0:00

Knee anatomy on MRI.

0:01

Here is an MRI, sagittal or lateral, T1 fat weighted.

0:06

In the middle, sagittal or lateral, water weighted.

0:10

And on the right, coronal AP type projection, also water weighted.

0:16

We're focused on the corner, the posteromedial corner, which has five

0:21

main structures. The posterior oblique ligament, which is discussed on its own

0:26

but we can see a component of it, the capsular component,

0:28

right here along the posterosuperior aspect of the medial meniscus.

0:33

We can scroll it a little bit and we see

0:35

it right there, and perhaps right there, as a linear pointed structure.

0:41

Then we've got the OPL,

0:43

which we can't really separate from the posterior capsule.

0:46

But there it is, right there.

0:48

So the capsule and the OPL are seen as one, not as two distinct structures.

0:53

And the OPL is the oblique popliteal ligament.

0:57

Now, we've got the semimembranosus.

1:00

The semimembranosus, a dynamic stabilizer

1:04

and an anterior reflected portion of it is called the pars reflexa.

1:08

Then the semimembranosus continues

1:10

on down as the direct component of the semimembranosus.

1:15

There are actually five components,

1:16

a capsular, an inferior, a dista,l and then the two major ones, which I've just shown

1:21

you, the anterior pars reflexa and the distal... Sorry, and the direct...

1:26

and the direct component.

1:28

You can also see the direct component of the semimembranosus in the coronal.

1:31

It's this big, fat, dark blob.

1:34

It almost appears to wrap around the tubercle of the tibia.

1:40

Now, another structure that is seen

1:42

in this projection is the POL or posterior oblique ligament of the knee.

1:47

How do we find that?

1:48

Find your middle layer of MCL, also known as the deep portion

1:53

of the superficial MCL, layer number two or middle layer.

1:58

And then follow that posterior,

2:00

and that will turn into, it will become the POL.

2:05

So you're in POL right now.

2:07

You see the posterosuperior aspect of the meniscus and the POL, fused.

2:12

I'll make it a little lighter for you.

2:14

Then the POL is going to wrap around behind that meniscus and it's going to be

2:18

continuous with the posterior capsule and the OPL, the oblique popliteal ligament.

2:25

So you've seen several structures of the posteromedial corner.

2:29

You've seen the POL, you've seen the semimembranosus and two

2:33

components, the anterior pars reflexa and the continuation of the direct head.

2:40

Two other very important components are

2:42

the posteromedial meniscus itself and its capsular attachment, which is seen here as

2:48

these fuzzy areas of gray signal intensity on PD spur and on the T1 fat image.

2:56

Let's move on to another vignette, shall we?

The Posteromedial Corner Anatomy on MRI

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0:00

Knee anatomy on MRI.

0:01

Here is an MRI, sagittal or lateral, T1 fat weighted.

0:06

In the middle, sagittal or lateral, water weighted.

0:10

And on the right, coronal AP type projection, also water weighted.

0:16

We're focused on the corner, the posteromedial corner, which has five

0:21

main structures. The posterior oblique ligament, which is discussed on its own

0:26

but we can see a component of it, the capsular component,

0:28

right here along the posterosuperior aspect of the medial meniscus.

0:33

We can scroll it a little bit and we see

0:35

it right there, and perhaps right there, as a linear pointed structure.

0:41

Then we've got the OPL,

0:43

which we can't really separate from the posterior capsule.

0:46

But there it is, right there.

0:48

So the capsule and the OPL are seen as one, not as two distinct structures.

0:53

And the OPL is the oblique popliteal ligament.

0:57

Now, we've got the semimembranosus.

1:00

The semimembranosus, a dynamic stabilizer

1:04

and an anterior reflected portion of it is called the pars reflexa.

1:08

Then the semimembranosus continues

1:10

on down as the direct component of the semimembranosus.

1:15

There are actually five components,

1:16

a capsular, an inferior, a dista,l and then the two major ones, which I've just shown

1:21

you, the anterior pars reflexa and the distal... Sorry, and the direct...

1:26

and the direct component.

1:28

You can also see the direct component of the semimembranosus in the coronal.

1:31

It's this big, fat, dark blob.

1:34

It almost appears to wrap around the tubercle of the tibia.

1:40

Now, another structure that is seen

1:42

in this projection is the POL or posterior oblique ligament of the knee.

1:47

How do we find that?

1:48

Find your middle layer of MCL, also known as the deep portion

1:53

of the superficial MCL, layer number two or middle layer.

1:58

And then follow that posterior,

2:00

and that will turn into, it will become the POL.

2:05

So you're in POL right now.

2:07

You see the posterosuperior aspect of the meniscus and the POL, fused.

2:12

I'll make it a little lighter for you.

2:14

Then the POL is going to wrap around behind that meniscus and it's going to be

2:18

continuous with the posterior capsule and the OPL, the oblique popliteal ligament.

2:25

So you've seen several structures of the posteromedial corner.

2:29

You've seen the POL, you've seen the semimembranosus and two

2:33

components, the anterior pars reflexa and the continuation of the direct head.

2:40

Two other very important components are

2:42

the posteromedial meniscus itself and its capsular attachment, which is seen here as

2:48

these fuzzy areas of gray signal intensity on PD spur and on the T1 fat image.

2:56

Let's move on to another vignette, shall we?

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Description

Faculty

Stephen J Pomeranz, MD

Chief Medical Officer, ProScan Imaging. Founder, MRI Online

ProScan Imaging

Lesson

MRI Mastery Series: Knee Pre Course Activities

Lesson

Knee - Anatomy of the Supporting Structures

Lesson

Supporting Structure Anatomy: Focus on the Posterior Corners

Lesson

Case Review: Supporting Structure Injuries

Lesson

Meniscus MRI

Lesson

Pivot Shift Injuries and Meniscal Pathology

Lesson

More Meniscus Tears with Case Examples

Lesson

Applying What You've Learned

The Posteromedial Corner Anatomy on MRI