0:00

Thank you very much and uh, again, uh, it is great to be

0:04

with you for this third day of our course.

0:08

Uh, we're moving distally from

0:11

what we covered in the first two days,

0:13

which was the region of the shoulder.

0:15

We're gonna talk today about the region of the elbow,

0:20

and as indicated, I will give two talks, one related mainly

0:24

to ligaments and elbow instability,

0:27

and a second, a shorter talk dealing with the tendons, uh,

0:32

about the elbow.

0:34

Let's begin then by talking about elbow stability

0:38

and instability and once again, okay.

0:42

Whoops. Okay, so with that in mind, I just wanted

0:47

to start by showing you what a coronal section

0:51

through the elbow joint looks like.

0:54

There are three functional spaces they all communicate.

0:57

If you were to do an arthrogram of this joint, number one,

1:01

and the one we will emphasize throughout this talk is the

1:06

humeral portion of the elbow joint.

1:10

This is the joint between the trochlea of the humerus

1:13

and the trochlea notch of the proximal portion of the ula.

1:17

It is a very important part of this articulation,

1:21

particularly with regard to elbow stability.

1:25

The second numbered areas, uh,

1:27

number two is the radiohumeral part of the elbow joint.

1:31

That part between the Capella and the radial head.

1:34

Clearly important

1:36

and important also with elbow stability,

1:39

depending upon other abnormalities that might be present.

1:43

And then the final portion of the articulation,

1:46

which is labeled number three, the proximal radi joint.

1:50

We'll talk briefly about that,

1:52

but we'll not spend a lot of time on it.

1:56

I've indicated there is a lock of the elbow joint

1:59

and that lock takes, uh, place in that part

2:03

of the articulation.

2:04

That is number one in this particular, uh, coronal section,

2:11

a brief word or two about the fibrous capsule.

2:14

It is a capsule that completely invests the joint.

2:17

If you were to try to inject material into it,

2:20

you would see, you would inject about 20 or 25 milliliters

2:24

before you would encounter a great deal of resistance

2:27

and extravasation of the fluid.

2:30

It envelopes three intracapsular extra synovial fat pads.

2:35

Now to radiologists, they may,

2:37

that might surprise you per perhaps you thought there were

2:40

only two fat pads, but there are actually three.

2:44

There are two fat pads that are located anteriorly

2:48

as shown in the upper, uh, picture here.

2:52

One is located in a small depression in the distal humerus.

2:55

It's called the radial fossa. The other

2:58

Is located anteriorly in a somewhat larger fossa

3:03

that is called the OID fossa.

3:05

And then posteriorly,

3:07

the largest fat pad is in fact the ILI fat pad.

3:12

These, there are three fat pads

3:14

because there are three regions of depressions

3:17

or fosse involving the distal humerus.

3:20

And these fat pads, in fact sit in each

3:23

of those three areas.

3:25

Now we learned, of course, early on when trying

3:28

to view a joint effusion with conventional radiography.

3:31

We would turn our attention to the lateral radiograph

3:34

and we would look for elevation of that anterior fat pad,

3:39

which you now realize was actually two fat pads.

3:42

And we would look for visualization

3:45

of a posterior fat pad

3:47

because normally it was not readily apparent.

3:51

Here in a sagittal section through the ulnar aspect

3:54

of the joint, we see only of the two of the three fat pads.

3:58

This is the OID fat pad here,

4:02

and this is the EUM fat pad.

4:04

If we would go ahead and put air

4:06

or fluid within the joint, we would see elevation

4:09

of these two fat pads

4:11

and are shown here in a more lateral sagittal section,

4:15

we would see elevation of the radial fat pad as well.

4:21

To show you an example of that, here I provide you with a,

4:24

what we see with the joint effusion in the ct.

4:29

Uh, images. At the top you can see elevation

4:34

of the oid and aquin on fat pads

4:38

and on the transverse image you can also see fat,

4:41

which has been pushed away from the bone.

4:44

If we go to the MR imaging with fluid in the joint,

4:47

you can see two of the three fat pads outlined

4:50

by arrows here,

4:52

but there are three, two are located anteriorally,

4:55

one is located posteriorly.

4:58

Now we always think of the ends of the bones covered

5:01

by articular cartilage,

5:03

but I want to turn our attention now to the trochlea notch.

5:07

The trochlea notch of the only consists

5:10

of the OID process anteriorly and the eon,

5:14

and it's not an eon process.

5:16

The proper term is the eon.

5:19

Typically there are is cartilage throughout the tr

5:23

or notch except for this area shown in the box

5:27

where you may have little or no cartilage.

5:30

This can produce a diagnostic problem for you.

5:35

They illustrate that I show you a cric sagittal section,

5:40

uh, through the elbow, showing you an area devoid

5:43

of articular cartilage involving a portion

5:46

of the tr notch.

5:48

Here we can see theon with its articular cartilage,

5:52

the OID process, but in that deep region between

5:56

The two, there may normally be no articular cartilage.

6:02

The second an anatomic point I wanna indicate at this, uh,

6:07

region of the talk is that there is a surface irregularity

6:11

that one can see in the Capella

6:15

as shown here in coronal section and a coronal radiograph.

6:20

This in this area, the articular cartilage

6:23

of the Capella ends near its junction

6:27

with the lateral condyle and epicondyle.

6:30

And so this can look somewhat irregular.

6:33

As you can see in this particular example.

6:36

We call this the pseudo defect of the cap

6:39

or the capitulate, whichever term you prefer.

6:43

Now, in a few minutes,

6:45

I'm gonna be talking about a pseudo pseudo defect

6:48

that may also occur in this area.

6:52

If we turn to the sagittal view,

6:54

and I show you that same pseudo defect, that normal variant

6:59

and how it can simulate an osteochondral

7:02

irregularity or injury.

7:04

So be aware of this particular region.

7:07

It can cause diagnostic confusion.