As most of you know, I think there is a fundamental distinction between symmetry and balance. I see it in feet all the time and if you stick "symmetry" and "balance" into the search box on the right you will come up with an awful lot of previous blog posts!
So for them, balance can only be achieved at the expense of symmetry - or vice versa, of course.
Again, I've blogged before about the proposition (by an eminent veterinary professor) that "A horse's leg is like a table". I actually don't agree with that, but I found that this photo was a fabulous illustration of how, even if that were true, balance is not necessarily the same as symmetry.
So I was really fascinated to come across this article, which discusses symmetry versus balance in people:
"People seem to confuse symmetry with balance. Balance is a desirable functional quality, but symmetry is only an appearance. The back of the body can be in perfect balance with the front even though they are completely asymmetrical. Symmetry is not the only path to balance, and perhaps not the optimal one for a given person."
The article is well worth a proper read, but here is an interesting sample:
This is obviously a bad idea. Given that the bones are always a little off here and there, we should completely expect that our bony landmarks, soft tissues, and functions will be at least a little different from side to side. If you could somehow even up just one part of the body but not all the others, you would have local symmetry at the price of global balance. Bad trade."
And this is my big concern about what happens when we require symmetry (as opposed to balance) in horses. Balance is definitely a good objective. Symmetry? I'm not so sure, particularly if we don't know exactly why an asymmetry has arisen.
As is often the case, we are short of research and evidence specific to equines BUT there is a series of interesting papers from human medicine highlighting the lack of correlation between asymmetry and biomechanical problems:
"My favourite direct evidence — not the best, but my favourite — has always been the simple leg length study published way back in 1984, in the venerable British medical journal Lancet. That paper that showed that leg length differences were unrelated to back pain — no correlation even, let alone a causal relationship."
This is a huge subject, particularly when we are talking about lameness, and its one I am sure I will keep coming back to. In the meantime, I am still on the quest for balance, if not for symmetry :-)