I am Your Dog’s Bones

 

Whether your dog is chasing squirrels or romping around the yard with a ball in his mouth, his bones are always there to support him. Movement is the well-orchestrated effort of nerves, muscles and bones working together and making it all happen. A dog’s skeleton is composed of a variety of bones of different shapes and sizes meant to provide structural framework and general support for his whole body. So today, let’s discover more about dog bones, the various tasks they carry out throughout a dog’s life and potential problems a dog’s bones may encounter.

Introducing Your Dog’s Bones

Hello, it’s your dog’s bones talking today! Yes, there are many of us! Wondering how many bones dogs have? Dogs have over 300 bones, but if you want exact figures, we are closer to give or take 319, depending on how many bones are in a dog’s tail. If you’re looking for a comparison between the number of dog and human bones, consider that humans have about 206, so yes, dogs definitely win in the bone quantity department– if there was ever a contest for that!

Let’s start off by looking a bit at our composition. We are mostly made of minerals, primarily calcium and phosphorus and are somewhat, like onions, that is, we’re composed of many layers. Most of us are covered by a protective layer known as periosteum that’s responsible for delivering blood and nutrients to us. Periosteum also contains cells that help us grow and repair. If you’re wondering what periosteum looks like, imagine that white thin layer that lies between an egg and its shell. Yes, that pretty much looks like us.  Right under the layer of periosteum is compact bone, the smooth and very hard bone people are most familiar with when they think about us. Under the compact bone is what’s known as cancellous bone, also known as spongy or trabecular bone. As the name implies, this is the spongy part that is often found at the ends of the dog’s bones and joints. Finally, comes the innermost part of us, the bone marrow that carries important functions. Put together all these parts, and you get an idea of our composition. Now, let’s get a rundown of what we do.

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Did you know? Despite their significant differences in size, Chihuahuas and Great Danes have approximately the same number of bones.

We Provide Protection

We do our best job to protect your dog from getting hurt. If you look at your dog’s ribs, you will notice how we are arranged like a shield meant to protect your dog’s important internal organs such as the heart and lungs. Your dog’s thick skull is also there to protect that brain from dangerous concussions. Yup, being thick-headed is good thing for dogs!

Fun Fact:  The bones of the dog’s ears are there for neither protection nor support, but rather their primarily role is sound transmission, allowing dogs to use their sense of hearing, explains veterinarian Race Foster.

We Allow Movement

As mentioned, it is thanks to the teamwork between nerves, muscles and bones that your dog is capable of romping around. Many of us fit together like jig-saw puzzles connecting to their neighboring bones. Areas where we join one another are called joints which play a great role in locomotion. We interlock together in different ways, for example, the dog’s hip is an example of a ball and socket joint while the dog’s elbows are hinge joints.

We Produce Cells

When people think about us, they often get a mental picture of bones seen in a museum or those big  knuckle bones fed to their dogs, and this makes sense, as most likely those are the only types of bones people will ever see. But we are far from the dead, dry bones seen at museum exhibits. When we are still in the body of a live person, animal or dog, we are well alive, so much so that we grow, repair and even create blood cells. You see, in our bone marrow, that dark tissue found in hollow bones, special stem cells work hard to produce red and white blood cells.

We Store Minerals

Not many people think of bones as a warehouse for important substances the body needs. We store fat and several important minerals and keep them ready for when dogs need them. These minerals are constantly moved around, being deposited and taken out as needed. All this is coordinated by the parathyroid gland which produces a special hormone which tells us to release calcium into the bloodstream as needed.

When Things Go Wrong

Many things can go wrong with us as we’re not indestructible. One of the most common problems affecting us are fractures, which can happen to many of us. We also may be subjected to issues when puppies grow if owners are not attentive enough to care for us. We may also get infections and problems associated with low calcium levels in the blood. Here’s a brief rundown of several problems we may encounter. This is not a complete list, but just a few problems that may affect us.

Dog Bone Fractures

When we are subjected to high impact accidents as when hit by car, we can dislocate and/or break and cause significant pain. Some types of fractures (like to toe fractures) may just need a splint, but others may require expensive and complex surgical repair. Sometimes we also can break due to an underlying condition that weakens us.

Dog Bone Cancer

When cancer affects us, dogs may suffer from what’s called a “pathological fracture” as we are destroyed from the inside out. While this fracture can affect any bones, the dog’s bones of the leg are most susceptible. What happens it that, as bone is destroyed, it’s replaced in part by tumorous bone, but this is not as strong as real bone and therefore the leg becomes prone to fracturing. Unfortunately, there’s no way to repair this type of fracture surgically.

Dog Bone Infection

Yes, we can sometimes get infected too. Osteomyelitis is the medical term for infection of the bone or bone marrow and it can be caused by bacteria or a fungal infection. In the case of bacteria, an infection in the body may spread to us, or the infection may be more localized. Bacteria may enter from bites, wounds or injuries or even complications from a surgery affecting the bone. Fungal infections affecting us include coccidiomycosis, blastomycosis, and cryptococcosis. Dogs affected by fungal infections that involve the bones usually develop pain, a fever and swelling.

Problems With Growth Plates

When puppies are born, they are equipped with all the bones they need, but as they grow, their bones need to increase in length. You see, us bones tend to grow from areas of immature, soft bone that are called growth plates which are located by the ends of the puppy’s bones. These growth plates are weak and can be prone to injury or even fractures, explains veterinarian Dr. Race Foster. It’s important therefore not to overexercise puppies such as jogging them on hard surfaces. As the puppy grows, we grow and finally harden with calcium and minerals, a process that is known as “closing the growth plates.“Generally, by one year of age the puppy’s growth plates close and significant bone growth ends.

“Vitamin D deficiency is characterized by an inadequate mineralization
of the bone and growth plates, also know as rickets.” Dr. Sally Perea

Effects of Low Calcium

As mentioned, we store minerals and this includes calcium. When dogs give birth and have a large litter, sometimes they may lose too much calcium at once which may cause what’s known as hypocalcemia (low calcium), milk fever or eclampsia. What basically happens in dog eclampsia is that mother dog’s body cannot keep up with the increase demands for calcium associated with nursing. When this happens, blood levels of this mineral become suddenly depleted and her parathyroid gland is not fast enough to start removing it from the bone. With not enough levels of calcium circulating in the body, affected dogs develop a stiff gait, fever and rapid breathing and death can occur if no treatment is given. While well-meaning dog owners may supplement calcium during a dog’s pregnancy, doing so is not recommended, explains Dr. Race Foster. Wrong amounts of  supplementation during pregnancy and inappropriate calcium to phosphorous ratios can actually trigger eclampsia  in the first place.

Did you know? Too much of a good thing applies to calcium as well. While breeders and dog fanciers may advocate giving puppies calcium supplements, this is risky business. Too much calcium in puppies is detrimental to their development and can cause skeletal deformation, warns veterinary nutritionist Dr. Jennifer Larsen.

Aging Bones in Dogs

After years and years of providing locomotion, protection and support, sadly we start feeling the effects of time. As time goes by, the cartilage that cushions joints starts to wear down. Without this protection, us bones are left rubbing against each other, which causes friction and damage to us over time. Large dogs are mostly affected, and the weight-bearing joints such as hips, elbows and knees are particularly vulnerable.  Bones spurs may also appear. While there is no cure for old age, there are supplements and medications that can fortunately reduce inflammation and pain.

As seen, us bones do a whole lot, but we are also prone to problems! Make sure you keep us in good shape and report to your vet immediately as soon as you notice problems. I hoped this helped you discover more about us! Best regards,

Your dog’s bones 

Disclaimer: this article is not meant to be used as a substitute for professional veterinary advice. If your dog is having health problems, please see your vet for proper diagnosis and treatment.

 

References:

• Pet Education, Skeletal Anatomy: Bones, Joints and Muscles in Dogs, retrieved from the web on September 5th, 2016
• Pet Education, Eclampsia (Puerperal Tetany, Milk Fever, Hypocalcemia) in Dogs, retrieved from the web on September 5th, 2016
• Focus on Nutrition, Feeding Large Breed Puppies, retrieved from the web on September 5th, 2016
• Nutrient Requirements of Dogs and Cats. National Research Council of the National Academies. The National Academies Press, Washington, DC, 2006

Photo credits:

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