Feel it for yourself
Wiggle the tip of your nose. It bends and springs back! That's cartilage. Now gently fold the top of your ear. It bends and pops back too. More cartilage!
Cartilage is firm, like rubber, but smooth and bendy. It isn't as hard as bone, so it can bend without breaking.
Your windpipe has cartilage too. It makes rings that keep the tube open, so air can always get through. Gently feel the front of your neck, below your chin. Those little ridges are the rings.
Three kinds
Smooth, glassy cartilage covers the ends of your bones in your joints. It also joins your ribs to your breastbone, and it makes the rings in your windpipe.
Stretchy cartilage shapes your outer ear. It can bend a lot and spring right back.
Tough, cushiony cartilage makes the discs between your back bones and the pads inside your knees. It's made to take a squish.
A skeleton that starts soft
Before a baby is born, most of its skeleton is made of cartilage first. Then, bit by bit, the cartilage turns into bone.
This keeps going all through childhood. Kids still have cartilage in their growth plates, the spots near the ends of their bones where they grow longer.
A baby's kneecaps are still all cartilage, and so are many of the small bones in a baby's wrist.
Sharks and rays never switch to bone. Their whole skeleton stays cartilage for life! Cartilage is lighter than bone, which helps a shark stay up in the water.
No blood vessels
Cartilage has no blood vessels inside it. It gets what it needs from the liquid around it, a bit like a sponge soaking up water.
When you move, the cartilage in your joints gets squeezed and let go. That helps it soak up what it needs.
Because it has no blood vessels, cartilage heals much more slowly than bone. That's one more reason to look after your knees and other joints.