collarbone
A long, thin bone between your neck and each shoulder.
Your collarbone is the long, thin bone that runs from the center of your chest out to each shoulder, forming a horizontal line beneath your neck. If you touch the base of your throat and move your fingers outward toward your shoulder, you'll feel this smooth, slightly curved bone just under your skin.
The collarbone's formal medical name is the clavicle. It connects your shoulder blade to your breastbone, helping to hold your shoulder in place while still allowing your arm to move freely in all directions. Without your collarbones, your shoulders would collapse forward toward your chest.
Collarbones break more easily than many other bones because they're relatively thin and positioned right where you might land if you fall on an outstretched arm or directly on your shoulder. Athletes who play contact sports like football or hockey sometimes break their collarbones this way. The good news is that collarbone fractures usually heal well, though they need time and sometimes a sling to keep the shoulder still while the bone mends.
You can often see the outline of someone's collarbones at the base of their neck, especially when a person is thin or has their shoulders pulled back with good posture.