Hunter's Bump part 1

The lumbar are the 5 or 6 vertebrae, depending on the breed of your horse, that lay between the rib cage and hips. This delicate and crucial part of the horses body, and our own for that matter, is under a reasonable amount of constant stress from day to day activity. Although supported by a considerable amount of muscle these 5-6 bones are the only bones that attach a horse's front end to his hind, and muscle as we all know can easily become overworked or damaged including the ones that support the lower back.  

Today we’re going to have a quick look at my approach to understanding horses with roach backs or hunters bump. I would like to point out the obvious, I am not a vet. I do not have the training nor the tools to diagnose medical conditions.  

In the 10 years of practicing as an equine sport therapist I have seen more than a few cases of what we’re going to call hunters bump. You know the one the characteristic raised lumbar and pinched bum look. 

Out there on the internet you’ll find of great medical information so we’re going to get right down to my layman's analogy instead of covering the medical side so to speak. First I would like you to imagine the ilium or the top points of the hips as a bridge. Yes we are about to turn the sacroiliac joint into a traffic metaphor.

Just as cars would travel in both directions through the gates of a bridge, the spine glides with the movement of the horse both forward and back, and side to side. Even though this movement is much more 3 dimensional than traffic you can still imagine that when the bridge (those iliums of the pelvis) is open the traffic (the sacrum , which influences the lumbar) can move through as it should with equal movement in each lane. When the bridge closes (muscles contract to a point the the iliums become very inflexible thus pinching together) the cars pile up on one side (the lumbar pops up, crunching together).

Just like on the road there are many ways to cause bridge closures that block traffic.

If the bridge is overused and under maintained then we experience closures due to cracks in the bridge. We can relate this to repetitive strain injuries. We don’t need to get into the gritty details of how the repetitive strain was caused we just need to understand that repetitive strain is one way we can end up with “a bridge closure”.

Then we have our crashes, and just like cars can crash, and close a bridge, horses can crash, and close their “bridge” too. We all dread this happening when we see our horses crash in the pasture, or into a jump.

When these injuries occur, whether they happen slowly over time or all at once, the top of the pelvis or iliums become restricted and and make it difficult for the sacrum to glide through performing its natural range of motion. Thus we have a similar scenario to a bridge closing and traffic piling up.

Next week we’ll discuss strategies on how to help a horse who may be suffering with this type of restriction but before we can do that we need to have a bit more of an understanding of what’s going on under the skin.

Here we have a section of deer lumbar that Emmie and I found out hiking a while back. You’ll see how they curl and lock together like a puzzle. This attachment is very strong and supported by many muscles both big and small. It’s this interlocking design that keeps vertebrae from being drastically separated and damaging the spinal cord. It never ceases to amaze me how much they can become restricted and lock up.

Now we are going to look at the spinal column. You can see how easy it is to see light at the end of the light at the end of the tunnel while looking through the healthy aligned vertebrae. When looking at the restricted sets, however, this light is not visible. In the same way light can be blocked from making it through the vertebrae so can the spinal cord. This is why we see muscle atrophy and hind end gait restrictions with hunters bump affected horses.  

Many practitioners feel that once the damage is done there is no undoing it. During the many years of my practice however I have seen more than a few horses recover from this sort of injury. Even if we may never be able to get it back to 100% we owe it to the horse to try. The nerve supply that passes through the lumbar is essential to the health of your horse's back end, thus the health of the horse and the quality of their lives.

Join me next week for some ideas on how you can help your horse recover from a hunter bump type condition. 

Happy Horsing Around 

Cyndi Bird CEST

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