Did you know ostriches are born with four kneecaps (patella)? The evolutionary reason for this is still not fully understood but theories include that it allows this heavy fast bird to straighten its knee faster thereby helping it to run faster. I have dedicated so much of my career to issues of the human patella. Many issues can arise from this small but fascinating bone. See below to learn some fun facts about this simple yet complex structure in our knees.
- The patella is a roughly triangular shaped bone called a sesamoid bone from the Latin sesamun “sesame seed”. It is the largest of this type of bone in our body as compared to the tiny sesamoid bones in say our foot.
- Babies are born with a patella made of cartilage instead of bone partly due to its flexibility for the birthing process
- The patella slowly turns from cartilage to bone between the ages of 2-6 years old
- Some people’s patella bone never fuses and so they may have two separate bones know as a bipartite patella. Rare genetic disorders cause some people to not develop a patella bone.
- “The knee bone is connected to the thigh bone” – this is sort of true as the quadriceps tendon in your thigh attaches to the upper part of your patella and patella tendon below your patella attaches to your shin bone.
- The patella sees an average of 2.5-3.5 times your body weight with stairs and up to 7-8 times your body weight with deep squat.
- The patella is vital to protect the inner structures of your knee acting as a shield. The patella increases the leverage of the knee extensor (straightening) muscles, so they don’t need as much force to straighten the knee.
- For such a small bone it is prone to injury including fractures, dislocations, patellofemoral syndrome and arthritis. Some people even have the patella removed due to severe injury or arthritis.
These are just some of the interesting facts about the patella and demonstrate how intricate and fascinating a structure it is in our bodies. Given that injuries to this bone and surrounding tendons, ligaments and joints are so common, it is important to properly manage these injuries to prevent damage to the surrounding structures as they are all interconnected. If you are experiencing issues of the patella or patellofemoral joint please visit the patellofemoral disorder section of my website to learn more.
By Dr. Beth Shubin Stein