Feel your collarbones
Put your fingers at the bottom of your neck. Slide them out toward your shoulder. That long bone you feel, just under the skin, is your collarbone.
Each collarbone is shaped like a long, flat letter S. One end joins your breastbone. The other end joins the top of your shoulder blade, at the point of your shoulder.
Try it: shrug your shoulders up to your ears. Feel your collarbones lift? They move every time your shoulders do.
A bar for your shoulder
Your collarbone works like a bar that holds two things apart. It holds your shoulder out to the side, away from your chest.
That gives your arm room to swing, reach and throw. Without collarbones, your shoulders would slump forward and in.
It's also the only bone that links your arm to the middle of your skeleton. Everything else that holds your arm on is muscle.
First to start, last to finish
While a baby is still growing, long before it is born, the collarbone is the very first bone that starts to turn hard.
But it's one of the last bones to finish growing. The end near your breastbone keeps growing into the early grown-up years, until about age 20 to 25.
It's also the only long bone in your body that lies sideways instead of up and down.
Bumps and breaks
The collarbone sits right under the skin at the front of your shoulder. So it's one of the bones kids break most often, usually from a fall onto a shoulder or a hand.
The good news: collarbones heal very well in kids. Often the arm rests in a sling, a cloth holder, for a few weeks while the bone mends.