Hi OFH,
I have just had a quick look at the MRI’s see them annotated below:-
The second pic is the para para-sagittal view, which usually has a better chance at trapping cerebellar tonsillar herniation and your daughters show that her tonsils are low lying and protrude through the foramen magnum, see the red line.
The first pic is the mid sagittal view which, if we start at the top shows:-
Blue arrow – a possible narrowing/flattening of the corpus callosum
Green arrow – a flattening of the top of the pituitary gland (partially empty sella)
Purple arrow – encroachment of the posterior arch of C1 into the spinal canal
Red arrow – a retroflex odontoid
Yellow lines – poor alignment (loss of lordosis) of the upper neck vertebrae
Orange ‘V’ shape – The medical sign I see is the ‘V’ sign – between the front of C2 and the back of the anterior arch of C1. Usually these 2 anatomical parts are quite parallel. This type of instability, between C1 and C2, is called atlanto-axial instability, it could be a major player, along with the low-lying cerebellar tonsils, in your daughters headaches and raised intracranial pressure issues.
If it was my daughter, I’d be getting her into a Philadelphia collar (with linings!) as soon as possible, to see if it helps alleviate any of her symptoms.
Here’s another post on atlanto-axial instability
http://prettyill.com/forums/viewthread/897/#4194
Regards
Barbara.
(UK)