@cloudel – Yes, those synchondroses on babies' skulls do make us parents use extra caution. There is one on the back and the front of a baby's head, so you have to be careful in both directions.
The synchondrosis on the back of the head usually closes up after a couple of months, but the one on the front can take over a year. My pediatrician said that this is because about half of your brain's growth happens during your first year of life, and the skull has to accommodate it.
It's pretty cool how our bodies are designed with synchondroses that allow for flexibility like this. It's also a little scary because of the potential for damaging the area.