Knee joint
The knee joint is the largest and most complex joint in the human body. It connects the femur, tibia, and patella, allowing flexion, extension, and slight rotation of the tibia.
Bone structures
The articular surfaces are formed:
- Condyles of the femur - two convex ridges (medial and lateral)
- Tibial plateau - the upper platform of the tibia with two concave fossae
- Patella (patella) - the largest sesamoid bone, sliding along the intercondylar groove of the femur
All articular surfaces are covered with hyaline cartilage up to 6 mm thick - this is the greatest thickness of cartilage in the body.
Menisci
Between the femoral condyles and the tibial plateau there are two meniscus - C-shaped cartilaginous pads:
- Medial meniscus - larger, less mobile, more often injured
- Lateral meniscus - smaller, more mobile
The menisci perform the functions of shock absorption, load distribution and stabilization of the joint. They increase the contact area of the articular surfaces by 60%, reducing pressure on the cartilage.
Ligamentous apparatus
Four main ligaments provide stability to the knee joint:
| Bunch | Function |
|---|---|
| Anterior Cruciate (ACL) | Prevents shin movement forward |
| Posterior Cruciate (PCL) | Prevents shin movement backwards |
| Medial collateral (MCS) | Stabilizes the joint from the inside |
| Lateral collateral (LCS) | Stabilizes the joint from the outside |
A torn ACL is one of the most common sports injuries, especially in football and alpine skiing.
Biomechanics
The knee is not a simple joint. During flexion, a combination of rolling and sliding of the condyles occurs, and in the last 20° of extension there is a screw-home mechanism (screw-home mechanism), in which the tibia slightly rotates outward, fixing the joint in a straightened position.
Injuries and illnesses
The most common damages:
- Tear of the meniscus - pain, joint blockade, swelling
- ACL rupture - instability, “wagging” of the leg
- Gonarthrosis - degenerative destruction of cartilage, the most common cause of endoprosthetics
Knowledge of the anatomy of the knee joint is necessary for orthopedists, sports doctors and rehabilitation specialists for accurate diagnosis and treatment.
You can view the menisci, cruciate ligaments and patella in detail in 3D atlas Humio - rotate the knee joint model and study each structure layer by layer.