lumpy bit on foot

[parsley]

Bomber has a slow growing lumpy bit on the outside of his foot just about the corornary band. How can I tell if it a sidebone? He isn't lame and doesn't mind me touching it and it isn't growing very fast at all.

Also - is is usually to only get them on one side (its on the front)

 

[Louby]

My old horse had high ringbone with large lumps visable on the outside of her pasterns. When she was xrayed it shown bad sidebone too, it wasnt uniform either and the vet said that sidebone rarely caused lameness and not to worry about it. I was shocked at how much extra bone there was but the vet wasnt concerned at all.
I think only xrays show sidebone, I could be wrong though.