Trade encourages specialisation, which brings prosperity; global capital markets, for all their problems, allocate money more efficiently than local ones; economic co-operation encourages confidence and enhances security. Yet despite its obvious benefits, the globalised economy is under threat.
RA (the most common disease cause) and Paget disease of the cervical spine can cause atlantoaxial dislocation or subluxation, basilar invagination, or platybasia. Metastatic tumors that affect bone can cause atlantoaxial dislocation or subluxation.
Occasionally, the atlantooccipital membrane may be partially ossified, resulting in an apparent bone fragment posterior to the superior articular process. This should not be confused with a fracture of the atlas or occipital condyle (Figs. 8A and 8B).