The average cat tail can only bend a little further back (forward towards the shoulders) past 90 degrees at the very base, some bend even less. Blasa's can lay flat against her back - she often walks around with her tail like that.
She has no noticeable health issues associated with it - though strangely she's one of those cats that likes having her tail played with. She's never had her tail injured, as far as I know.
Does anyone else have a cat with a tail that can do this? Can there be spine problems for some cats?