What five conditions lead to an increased interpediculate space (distance between the pedicles) on an AP film?

What five conditions lead to an increased interpediculate space (distance between the pedicles) on an AP film?

1. Fracture
2. Dysraphic states (malformation of neural arch of spine--spina bifida)
3. Intramedullary tumor
4. Syringomyelia
5. AVM