ANATOMY - Knee
Your knee is one of the most used and abused joints in your body. You use your knee joint over one million times per year and as a result it is one of the most injured joints in your body. Your knee is more vulnerable to injury because it is one of the most mobile and flexible joints in your body. The more mobile a joint is, the less stable the joint is and thus, the more vulnerable it is to an injury.
Your knee is made up of three bones carefully designed to provide smooth, stable motion. These bones are called the tibia (shinbone), the femur (thighbone) and the patella (kneecap). These bones are enclosed in the joint capsule lined with a special tissue called synovium, which produces a thick liquid called synovial fluid which is necessary to lubricate, protect and nourish your joints.
Your knee is kept in alignment by ligaments and tendons. There are two large ligaments in the center of your knee, which cross each other, thus they are called the cruciate ligaments. These ligaments prevent your shinbone (the tibia) from moving forward and backward on your thighbone (the femur) The most famous of these is called the anterior cruciate ligament or ACL for short. This is called the anterior cruciate because it originates near the back of your thighbone and ends at the front or anterior part of your knee. The other ligament is called the posterior cruciate ligament or PCL for short. As you may have already guessed, this ligament starts from the front part of your thighbone and ends at the back of your knee called the posterior aspect of your knee.
On either side of your knee there are another set of stabilizing ligaments called the collateral ligaments. There are two major sets of these ligaments. On the inside part of your knee (the side closer to your other knee) this is called the medial collateral ligament ( MCL), the other is on the outside of your knee (the side closer to your hand) which is called the lateral collateral ligament (LCL). They supply stability when your knee moves from side to side or when you make any sharp cutting moves.
Knee Anatomy
Between the thighbone (femur) and shinbone (tibia), there are two semicircular rings of cartilage which are called menisci ("MEN-NIS-KI"). These also supply more added stability to your knee when the knee twists or pivots. Just like the collateral ligament, the inside meniscus is called the medial meniscus. This meniscus is also partially attached to the medial collateral ligament. Thus sometimes, when one is injured, the other is also injured. The outside meniscus is called the lateral meniscus. Unlike the medial side, this lateral meniscus is not attached to the collateral ligament. Thus, there is a rare association of a meniscus and collateral ligament tear.
The major two tendons of your knee are connected to your kneecap (patella). The tendon below the patella is called the patellar tendon (but really is technically a ligament since it connects your bone to another bone). The tendon above your patella is called the quadriceps tendon.
The kneecap or patella moves between a specially designed groove on your femur called chondyles. Movement of your patella outside of these chondyles can result in a subluxation (when it just moves partially out of the groove) or a total dislocation when the patella moves completely out of the groove.
