Not calcified, so they're transparent to X-rays. There are two rows with four bones each in the wrist. It takes 4-6 years for all but one to calcify. It takes 8-12 years for the final bone, the pisiform, to calcify.

The two that you can see there, the capitate and hamate bones, calcify first by four months of age. The next bone, the triquetrum, won't calcify until around two years at the earliest.

[–] SorteKanin@feddit.dk 1 points 4 months ago* (last edited 4 months ago) (1 children)

m8 you just blew my mind 🤯

[–] SoleInvictus@lemmy.blahaj.zone 2 points 4 months ago* (last edited 4 months ago)

Baby bones are wild. When they're first born, they're more cartilage than bone, with some bones starting completely as cartilage, like the wrist bones, and others being a mix of bone and cartilage, like what you're seeing in the "missing" ends of the finger bones. It's tough cartilage, though, which is why it doesn't just squish around like with the cartilage in your ears or nose