Navicular - definition of navicular by The Free Dictionary Navicular - definition of navicular by The Free Dictionary Related to navicular: Navicular fossa na·vic·u·lar n. 1. A comma-shaped bone of the human wrist, located in the first row of carpals. 2. A concave bone of the human foot, located between the talus and the metatarsals. In both senses also called scaphoid. adj. Shaped like a boat; scaphoid. [From Latin nāvicula, boat, diminutive of nāvis, ship; see nāu- in the Appendix of Indo-European roots.] navicular (Anatomy) a small boat-shaped bone of the wrist or foot [C16: from Late Latin nāviculāris, from Latin nāvicula, diminutive of nāvis ship] na•vic•u•lar 1. boat-shaped, as certain bones. n. 2. the bone at the radial end of the proximal row of the bones of the carpus. 3. the bone in front of the talus on the inner side of the foot.

[1535–45; < Late Latin nāviculāris of, relating to shipping = Latin nāvicul(a) a small ship (nāvi(s) ship + -cula -cule 1) + -āris -ar 1] ThesaurusAntonymsRelated WordsSynonymsLegend: carpal , carpal bone , wrist bone - any of the eight small bones of the wrist of primates Adj. anatomy , general anatomy - the branch of morphology that deals with the structure of animals formed - having or given a form or shape Translations a. en forma de nave; ___ abdomen → abdomen ___; ___ bone → hueso ___; ___ fossa of urethra → fosa ___ de la uretra. Want to thank TFD for its existence? Tell a friend about us , add a link to this page, or visit the webmaster's page for free fun content .

Link to this page: Reports: Yao could miss season Palpal coxae and trochanters reddish orange, more distal segments orange; second trochanters and femora with white, navicular setae, trochanters and femora with small tubercles, densest on posterior surfaces; coxae with long, white setae, without thickened white setae posteriorly; tibiae with short, stiff setae but without tubercles. Bones chewed by canids as evidence for human excarnation: a British case study They also include a recommendation for an x-ray of the foot if there is pain in the mid-foot zone with bony tenderness at either the base of the 5th metatarsal or the navicular, or an inability to weight bear for more than four steps immediately following the injury (Stiell, Greenberg et al. Navicular | Define Navicular at Dictionary.com navicular [nuh-vik-yuh-ler] /nəˈvɪk yə lər/ Anatomy Spell 2.

Also, naviculare [nuh-vik-yuh-lair-ee, -lahr-ee] /nəˌvɪk yəˈlɛər i, -ˈlɑr i/ (Show IPA). the bone at the radial end of the proximal row of the bones of the carpus. 3. the bone in front of the talus on the inner side of the foot. Origin of navicular Late Latin 1535-1545 1535-45; < Late Latin nāviculāris of, relating to shipping, equivalent to Latin nāvicul(a) a small ship (nāvi(s) ship + -cula -cule 1; ) + -āris -ar 1 Dictionary.com Unabridged Examples from the Web for navicular Expand Historical Examples The Vertebrate Skeleton Sidney H. Reynolds Obscure lameness; foot suspected of navicular disease; very lame. The Vertebrate Skeleton Sidney H. Reynolds Its posterior part shows a transversely elongated facet for articulation with the navicular bone.

British Dictionary definitions for navicular Expand a small boat-shaped bone of the wrist or foot Word Origin C16: from Late Latin nāviculāris, from Latin nāvicula, diminutive of nāvis ship Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012 Word Origin and History for navicular Expand adj. "boat-shaped," 1540s, from Late Latin navicularis "pertaining to a boat," from navicula, diminutive of navis "ship" (see naval ).

Online Etymology Dictionary, © 2010 Douglas Harper Navicular Problems: Symptoms and Treatment | TheHorse.com Navicular Problems: Symptoms and Treatment Newsletters So many times, a horse gets labeled as suffering from "navicular," and people shy away from him as if he were Typhoid Mary, not knowing how to treat or even visualize the problem. In recent decades, however, much has been learned about the area where the navicular bone lies. And many "set in stone" diagnostics (such as "lollipops" in the bone seen on radiographs) have gone by the wayside. Veterinarians and horse owners now know that there are many problems that can affect that area of the horse’s anatomy; some can be helped, but not all of them can be fixed. It also is known that in certain breeds of horses, the problem can become worse with age. In this era of horses living longer, it behooves owners to recognize the early signs of navicular syndrome, and know the options for your horse. The navicular bone is a small bone that sits deep within the hoof at the back junction of the coffin bone and the short pastern bone.

The navicular bone has the physical shape of a small canoe, which led to the name "navicular" bone; the prefix "navicu" means "small boat" in Latin. The navicular bone is also known as the distal sesamoid bone (the commonly known sesamoid bones behind the fetlock joint are the proximal sesamoid bones). Associated with the navicular bone are several soft tissue structures. On the upper (proximal) aspect of the bone is the collateral sesamoidean ligament, which attaches the navicular bone to the distal end of the short pastern bone (remember that a ligament attaches bone to bone and a tendon attaches muscle to bone). On the lower (distal) aspect of the bone are the impar ligaments, which attach the navicular bone to the coffin bone. Cushioning the navicular bone from the pressure of the DDFT is a thin, soft serous sac called the navicular bursa.

The navicular bone is similar in structure to most bones -- there is a central marrow cavity, small channels (along the distal aspect of the bone) for blood vessels and nerves to enter, and a smooth surface on the back side (palmar or plantar) where the deep digital flexor tendon glides over the bone. The navicular bone and its associated structures have complex anatomy, but just what is the function of the navicular bone? The primary function of the navicular bone is to provide a gliding surface at the point where the deep digital flexor tendon changes angle; the tendon courses down the back of the cannon bone and bends around the back of the fetlock, between the proximal sesamoid bones, then makes a sharper bend over the navicular bone, and attaches on the bottom of the coffin bone. Now that we have a better understanding of the navicular bone and its associated structures, it should be easier to understand, and believe, that the idea of "navicular disease" is more complex than one single pathology affecting the navicular bone.

The term "disease" is defined as "a definite morbid process, often with a characteristic train of clinical signs." The term "navicular disease" first was used to describe a lameness caused by pain associated with the navicular bone or surrounding area. Now, because the disease process leading to pain in this area has been determined to be caused by a variety of abnormalities, the label of "disease" is not really appropriate. Next, the term "navicular syndrome" was used. The word syndrome means "the sum of signs of any specific morbid state," and really is not correct since a variety of specific "morbid states" concerning the navicular area can lead to the same set of clinical signs. Currently, it is popular to call problems with the navicular area "caudal heel pain syndrome," which probably is the most correct. As we will see, lameness emanating from this area can be caused by a variety of problems affecting the caudal aspect of the horse’s foot, all leading to the same basic set of clinical signs. What Is It, What Horses Get It, And What Does It Look Like?

Several different problems can lead to pain and lameness in the navicular/caudal heel area, including inflammation and injury of the supporting ligaments, problems in the flexor surface of the bone or flexor tendon itself in that area, and/or problems within the navicular bone itself (more on the specifics later). These problems are more common in the performance horse, and in general are the most common cause of "chronic" forelimb lameness in the horse. Caudal heel pain has been diagnosed in most breeds of horses, but there does appear to be a breed predisposition, with Quarter Horses, Thoroughbreds, and warmbloods being diagnosed with the syndrome more frequently than others. Affected horses tend to be between the ages of seven and 14. Other common predisposing factors are conformation abnormalities of the hoof, including a broken forward or backward hoof axis, underrun heels, sheared heels, contracted heels, mismatched hoof angles, and disproportionally small feet. Navicular syndrome typically affects both front feet to varied degrees. Typically one foot is more painful, so lameness of a single leg often is noticed first.

Careful/further observation shows that the horse will be short-strided in both limbs and might swap lame legs when navigating tight circles or corners. Longeing in relatively tight circles on hard footing generally reveals a switching leg lameness, with the lame leg being on the inside. Because the heel area of the foot is causing the lameness, the foot tends to land toe-to-heel, which is opposite of the normal heel-to-toe landing. When first learning to observe these subtle facts, it might help to capture your horse on video, focusing on the legs and feet and later observing the video in slow motion. In addition, navicular syndrome pain often gets more severe with work and less severe with rest. Although there are other problems that could create this clinical picture, these are a typical collection of clinical signs associated with navicular syndrome. After evaluating a horse, the next step for your veterinarian is to perform some diagnostic tests to build evidence for a case of navicular syndrome. When trying to localize the area causing lameness, it is typical to perform some manipulations of the anatomy in an effort to make the lameness worse.

The most important thing to remember about limb manipulations is that they are not very specific, as it is difficult to create pressure or tension on one specific structure without affecting another. For example, it is common to perform a hock flexion when suspecting hock pain, but it is impossible to flex the hock flexion without also flexing the stifle and hip joints as well. In the case of navicular syndrome, a fetlock flexion test often is done for completeness, but a positive result does not rule out a specific problem. Two tests that do focus somewhat more specifically on the navicular area are the "wedge test" and the "frog pressure" test. In the wedge test, the foot is placed on a wedge of wood, forcing the foot into a hyperextended position while the opposite leg is held in the air; after a period of time, the horse is trotted off in a straight line and watched for an increase in lameness.

With the frog pressure test, the foot is placed over a small block of wood (often the handle of a hoof knife or hammer), placing pressure on the caudal aspect of the frog while the opposite leg is held in the air; after a period of time, the horse is trotted off in a straight line and watched for an increase in lameness. Both of these tests apply pressure to other areas of the foot and are not 100% specific for the navicular, so their results are interpreted relative to other findings. Hoof testers can be helpful when applied to the heel quarter of the hoof wall and the opposite side frog sulcus, applying pressure to the navicular bone sitting deep underneath. Again, this test applies pressure to other areas of the foot and is not 100% specific for the navicular, so the results have to be interpreted relative to other findings. If the clinical examination fits and the aforementioned tests look more positive than negative, you are coming closer to a diagnosis of navicular syndrome. The next step will be to confirm that the pain is coming from the caudal heel area using local anesthetic.

When a local anesthetic is injected around the area of a peripheral nerve, the tissue below the injection site loses sensation, with the tissue above the injection site retaining sensation. For lameness, the anesthetic is started as low as possible, attempting to narrow the area affected in a predictable way. When the palmar digital nerve that innervates the back of the leg and hoof is "blocked" very low in the pastern area (a "low PD block"), the heel area loses sensation and the toe retains sensation. After a low PD block is administered, the "block" is tested with something hard and pointed (typically a pen tip). Sensation in the skin should be gone in the lateral and medial heel and retained in the front of the foot when tested at the coronary band -- if the toe loses sensation, the block is not localized to the heels. If the pain is coming from the navicular area, the lameness should be improved, and if bilateral navicular syndrome is in fact the cause, the horse often will become overtly lame on the opposite limb. Nerve blocks often are not 100% effective, but you generally see a significant improvement (75% or better) if you are on the correct path.

If there is a positive result (reduced lameness) to the local anesthesia, the next step to confirming the diagnosis and determining a prognosis is obtaining radiographs of the caudal heel area. The variety of findings veterinarians see in radiographs illustrate the number of different pathologies that cause pain and subsequent lameness in the caudal heel area. Injury to this area could be a result of chronic, repetitive trauma resulting from the previously mentioned conformation abnormalities, changes in blood flow to the area as a result of conformation abnormalities, problems related to breed, and probably several as yet unknown factors. Pathology known to be related to navicular syndrome includes: enlargements of the vascular channels or synovial fossa within the navicular bone; cyst-like lesions within the navicular bone; mineralization or calcification of the ligaments associated with the navicular bone; bone disease affecting the coffin joint in the area of the navicular bone; degeneration of the flexor surface of the navicular bone; degeneration of the flexor tendon in the area of its passage over the navicular bone; fractures of the navicular bone and any combination or degree of the aforementioned pathologies.

It typically takes three different radiographic views to evaluate the navicular area. Your veterinarian will want to look at the front, side, and flexor surface of the bone. One problem with the evaluation of navicular radiographs is the possible lack of correlation between the degree of radiographic pathology and the degree of clinical lameness. This is one factor that makes the prepurchase evaluation of navicular radiographs difficult; in some cases there can be substantial radiographic abnormalities on a horse that cause little or no clinical lameness. Unfortunately, there is no crystal ball for these cases and future soundness is uncertain. There is no question that "bad" navicular radiographs, despite a very sound horse, will discourage most sales. It’s useful to have radiographs from a earlier time for comparison, but such cases still can be difficult. Additional diagnostic tools include nuclear scintigraphy (the "bone scan") and thermography, but typically a good clinical examination, local anesthesia, and radiographs will lead to a diagnosis. Treatments The treatments for navicular syndrome are varied and range from conservative to aggressive. They can involve therapeutic shoeing, various medications, and surgery.

The response to therapy can be unpredictable and does not always correlate to the degree of lameness or radiographic abnormalities. Therefore, it generally is best to make gradual changes, working from conservative to more drastic. Many horses will respond favorably to shoeing changes and medication. If the horse’s foot has abnormal conformation, the first goal should be to get the foot back in balance; changes should be made gradually, and the response to changes carefully noted. Shoeing Treatment If the axis between the coffin bone and the short pastern bone is broken, the hoof angle should be changed gradually so that normal alignment is obtained. Underrun and contracted heels should be corrected. Remember that blood flow through the foot is largely dependent on the pumping action of the normal foot. As pressure is applied to the heel of the foot, the heels expand, compressing the digital cushion under the sole and pumping blood throughout the foot. The blood flow through the foot thus can be negatively affected by the application of tight-fitting shoes and the placement of nails in the heel area. Poor foot conformation also can contribute to poor blood flow. All horses should have a rim of extra shoe onto which the heels can expand.

The nails should be kept as far forward as possible to maintain normal foot health. Other changes to help the horse suffering from caudal heel pain include trimming the toe as short as possible and utilizing round (rocker) or squared-toe shoes. This encourages easy breakover and reduces stress forces up the front of the limb. Farriers often will set the shoe back slightly from the toe, again to encourage breakover. They will also frequently shoe with a full-fitting heel, allowing normal heel expansion. Some practitioners and farriers feel that applying a small pad to raise the angle of the foot will decrease the tension on the flexor tendon and will benefit these horses. This might be necessary to establish a normal pastern-foot axis. The correct angle of rise will vary from horse to horse, so the rise should be gradual, watching for the best effect. The response to increased hoof angle with pads varies greatly depending on the specific problem affecting the horse, but too steep an angle can make the horse more lame. Some horses respond well to an egg bar shoe that provides additional support to the caudal heel structures. Again, it is important to remember that each case has varied pathology, so each case must be treated individually when applying therapeutic shoeing.

Medical Treatment Medication generally involves the use of an anti-inflammatory drug such as phenylbutazone (Bute), and works better in some cases than others. Depending on the horse’s work schedule and the cause of his pain, you might be able to only dose him on days surrounding work, thereby minimizing total dosing. The specific medication program should be worked out by your veterinarian. Many cases of navicular syndrome respond to therapeutic shoeing and varied degrees of anti-inflammatory therapy. If you are showing, remember that you must stay within the limits for the non-steroidal anti-inflammatory drug (NSAID) if showing under American Horse Shows Association (AHSA) rules. Many horses with navicular syndrome remain sound enough for AHSA competition through the use of therapeutic shoeing and allowable NSAID dosing programs. This becomes a different issue when the horse is showing at Federation Equestre Internationale (FEI) competitions due to their "zero tolerance" drug rules. Another popular drug used in the treatment of navicular syndrome is isoxsuprine, which is a vasodilator and addresses the decreased blood flow aspects of these disease processes.

The effectiveness of isoxsuprine in the treatment of navicular syndrome is somewhat controversial, with some research showing a positive response and some not supporting its use. (In my experience, the therapeutic response to isoxsuprine has not been very impressive, but as we have learned in this article, navicular syndrome has some factors that might respond to this therapy and others that won’t.) There have been cases of positive drug tests for isoxsuprine under AHSA rules. (Isoxsuprine is not allowed and requires a medication report and 24 hours off the drug before competition.) Some of these positive tests were on horses which were not intentionally given the drug, but were exposed to it by eating from feed tubs that once contained it from another horse. (Wash those feed buckets!) Two other drugs being evaluated for their ability to improve circulation to this area of the foot are pentoxifylline and metrenperone, but much more research needs to be performed before their clinical usefulness in the horse can be established. Surgical Treatment The most reliable surgical approach to navicular syndrome, and one that has been performed for many decades, is digital neurectomy (also known as "nerving" or "having the horse nerved").

The suffix "ectomy" means "to cut or transect," and a digital neurectomy is just that -- cutting the digital nerve in the low pastern area. There have been a variety of surgical techniques developed for the digital neurectomy, ranging from simply cutting the nerve with a scalpel blade to performing the transection with a high-tech surgical laser. The reason for exploring different techniques is to minimize complications and to prolong the inevitable regrowth of the nerve. Even with removal of a one-inch section of the nerve and using a variety of techniques to seal or "cap" the nerve endings left behind, the nerve regenerates, causing the foot to regain sensation and the lameness to return. Studies demonstrate that approximately 60% of horses with navicular syndrome which have had a neurectomy are sound one year after the surgery; however, the procedure is not a permanent cure and probably will need to be repeated to maintain soundness (see "Neurectomy" in the October 1997 issue of The Horse or go to ). There are occasional complications of this procedure, the most common of which is the formation of neuromas. These are benign, but very painful tumors that grow at the end of cut nerves.

Some nerved horses can show under AHSA rules (the procedure is allowed, but only at a lower place on the leg as a higher cutting of the nerves could create a dangerous situation). The neurectomy is a viable option for many horses when all else fails. One thing to keep in mind is that this is not a treatment; it only eliminates the pain. The disease process potentially is continuing inside the hoof. The neurectomy should be considered only after all other therapies have been exhausted and after a thorough consultation with your veterinarian. About the Author navicular - definition and meaning navicular from The American Heritage® Dictionary of the English Language, 4th Edition n. A comma-shaped bone of the human wrist, located in the first row of carpals. n. A concave bone of the human foot, located between the talus and the metatarsals. adj. Shaped like a boat; scaphoid. from Wiktionary, Creative Commons Attribution/Share-Alike License adj. Shaped like a boat. n. A navicular bone. from the GNU version of the Collaborative International Dictionary of English adj. Of, pertaining to, or resembling, a boat or ship. adj.

Shaped like a boat; cymbiform; scaphoid n. The navicular bone. from The Century Dictionary and Cyclopedia Relating to small ships or boats; shaped like a boat; cymbiform. Specifically In anatomy, scaphoid: applied to certain bones of the hand and foot. See II. In entomology, oblong or ovate, with a concave disk and raised margins, as the bodies of certain insects. In botany, resembling or belonging to the genus Navicula; boat-shaped. n. In anatomy: n. The scaphoid bone of the carpus; the radiale, or bone of the proximal row on the radial side of the wrist. See cut under hand. n. The scaphoid bone of the tarsus, a bone of the proximal row, on the inner or tibial side, in special relation with the astragalus and the cuneiform bones. See cut under foot. n. A large transversely extended sesamoid bone developed in the tendon of the deep flexor, at the back of the distal phalangeal articulation of the foot of the horse, between the coronary and the coffin-bone.

See cut under fetter-bone. from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved. n. the largest wrist bone on the thumb side adj. shaped like a boat Etymologies from The American Heritage® Dictionary of the English Language, 4th Edition From Latin nāvicula, boat, diminutive of nāvis, ship; see nāu- in Indo-European roots. Examples He told the court Mr Ladhams failed to reveal during negotiations for the sale that Sound Action had undergone extensive treatment for what is known as a "navicular" problem in her front hooves. Navicular bones - definition of navicular bones by The Free Dictionary Navicular bones - definition of navicular bones by The Free Dictionary Related to navicular bones: Navicular tuberosity na·vic·u·lar n. 1. A comma-shaped bone of the human wrist, located in the first row of carpals. 2. A concave bone of the human foot, located between the talus and the metatarsals. In both senses also called scaphoid. adj. Shaped like a boat; scaphoid.

[From Latin nāvicula, boat, diminutive of nāvis, ship; see nāu- in the Appendix of Indo-European roots.] navicular (Anatomy) a small boat-shaped bone of the wrist or foot [C16: from Late Latin nāviculāris, from Latin nāvicula, diminutive of nāvis ship] na•vic•u•lar 1. boat-shaped, as certain bones. n. 2. the bone at the radial end of the proximal row of the bones of the carpus. 3. the bone in front of the talus on the inner side of the foot. [1535–45; < Late Latin nāviculāris of, relating to shipping = Latin nāvicul(a) a small ship (nāvi(s) ship + -cula -cule 1) + -āris -ar 1] ThesaurusAntonymsRelated WordsSynonymsLegend: carpal , carpal bone , wrist bone - any of the eight small bones of the wrist of primates Adj.

anatomy , general anatomy - the branch of morphology that deals with the structure of animals formed - having or given a form or shape Translations a. en forma de nave; ___ abdomen → abdomen ___; ___ bone → hueso ___; ___ fossa of urethra → fosa ___ de la uretra. Want to thank TFD for its existence? Tell a friend about us , add a link to this page, or visit the webmaster's page for free fun content . Link to this page: wrist bone References in periodicals archive ? However, she and her colleagues' recent analyses of the fossilized navicular bones from several species of ancient horses of various sizes suggest that this crippling condition has afflicted the animals for millions of years. Of the 48 navicular bones of this species that she and her team analyzed, 3--about 6 percent--had lesions that could be linked to ENS.

Navicular | Definition of Navicular by Merriam-Webster noun na·vic·u·lar \nə-ˈvik-yə-lər\ Medical Definition of navicular : a boat-shaped bone:a: the one of the seven tarsal bones of the human foot that is situated on the big-toe side between the talus and the cuneiform bones —called also scaphoidb: scaphoid 2c: a small bone enclosed within the hoof of the horse behind the junction of the coffin bone and short pastern bone Illustration of navicular Navicular Cases - Sandy JudyEquine Art & Hoofcare Sandy JudyEquine Art & Hoofcare Navicular Cases What is Navicular Disease? Navicular disease or syndrome (also called caudal heel pain syndrome) is surprisingly misunderstood by horse health professionals and horse owners alike. (And lots of writers too! Read this link ) Due to this widespread disagreement in how navicular syndrome is caused and how it should be treated, many horses have suffered through costly medical and shoeing treatments ultimately ending in euthanasia! The fact that an affected horse can be permanently healed through holistic hoof care is universally ignored.

While not all horses affected by navicular syndrome can be cured with restoring proper hoof function and form, many can. The hoof is designed by nature to work in a very specific way. If it is distorted and deformed by contraction, excess horn growth and/or shoes, it generally reports pain in the heel. If the heels are long/high and the bars are long/high, the pain in the foot reported by the corium above the excess horn and below the navicular bone makes the horse lame. Long toe/low heel syndrome is also another cause. I believe these two causes are very different but both do damage to the navicular bursa, the ligaments and tendon attachments, and ultimately to the navicular bone itself. My belief is based on what I believe to be true about how the hoof works. Basically, if you pinch your finger long enough in the same spot, you are going to do damage to the underlying parts of your finger. This isn't rocket science but it's amazing how many well-educated professionals don't acknowledge this simple fact! At first it may not even be noticed that the horse is taking short strides and landing toe-first.

Shoes, being metal, constrict the expansion of the hoof, prevent proper breakover, and conduct cold into the hoof thus reducing the pain felt until major damage has been done. So-called "orthopedic" shoes and drugs constrict the blood flow and nerve function even more. This fools the owner into thinking her horse is "cured of navicular" with new shoes and drugs. The conventional medical treatment eventually calls for surgically removing the nerves which report the pain. That's the equivalant to shooting the messenger because he is reporting damage. But these nerves eventually grow back and the "treatment" advised then is euthanasia. Something as simple as hiring a trained hoofcare professional that would trim the foot and rehabilitate the horse is not as costly as dead-end conventional treatments and the horse may come sound, sometimes even after just one trim! (This is if the horse is young and hasn't sustained any significant bone damage.) HOWEVER....if the hoof has been in a state of deformity for some years, bone spurs form on the navicular bone. The impar ligament which attaches the navicular bone can become stressed to the point of forming ossifications (tension causes bone to form).

Combined with the erosion of the inside of the navicular bone from pressure of blood being backed up, the navicular bone shows changes on x ray. The worst navicular damage I've ever seen in a cadaver foot showed the navicular bone fused to the short pastern and the coffin bone. For more education on Navicular Syndrome, read the new book " Navicular No More" by Hiltrud Strasser, DVM Holistic treatment differs greatly from pallative (conventional) treatment. Veterinarians differ widely on their opinions of navicular disease. Some have at least started to call it "caudal heel pain syndrome" which simply says they have figured out that it is a chronic syndrome of pain in the back part of the foot. But some "researchers" have gone so far as to butcher horses while still alive in the effort to surgically remove the navicular bone. When you understand the purpose of the navicular bone and its normal function in a healthy foot, this is probably the most absurdly inhumane thing that someone sworn to be a health professional could possibly do.

The navicular bone simply acts to provide the deep flexor tendon a way to make the 90 degree bend to attach to the underside of the coffin bone. Anytime you have a tendon that must bend and slide over a joint, you see a bone develop evolutionarily to provide ease of movement. This is mechanically like a rope and pulley system. The navicular bone is the pulley and the flexor tendon is the rope. As the muscles of the shoulder contract to lift the foot, the DDFT (deep digital flexor tendon) slides over the joints of the elbow, metacarpal, fetlock joints and navicular bone, Sesamoids are bones that act in a similar way at the fetlock joint. (the navicular bone is the distal sesamoid) The navicular bone, being shaped like a little boat (navy) is connected to the coffin bone and the short pastern by ligaments. It also has a little fluid filled pillow, the navicular bursa, which protects it. This bursa can become damaged (loss of fluid). What causes this damage? High sharp bars pushing up and in due to contraction of the hoof!

Since the bar horn is very sharp and hard and it is directly below the navicular area, when it grows to excess (which happens when it is contracted or not trimmed or anytime the horse isn't moving 15 miles a day over abrasive terrain) it pinches the corium between the DDFT. There is approximately only 5 mms or 3/16" between the DDFT/navicular bone/bursa and the bar/sole horn. Since horn is very plastic, when the bars are overgrown and not trimmed, they push upwards pinching the corium. This causes pain as the corium is very blood and nerve rich. The ingrown bars can be sharp and cause extreme pain. So the horse evades the pain by putting his front feet back behind the vertical. See photo below. Contraction: The most damaging cause of Navicular lameness! This photo shows a severely contracted foot. The blue lines indicate where the walls of the hoof should be.

This is a 4 yr old QH which was raised in a stall and shod from an early age (some are shod as early as 1 and half yrs old!!!) The horse has been out of shoes for 2 weeks in this photo and I had not yet trimmed him (Before). His heels are long/high and under-run, bars are high/long and pushed up into the hoof capsule. The bars were also weight-bearing making them extremely painful. The horn quality of the wall horn is extremely poor and thin. The owner was advised by her farrier that there was "nothing to nail to". It's like the Chinese foot-binding practice and shoeing a young horse that is kept in a stall deforms the bones in the feet. This kind of problem is something that may never be resolved to a satisfactory outcome. A horse experiencing heel pain from high bars, heels and contraction issues This horse was diagnosed with navicular syndrome. This photo was taken before I trimmed it for the first time and after the shoes had been removed for 2 weeks. Veterinarians diagnose navicular disease, aside from visible lameness, by the degeneration of the navicular bone showing holes or erosion which can be seen on X-ray.

The mistaken belief is that the bone loss is the cause for the pain. Bone spongiosa does not contain nerves! This "mysterious" bone loss is not hereditary or some kind of disease! It is simply the eroding that happens from blood pressure which is backed up into the back part of the foot, including the navicular fossa due to high heels The high heels force the occlusion of the deep digital arteries via pressure on the dorsal laminar corium. Bone dissolves under pressure! When there is pain from the corium, which is getting pinched from the sharp ingrown high bars, the horse puts his weight on his toe. This allows the heel and bar horn to grow even faster. The dorsal corium is pinched up against the dorsal wall due to the coffin bone being pushed forward and tipped up by high heels. This blood pressure increases in the coffin bone and the navicular bone dissolving the openings. Also the distal edge of the navicular bone is attached to the coffin bone by the impar ligament. This ligament gets overstressed with high heels as it puts the navicular bone in an unnatural position.

So simply put, if the bars are trimmed to remove the pain and the heels are lowered so that the coffin bone is ground parallel, so-called navicular disease can be "cured" in one trim! HOWEVER, if the damaging high bars and heels have existed for many years AND the hoof is deformed and contracted due to shoes, improper trimming and/or not enough movement on abrasive ground, OR if the horse has been treated for lameness by drugs and "orthopedic" shoeing, the damage may be very extensive and include other organ damage. So there is much to consider when trying to holistically fix a very damaged hoof by trimming and rehabilitating. But deciding to start rehabilitating a horse that is mature or aged (in it's teens) is one that ultimately needs to be made by it's owner knowing full-well what is involved. Stalls and lack of movement can help to cause navicular disease It has been said that what's best for the inside of the horse is the outside of the stable. Stabling horses in a 12 x 12 foot stall or smaller is like putting your child in a closet or phone booth. It is stressful and causes physical and mental problems that may last a lifetime.

When horses are kept with their heads up to see out of a stall door, this causes problems with their feet and lungs. They can also get cast in a stall and hurt themselves, even to the point of breaking a leg. I do not recommend putting horses in stalls, but sometimes it is a temporary necessity. If you must put your horse in a stall due to circumstances like a show or immediate need, it is best to keep it as clean as possible. The reason for this is that ammonia in filthy bedding breaks down the protein in hoof horn. I like to use the stall time to soak hooves in ACV water. I put the feed or hay at ground level if possible and make sure there is plenty of good ventilation. Horses do not need blankets but here again you may want to keep the horse clean right before an event or keep a wet horse from getting chilled. Horses should be out 24/7 but this is not always possible. However, limit the time your horse has to spend in the stall and take into consideration the stress you are causing by offsetting it with a homeopathic like Rescue Remedy or put some magnesium in their feed to reduce acid damage.

The horse in a stall is like a fish out of water; it won't die immediately, but it will eventually because it is not in the environment it evolved to live in. When a veterinarian recommends stalling to limit movement, ask yourself if the damage done by stalling is worth the price. Even horses that have had catastrophic injuries like puncture wounds or broken legs can benefit by movement as blood circulation will help to heal the injury. Typical "Navicular" shod foot that is contracted with high heels Because the blood flow is restricted to the laminar corium in the dorsal surface of the coffin bone, attachment there will be damaged and the horse, once the shoe is removed and the foot is trimmed properly, will experience inflamation (laminitis) and abscessing. The crack in this foot is in the center of the hoof. The front wall begins to flatten then an inward crack begins. By the way, this is a four year old horse! Navicular "disease" has been diagnosed by veterinarians even in 2 year olds!

Another "navicular" foot Although this foot has been barefoot for some time, it was shod and then the shoes were removed and a conventional farrier trimmed it every 6 to 8 weeks. It is contracted with high heels and long bars and lateral walls. The coffin bone is tipped forward and down and squeezed tightly forward against the dorsal wall. An inward quarter crack is just beginning (under the R). This is a 5 year old! Similar to the hoof above The quarter crack starting can be seen in almost the exact same place as the hoof above. The long heel has begun to collapse under the foot which jacks the bars up. The coffin bone is tipped forward but it does not appear as much because the heel is so long that it has collapsed. Never shod, regularly trimmed by a farrier Again it's obvious to see that the heels and lateral walls are long. The difference in this foot and the one above is that the coffin bone has begun to rotate away from its dorsal wall connection. Though this is not a navicular case, I put it here to help people understand that heel pain in a contracted foot and heel pain in a wide foot can manifest as two different "diseases".

(Look at this horse's case by clicking here .) The inward quarter crack that is only just forming on the foot above has completely manifested on this foot. Typical hoof with problems associated with navicular disease This hoof has similar issues to the ones above. The long heel, bulging profile, and dragged-down toe hairline indicate a coffin bone that has significant rotation. Poor laminar wall attachment is indicated by the toe flare as well as the quarter crack coming from the long lateral walls and high bars. This hoof was significantly more contracted than the other front foot and had medial to lateral imbalances as well. The other front foot was in a simlar state of poor attachment with medial to lateral imbalances too. The sole view shows barely any concavity. This is a 3 yr old warmblood/TB with mostly natural up-bringing (out 24-7) but had gotten this bad with irregular farrier trimming Medial to lateral imbalance This photo shows an imbalance in weight distribution on the hoof capsule. You can see that the horse has put more weight on the inside (medial) wall while the lateral wall has flared out.

There is ringbone on the lateral side of the pastern joint created from compensating for the imbalanced hoof capsule. These imbalances create problems in the joints all the way up to the shoulder and back. Not only do they cause problems in this limb, but because of compensation, will cause the other three feet to wear abnormally. What is the solution? You guessed it right? Its trimming the hoof to rebalance the coffin bone and grow in a better attachment and suspension with even weight-bearing from side to side and front to back. We can no longer repair the damage done to the coffin bone or the ossifications the body sent in to stabilize the joint from un-natural weight distribution but the joints will adjust to a rebalanced hoof and the health of the attachment will help re-suspend the coffin bone properly. Damage by shoes and under-run heel This is the BEFORE. You see how the foot grows forward then the heel collapses and the toe wall in a shod horse stretches the toe wall laminae as in the shod horse above.

Damage comes out later as abscess in toe wall and whole sole This owner trims this horse with my help (occasionally) But the damage done by years of pressure erupted in a major abscess that encompassed the toe wall and the sole. See subsequent views of this foot below. Abscess exits at the coronet starting to grow out. Though abscess exits generally come out at the coronet, people often believe that that is where the damage exists. That is only the exit point. The damage is to the whole dorsal toe wall corium and the damage goes from the toe up. You can actually see this dorsal wall has bulged out and has a channel from the toe up. The horse was lame for several weeks before the abscess popped out. When pressure damages corium to the point of necrosis (tissue death) the body identifies the damaged tissue and cleans it up with an abscess. The abscess itself has enzymes that dissolve the dead tissue and produce pressure which helps it to find an exit out of the hoof capsule. This pressure is extremely painful. If you've ever experienced a boil or a hematoma under your fingernail, you'll have a mild idea what this pain is like.

We once dissected a cadaver foot that looked relatively healthy. When we removed the wall horn, an abscess of black goo was traveling up between the lamella. It was under pressure and must have been the cause for the horse's euthanasia. Imagine if you were given a death sentence because you had a bad blood blister under your finger nail!! If people would just apply common sense to understanding the hoof and how it works, there would be a whole lot less horses put down due to lameness. Damage from loss of suspension and attachment in the toe cause solar abscess What you are seeing here is the new sole that has grown underneath the abscess. The white areas are excess bar material which should have been trimmed out as the bars were the ultimate cause of the damage done to the dorsal laminar corium. New navicular case Right front Also a quarter horse with one front foot more contracted than the other. He presented with some lameness on his RF. This photo was taken after his first trim. His RF was very much smaller than his LF. The typical "coke can" foot when I started. "Navicular disease" is usually a contraction issue. The bars get pushed up deep within the hoof near the navicular area.

If caught very early, say when the horse is less than 2 years old, it can often be fixed in one or two trims. Once contraction has deformed the feet, both bones and joints, it is more difficult to change. One of the things apparent to me looking at this foot is the "dead" looking white horn. Sometimes the horn will look black even if it is white horn. Sometimes the horn will appear like dried out rubber. RF starting to decontract Sometimes things look worse before they look better. But color is starting to come back and as the trim promotes expansion, bruising and separation can be seen in the white line. With the whole foot starting to open up, the vertical wall cracks in the lateral walls and the white line separation are a part of the side effects of opening the foot. The owner said the horse's stride has improved but he continues to favor this foot while standing. De-contracting is painful. But once the foot stabilizes in the new wider capsule, the navicular pain should be resolved. Chances are that this coffin bone is contracted too. What happens when the lateral walls pull on the contracted bone? It sends out ossifications to stabilize itself.

Sometimes, as in another case I had, the palmar process fractures then heals in the new better position. This horse has joint adaptation. His pasterns were almost straight up when I started. They have relaxed somewhat, but the hardest thing to fix is not the feet, not even the bone but the joint capsules which hold the foot in an unnatural position. This horse is 9 years old. It has been said that joint adaptation takes as long to fix as it did to make. I'm hoping this isn't entirely true! Two Fronts starting to look like they belong to the same horse! When I started trimming this horse, the right front was SOOOOO much more contracted than the left but all four were like Coke cans. This is a recent (3-2010) photo of both fronts and now it's becoming hard to see which foot was the "club" foot. RF lateral view This is the same foot after several trims. I am trimming this horse every 2 weeks. I am lowering the heels, digging out the bar and removing displaced heel that is inside the bulb. I haven't done much with the toe wall as I have needed it to help force the joint capsule to stretch.

Because the horse was so upright, he had very little toe at all. It is important to leave the toe, no matter how ragged it looks, in a horse that wants to knuckle over. Also important is lots and lots of walking on firm, level ground to help those joint capsules to relax and stretch. The owner is using massage and liniment too along with regular soaking of the hoof and stretching exercises and has made siginficant progress. Progress in getting pastern at a better angle This is before my regular every two week trim and as you can see, he is standing with much better angles. The hoof is almost 45 degrees with a 30 degree hairline.. The owner took him to a local horse show and he won 5th out of 10 with a novice rider! His former owners saw him and didn't even recognize him. The owner says his personality has gone from a blank "duh" to an interested happy guy. Horses that seem dull may be because of constant endorphins due to foot pain. As the foot comes back to health, the horse often appears more interested in his environment. It is very common to see horses that have improved hoof health to become easier to train.

March 2010 This photo was taken just after a trim while he still has his winter fur. The improvements to see here are the attachment that has grown down. In the photo above, the dorsal wall shows a stretched attachment. Though the angle of this photo and the fact that it was taken with a flash in a dark barn distorts comparison with the above photo, you can still see that the hairline has improved. Look at the above photo hairline just above the heel and see the arch? This photo shows that arch has straightened out. Because of the wet weather, there is a lot of abscessing (in all horses!) this time of year. So the heel appears more under-run in this photo but that is in part an artifact of the photographic conditions as well as the abscessing in the bulb. the joint appears more upright too due to soft ground conditions. Joint adaptation is harder to fix and keep fixed when the toe continually sinks in soft wet ground. But overall I'm happy with this foot's improvement and the owner has gone to having trim him every 4 to 5 weeks now.

Look at conformation to determine heel pain This horse has a higher heel in the right front than in the left front which is why the right is placed so far behind the vertical. You can see she is also holding her weight off the heel of the left front by bucking the knee. To compensate for pain in the front feet, she is putting her hind legs forward to carry more weight. This also makes the horse tuck its hip and the shoulders are hunched and scrunched up. Look at the photo below after my first trim that lowered heels and bars in the fronts and hinds, and backed up toes in the hinds. After trim, horse stands balanced Much relieved, this horse now stands with her front and hind legs perpendicular to the ground. she is so tired of the hard work of just standing unbalanced for so long, she is resting her hind leg. Some massage and body work would help this horse a lot. Look at the difference in the shoulder and hip angles from the first photo to this one. Contracted coffin bones A healthy coffin bone is parabolic in shape. Both of these coffin bones are oval, not parabolic. The palmar process on one side of the smaller one is actually beyond-the-vertical.

Below a fairly healthy coffin bone on the left seen from the bottom is compared to a coffin bone that is very contracted. I don't believe anyone can fix a hoof when the bone is this deformed. 20 yr old TB mare with two different feet This is so typical to see in horses! One foot is very upright and "clubby" while the other is flat and either under-run or foundered. The trick is to get the contracted foot to open up while getting the flat foot to tighten up it's connection. With this mare, both feet were almost dead with very little blood circulation from years of shoes and contraction. She was very shut down and depressed with poor conditioning. This photo was taken BEFORE trimming. The clubby foot has a very contracted coffin bone that probably has a lot of bone loss. After a few trims Still apparent is the difference in the two feet. Since this horse has only had a couple of trims, she is still in the beginning stages of transition to health. But she has already improved in her attitude and movement.

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Question: If a bone is navicular, it is shaped like what?
Answer: A boat