BeneFIT PT’s Anatomy Series: The Knee (part 1)

We are continuing BeneFIT  Physical Therapy’s Anatomy  Blog Series this month with the Knee Joint. Each month we will feature a different part of the body.  BeneFIT PT’s staff is highly trained in knowing all about human anatomy so that we can effectively help our patients with their specific areas of concern, rehabilitation and strengthening.

Our knees are vital to sports and from the most mild to demanding exercises, including walking, jogging and running. Thus, when we injure a knee, it’s important to identify the specific injury as that will indicate treatment and after care. The knee is the largest joint in the body and is made up of four components: bones, cartilage, ligaments and tendons, and muscles. The knee joint is one of the most commonly injured joints due to the constant workload it must handle. 

Bones

Knee Anatomy

The major bones of the knee joint: Femur, Tibia, Patella, and Fibula. © Lisa Arjo Sukamto | Dreamstime.com

The knee joint is primarily made up of three bones: thighbone (femur), shinbone  (tibia), and kneecap (patella).  Additionally your knee has Articular cartilage on the underside of the patella (kneecap) which is the side closest to your femur.  Articular cartilage is also at the ends of both the femur and tibia. This cartilage helps your knee bones glide smoothly across one other as you bend or straighten your leg.  Your fibula, although not technically a part of your knee joint, is important as our lateral knee ligament starts above the knee and will end on the top of the fibula. 

The Meniscus

Knee Anatomy

Knee Meniscal Anatomy. © Medical Stocks | Dreamstime.com

The meniscus acts as a “shock absorber” between your femur and tibia. The meniscus differs from articular cartilage in that it is tough and rubbery to help cushion and stabilize the knee joint. When a person talks about torn cartilage in the knee, they are usually referring to torn meniscus.  

The meniscus is split into two halves, the lateral (or outside part of the knee) and the medial (which is on the inside part of the knee).  Both halves sit on top of the tibia plateau which is the top of the main bone in our lower leg.  They are stuck onto that plateau similarly to how oysters or clams are stuck to their shell.  If we were to look at our meniscus from above they would look like to half moons.  The outside of our meniscus has a good blood supply while the inside does not.  This is the main reason why some meniscus tears will get removed during surgery while others will get repaired.  The tear in a part without the blood supply will never heal so it just gets snipped out.  

Ligaments

Ligaments connect bone to bone. The four main ligaments in your knee are similar to strong ropes that hold the bones together and keep your knee stable.

There are Collateral Ligaments and Cruciate Ligaments.  

knee anatomy

(figure 1). The 4 major ligaments of the knee.

Collateral ligaments are found on either sides of your knee. The medial collateral ligament (MCL) is on the inside of your knee, and the lateral collateral ligament (LCL) is on the outside. They control the sideways motion of your knee and brace it against unusual movement.

Cruciate ligaments are found inside the knee joint. They cross each other to form an “X”. The anterior cruciate ligament (ACL) is in front and the posterior cruciate ligament (PCL) is in back (see fig.1). The cruciate ligaments control the forward and backward motion of your knee.

Tendons

Tendons connect muscles to bones.  The quadriceps tendon (see fig.2) connects the quadriceps muscles in the front of your thigh to your patella. The tendon stretching from your patella to your shinbone is the patellar tendon.  Additionally, on either side of the kneecap is what’s called a retinaculum.  It’s a type of tissue called fascia that is found throughout our body.  It assists with support in keeping the kneecap where it belongs.  There is a lateral and medial retinaculum so named based on the side of the knee it is located.

knee anatomy

(figure 2). The knee has two main tendons, the quadriceps tendon above the knee and the patella tendon below.

 

Check back next week for our second knee anatomy post which includes a discussion on the different muscle groups surrounding the knee.

If you are in any pain or discomfort in your knee, and want to get it checked out just contact either of our offices.  Our Doctors of Physical Therapy can see you without a prescription, covered by your insurance, often times within 24 hours from your call!

 

Sources:

Knee Text References

https://www.healthpages.org/anatomy-function/knee/

https://orthoinfo.aaos.org/en/diseases–conditions/common-knee-injries/

Knee Blog Picture References 

Fig1 – 

https://www.activephysioworks.com/blog/whatever-it-takes-documentary/

Fig2 – 

https://physiqz.com/physical-therapy/strengthening-exercises-and-stretches-for-knee-pain-treatment/