As the weather is getting colder for us on the East Coast, there are so many things to look forward to: cozy blankets, falling leaves… and creaky knees! I’m decidedly less excited about that last one, though.

However, inspired by something that I am dealing with right now, I thought that this would be a wonderful time to write about the anatomy of the knee for dancers. Per my guiding principles, when you can understand the bones and muscles making up a specific area, you can understand injury to that area much more clearly.

Now, the knee is complicated– to say the least. Because the patella, or kneecap, is a floating structure, the knee is made up of a very complex network of ligaments that allow for all the various movements of this joint, as well as fluid-filled sacs that act as “padding” to reduce friction and absorb the forces that impacts the knee joint.

As dancers, it’s critical that we spend the time to understand this joint because it is so heavily implicated in everything that we do! Think about all of our jumps– each of them is powered by a plié, which is none other than a flexion of the knee joint. Think about the landing of all of our jumps– that force is absorbed by the knee joint as we return to the floor.

The BONES of the Knee Joint

There are three primary bones involved in the knee joint: the tibia (shin), the femur (thigh), and the patella (kneecap).

In this diagram below, the right knee joint is displayed as if you were looking straight at it. This kind of view is known as a anterior angle.

As the femur moves, the patella “glides” along or articulates with it. The two sides of the femur that “hug” the patella are known as condyles. The smaller bone, the fibula, is not directly implicated in the knee joint, but instead moves along with the fibula, a bone that is implicated in the knee joint.

In Between the Bones…

You are probably familiar with these structures, menisci (singular: meniscus), as a lot of athletes end up with injuries to these particular structures. The menisci are thick pieces of cartilage, and their primary role is to act like shock absorbers between the shin bone (tibia) and the thigh bone (femur) while also stabilizing the joint as it moves.

The joint is further stabilized by the Medial Collateral Ligament and the Lateral Collateral Ligament. These ligaments are located on either side of the joint.

The Quadriceps tendon and the Patellar ligament run on top of the patella bone. The Quadriceps tendon begins higher than the knee joint, and runs over the patella to make up the patellar ligament. The Patellar ligament is attached to the tibia.

As such, the patella is encapsulated.

As an additional way to minimize the grinding of these bones, the knee joint contains several bursa, or fluid-filled sacs. They may be found both deeply and superficially. Several knee injuries are caused as a result of inflammation of the bursa, which will be covered in the following articles.

There are two other very commonly injured ligaments of the knee: the Anterior Cruciate Ligament (ACL) and the Posterior Cruciate Ligament (PCL).

These ligaments are named based on where they attach to the tibia (NOT where they start from!). As such, the ACL attaches to the front of the tibia, running from the back of the femur. The PCL attaches to the back of the tibia, running from the front of the femur. These ligaments maintain the alignment of the tibia and the femur.

Finally, the IT Band (Iliotibial band) is involved similarly in stabilizing the joint. The IT band is a thick band of tissue, and rubs from the hip all the way down to the lateral tibia. Pain is often felt at the point where the IT Band runs over the lateral condyle of the femur as a result of friction during overuse.