0:00

I'm back to the axial projection, my least

0:03

favored nation status projection for rotator cuff.

0:07

We're still in the upper half of the shoulder.

0:10

We're not quite at the humeral equator.

0:13

But there are a few structures I'd like to draw for you.

0:17

One is the biceps labral anchor complex.

0:20

Now I'm a little below where it normally takes off,

0:22

but I have this nice diagram that I can share with you.

0:25

And the biceps takes off in the anterosuperior quadrant.

0:29

It may come off like this, directly off the

0:33

front of the labrum, and merge with it, almost

0:36

like it plugs into the tip of the labrum.

0:39

But it usually comes over the top of the labrum,

0:41

as we'll see later on in the coronal projection.

0:46

It also has a tremendous amount of variability as

0:48

to where it takes off from anterior to posterior.

0:51

So it can take off in the front, it can

0:53

take off mid-coronally, it can even take off

0:55

in the back, and have a very long course.

0:58

Over the top of the humeral head, much like

1:00

this, and then it reaches the intertubercular

1:05

groove and descends as the biceps long head.

1:08

The reason that this configuration is important,

1:11

and I'll draw it and color it in to emphasize

1:14

it, is because it contributes to, much as you

1:18

would imagine here, depressing the humeral head.

1:22

Keeping the humeral head from floating up,

1:24

keeping the humeral head from disintering.

1:28

Now, there are a few other wispy

1:30

structures that are drawn in here.

1:32

One you can see right there, I'll put an arrow on it.

1:35

And that is, those are the lower fibers

1:38

of the superior glenohumeral ligament.

1:40

They're not considered really cuff contributors.

1:44

But the biceps and its labral anchor,

1:46

because of its position, on top of the

1:49

humeral head for a short distance is.

1:53

There's another structure here that is also.

1:56

Considered part of the rotator cuff complex.

1:59

And that is the coracohumeral ligament.

2:02

Now ideally, I'd love to show this

2:04

to you on a slightly higher cut.

2:06

These are the lowermost fibers of it.

2:09

It contributes to the anterior boundary of the rotator

2:12

interval, which is this triangular space right here.

2:15

But as it gets to the humeral head up higher,

2:17

it sends fibers underneath the rotator cuff

2:21

to contribute to the deepest layer, layer

2:23

number six, of the rotator cuff complex.

2:27

So those are two additional important

2:29

structures that you see in the axial projection.

2:32

The CHL, the coracohumeral ligament,

2:35

and the biceps labral anchor complex.

2:39

Another structure that plays into the stabilization

2:42

of the shoulder is the capsule that is very thin.

2:45

So we don't often comment specifically on capsular

2:48

rupture or tear as a component of the rotator

2:52

cuff, but deep somewhere in the back of your mind.

2:55

Is the knowledge that it does.

2:58

So, in a few moments, on our next segment, we'll

3:01

move on to a lower more axial cut, and see how

3:06

it contributes to evaluation of the rotator cuff.