 Now we shall show the meniscus. For that again, I'm going to flex open the knee. We have flexed open the knee So these are the two femoral condyles and these are the two tibial condyles This is the tibial plateau and this in between portion is the intercondyler eminence. We see this filmy structure here This is the intra patellar fold. It's a fold of synavium and it's got two extensions Which are known as the alar folds. So let's keep that aside this structure, which I've lifted up here This is the lateral meniscus. We noticed that the lateral meniscus as the term implies the peripheral portion is wide and the inner portion is narrow So therefore in section it looks like a wedge. The peripheral portion is attached to the fibrous capsule And it is also attached to the margins of the lateral tibial condyle by means of this ligament part of which we have retained here This is referred to as the coronary ligament Which stretches from the margins of the lateral tibial condyle to the margin of the meniscus and that's what holds the meniscus in place The lateral meniscus has got an anterior limb which we can see here Which is attached to the anterior part of the tibial condyle and it's got a posterior limb It is more shaped like a C and we notice that the lateral meniscus is free from the fibular collateral ligament And my instrument is passing freely under the fibular collateral ligament. This brings a very important clinical correlation The lateral meniscus is very infrequently ruptured compared to the medial meniscus One reason is because it is free from the fibular collateral ligament and the second reason why it is very infrequently ruptured is because Austria part of the lateral meniscus, which is not visible in this dissection gives Partial origin to some of the fibers of the popliteus muscle which is in the back of the knee And when the popliteus muscle contracts, it moves the lateral meniscus out of the way And therefore injury to the lateral meniscus is much less common. And when it does occur, it's usually a marginal tear This is an orthoscopic view of a normal lateral meniscus and a torn lateral meniscus we prepare So that's about the lateral meniscus now Let's take a look at this fibro structure here. This is the medial meniscus We can see that the basic characteristics are same It is why that the periphery narrowed in the center and the peripheral portion is attached to the margins of the medial tibial Condyle by means of this ligament here, which we have retained This is the coronary ligament the medial coronary ligament It extends from the margins of the medial tibial condyle to the margins of the medial meniscus This is the anterior limb of the medial meniscus and the posterior limb again is not visible here The two anterior limbs are bridged over by this ligament structure that I've lifted up here This is known as the transverse ligament of the knee which holds the two anterior ends of the menisci together The medial meniscus in contrast to the lateral meniscus is more semi circular That is one difference The second difference is as we trace the medial meniscus posteriorly We notice that it is densely adherent to the tibial collateral ligament We can lift up the lower portion of the tibial collateral ligament and my instrument has gone in But as I push my instrument up We find that it cannot go any further up because it is densely adherent to the medial surface of the medial meniscus So this again brings an important clinical correlation because of the medial meniscus attachment to the fibrous capsule and the tibial collateral ligament The medial meniscus is torn much more frequently than the lateral meniscus and it has a very unique type of tear Where the peripheral portion remains attached to the capsule and the tibial collateral ligament and the inner portion gets separated And that kind of tear is referred to as the bucket handle tear apart from that the medial meniscus can also have a marginal tear So therefore the medial meniscus is torn much more frequently than the lateral meniscus These menisci they act as a cushion between the femoral condyles and the tibial condyles and they help to partially stabilize the knee This is the coronal MRI the knee joint to show the internal structures Note that the tibial collateral ligament is densely adherent to the medial meniscus for the fibular collateral ligament is free Also take note of the anterior and posterior cruciate ligaments The next structure that we notice is this tough ligament that I have lifted up here with my instrument This is the anterior cruciate ligament the anterior cruciate ligament extends from the anterior part of the tibial Condyle and it gets attached to the medial surface of the lateral condyle of the femur further posteriorly When a person is walking uphill, there's a tendency for the femur to dislocate posteriorly on the tibial So therefore anterior cruciate ligament prevents posterior dislocation of the femur on the tibia It also prevents hyperextension of the knee and it also helps to regulate the internal rotation of the knee So that is the role of the anterior cruciate ligament If the anterior cruciate ligament is torn then we can elicit what is known as a drawer sign When the person is sitting with the knee partially flexed We can pull the tibia forward against the femur and that is known as the anterior drawer sign Associated with pain which is an indication of anterior cruciate ligament tear We cannot see the posterior cruciate ligament because in this dissection it is located further posteriorly That brings me to a few clinical correlations pertaining to the knee I've already mentioned about the injury to the lateral meniscus Which can rarely produce marginal tear injury to the medial meniscus Which is more common can produce bucket handle tear as well as marginal tear Which is much more frequent than the lateral meniscus tear When there is pain on medial rotation of the tibia Associated with booking open of the lateral part of the knee and pain on the medial side That is indicative of medial meniscus tear Contrary wise when there is pain on lateral rotation of the tibia With pain on the lateral aspect of the knee and booking open of the medial side of the knee That is indicative of lateral meniscus tear Then there is something called the unhappy triad of knee injury which happens in very severe contact sports In such a situation three structures are torn one anterior cruciate ligament Two the tibial collateral ligament three medial meniscus So this is referred to as the unhappy triad of knee injury It is a potentially career changing injury especially which happens in sportsmen and all of these Required arthroscopic repair nowadays arthroscopic surgery is done very frequently for the knee This is an arthroscopic view of the interior of the knee joint showing a femoral screw and anterior cruciate ligament graft And last but not the least as we can see this cadaver There is partial degeneration of the highline cartilage on the femoral surface as well as on the tibial surface So therefore degenerative osteoarthritis of the knee is also very common because it's a weight bearing joint And therefore knee replacement arthroplasty is also quite commonly performed in advanced age This is the next ray after total knee replacement showing the femoral and the tibial component and the intervening plate So these are some of the structures that we can see the open knee from the anterior aspect the femoral tibial articulation And the various ligaments that we can see here. That's all for now. Thank you very much for watching Dr. Sanjay Sanyal Sanyal please like and subscribe if you have any questions or comments Please put in the comment section below. Have a nice day