I am a doctor of Chiropractic who also has C1M and am looking for answers. I looked at all of the views of the MRI and would say that there IS what we would consider "crowding" at the foramen magnum ( the hole in the base of the skull). She probably also had this MRI laying supine, right? Well what happens when she is standing with the weight of the brain pushing downward? Go to the Mayo clinic website and look up Chiari 1 Malformation, and diagnosis, it will tell you exactly what studies are needed to confirm the diagnosis. There is a very good Chiari Center in Aurora Colorado as well.
Good luck to you and your wife!
Cseegers