 So, this is going to be a demonstration of the interior of the knee joint. This is a supine cadaver, this is the left leg, I am standing on the left side and the camera person is also on the left side. So, we have sliced here the quadriceps tendon and the patellar ligament. We have sliced the iliotibial tract and we have sliced the capsule and we have reflected the patella along with the quadriceps tendon and the ligament the patellar. First let us take a look at the reflection of the fibroscapsule. When we are cutting the fibroscapsule we can see the remnant of the fibroscapsule attached to the margin of the femoral condyne here. We can see it here and I am picking it up the bits of the remnant of the fibroscapsule here. So, the fibroscapsule was attached here and from there the fibroscapsule got attached to the margins of the patella here. On the lateral side and on the medial side the fibroscapsule got reinforcement from these structures here. This is the lateral and the medial patella retina column respectively which got attached to the sides of the patella and to the tibial condyne and we can see the remnants of the fibroscapsule here also to the tibial condyne. So, this is about the fibroscapsule and inside the fibroscapsule of course is the reflection of the sinusoidal membrane. Having reflected the patella we can see the surface of the femur which was articulating with the patella. So, these are the femoral condyne, this is the lateral femoral condyne, this is the intercondyler groove and this is the medial femoral condyne covered by highland cartilage and we can see because this is an elderly cadaver the highland cartilage is partially degenerated. So, just to bring up to speed this is the base of the patella, this is the apex of the patella, these are the sides of the patella. This is the outer surface, this is the articular surface which is covered by the highland cartilage which also shows signs of degeneration. Now, let us take a look at the articular surface of the patella. We can see that there is a ridge here. This ridge fits into the inter groove here between the two condynes of the femur. This is the lateral articular surface, this is the medial articular surface. The lateral articular surface is larger because it articulates with the larger condyler surface of the femur and the textbooks describe it as having two ridges which divided into an upper middle and a lower portion but we cannot see that here so clearly. This is the medial portion of the articular surface of the patella which articulates with the medial femoral condyne here and there is a small vertical ridge on the medial most part of the medial portion which is the non-articular part of the medial surface. So this is what constitutes the femoral patella articulation. At this point, let me mention a few words of clinical correlation. There is something called a Q angle. That Q angle is the angle between the long axis of the femur and the mid-patella line. When we have a condition known as gyrovalgon or knock knee, the line of weight bearing goes through the lateral femoral condyne to the lateral tibial condyne and the knees are bent inside. In such situation, Q angle which normally is 9 degrees, Q angle becomes more than 17 degrees in which situation there is a tendency for the patella to dislocate laterally. There is an opposite condition known as bow leg or genu varum when the line of weight bearing goes through the two medial condyles, the medial femoral condyne and the medial tibial condyne. And in such situation, Q angle which normally is 9 degrees, it becomes less than 9 degrees and that is known as bow leg or genu varum. There is a theoretical tendency for the patella to dislocate immediately. However, lateral dislocation of the patella is more frequent. So that is about the femoral patella articulation. Thank you very much for watching. Dr. Sanjay Sanyal signing out. Mr. Kendall Kumberbatch is the camera person. If you have any questions or comments, please put them in the comment section below. Have a nice day.