Anatomy of the Knee

Bones Tibia The tibia is the lower leg bone. Also called the shin bone, it is the second longest bone of the body, and is located below the knee. Femur The femur, also known as the thigh bone, is the longest, largest and heaviest bone of the body. It is located above the knee. Fibula The fibula is the thin bone located on the outside of the tibia. Patella The patella, or knee cap, is a bone that is connected to the patella ligament, below, and the quadriceps tendon, above. The underside of the patella has a smooth surface and glides over the knee joint when the leg is extended or bent. Soft Tissue Meniscus The medial meniscus and the lateral meniscus act like cushions and distribute the weight of the femur. Collateral ligaments The lateral and medial collateral ligaments minimize side to side movement and help stabilize the knee. Condyle The condyle makes up the rounded end of the femur. This smooth surface allows the femur to move easily over the tibia’s meniscus.

Patella ligament The patella ligament helps secure the patella over the front of the knee joint. Anterior cruciate ligament The anterior cruciate ligament (ACL) connects the front of the tibia to the back of the femur. It keeps the tibia from sliding forward and limits its rotation. ©2002 Swarm Interactive.

Quadriceps tendon This tendon connects the patella to the quadriceps femoral muscle above it. The muscle and tendon pull the patella over the front of the knee joint to extend the lower leg.

Posterior cruciate ligament The posterior cruciate ligament(PCL) keeps the tibia from sliding backward.