When Do Babies Get Kneecaps?

As adults, most of us take our kneecaps for granted. They’re simply there, supporting our thigh muscles and protecting our knee joints, day in and day out.

It’s often only when we get ready for parenthood that we might start to think about this funny little body part.
When do kneecaps develop, after all? Are babies born with kneecaps or do they appear later? And when are kneecaps considered fully-formed?

Let’s answer some of these (k)need-to-know questions.

In this article 📝

Do babies have kneecaps?

You wouldn’t be alone if you thought that babies were born without kneecaps.

It’s the kind of thing that often appears in lists of interesting baby facts, but it isn’t quite true.

Babies do have kneecaps when they’re born, they just aren’t made of the same material as our adult kneecaps.

From early on in your pregnancy, in the embryonic stage between weeks five and 10, your baby has already started to develop a piece of tough tissue in their tiny knee joint where their bony kneecap will eventually be. This is called a cartilage patella. (“Patella” is the medical term for kneecap.)

Cartilage is a flexible material that helps our joints slide over each other and acts as a shock absorber whenever they experience any kind of impact.

We all have cartilage all over our bodies, but babies have a lot more.

Your peanut’s kneecaps will still be made of cartilage when they’re born.

Only when they move through toddlerhood and into childhood will some of this cartilage slowly turn into bone.

Why aren’t babies’ kneecaps made of bone?

Being born requires a lot of flexibility – probably way more than we give babies credit for.

Of course, the more malleable a baby’s body is as it goes through the birth canal, the better, for mama and baby alike.

This is probably why evolution has opted to keep hard, rigid, bony kneecaps for later, and to give babies cartilage kneecaps that aren’t likely to cause injuries during birth.

Softer kneecaps are also kinder to babies as they learn how to crawl and walk.

We all know how painful it can be to land hard on our knees – it’s the kind of blow that can draw tears at any age.

As your baby rises, teeters and falls over in their early walking attempts, their soft little kneecaps help to make those inevitable tumbles gentler, rather than harder.

When do babies’ kneecaps turn into bone?

The process of cartilage turning into bone is called ossification and it happens very slowly. Your little one’s kneecaps will only start to harden between the ages of two and six.

This hardening often begins in different places, and these areas slowly grow together to form solid bone.

Some cartilage gets left behind, though. Even as adults, we need cartilage in our kneecaps to support them and keep them flexible.

Your baby will be 10 or 12 years old by the time their kneecaps are fully developed, so not really a baby at all. (But then again, they’ll always feel like a baby to you.)

Can babies walk without kneecaps?

If you’re wondering whether it’s safe for your baby to walk or run without bony kneecaps, the answer is absolutely yes.

Of course, developmental issues and injuries can happen, and if there seems to be any unusual swelling or your little one seems to be in pain, it’s always a good idea to chat to your doctor.

But for the most part, that little piece of cartilage deserves your trust. Like other parts of your baby’s body, it’s probably growing and changing at just the right pace all the time.

👶 More baby milestones:
Your Guide to Baby’s First Haircut
When Do Babies Lose Their Hair? And Why?
Baby Growth Spurts: What are the Milestones?
When Do Babies Walk? The Timeline for Toddling
When Do Babies Start Talking?
When Do Babies See Color?
When Do Babies Start Smiling?
When Do Babies Sit Up?
When Do Babies Start Teething?
When Do Babies Stop Spitting Up?
When Do Babies Start Cooing?
When Do Babies Grow Hair?
When Do Babies Clap?
When Do Babies Start Dreaming?
When Do Babies Make Eye Contact?
What Are the Different Stages of Crawling?
When Can Babies Eat Baby Food?
When Can Babies Hold Their Head Up?
When Do Babies Start Laughing?