The Most Common Question: Are Navicular Syndrome & Navicular Disease hereditary?
The most correct answer is: "Navicular Disease "may" be hereditary, since the cause or causes are not clear but there is pathology and it is not contagious, whereas Navicular Syndrome is "probably not" hereditary since the cause is understood, treatable, reversable and curable if caught before permanent damage is done. What is often quasi-hereditary is that a horse may have desirable attributes making it suited to be used, handled, treated, worked, fed, trained and shod or trimmed in the same way as one or both of its parents, for example, a high-performance race horse or a champion Western-Ridden Horse. We see trends in Race Horses and Western-Ridden Horses who have similar hoof angles and generally the parent was trimmed or shod in a similar way for similar cause and we know that certain trimming and shoeing styles do cause Navicular Syndrome. Changing the foot angle to a more natural one can cure Navicular Sydrome.
What's the difference between Navicular Syndrome, Navicular Disease and "Caudal Heel Syndrome"?Since people often use the terms interchangeably, I'll first explain the difference and why the confusion occurred.
Navicular Syndrome is a progressive condition affecting any one or all three of the Navicular Bone,
Navicular Bursa or DDF/DDFT (Deep Digital Flexor Tendon) at the Navicular Fulcrum** in the Horse.
The key distinction between Navicular Syndrome and Navicular Disease is no bone pathology is
present in Navicular Syndrome (explained in detail in the Navicular Disease section below). Navicular Syndrome
presents no clearly defined visible proof of abnormalities in the Navicular Bone itself consistent with past
confirmed cases of Navicular Disease, even though pain response testing for Navicular Syndrome and Navicular
Disease may yield similar or identical results. Recently it was proved that Navicular Syndrome
has a very simple cause and a very simple treatment and cure.
Navicular Syndrome causes gradual and progressive lameness, and usually over many years rather than just a few weeks or months, however the horse may not display signs of pain that are obvious, noticed and consistent until Navicular Syndrome has advanced. This horse's death and alot of pain and expense could have been avoided. Due slow onset of Navicular Syndrome, it usually progresses undiagnosed until it's very serious. Knowing the early signs to watch for and treating it early with the method in the ebook above could have saved this horse!
One of the most difficult aspects of treating Navicular Syndrome is misdiagnosis of other problems as Navicular Syndrome, and is one of the main reasons why "Navicular Syndrome" has such a low cure rate. These other problems range from simple chronic low-level laminitis, bacterial and fungal infections, actual fractures in the Navicular bone or other bones, and even wood splinters in the foot ( which when wet may take on gnerally the same density as foot tissue and be missed by low-quality portable radiograph/x-ray equipment). Obviously, even the best Navicular Syndrome treatment won't correct those problems if they were misdiagnosed as Navicular Syndrome!
PDN Block (Palmar Digital Nerve Block ) is often mistakenly the deciding test to deem a horse as having Navicular Pain. If the horse goes sound, there may be a positive diagnosis, since it was once believe the PDN only affects a limited area of the foot. However, recent studies indicate that the Palmar Digital Nerve sensitivity may extend farther toward the toe than once believed, allowing horses with laminitis, fractures or embeded foreign objects in their feet to be misdiagnosed.
In general, the horse with Navicular Syndrome will have pain response to hoof testers applied to the frog. Horses with advanced Navicular Syndrome will have pain response from simple pressure of a thumb or finger pushed between the bulbs of the heel - so much so that you must use caution and keep your face turned away, lest the foot come up off the ground like a rocket to avoid the pain stimulus!
Navicular Disease is a degenerative bone disorder affecting the Navicular Bone in the Horse.
The key distinction between Navicular Syndrome and a diagnosis of true Navicular Disease is actual pathology; clearly defined visible proof of abnormalities
in the Navicular Bone itself by way of x-rays or other devices, such as MRI (Magnetic Resonance Imaging) and which are
consistent with past cases of Navicular Disease. No pathology, no disease.
Navicular Disease has been written about for centuries and arguably has affected horses for as long as we have have used them for work.
Joseph Bridge wrote about the first recorded diagnosis of navicular disease in his book entitled "No Foot, No Horse"
back in 1752, referring to it as a lameness caused by changes in the "distal sesamoid bone" which is what the
Navicular Bone was called back then. Of course the research he did on Navicular Disease would have been post-mortem (after the horse died) since there were
no x-rays available back then to see actual changes in the Navicular Bone of a living horse, but these days, we can see
actual evidence of deossification - the loss of bone material - with x-rays.
Certain cases of Navicular Disease ( depending on their cause and how much damage has been done ) can be treated with some success with Gallium Nitrate to restore and maintain the Navicular Bone.
Caudal Heel Syndrome
Caudal Heel Syndrome is a "catch-all" term used to describe pain in the back (caudal) part of the hoof which has no known specific origin. It is a way of saying "Gee, I don't know what's wrong ...that'll be 500 dollars. The key distinction between Navicular Syndrome, true Navicular Disease and Caudal Heel Syndrome is that with Caudal Heel Syndrome ( IF PROPERLY USED ) there is no pathology and NO ISOLATION of the pain to the Navicular Fulcrum Area. If there was pathology, there would be a definitive diagnosis. If there was proof that the pain was in the Navicular Fulcrum Area, it would be Navicular Syndrome.
Please note however that this term is also often misused by vets who know it is Navicular Syndrome and want to avoid
a discussion about Navicular Syndrome, and also often used when the vet is too lazy or too incompetent to do further
exploration to ISOLATE & DETERMINE the source of the pain causing unsoundness and to them sounds better for justifying
a service fee/bill than "Gee, I don't know." While horse owners want "some" answer to justify the fee, this term
would probably be better retired and replaced with the truth: "I am pretty sure what it isn't, and trends indicate
that it may be X , Y or Z. The other tests would cost you $XXX and may still not be definitive. So far you've
incurred fees of $500. What would you like to do?"