Ah, I think it’s actually the skull itself that has crushed the VA’s against the upper surface of C1. It’s a very narrow area between 2 bones that are normally held rigidly apart. Looking at your 3D CT scans, there is something of a ‘cock-robin’ type appearance to your C1, it appears further above C2 than it should be at the back.
Can you show me 3D CT views of the left side and the right side, as if the view was taken from 3 inch above your shoulder?