Knee Joint Anatomy

The knee is one of the most important joints in the body and has multiple functions including supporting an individual’s body weight when standing and maintaining balance while walking and running. Understanding the knee joint anatomy can help one understand how the knee works to function and enable movement.

Bones around the Knee

The knee joint comprises of four key bones: a) patella or the knee cap b) tibia, which is often referred to as the “shin” bone c) fibula, which is known as the outer shin bone and d) the femur or the thigh bone. The femur, tibia and patella facilitate the movement of the knee joint. The tibia’s key function is load bearing or supporting the weight of the body while the fibula provides a surface for muscles to be attached. All the bones are covered with cartilage to ensure smooth movement.

The Knee Joint Capsule

The knee is surrounded by the knee joint capsule, which contains the synovial membrane. The synovial membrane produces synovial fluid, which lubricates the knee in order to reduce friction and wear and tear.

Ligaments of the Knee Joint

Any two bones in the human body are connected by ligaments. The anterior cruciate ligament and the posterior cruciate ligament are at the centrecenter of the knee joint. The medial collateral ligament and the lateral collateral ligament are on the sides of the knee joint.  Ligament injuries cause knee joint instability.

Tendons of the Knee Joint

Muscles are attached to bones with tendons. The key tendons are the patellar tendons and the quadriceps tendons. The patellar tendon covers the knee cap. The hamstring muscles also connect to the knee joint through a series of tendons. In the case of sports injuries involving torn ligaments, sometimes tendon grafts are used as a replacement.

Cartilage of the Knee

Cartilage is the smooth lining covering the knee joint. The knee joint has two types of cartilage: a) articular cartilage and the b) meniscus. The articular cartilage covers the end of the bone and the wearing awaya way of articular cartilage results in knee arthritis. The meniscus can be found between the end of the thigh bone and the top of the tibia. It is a shock absorber for the knee.