Bad knees. Everyone has heard about someone with a chronic knee ailment, particularly among the elderly in the community. Knee problems usually plague the patient for the remainder of their life and, on top of that, having dysfunctional knees is a huge physical set-back for human movement and quality of life. So what makes this joint so important and so complex that it is one of the major joint ailments in humans?
Learn another knee problem: Hyperextended Knee
Here is an image to be used as reference as the functionality and anatomy of the knee are explained. You may want to pull it up in a new window as you read.
To begin with, the two bones that comprise the knee are called the femur and the tibia. The femur, on top, meets with the tibia, on the bottom, to form this massive human leg joint. If you look, you can see little pads that cushion the connection between these two bones. These are comprised of two basic types of cartilage. The white covering that looks like paint on the tips of the two bones is the “articular cartilage”, the padding that covers the entire surface of each bone’s tip. Then you can see two cushion-type pads that provide more protection. These are various types of “meniscus”. This is how the femur and tibia come together and form the knee joint, but how does it function and move?
The knee’s movement is completely dictated and enabled by “ligaments”. These are the pink cords you see running throughout the joint. They each stabilize movement of the knee in their own way. The “lateral ligament” is the long tendon running along the side, attached to the sides of both the femur and tibia. This ligament limits sideway motion and ensure that the knees don’t collapse outward when people walk. Then comes the infamous ACL, the anterior cruciate ligament, connecting the femur and tibia at the very core of the knee. This ligament is wildly important because it limits forward motion and rotation of the knee, keeping the center core of the knee stabilized and gluing it all together. Finally, there is the lesser known PCL, posterior cruciate ligament, which limits backward movement and polishes off this system of ligaments and limited movement that stabilize the knees as you move.
As you can see, this joint is not only the largest within the human body, but the most complex. It is a base for much human movement and the ligaments and cartilage are very fragile in comparison to their importance of function. This explains why knee problems are so prevalent. The inner workings of the knee are not quite as long-lasting as other parts of the human body, and so people must watch their grandparents struggle around as their femur and tibia grind together past dead cartilage and weakened ligaments. Regardless, this joint is a wonder of nature and it’s fantastic that humans have them at all.