Patella

SkeletalSkeletonLegLeft and right

View left in 3D View right in 3D

What it is

The kneecap: a triangular sesamoid bone, apex down, embedded in the quadriceps tendon, with a ridged cartilage-covered back that runs in the femoral groove.

Function

Increases the leverage of the quadriceps by about 30% and protects the front of the knee.

Size

≈ 4.5 cm tall, 4.5 cm wide, 2–2.5 cm thick

Clinical note

Its posterior cartilage is the thickest in the body (up to 5 mm); anterior knee pain often arises here.