Happy riding to you . This is John "TheFootDoctor" and i want to talk to you about Navicular disease today since it's all too common. Shoeing can play a major role in whether or not your horse will get navicular or not.
Definition of Navicular: Degeneration and erosion of the navicular bone.
You have been noticing so far alot has been mentioned in this blog about the length of toe on your horse. There's a reason for that. Length of toe is one of the biggest reasons for the cause of navicular. Let me make something clear first - Navicular disease is one of those diseases that usually cannot be explained - if your horse gets it usually no one's going to tell you exactly what caused it as that is still somewhat of a mistery. However common sense will tell you what can or what would seem to contribute to Navicular disease.
When your horse has the long toe syndrome ( the shoe not moved rearward on the foot ) the result is a foot that labors on the ground as the horses body continues to move forward. As that foot remains somewhat frozen to the ground and breakover is delayed due to the excessive length of toe extreme stress is put upon the deep flexor tendon and navicular bone. That Deep Flexor tendon wraps right over that navicular bone and without ease of breakover it presses directly against the navicular bone pressurizing the bone. It could very well be this excessive pressure and wear and tear on the bone which causes navicular , at least would make navicular worse if your horse already is getting Navicular.
This next photo will show some modeling (erosion and degeneration ) of the navicular bone in the areas of the most stress from the deep flexor tendon.
The discoloration (shadowing of the bone ) is the erosion and degeneration of bone. Usually with the long toe syndrome is some sheered heels and contraction you have been reading about here. So add those two to the long toe and you're increasing your odds of failure. The sheered heels add to the laboring of breakover by allowing the heels to also sink deeper into the ground furthering the stress and stretch of the deep flexor tendon already being overworked by the long toe.
Now add the contraction ( narrowing of the heels ) and not only is the navicular bone having extreme pressure put on it from the deep flexor tendon but now also it's being squeezed from the sides giving it no room to breathe within the joint. At that point things couldn't be much worse for your horse.
Once Navicular sets in it's rare that it ever goes away - it becomes a chronic condition. In the early phases if detected by Xrays early enough corrective measures could be used and the possibility of bone regenerating is worth considering. But you haven't heard enough yet .
This next photo shows the coffin bone joint in the horizontal position that is most beneficial and important as well in warding off Navicular disease. Think and look at this - if that coffin bone joint is not horizontal but rather cocked at an angle it's putting twist onto the navicular bone as well since the navicular bone rides against the coffin bone. It's really paramount your horse's foot be level. OK - here's the photo.
See the horizontal plane of the coffin bone ? This is a rear view photo. That lower mass is the coffin bone. If for example that left side of the hoof wall was much shorter than the right side the coffin & navicular bone would be out of alignment . Under those conditions constant pressure and repetition of movement will wear away bone. These joints are supposto move like silk ,smooth and easily .
So right here you have just witnessed 4 specifics necessary for proper foot care -
1. Excessive long toe laboring the foot and stressing the deep flexor tendon
2. Sheered heels allowing the heels to sink before the foot breaks over furthering stress and stretch to the deep flexor tendon and pressurizing the navicular bone in the process.
3. Contracted heels as a result of the two above - adding to the problems by squeezing the navicular bone from the sides now hindering the navicular bone from finding its most comfortable mesh with the other bones.
4. And finally the horizontal plane of the coffin bone for when out of level causes continuous bind to the navicular bone, in and of itself enough in my mind to cause navicular disease.
This isn't all of what's necessary for your horses foot to function properly. But the rest is still to come.
I did throw one twist into this - if you notice the last photo above has vertical lines indicating one side of the pastern bone is longer than the other , if you study it for a minute you should pick up the inconsistency in bone growth. Not much you'll be able to do about that , mainly the focus should be on getting the coffin and navicular bones happy. The Uneven growth patterns of bones are those things that should be considered if you're wanting a horse for maximum performance - it would always be good to know exactly what you're dealing with , there's the value of Xrays.
If you can master these few major steps in your shoeing or trimming of your horse you've made a big jump ahead in prevention of not only navicular disease but of lameness in general. These concepts i've just shared with you are not only just beneficial to prevention of navicular but the overall soundness of your treasured animals. Keep on top of these issues and you and your horse will both sleep better at nite.
As usual , happy and safe riding and always remember to www.Care4Horses.com
You may also want to check out my blog at Http://Farrieritis.Care4Horses.com you'll also find a wealth of information there.
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Thank you for showing up John "TheFootDoctor" Silveira
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