Knee Anatomy

A lot of our patients who suffer from osteoarthritis know exactly where the pain exists in their knees but don’t know what is actually happening inside their leg or even what specific component of the knee is actually hurting. In this educational post, we break down the anatomy of the knee into its basic parts. We also encourage you to look up and learn more about each part. Getting to know how your body functions is a great investment!

So what parts make up the knee?

We depend upon our knees every day for walking, jumping, squatting, sitting, kicking, dancing and so on. The knee is our largest joint and allows us to do so many things; but what exactly is the knee?

Imagine the knee as a really complicated intersection where two major highways meet. Here in Georgia, we have a major intersection we call Spaghetti Junction where highways loop around and overlap. Similarly, your knee is a complex weaving of bones, cartilage, ligaments, bursa, tendons, and muscles that form an anatomical masterpiece. Below is a list of the knees main components:

4 Bones

The knee connects four bones: the femur, patella, fibula, and tibia.

  • Femur: This is the longest and strongest bone in your body, and is also known as your thighbone.
  • Tibia: This is the second largest bone in the body, and is also known as the shinbone. It provides most of the support to the muscles in your lower leg such as the calf muscle.
  • Fibula: This smaller long bone runs parallel to your shinbone, and is important for stabilizing the ankle.
  • Patella: Commonly known as the kneecap, the patella allows your knee to extend and also protects the inner knee.

4 Ligaments

Ligaments are made up of tough, elastic tissue that supports joint movement.

  • Anterior Cruciate Ligament (ACL): This central ligament allows for rotation and forward movement of the tibia. It is closer to the front of your knee.
  • Posterior Cruciate Ligament (PCL): Another central ligament that allows backward movement of the tibia. Is it near the back of your knee.
  • Medial Collateral Ligament (MCL): This ligament acts as a stabilizer and is located on the inner side of your leg.
  • Lateral Collateral Ligament (LCL): Another stabilizing ligament that is located on the outer side of your leg.

3 Main Cartilage

Cartilage is elastic tissue that protects the bones from rubbing against each other.

  • Medial Meniscus: This thin fibrocartilage band is the inner cushion between the femur and the tibia. This is located on the inside (medial) part of your knee on top of the inner ball of the tibia bone. It acts as a shock absorber.
  • Lateral Meniscus: Another thin fibrocartilage band that sits between the femur and the tibia that minimizes friction between the two bones. It sits on the outer ball of the tibia bone. It acts as a shock absorber.
  • Articular Cartilage: This is thick tough cartilage that covers the ball of the ends of the femur and tibia where they come into contact with each other. Most of the body weight is born by these two surfaces and this is the tissue most affected by arthritis. It is the principal target of stem cell therapy of the knee. This treatment transplants the patient’s stem cells obtained from his or her stomach fat and implants them together with the patient’s platelet-rich plasma. This repairs the damage caused by the wear and tear of arthritis on these two surfaces.

4 Main Bursa

These are fluid-filled sacs whose main purpose is to reduce friction and minimize the impact between your bones and between bones and soft tissue. They also lubricate your joints.

  • Prepatellar Bursa: Located between the patella and the tissue above.
  • Suprapatellar Bursa: This is located between your femur and your quadriceps tendon.
  • Infrapatellar Bursa: You have two of these! There is the deep infrapatellar bursa (inner) and the subcutaneous infrapatellar bursa (outer) that surround the patellar tendon on the top of your shin (fibula) below the kneecap (patella).
  • Pes Anserine Bursa: This bursa sits between the top of your tibia and protects the tendons inside the knee.

2 Main Tendons

A tendon is made up of fibrous tissue, which connects muscle to bone, allowing for movement.

  • Patellar Tendon: This tendon stretches from the patella to the knee bone.
  • Quadriceps Tendon: This tendon connects your patella and your quad muscle.

4 Main Muscles

Muscles are a soft tissue whose purpose is to allow for force and movement.

    • Quadriceps: These four muscles are where your leg power comes from. They allow for the extension of the leg.
    • Gastrocnemius: This is your calf muscle!
    • Tibialis Anterior: This is the muscle that sits along your shin (tibia) and is used for inverting the foot.
    • Sartorius: This is the longest muscle in the human body, going from the hip to the knee. It allows for flexing and rotation.

You should take seriously damage to any component of your knee. We at Joint Regenomics use your own stem cells together with platelet-rich plasma to treat an assortment of knee, ankle, shoulder, elbow, and wrist conditions due to chronic arthritis, tendonitis, and bursitis. For more information about if stem cell therapy is right for you, contact Joint Regenomics or call Kim Teasley at 404.574.2373 to schedule your consultation. Visit us on the web at