The Posteromedial Corner: Posterior Oblique Ligament part 2
HIDEInteractive Transcript
0:00
Knee anatomy on MRI, the posterior oblique ligament,
0:04
also known as the ligament of Winslow.
0:07
Winslow's got his name on a lot of stuff.
0:10
It takes its origin right in front of the adductor tubercle.
0:15
So the tubercle would be about here.
0:17
There's the origin of the POL.
0:20
So most people describe the origin to be at
0:23
or near, or just anterior to this structure.
0:27
Then we've got three separate components: a capsular
0:30
or superior arm, a central tibial arm,
0:32
and a distal superficial arm.
0:34
So let's talk about the arms.
0:37
First, the central or tibial arm.
0:41
Now, that one's a little bit smaller,
0:43
but it's actually the most important.
0:45
So it may be the hardest to see or maybe hard to see,
0:48
not as easily seen as this fatter distal superficial arm,
0:51
but it extends posteriorly and obliquely.
0:56
Thus the name posterior oblique ligament of the knee.
1:01
It attaches to the posteromedial aspect of the medial
1:04
meniscus and the adjacent component of the tibia.
1:07
So we'll see on MRI that there's a component to the
1:10
posteromedial meniscus that's most important and critical
1:13
in the posteriorsuperior quadrant of the meniscus corner.
1:18
Now, the distal end of the POL passes deep to the anterior
1:24
arm, or reflected arm of the semimembranosus.
1:27
So here's the reflected arm of the
1:28
semimembranosus right there,
1:30
and underneath it is the central tibial arm of the POL
1:36
coursing right underneath it, the superior arm,
1:40
also known as the capsular arm.
1:42
It is superior to the joint line.
1:45
It is a somewhat horizontal course.
1:48
It's continuous with the posterior joint capsule.
1:51
It fuses with the capsular arm of the semimembranosus,
1:55
and it contributes to the back capsule of the
1:58
knee and the oblique popliteal ligament,
2:01
which are virtually indistinguishable
2:03
from one another on MRI.
2:07
Then we've got the distal superficial arm.
2:10
It attaches to the sheath and tibial insertion
2:13
point of the semimembranosus.
2:17
It blends with the posterior margin of the superficial MCL.
2:20
So this one is the easiest to see,
2:23
even though it's not the most important.
2:24
This one is. You may see a little cleft between the two,
2:28
but on sagittal MRI,
2:29
you'll actually see a different course of the fibers.
2:32
These will be more straight up and down,
2:35
and the distal superficial arm will have an obliquity
2:38
this way from proximal anterior to posterior
2:44
and inferior. And then it'll come back in,
2:47
making somewhat of a triangle.
2:49
Again, you'll appreciate this better on a real MRI image.
2:54
And this particular component passes superficial
2:57
to the pars reflexa of the semimembranosus.
3:01
So the anterior arm is located between the central
3:04
arm and the distal or superficial arm of the POL,
3:08
namely the pars reflexa bisects the
3:11
two and goes in between them.
Stephen J Pomeranz, MD
Chief Medical Officer, ProScan Imaging. Founder, MRI Online
ProScan Imaging
© 2024 MRI Online. All Rights Reserved.