Wednesday, 1 May 2013

Asymmetry - is the horse doomed?

I was wary of writing this blog post because its a difficult subject, and one where I don't think anyone yet has the answers. However its something I keep coming back to and its a subject where I think discussion, questions and sharing experiences are vital, so here goes...

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!
 A hoof can be asymmetric in appearance BUT still be balanced for the limb. Its common especially in horses who have had previous injuries or lameness and in fact, in these horses a symmetrical foot would actually be less supportive and impair the horse's movement and biomechanics.

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:

"Look at this drawing of a vertebrae...not exactly plumb. And yet surely many manual therapists would palpate it, sense it’s a little right of the others, tell the client the vertebrae is “out”; and then start trying to relocate it with various forms of (possibly painful) coercion. 

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 :-)

10 comments:

Cindy D. said...

You have no idea how badly I wish that we were on the same continent.

I really think that this very subject has much to do with what is going on with my mare. Unfortunately I also think that I am the only one who sees it, and I have zero knowledge when it comes to trimming. So she remains lame and I continue my quest to find some one who can help her.

Nic Barker said...

Well you are already doing the important first step, Cindy, of listening to what your horse is telling you. That's where we all started from, so you aren't in a bad place :-)

Cindy D. said...

Yes but I am over a year into it, and she isn't getting any better. So right now I am pretty darn frustrated and I hate seeing her in pain.

Nic Barker said...

Ah, time to change something then..a year is too long...

C-ingspots said...

Hello Nic, longtime reader and first time commentor here. Cindy above and my mare have the same problem. Heel pain. Do you have some insight into this opinion-heavy topic? Any advice on what really is the best solution to achieving useful soundness for a horse with this affliction? My mare has bone degeneration and a cyst in her RF and no cyst, but still suffers heel pain in the LF as well. My vet and farrier agree on the protocol so far, and she is better, but not rideably sound. She is on aluminum natural balance shoes with raised heels, her toes are squared and short, with the shoes set back for breakover improvement, which is supposedly to achieve less pull on ligaments attached to the navicular bone. I would appreciate any and all insight you've gained in this area. Thank you.

Nic Barker said...

Most of the horses who come here have a lameness which blocks to the palmar hoof (heel region) so you are in good company! What else is diagnosed depends on whether x-ray or MRI is available but the location of the problem is almost always the same place.

You'll have seen from the photos that strengthening and rebuilding this area out of shoes is a key objective with the rehab horses.

Remedial shoes are also aiming at supporting this area but are doing it from the outside, whereas we are looking at improving the internal and external structures (frog, DC, heels) in order to help the hoof function more effectively.

Its always useful to look at how these horses are landing and loading their feet so filming your horse and slowing it down can be a good way of checking whether things are improving.

Jassy Mackenzie said...

LOVE this blog post, Nic! And it is a topic that has been weighing on my mind in more than one way because the equine dentist who I've been using for the past few years (and has become more and more enthusiastic about the use of power tools) has now informed me that both my boys need power tool work done - both on the incisors - the 6yo, Msasa, apparently has a slight diagonal bite that is not resolving, and the 14 yo's upper incisors are starting to dominate. I am seeking a second opinion on this rather than going ahead with it, because if the horses are completely happy in their work, have no bitting problems, are chewing their food well - WHY does he want the mouths to be perfect? I am not a fan of achieving perfection at the expense of a balance that the horse might find necessary - Msasa has very squiffy feet and if they were trimmed symmetrical, he'd be as lame as a dog! It's for exactly the same reason that I am worried about the dentist carving him a 'perfect' mouth, rather than simply doing what is necessary to keep him eating and working comfortably and effectively.

bouncing_ball said...

Interesting re teeth. Can see your logic Jassy. And if it isnt broken, I would hesitate in trying to fix it. Interested to hear what your second opinion says.

Nic Barker said...

Very interesting, Jassy, and agree if it ain't broke...I think we too often are ready to jump in and intervene when we don't know enough about why something is the way it is...Every action has an equal and opposite reaction, after all...

Fritha said...

I found this really interesting, not only from an equine point of view but personally too. I have scoliosis and am far from symmetrical, and yet I have no trouble with balance when riding horses. I always worry that I am hurting a horse through not being symmetrical, and yet numerous physios, chiros, EMRTs etc who may have treated mine or horses I have ridden have never found any evidence to support this fear. Visually I am completely unbalanced but physically I am fine, and suffer little to no back pain.