Bones are made of protein, collagen, and minerals such as calcium. ... Compact bone: Also called "cortical bone," compact bone is the dense, hard outer layer. Cancellous: ...

Now let's zoom into the crust of that bone baguette - the compact bone. It's made up of tiny tubes called osteons, each just 2 tenths of a millimeter across, with a blood vessel running down the ...

3D-printed 'bones' made of living cells are formed at room temperature for the first time using a special gel that allows doctors to build structures minutes before surgery.