Patella

The patella (/pəˈtɛlə/), also known as the kneecap or kneepan, is a thick, circular-triangular bone which articulates with the femur (thigh bone) and covers and protects the anterior articular surface of the knee joint. The patella is found in most vertebrates such as mice, cats, and birds, but not in whales or most reptiles and amphibians such as snakes or frogs.

In humans, the patella is the largest sesamoid bone in the body. Babies are born with a patella of soft cartilage which begins to ossify into bone at about three years of age.

Structure

The patella is a sesamoid bone roughly triangular in shape, with the apex of the patella facing downards.The apex is the most inferior (lowest) part of the patella. It is pointed in shape, and gives attachment to the patellar ligament.

The front and back surfaces are joined by a thin margin and towards centre by a thicker margin. The tendon of the quadriceps femoris muscle attaches to the base of the patella., with the vastus intermedius muscle attaching to the base itself, and the vastus lateralis and vastus medialis are attached to outer lateral and medial borders of patella respectively.