 So now, let's go back to the case. Here's our axial and we now know something bad happened. We've got blood in the joint. We already know we've got a fracture. Something violent happened during the pivot shift. There's a lot more information on here. We can tell what's medial and what's lateral by looking at the patella. There's the medial facet. The cartilage is a little bit fatter. It's usually a little shorter than the lateral facet. So this would be lateral, this would be medial. And we get a quick glance at the MCL. We get a quick glance at some of the lateral collateral. That's not the story today. The story is the menisci. So let's have a look at the menisci coronally. The first thing you ought to notice is the lateral meniscus is too small. I mean normally the medial meniscus is bigger than the lateral meniscus. Or it's at least as visible. If we have a nice triangle on the medial side we can see the meniscus root. We can even see the root attachment right there. And it's lining up very nicely with the edge of the femur and the tibia. There is one of the attachments of the meniscus. Let's blow it up a little bit. Here's another attachment of the meniscus. The so-called coronary ligament attachment. But on this side we already know that in this relatively young person he's had a violent pivot shift that there's a meniscal problem. We're missing our triangle. So now we have to define the problem. And as I'm defining it I recognize that there is another fracture in the femoral terminal sulcus again illustrating the violence of whatever happened. We know that the ACL is going to be gone with this constellation of fractures. That's not why we're here. There's less than a 7% chance the ACL could still be intact. But I am interested in where did the meniscus go? Because this is about menisci. Did it go in? It's like belly buttons. Is it in any or an outie? And I can't find it in. I can't find a piece that got chopped off and went in. I'm looking really hard. In fact I'm looking at that root. We have a nice clean root meniscus and root attachment. Over here? Not so much. Where is it? Oh there's a root injury all right. The root ligament? Chop chop. The relationship of the meniscus to the root? Chop chop. We have a root trauma. A root tear. But we're not done yet because we've got to find this other piece. We already know that this meniscus in this younger person is floating outwards. It's not lining up very nicely with the edge of the tibia and the femur because it's no longer properly anchored. So in a sense this meniscus is separated from the anchors that keep it in the proper place. And you've got to remember this person is lying on their back. They're not even weight bearing. There are no hoop stresses. So imagine what happens to this poor little triangulated piece of cartilage when you stand up. It's like toothpaste. Boom. It goes out even further. Let's take a look at the anterior horn. Here's the anterior horn body junction. There's the anterior horn. There is the root attachment that includes a tether to the transverse meniscal ligament of Winslow and a tether to this little round structure here called the ligamentum mucosum. Don't worry about that. Let's go backwards now. We're missing the body. Keep going backwards. And our posterior horn is way too small. So let's look at the sagittal. And here's our sagittal. Let's work our way in from the body. Here's the body of the meniscus all the way out to the periphery. And the back of the body should be tethered to the popliteus tether. Let's look at it. What do we mean by tethered? I mean it should be attached. There should be an attachment high and low. A superior fascicle attachment and an inferior fascicle attachment. Let's draw it for you because this is the other part of the story. We've already established that the media meniscus has those short stubby little attachments that go all the way around. You can see them a little better in the mid-coronal plane as the menisco femoral ligament. I'll draw them for the medial side. I'm going to have a menisco femoral ligament and I showed you the coronary ligament earlier. In the back they're really short so we don't see them. But now I'm going to get a little bit thicker here, not too thick. And I'm going to show you what the lateral meniscus attachments look like. You don't see those as well coronally but you see them really well sagittally. So here's the lateral meniscus and it has an upper fascicle and a lower fascicle. And those fascicles are very important tethers. If you lose one the meniscus can actually twist on itself. And that can be a cause of locking, just one of these God. If they're both God then the meniscus can start to displace or float. So we should have an upper one, we do, although it looks a little lax right there. And we should have a lower one that goes straight on back and perforates through the popliteus tendon. We don't, I'm going to erase it so you can see it a little better. And I'm going to blow it up so you can see it a little better. Let's blow it up. So that should go right on through as a straight line. Here's the other piece of it right there. It's missing in action. It's still missing in action. In fact, they're both missing in action. There should be one going high and one going low. To make matters more complicated, we have an upper fascicle and a lower fascicle, but we also have a group that's on the outside, a lateral upper and lower group, and a medial more central upper and lower group. And they look a little bit different as you go from the center to the periphery. But that will be a story for another day. That's kind of getting into master level discussion. Right now, we're in pretty advanced discussion, but not quite master level yet. But this patient has a true menisco-capsular attachment. We are missing the lower attachment. We are missing the upper attachment. And we're also in a violent pivot shift situation. Let's go over to the medial side and see what that capsule looks like for a moment. We said that when you have a violent pivot shift, you get bleeding in the capsule. There it is. Too thick, but it's not a separation on the medial side. It's a sprain. It's bleeding. It's an injury. But on the lateral side, we've got ligaments that have ruptured, a meniscus that has displaced outward because it's no longer tethered. And just to be complete, here is the awful consequences of this pivot shift. The ACL is gone. The PCL is swollen. Here is our blood fluid level. The tibia is displaced anteriorly relative to the femur both laterally and medially as a sign of ACL deficiency, so-called passive anterior tibial translation. So in summary, you've learned about two very important types of vertically oriented tears. One not so bad, the vertical longitudinal, one that could be bad, the radial tear. You've learned how to measure length and depth of these tears. And you've also learned to a degree, we're not complete yet, the menisco-capsular attachments and what can happen to them and the sequela when you have a big-time rupture, the meniscus being displaced and floating out of the joint and no longer providing the proper support. Thank you.