In the practice of canine rehabilitation medicine, we spend a lot of time focusing on knees, backs, hips, shoulders and elbows, but it is important to remember the importance of feet. With regards to the texture, temperature and firmness of the ground, the feet are the first line of communication between the land and the body.
Imagine wearing stiff new shoes or high heels if you are not used to them. What if you want to dance, or need to run quickly away from a threat? Or imagine having a pebble in your shoe. Either way, all you’d be able to think about is sitting down and taking the shoe off.
Dogs’ brains are hard-wired to interpret critical information through the soles of their feet, as well as using the sensory nerves in the joints, tendons and muscles. These signals communicate where the ground is, how hard it is, and whether it can support the body. The bottoms of the feet register body weight and sudden changes in weight bearing. For instance, if the dog is running in a field and places a foot into a hole, the changes in the angle of the leg and pressure on the foot will trigger a fast withdrawal of that leg and shift of the body weight, preventing a serious accident.
However, modern environments can tend to alter the sensitivity of this feedback loop. Dogs spend much of their time on slippery floors, abrasive concrete or pile carpeting – all very different from tall grass, stones, sand, snow, or dirt! This, combined with limited exercise, can impede the foot-brain connection. Dogs, like many domestic animals, are highly adaptable, and most dogs with a normal nervous system can easily adjust to these environmental changes. But when a dog has neurologic deficits such as those that develop with advanced age, hind end weakness or spinal disease, the information (or lack thereof) from their feet can hinder their locomotion.
Normal toenails well above the ground with good contact between pads and ground.
One of the most common foot issues in domestic dogs is long toenails. Ideally, the nails should not touch the ground when standing on a firm level surface, but are long enough to provide traction when climbing a hill or digging. In a dog with long nails, the neurologic signals from the toenail touching the ground are interpreted by the brain as an inclined ground surface. This abnormal compensatory posture results in excess weight shifting onto the hind legs, overloading those joints.
Despite the health benefits, the average dog might get a nail trim several times a year. Many factors contribute to making nail trims a dreaded activity, among which is the fact that constant stimulus from long toenails contacting the ground sensitizes the nail bed, making it very uncomfortable for the feet to be handled and predisposing them to the development of arthritis.
If you look at a dogs toenail, you can see the hard, insensitive nail around a core of pink, living tissue or the “quick”. The quick contains sensitive nerves and blood vessels, and when nipped, it bleeds profusely.
When the toenails are excessively long, the quick grows longer, too. The goal is to remove the protective long nail so that the quick will recede. The easiest way to do this is to use multiple small, shallow cuts focusing on the top of the nail, parallel to the quick, not across it. It is possible to significantly shorten the toenails, and get an immediate postural response in a single session.
The quick is shiny and moist– like living tissue, and has a different texture than the nail. Nails need to be cut every other week to maintain their length, but to shorten the quick, one must cut once a week. Sometimes a dremel is tolerated better than clippers for this purpose.
The difference in posture before and after one nail trimming.
Getting into the habit of nail trimming early in life is not only a good habit for any dog owner, but can also prevent arthritis and mobility issues in the long term! So take a look at those feet today and consult your veterinarian or rehabilitation therapist with any questions about your dog’s nails! For additional information, here’s an extensive presentation by Dr. Leslie Woodcock, DVM on nail trimming in agility dogs: https://www.youtube.com/watch?v=MM4HQDb1Ef0