As you can see, it produces a smooth tapered appearance.

2:09

Let's turn our attention now to the footprint of the

2:14

subscapularis tendon.

2:15

All right, we will look at that particular footprint

2:18

and what has been pointed out in a number of articles

2:22

is indeed there are four anatomic regions typically

2:27

that are the terminal fibers of the subscapularis tendon.

2:31

They are color-coded for you in this particular drawing

2:35

of the footprint of the subscapularis.

2:38

And I've color coded the arrows that I'm using

2:41

to describe those four zones.

2:44

So these are zones of distal tendonous fibers

2:48

of the subscapularis.

2:50

Now, as you'll see in a few minutes, most of the tears

2:53

that we see in the subscapularis occupy zone one

2:57

or zone one and two, there are some distinctive tears

3:01

as I'll also show you in a few minutes.

3:03

They may occupy zones three and four,

3:06

but most occur high up.

3:09

To give you an idea of a couple of cases that demonstrated,

3:13

let's start with this one.

3:14

This is an MR arthrogram in a person who's recent had a

3:18

recent anterior Glen Al joint dislocation,

3:22

and typically with such dislocations, the tendons

3:25

of the lower zones are torn,

3:28

but the upper zone tendon shown here by

3:32

that orange arrow remains intact.

3:35

If we go to the transverse images, here is zone one tendon

3:40

and it is attaching to its footprint.

3:43

All the other zones, those tendons are disrupted

3:47

before they reach the lesser tuberosity.

3:50

Now, what does zone one do?

3:52

Zone one fibers are important stabilizers

3:56

of the biceps tendon.

3:58

So despite this large tear of the subscapularis tendon,

4:02

the biceps tendon still remains

4:05

centered within the bpal group.

4:09

Now let's look at the opposite situation

4:12

here I'm showing you on the right two images

4:14

of an MR arthrogram.

4:16

This is a transverse plane.

4:19

This is tearing intrasubstance tearing of zone one fibers,

4:23

and here you can appreciate the subluxation

4:27

of the biceps tendon, which is now extending over

4:31

that tuberosity.

4:32

And you can see that in this image as well at arthroscopy,

4:36

this is what it would look like.

4:38

Medial subluxation of the longhead of biceps

4:41

between those fibers.

4:44

That is a tear in the region of zone one fibers.

4:49

A further study is indicated

4:51

that when you look at the anatomy in more detail,

4:55

the surface area of that footprint is quite large,

5:00

but the facets that occupy that footprint that refer also

5:05

to zones one, two, and three

5:07

and four, you can see the surface area is greatest

5:11

with the upper facet labeled F1.

5:14

In these pictures, as I mentioned

5:17

before, the vast majority of tears that we see

5:21

in the subscapularis occupy either zone one

5:25

or facet one region, or zones one and two.

5:31

Let's turn our attention now to the vascular supply.

5:36

And the vascular supply is very interesting

5:39

and it's not unique to the rotator cuff tendons,

5:42

although it has been emphasized in that particular region.

5:45

There is a normal region in many tendons in the human body

5:49

where the vascularity is somewhat limited.

5:53

We call these critical zones. Here on your

5:56

Left is an anatomic preparation we did years ago.

5:59

Just to show you this particular area.

6:02

This is the critical zone of the supraspinatus tendon.

6:07

I've tried to draw that for you here

6:09

and you can see it exists

6:10

between the blood supply coming here from the bone

6:13

and the blood supply coming from the muscle.

6:17

Now, tears certainly occur within the critical zone,

6:21

but as I will show you over

6:22

and over again in the images to follow that, most

6:26

of the tears actually occur distal to the critical zone

6:31

of the supraspinatus

6:33

and also to the critical zone of the infraspinatus tendon.