The knee is one of the largest and most complex joints in the body. The knee joins the thigh bone (femur) to the shin bone (tibia). The smaller bone that runs alongside the tibia (fibula) and the kneecap (patella) are the other bones that make the knee joint.
The patellofemoral joint consists, specifically, of the posterior surface of the patella (knee cap) and the surface of the femur (thigh bone). The patella (knee cap) is shaped like an upside-down triangle. On average, the patella (knee cap) is approximately 4 – 4.5 cm of length, 5 – 5.5 cm of width and 2 – 2.5 cm thick. The distal femur forms into an inverted U-shaped (femoral sulcus). During knee movement (bending and straightening) the patella (knee cap) glides over the femur (thigh bone).
Supporting articles
Loudon 2016. Biomechanics and pathomechanics of the patellofemoral joint.