What is the scientific name for the kneecap?
General information only. This article explains the basics and is not medical advice. For anything about your own health, talk to a doctor or other qualified professional.
Quick answer
The scientific name for the kneecap is the patella, from the Latin for “small plate” or shallow dish. It’s a flat, triangular bone at the front of the knee. The patella protects the knee joint and acts like a pulley, giving the thigh muscles extra leverage to straighten the leg.
What the patella does
| Job | How |
|---|---|
| Leverage | Holds the quadriceps tendon away from the joint, increasing its pulling power by up to about 30–50% |
| Protection | Shields the front of the knee joint from knocks |
| Smooth movement | Its cartilage-covered back glides in a groove at the end of the femur |
The groove sits at the bottom of the thigh bone; see the largest bone in the human body.
A special kind of bone
The patella is a sesamoid bone, meaning it develops inside a tendon. It’s the largest sesamoid bone in the body. The name comes from sesame seeds, because most sesamoid bones are small. You also have tiny sesamoid bones in your hands and feet.
Babies’ kneecaps
Babies are born with kneecaps made of soft cartilage, which doesn’t show up on X-rays, so it can look as if they have no kneecaps. The patella gradually ossifies (turns to bone) between about ages 3 and 6, and the process continues into the teens.
The knee reflex
When a doctor taps just below your kneecap with a small hammer, your leg kicks forward. This is the patellar reflex. The tap stretches the tendon, and your spinal cord signals the thigh muscle to contract, without the brain needing to decide. It’s a quick way to check that nerves are working.
Other Latin names for body parts
| Common name | Scientific name |
|---|---|
| Kneecap | Patella |
| Collarbone | Clavicle |
| Shoulder blade | Scapula |
| Breastbone | Sternum |
| Shinbone | Tibia |
| Voice box | Larynx; see the medical name for the voice box |
Joints like the knee are filled with lubricating fluid; see what causes the sound when you crack your knuckles.
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