dog paw pads

Discovering The Function of a Dog’s Carpal Pads

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Hey, what’s that foot pad doing all alone on the dog’s front legs, right above the wrist? One may wonder at this point whether it’s a vestigial structure, in other words, an anatomical feature that no longer seems to have a purpose in the dog’s life. Last time we checked, it just sat there and Rover didn’t seem to put it to good use. However, just because we haven’t seen our dogs putting that foot pad to use, doesn’t mean that it’s useless and not worthy of existing! So today, we’ll be discovering the fascinating function of a dog’s carpal pads.

paw padsA Lesson in Anatomy

To better understand the function of the dog’s carpal pads, let’s first learn more about paw pads. Upon lifting your dog’s front paw (avoid doing this if your dog doesn’t like having his paws handled) you will notice several paw pads.

The largest of all is the central heart-shaped metacarpal pad surrounded by the several smaller digital pads associated with each toe. These paw pads are made of thick layers of fat and connective tissue and comprises five (yes, you heard it right five!) layers of skin so your dog can walk comfortably over several terrains. A little bit higher, on the inside of the leg is the dewclaw, another digit with its associated nail.

Then, hanging around the wrist area,  you’ll find the dog’s carpal pad. This pad is similar in structure to the other paw pads but it doesn’t have an associated nail, it’s only found on the dog’s front feet and it’s also known as “stopper pad.”

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Do these little hints help you get an idea about what’s the original purpose of the dog’s carpal pads?

Did you know? According to the book “Peak Performance EBook: Coaching the Canine Athlete, by Canine Sports Productions, the skin on the dog’s foot pads is the thickest skin on your dog’s body.

  Anti-lock Braking Systemcarpal pad

So far, we know that a dog’s carpal pads hang around the dog’s wrist area, that they are made of very tough skin and that they are only present on the dog’s front legs. We also know that they are sometimes referred to as “stopper pads.” So what’s the purpose of these pads? If you are still scratching your head, no worries! Their functions aren’t as obvious as we barely can see them in action unless we can witness stop action movements when dogs run at full speed.

According to veterinarian Chris Zink, in the midst of when a dog canters, there’s a brief moment when the carpal pad makes contact with the ground as the other front leg and the rear legs get ready for the next stride. During this time, should the dog decide to make a quick turn or stop abruptly, the carpal pad, along with its associated dewclaw, provides extra traction, and should the dog decide to stop, it’ll work as a braking device, hence its name “stopper pad.”

carpal padsBumper and Balancing Act

If you also watch carefully as your dog lands after a jump, you may also notice how the carpal pad makes contact with the ground.

In this case, according to the book “Peak Performance EBook: Coaching the Canine Athlete” the carpal pad functions as a bumper or cushion as the leg hits the ground.

Last but not least, the dog’s carpal pad may also help dogs stay balanced and avoid falls when dogs are walking on steep, slippery slopes.

As seen, those carpal pads are functional and quite important too!

References:

  • With A Flick of the Wrist, by Chris Zink, DVM, PhD (as seen in Dogs In Canada – September 2003) retrieved from the web on May 20th, 2016.
  • Peak Performance EBook: Coaching the Canine Athlete, By Canine Sports Productions, Amazon Digital Services LLC
    Photo Credits:
  • Paw (dog) showing pads, by Amos T Fairchild – own work (photo and GIMP modifications) CC BY-SA 3.0
  • Flickr, Creative Commons, Lil Shepherd, On the Turn, CC BY 2.0

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Where is a Dog’s Thickest Skin Located?

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thick skin dogA dog’s skin is thinner and much more sensitive than ours, states the Merck Veterinary Manual. Some of us may find this surprising, but turns out, our skin is three times thicker than our dogs’ and our pH is different too, which is why we shouldn’t use human shampoo for our dogs, explains Karen L. Campbell, a veterinarian specializing in dermatology in the book “The Pet Lover’s Guide to Cat and Dog Skin Diseases.” On the other hand though, dogs have a coat, so there seems to be a convenient trade-off: generally, the more hair, the thinner the outer layer of skin. While our dogs may have thinner skin compared to us, there’s an area of the dog’s body where the skin is much tougher compared to the dog’s other areas, so our trivia question for the day is the following:

 

Can you name where a dog’s toughest skin is located?

A The nose

B The neck

C The paw pads

D The abdomen

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The correct answer is…..

drum

The correct answer is C, the paw pads

Ever wondered how dogs are able to walk in the snow, hot pavement or over the hard surfaces such as asphalt without having to wear shoes? This is all courtesy of those tough paw pads. Sure, if we were to walk barefoot for most of our lives, the skin on the bottom of our feet would surely toughen, but until the day we decide to ditch our shoes, we will be prone to have softer feet with more delicate soles. Other than protecting a dog’s feet from abrasive surfaces and hot and cold temperatures, a dog’s paw pads act as shock absorbers for all the bones, tendons and ligaments found on the dog’s legs

A Lesson in Anatomy

Close-up of paw, notice the smoother center and more prominent papillae on the edge of the toes.
Notice the smoother center and more prominent papillae on the edges.

What does a dog’s paw pad anatomy look like? The skin on a dog’s paw pads is extra thick and not found in any other area of the dog’s body. It’s made of layers of insulating fat and connective tissue making them the perfect version of Mother Nature’s insoles.

The outermost  layer is the one we’re most familiar with, it’s called the stratum corneum and it’s the hairless pigmented layer we see when we look at our dog’s paws.

If you ever looked at your dog’s paw pads very closely, you might have noticed how the outermost layer is made of small conical papillae. These papillae are made to add further protection.

You may have also noticed how the central surface of your dog’s pads may be smooth compared to the outer edges. This is from long-term walking on rough surfaces such as concrete. The smoothness is due to the conical papillae being flattened rather than conical due to abrasion, while the papillae on the edge remain conical.

Dogs who tend to walk more on hard surfaces and are older tend to generally have tougher paw pads than dogs used to walking in grass and carpet and who are younger.

idea tipDid you know?  A dog’s foot pads contain many blood vessels which is why they tend to bleed easily when injured.

dog paw pad careStrong But Not Invincible

While a dog’s paw pads are pretty tough and able to withstand the many miles dogs put on their feet, consider though that this doesn’t mean you can walk your dog over hot asphalt or over ice melt without having any problems.

A dog’s paw pads can be prone to cracks, abrasions, ulcers and blisters when exposed to heat and cold, harsh surfaces and chemicals.

Most commonly, the dog’s outer layer of skin, the stratum coneum  sloughs off, exposing a raw layer of skin that is very sensitive and can take even weeks to properly heal.

In nature, injuries to a canine’s feet can have deleterious effects and may strongly incapacitate these cursorial animals who need to run to hunt for prey and run away from predators. Luckily, in a domesticated setting, we can take care of our dogs providing them food and resting their feet which gives time for their paw pads to heal.

Paw pads are prone to heal slowly because they’re more exposed to contaminated surfaces, dogs need to walk on them and dogs are prone to further aggravate the area through persistent licking and chewing. Fortunately, we can do a whole lot in preventing injuries from occurring in the first place such as inspecting a dog’s paw pads on a routine basis after exercising on rough surfaces and avoiding temperature extremes or exposure to chemicals and irritants. Also, keeping a dog lean will help put less pressure on the toes and joints so the dog is “lighter on his feet.”

Did you know? Because the tissues on a dog’s paw pads is highly specialized and has precise functions, it’s irreplaceable, and therefore cannot be replaced from other skin from the body, explains Dr. Tannaz Amalsadvala, a graduate of the Bombay Veterinary College in Bombay, India.

 

References:

  • Laboratory Manual for Comparative Veterinary Anatomy & Physiology, By Phillip E. Cochran, M.S., D.V.M,  Delmar Cengage Learning; 2 edition (April 12, 2010)
  • Laboratory Manual for Clinical Anatomy and Physiology for Veterinary Technicians, By Thomas P. Colville, Joanna M. Bassert, ISBN-13:9780323294751 Publisher:Elsevier Health Sciences
  • “The Pet Lover’s Guide to Cat and Dog Skin Diseases” by Karen L. Campbell DVM MS DAVCVIM DACVD, Saunders; 1 edition (November 14, 2005)
  • DVM360,Paw tissues unique; injuries need special care, attention, By Tannaz Amalsadvala, B.V.Sc. & A.H., MS retrieved from the web on May 3rd, 2016.
  • Merck Veterinary Manual, Description and Physical Characteristics of Dogs, retrieved from the web on May 3rd, 2016.
  • Lloyd, DH and Garthwaite, G (1982) Epidermal structure and surface-topography of canine skin. Research in veterinary care, 33 (1). pp. 99-104.

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