Some backing spectacular bet, revealing a bit of backbone (8)
I believe the answer is:
vertebra
'bit of backbone' is the definition.
('vertebra' is part of 'backbone')
'some backing spectacular bet revealing a' is the wordplay.
'backing' is a reversal indicator.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'arbetrev' is hidden in the letters of 'spectacular bet revealing a'.
'arbetrev' in reverse letter order is 'VERTEBRA'.
(Other definitions for vertebra that I've seen before include "Bone in the back" , "Spinal bone" , "Disconcerted" , "Backbone segment" , "Part of the spine" .)