You might take your dog's paws for granted. For that matter, so may your dog. But to know your animal thoroughly and be well equipped to care for it properly, you cannot overlook these four vitally important components of your canine companion's anatomy. The conscientious owner should be acquainted with the basic structure of a dog's paws, their function - and the key role they play in virtually all of an animal's waking hours.
Keep in mind that paw injuries, if unnoticed or ignored, can lead to a variety of chronic health problems. A painful paw injury that is not treated promptly may cause a dog to become less active, and long stretches of inactivity can result in loss of muscle tone and unhealthy weight gain. Another example: To take pressure off an injured paw, a dog may radically alter its natural gait. This pain relieving strategy', if practiced over an extended period, can compromise the animal's general-musculoskeletal health and, consequently, its overall physical dexterity.
Anatomy of a Paw
In several respects, the canine paw is quite similar in structure to a human hand; a "wrist," four longer digits (analogous to our fingers), and only on the front legs a fifth digit, called the dew claw. The dew claw 's unlike the human thumb, however, since it is not "opposable" - it cannot be positioned opposite to any of the other digits in order to grasp an object. Also, the dew claw is situated a short distance above and behind the front paw rather than at the end of a row of digits. (Picture the human thumb positioned on the wrist, an inch or so up the inner forearm.) While our thumbs serve many purposes, the canine dew claw is of no use.
The four digits that are schematically similar to human fingers are a dog's toes. And, according to James Flanders, DVM, the most important among these are the two central digits, since they bear most of the dog's weight. (A dog walks on its toes, whereas humans and other mammals walk with their feet planted squarely on the ground.)
"An injury to an inside or outside toe isn't as significant as an injury to one of the two middle toes," says Dr. Flanders, an associate professor
of clinical sciences at Cornell University's College of Veterinary Medicine. "And if for some reason we have to remove one of a dog's toes
a tumor, for instance - we worry more if its one of the two inside toes."
Beneath and just behind the toes is the foot pad - a large, thick, tough and spongy layer of muscle and fat covered by a rough surface. There re three types of pads - digital, palmar and carpal and they act as shock absorbers, cushioning the bones in the foot against pressure when the animal is standing or running.
The paws also serve as cooling devices, Dr. Flanders points out, because that's where dogs do a large part of their perspiring. "The dog has a special type of sweat glands in its pads that help the animal cool itself," he explains.
In general, the anatomy and function of the canine paw is similar in all breeds, varying only according to size and proportion.
Strong but Vulnerable
While all components of a dog's paws are quite tough and durable, they are not invulnerable. On the contrary, they are subject to
a wide variety of injuries and disorders that make it painfully difficult, if not impossible, for a dog to walk and run normally. These include
fractured and dislocated bones; warts and corns; broken and deformed nails; and infections in the nail bed or in the spaces between the toes.
Bone fractures and foot pad injuries are most common in warmer months, says Dr. Flanders. This is because dogs tend to be outdoors more regularly and thus more likely to come in contact with thorns, broken glass, stones and other sharp or rough materials that can cause punctures, abrasions and lacerations of the pads. In very hot weather, their foot pads may be burned by hot pavement; in extremely cold weather, the pads can be damaged by frostbite. Also, he points out, a foot pad can be worn down by excessive walking or running. "Some owners don't realize that there's a limit to what a dog can do," he says. "They'll take the animal hiking on long trails, and the poor dog's pads will become so severely traumatized that they can't go any farther."
But paw injuries can also occur indoors, he adds. A foot bone can be broken if a heavy object falls on it, for example, or a toenail can be ripped off if it gets trapped in carpeting.
According to Dr. Flanders, paw injuries are frequently seen in the typical veterinary practice. At the Cornell University Hospital for Animals, he says, "We'll see one or two per month, if not more, especially in the summer."
Treating the Injured Paw
Indications that something is wrong with a dog's paw are usually obvious, says Dr. Flanders. "The animal will limp noticeably," he says, "and maybe it will hold its leg up off the ground. Or you may spot a bloody footprint on the floor. And sometimes the animal will lick and chew at one of its paws, especially if there is some foreign body or plant material wedged between the toes. Most of the time, a veterinarian can diagnose the problem by simple observation, but if the injury is not obvious or seems to be severe, we'll take an X-ray."
Treatment varies, of course, depending on the extent and location of injury. "If it's a superficial lesion in the paw," says Dr. Flanders, "we may just use an antibiotic ointment. If there are lacerations, we'll usually clean the wound and suture it. In either case, we'll usually bandage the foot to protect it, since the wound can be traumatized if the dog puts weight on it, and the lesion or laceration will be slower to heal. Bandaging is most important in treating pad injuries, because the pad tends to break apart until the wound is completely healed."
In extreme cases, all or part of a dog's foot pad may be entirely ripped off, in which case a veterinary surgeon may attempt to restore the pad by borrowing from another pad and creating a usable "flap" over the injured area. In the worst case, says Dr. Flanders, the pads on an entire paw will be torn away, and this may call for amputation of the foot. "And usually," he notes, "we'll remove the entire leg, since a stump is of absolutely no use to a dog, and most dogs will do fine getting around on three legs."
The speed with which a dog is likely to recover from a paw injury also depends on the severity of the trauma. "If it's just a skin lesion," says Dr.
Flanders, "the paw, even if sutured, will probably heal within a week or so. A serious pad injury, though, can take a month or more to