No, I think he used the word founder, but he also said that in his opinion the horse stood to straight. He never said why that would be a problem that I heard, but my vet said he was probably THINKING navicular. My vet said that use to be what some vets thought might have been a cause of it.
Becky
I think of ~ringbone~ when I see really upright pasterns... In addition to jarring trots ;~D
But as for anecdotal notes about pasterns and Navicular, Bay doesn't have upright pasterns, quite the opposite, I think they are too long and sloping to be ideally strong. But they held him up under heavy work into his 20's so it's all relative.