Knee Anatomy

The first step in diagnosing your knee problem is to understand all the nuts and bolts that make up its structure (i.e.; muscles, bones, cartilage, etc.).   Knowing what holds it together, will eventually help you in identifying any issues you may have. Here is a quick glimpse at what the knee looks like:


(Taken from



Four major bones are involved in keeping things together and making sure that everything moves smoothly. They are:


  • Shin bone (tibia) – This bone goes from your knee all the way down to your ankle. Directly on the top of the tibia, on each side of the tibial plateau, are cartilages called menisci. Basically, these are pads which act as shock absorbers between the femur and tibia.
  • Calf bone (fibula) – This is a long, thin bone which runs parallel to the tibia, from knee to ankle. The main purpose of this bone is to stabilize the ankle and support the tibia and surrounding lower leg muscles.
  • Kneecap (patella) – The patella’s main function is to cover and protect the knee joint and it also relieves friction between the bones and muscles when bending and straightening the knee. It glides along the bottom part of the femur between two dedicated grooves called femoral condyles.
  • Thigh bone (femur) – This bone is considered one of the strongest in the body, and is the only one in the thigh. It’s main purpose is to transmit force from the tibia to the hip joint.




Ligaments are thick connective tissues that link bone to bone around a joint. There are four major ligaments surrounding the knee joint:


  • MCL (Medial Collateral Ligament) – Stabilizes the knee joint and controls the side to side movement. Runs down the inside of your knee joint.
  • LCL (Lateral Collateral Ligament) – Also controls the side to side movement. Runs on the outside of your knee.
  • ACL (Anterior Cruciate Ligament) – Controls the backward and forward motion and stops the shin bone from moving ahead of the femur.
  • PCL (Posterior Cruciate Ligament) – Also helps control the backward and forward motion.





The lateral meniscus and medial meniscus are used as shock absorbers between the four knee bones. These are an extremely important part of the knee structure. Imagine the pain you would feel walking bone on bone.


There is also the articular cartilage which you will find at the end of any bone that is part of a joint. Synovial fluid covers this cartilage, which makes it easier for the bones to move together.



Muscles and tendons


There are several muscles surrounding the knees which provide it with protection as well as ensuring that an appropriate level of force passes through the joint, such as the quadriceps, hamstrings, and the calf muscles. It is important to keep these muscles strong and active, especially if you’ve already experienced a knee injury. Having strong and active muscles surrounding your knee diminishes the amount of “work” your ligaments must do during regular activities.


Tendons are essentially soft tissues which link the major muscles to the bones and assist in stabilizing the knee.





These are little bags of fluid which are located around the joint and their purpose is to provide cushioning between all the ligaments, muscles, bones and tendons. There are approximately 13-14 of these bags around the knee area.

If you are a visual person, like myself, then you will love this video which goes through the anatomy of the knee, but in a more interesting way:


The Adobe Flash Player is required for video playback.
Get the latest Flash Player or Watch this video on YouTube.



Please go to our SHOP for a list of available knee braces and other products. Also, you can sign up for our NEWSLETTER to keep up-to-date on the latest information about knee braces and knee pain in general. Thank you.


April 5, 2015

Hi everyone,

Thanks for all the emails and feedback on this post. I added more information on the major bones and also added a link to a YouTube video that you might find interesting.