Knee Anatomy

Anatomy of the Knee

Knee joint, the largest and the most complex joints in the human body, mainly consists of six components such as ligaments, tendons, bones, nerves, muscles and blood vessels. The knee joint is formed by tibial plateau, the femur and the knee cap. The knee, which is also known as the synovial joint is enclosed by ligament, capsules and lubricated by synovial fluid.

Knee Joint – The knee joint is mainly formed by the bottom of the femur and the top of the tibia. The end of the femur is made up of femoral condyles which are positioned on the surface of the tibia called the tibial plateau. The tibial plateau is further divided into lateral tibial and medial tibial plateau.

Patellofemoral Groove– The patella is located through a groove in between two femoral condyles. This space is called the patellofemoral groove.

Articular Cartilage – The articular cartilage is the covering at the ends of a joint and is about a quarter of an inch in thickness. It is slippery, white, shiny and rubbery in consistency. It acts as a shock absorber and its smooth surface facilitates motion.

Ligaments – The ends of the bone are bound together with the help of ligaments which are tough and located on both sides of the knee joint – medial collateral ligament and the lateral collateral ligament. The anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL) are both located inside the knee joint in the front and back respectively. The front and back motion of the knee is controlled by the ACL and PCL.

Tendons – The tendons attach the bones and the muscles together. The patellar tendon is the largest tendon in the knee and is connecting the tibia and the knee-cap. The tendons reach to cover the patella right up to the thighs. The quadriceps tendon connects the front of the thigh and the quadriceps muscles. The hamstrings located behind the leg also connect to the knee in different places.

The Muscles – The extensor mechanism controls motor functions of the knee such as riding a bicycle or kicking a football. The extensor mechanism consists of the quadriceps muscles, medial retinaculum, quadriceps tendons, lateral retinaculum, patella, patellar tendon and tibial tuberosity.

The Blood Vessels – The popliteal nerve carry the blood vessels down the back of the leg through the popliteal artery and vein which provides the largest supply of blood to the leg. The leg will not survive if there is damage to the popliteal nerve. Blood is carried back to the heart through the popliteal vein.