Counting your pet’s appendages.


I fell off my bike last week and, being old enough that I no longer bounce well, I broke my toe. My big toe. Which got me thinking about toes. “Maybe I should write about broken toes in dogs,” I thought. “Dogs don’t have big toes … and they don’t all have the same number of toes,” I thought, my mind tumbling down the rabbit hole of free association. Human doctors have it easy. Most of their patients have the traditional five fingers per hand, five toes per foot. Counting them is standard. Start at the inside and count outward. One, two, three, four, five. If you want to get fancy, name your fingers. Thumb, index, middle, ring, pinky. Want to get really fancy? Use medical terminology. The big toe is the hallux; the thumb, the pollux. Bear with me and indulge my love of etymology. Hallux is derived from the Latin allus, meaning “great toe,” which is in turn derived from a Greek word meaning “to spring or leap,” evidently referring to the big toe in action. The definitive etymology of pollux is more elusive. Some sources suggest it stems from a Latin word meaning “to project,” I assume because thumbs stick out away from the rest of our fingers. I prefer the explanation that pollux comes from the Latin polus, meaning “a pole on which the heavens turn” (like the star Polaris) … and thus might refer to our wonderful opposable thumbs.

To talk about paws, we have to clarify a few terms. Imagine your pet’s paws as analogous to human hands and feet. The hand bones that go from our wrists to our knuckles are called metacarpals. Same for front paws on Castor the cat and Pollux the poodle. Our metacarpals are numbered one through five, starting with the one connecting to the thumb, and we have five fingers per hand, called digits, numbered the same way. Same for Castor and Pollux, starting with the shorter first digit on the inside of the front foot often called the dewclaw. More about dewclaws in a moment. Stay tuned.

Now, for hind feet. The bones that go from our ankles to the base of our toes are called metatarsals. Same for hind paws on Castor and Pollux. Human metatarsals are numbered one thru five, starting at the big toe. Here’s where it gets tricky. The majority of dogs and cats only have four metatarsals, and four hind toes. But some have five — a dewclaw on the hind foot. It may be fully developed, complete with a joint articulation, or it may be rudimentary — nothing more than a toenail dangling from a bit of skin. Some dogs even have two or more of these rudimentary dewclaws per foot. So how do we standardize numbering the bones of the hind feet, taking into account all these variables? Since there may or may not be dewclaws, and since embryologically the hind dewclaw is analogous to the human big toe, we always count the hind dewclaw as No. 1 … whether it exists or not! Thus for your typical four-toed pet, the existing hind toes and associated metatarsals are numbered two, three, four, and five. No No. 1.

What about “double-pawed” cats? The technical term is “polydactyl,” meaning “many toes.” Sometimes those extra toes are fully developed, complete with articulated joints. Others are just extra-large, or additional, rudimentary dewclaws. Even among veterinarians there is confusion about how to officially describe all these tootsies. I usually resort to drawing pictures on the medical records. Who cares about counting toes, anyway? Why does it matter? Medical clarity. If we are removing a tumor from between two toes, we want to all agree on exactly where that growth was. If it grows back, is it in the same place, or a new location? We need a standardized system.

Why else does anyone care about dewclaws? In dogs, if you want to show Pollux, different breeds have different standards. For example, the official American Kennel Club standard for the Great Pyrenees includes double dewclaws behind and single dewclaws in front. On the other hand, the standards for poodles, and many other breeds, specify that any dewclaws should be removed. Pollux doesn’t care, but dog-show judges do. Then there are folks who use their dogs for hunting or as guard dogs. Many such dogs traditionally have their dewclaws removed, on the theory that these extra protuberances can affect job performance by being vulnerable to trauma, such as getting caught in brush when running through fields. In some areas, dogs wear “hunting boots” to protect their paws from harsh environments, and hind dewclaws can rub on the boots and cause sores. Veterinarians have varying opinions. Some think dewclaws have no use and, having seen enough dogs injure themselves, favor routine removal of all hind dewclaws except for show dogs that are “required” to keep them. Others think we should leave dewclaws alone unless an actual injury occurs.

Traditionally, purebred dogs requiring dewclaw removal would have the procedure done within the first two to three days after birth. Veterinarians were taught to just snip them off. No anesthesia. Tail docking was often done at the same time, also without anesthesia. Nowadays there is more thought given to pain control, with some practitioners using epidural or local anesthesia, or even on occasion gas anesthesia, but then one has to balance the humane concerns with the anesthetic risks. For animals that are not going to be used for show or breeding, another option is to remove dangling dewclaws when the pet is anesthetized for neutering. Double-pawed cats may also benefit from surgical intervention in cases where the claw of an extra toe curls inward, and repeatedly grows into the flesh of the paw.

I’m out of time now, so I’m gonna go put my feet up and give my broken toe a break. This little piggie went to market, this little piggie went to town, this little piggie ….