@justnerdsip: Can you wiggle the bone in your wrist? Can your partner? . . . It's the pisiform, a pea-sized wrist bone (its name means pea-shaped) at the heel of your hand below your pinky. It sits inside a tendon and can slide about a centimeter when your hand is relaxed; when you make a tight fist, the tendon pulls tight and holds it. It's also the last wrist bone to harden: in kids it's still cartilage, and it turns to bone around age 9 to 12. Sources: Healthline, Pisiform bone; Journal of Wrist Surgery (pisiform shuck test); PMC review of carpal ossification. Send this to your partner and wiggle theirs. Replace social media. Improve your attention span. Get NerdSip on the App Store. #wristbones #humanbody #bodyfacts #anatomy #DidYouKnow