 Okay, welcome to our practical approach to one thing and one thing only today, menisci. So I'm starting out with exactly what I said I wasn't going to do, a slide. You know, this is not meant to be didactic. It's meant to be an interactive experience so that you really understand how to talk about, not talk about, menisci. But I have to have some just basic framework of anatomy and here it is. So I made this simple diagram and on your left is a kind of a broader half circle and on your right is sort of a tighter C-shaped circle. The one on the left happens to be the medial meniscus, your left. The one on your right is the lateral meniscus. This part of the meniscus actually attaches down into the screen. That's called the root ligament. We can't see that. But this is the meniscus root. Here's the front root. There's the back root. And then the rest of this is the anterior horn and we'll keep it simple. The front third is the anterior horn, the middle third is the body, the posterior third is the posterior horn. Once again, these are the roots attached by ligaments. The menisci are also attached out peripherally by the capsule. Some tighter than others. In fact, the medial side has a tighter attachment than the lateral side. That's why it's more prone to certain types of menisco-capsular injury. And the same rules apply here. A third, a third, and a third for anterior horn body and posterior horn with attachment on the outside. Now on the inside, the free edge of the meniscus is not attached. It's like the wing tips of a manta ray. It's just floating and synovial fluid and sometimes it'll get a little bunched up or squished. And when it does that, it looks a little funny, especially when there's synovium. That is the normal phenomenon and pitfall known as meniscal flounce and we're going to see it. Now the meniscus is also divided up into thirds. An inner third, a middle third, and an outer third. And in every meniscal tear, we want to comment on that because the tears that occur here, you should almost never ever operate on. They're all going to heal well enough on their own, better than they would do if somebody manipulated them or cut them out. The ones in the middle, kind of maybe yes, maybe no, but usually not surgical candidates. The ones on the inner free edge, those are the ones that are more likely to require surgical intervention. And these areas are also known as the red-white zone in the middle, the red-red zone on the outside, and the white-white zone on the inside in orthopedic parlance. Now this next slide, and this will be the last slide before we go into cases, demonstrates the meniscus in cross-section. And you might have noticed in the last slide there are some different colors in there and I don't really care about those too much. But the bottom line is within the meniscus there is specialized anatomy that conducts synovium from the joint to the outside. So there is a pathway of flow, I can draw it for you, see if it'll let me. There's a pathway of flow that goes this way. Notice it goes right along this purple and yellow anatomy and that persistent flow along these bands of collagen that live inside the meniscus represents the normal intraminiscule signal, which you now see is not present in the inner third as depicted by this purplish area. It starts around the middle third depicted by the yellow and then kind of breaks off into two bundles, one here and one there. It kind of makes like a little fork or a couple of bunny ears if you turn it straight, right side up, and those bunny ears are normal. They should be relatively faint. They should never be equal to or brighter than a highland cartilage. They should never go all the way back to the capsule. They should never go up and down. They should never have complex character. They should have exactly what I've drawn here, this gently sloping character. Now, a lot of your colleagues will refer to these signals in different ways. You'll hear them call contusions, you'll hear them called degeneration, you'll hear them called mixoid change, you'll hear them called cysts. And each one of these has an appropriate setting where it's to be used. But let's give an example. You're fresh out of training and you call the signal in the meniscus in a 32-year-old otherwise healthy girl that just ran three miles meniscal degeneration, but the rest of her knee looks fine. Why in the world would you use the term degeneration? She has no DJD, her meniscus is of normal size, she just ran three miles. It is a silly term to use in that setting. Or if I hear degeneration in the 13-year-old, what 13-year-old has a degenerated meniscus? Nobody, except maybe somebody with a discoyed meniscus, this is silly stuff. This is like saying, let's give all the banks any of the rules they want. That's silly stuff. Let's stop doing silly stuff. And your job, your primary job is to save the whales, save the menisci. The slightest amount of trimming in the meniscus changed the knee dynamics forever for that person's entire life. It is a total game changer. So the worst thing you can do is call something that is not there.