EDIT: Outer dilation?

Today at my 37 week appointment my OB checked me. She said I was 1 cm dilated on the outside of my cervix.. she said she could scratch his head.

I was just confused what that meant..

what does it mean to only be dilated on the outside. And if I was only dilated on the outside how could she feel his head?

anyone?

Edit: so she was saying that I was dilated on the outside of my cervix, but not the inside. But could scratch the baby’s head..