Knee Joint Anatomy

Interactive 3D anatomy viewer for the knee joint — explore 27 anatomical structures across 6 layers including muscles, tendons, ligaments, menisci, cartilage, and bones, with clinical notes by Aurelia RMT.

Key Structures by Layer

• Superficial Muscles — Rectus femoris, vastus lateralis, vastus medialis, vastus intermedius (quadriceps group); biceps femoris, semimembranosus, semitendinosus (hamstrings); gastrocnemius, popliteus
• Tendons — Quadriceps tendon (suprapatellar), patellar ligament (infrapatellar), iliotibial band (IT band), popliteal tendon, biceps femoris tendon
• Cruciate Ligaments — ACL (anterior cruciate; prevents anterior tibial translation), PCL (posterior cruciate; prevents posterior translation)
• Collateral Ligaments — MCL (medial collateral; resists valgus stress), LCL (lateral collateral; resists varus stress)
• Menisci & Cartilage — Medial and lateral menisci (fibrocartilage shock absorbers); articular cartilage on femoral condyles, tibial plateau, and patella
• Bones — Femur (medial and lateral condyles), tibia (tibial plateau), fibula (head), patella (sesamoid bone in quadriceps tendon)
• Vessels — Popliteal artery and vein, superior and inferior genicular arteries, anterior tibial artery

Frequently Asked Questions

What are the ACL and PCL?

The ACL (anterior cruciate ligament) prevents anterior tibial translation and is commonly injured in pivoting sports. The PCL (posterior cruciate ligament) prevents posterior translation and is the stronger of the two cruciate ligaments.

What is a meniscus tear?

A meniscus tear is damage to the C-shaped fibrocartilage discs that cushion and stabilize the knee. Tears commonly occur from twisting or pivoting on a loaded, flexed knee. Degenerative tears can develop gradually with age.

What is patellofemoral pain syndrome (runner's knee)?

Patellofemoral pain syndrome is anterior knee pain from abnormal patellar tracking in the femoral trochlear groove. It is often linked to VMO weakness, tight lateral structures, and increased Q-angle — one of the most common knee complaints in active individuals.