What are "Floating Ribs" in Dogs? All You Need to Know
If you don't know what floating ribs are, there is no need to worry. You haven't missed a whole lot.
Many people are unaware of this part of a dog's anatomy for the simple fact that this body part isn't as obvious as other parts.
It also doesn't help the fact that, term "floating ribs" isn't commonly used in everyday conversation, even among dog owners who frequent the dog part and love to spend time chit-chatting about their canine companions.
Floating ribs are also a body part that doesn't typically get much attention.
In other words, they don't play any major role in your dog's health concerns as other body parts such as your dog's hips, knees or spine.
However, this doesn't mean that they don't deserve any attention. It's always beneficial learning more about your dog's normal anatomy and all the internal structures that make up his body.
And of course, if you ever notice anything worrisome in your dog, it's always best to play it safe and consult with your veterinarian.
Following is a summary of what we'll discover today:
Getting Acquainted With Your Dog's Rib Cage
Your dog's rib cage is made up of several pairs of ribs which act as a framework meant to protect several important organs.
In particular, the first sets of ribs help protect your dog's lungs and heart, while the last sets help protect farther organs such as the liver, stomach, pancreas and kidneys.
A long and deep rib cage, with well-sprung ribs, helps increase lung capacity in dogs. Indeed, these are all desirable signs in dogs built with endurance in mind.
In particular, a dog's last rear ribs showing signs of being long, are an appealing feature because they are proof of plenty of lung room.
Too bad, that show dogs are often too "plump" meaning they are in optimal "show condition" making the ribs difficult to judge. This is why you often see judges palpating a dog's thorax.
Things get much easier when the dog in question belongs to one of the super lean breed categories such as greyhounds and salukis.
In these latter breeds, the ribs are readily seen, so much so, some people think they are malnourished! Intrigued? Discover why Saluki's are so skinny!
What are Floating Ribs in Dogs?
Dogs, as it happens in humans, have three different types of ribs: true ribs, false ribs and floating ribs.
Let's delve deeper into some definitions of all the three different types of ribs in dogs.
True Ribs
True ribs, also known as sternal ribs, are ribs that attach to the thoracic vertebrae of the vertebral column at the top and to the sternum (breastbone) at the bottom.
False Ribs
False ribs are ribs that do not attach to the sternum (breastbone), but are attached to the top thoracic vertebrae, and the costal cartilages of the preceding true ribs.
Floating Ribs
Floating ribs are the very last ribs and are only attached to the thoracic vertebrae at the top. They are not attached to the sternum nor the costal cartilages of the preceding ribs.
Since floating ribs only attach to the thoracic vertebrae of the back, they are also known as "free" or "vertebral" ribs.
Dogs have only one floating rib per side which attaches only to the thoracic vertebrae.
How Many Ribs Do Dogs Have?
Dogs have 13 pairs of ribs, which means they have a total of 26 ribs, that's 13 ribs per side of the body.
This means that, if you look at your dog by his side, starting from the head towards the tail, the first 9 ribs are true ribs, the next 3 ribs are false ribs, while the last rib is the floating rib.
Humans, on the other hand, have 12 pairs of ribs, which means they have a total of 24 ribs, that's 12 ribs per side of the body.
This means that, if you divide the human body in half (left and right), starting from the head towards the feet, the first 7 ribs are true ribs, the next 3 are false ribs, and the last 2 ribs (ribs 11 and 12) are floating ribs.
Ribs and floating ribs in dogs
Why Do Dogs Have More Ribs Compared to Humans?
Dogs have 26 ribs, while humans have only 24, why is that? The answer lies in the differences between these two species' evolutionary past.
Humans are bipedal, meaning they walk on two legs, have a vertical spine and a more compact rib cage. These features allow an efficient use of energy.
Dogs are quadrupedal, meaning they walk on four legs, have a horizontal spine and a well-sprung rib cage boasting ribs that are more curved, thicker and more numerous than humans.
These features allow greater lung capacity allowing them to excel in activities that require endurance such as running and hunting.
Can You See Your Dog's Floating Ribs?
In general, you shouldn't be able to readily see your dog's ribs, unless your dog is underweight or suffering from a health ailment causing weight loss and malnutrition.
However, floating ribs tend to be easier to notice considering that they're the last ribs and they tend to protrude more than the others since they have less of an attachment to the dog's breastbone, explains veterinarian Dr. Cree.
Many dog owners are alarmed when they first notice their dog's floating ribs. They think it's a tumor or something their dog ate (such as a sharp bone) and it is sticking out of their tummies.
Why is My Dog's Rib Sticking Out From One Side?
In some dogs, floating ribs may be more visible, particular in certain positions that make them "flare" out. For instance, floating ribs are more noticeable when dogs are lying down or when they're standing up and eating.
Also, the bony protrusion may become more visible when dogs are particularly full such as after eating a meal.
You can see this in young dogs who gorge themselves on food and get some distention as a result. The left side is usually the most affected.
This is because the dog's stomach is on the left side of the body under the last 2 or 3 ribs, and therefore, in a slim dog it is possible to see a slight swelling under the ribs from it, explains veterinarian Dr. Fiona.
It is important to seek the vet as soon as possible if, on top of showing any protrusion/distention, the dog is acting sick (nausea, drooling, vomiting, loss of appetite).
A larger abdomen can suggest organ enlargement, stomach bloat (where the stomach risks flipping on itself), fluid buildup or obstruction impacting the stomach or intestinal tract, explains veterinarian Dr. Alan.
These are serious conditions that require prompt medical attention.
Floating Rib Look-alikes
Sometimes what looks like a rib sticking out from one side is actually some type of bump or mass.
In this case, it's important to see the vet to have it evaluated as it can be anything from a benign lipoma (squishy lump of fat) to a bug bite or even a bone tumor of the rib. More about this is discussed here: Rib Bone Cancer in Dogs.
In some cases, a large tumor may be pushing the rib cage out, but in such a case, one would notice other serious symptoms such as trouble breathing.
A fine needle aspiration or X-ray can provide an insight on whether there are any masses or anything else going on in the dog's rib area.
Can a Floating Rib Be Broken (Fractured)?
Rib fractures in dogs aren't unheard of, but it would take quite some force to cause a fracture.
Think along the lines of blunt trauma occurring as a result of a dog being hit-by-car, falling from a certain height or small dogs being attacked by large dogs.
A dog's thoracic wall is relatively resilient overall. It would take some major trauma to cause a rib to fracture, explains Dr. Matthew Beal, a board-certified veterinarian specializing in emergency critical care.
Not to mention, the dog would show signs of significant pain, and potentially respiratory problems.
If you suspect a rib fracture, please consult with your vet. An x-ray can quickly diagnose the problem.
In general, uncomplicated fractured ribs will heal on their own. Vets may dispense pain meds to make dogs more comfortable while they're on the mend.
It's best to avoid giving aspirin to relieve pain in these cases, because it may prevent the vet from being able to dispense stronger and more appropriate meds because it's risky to switch from one anti-inflammatory to another, explains veterinarian Dr. Nicky.
To discover more about this, read about the wash-out period.
Can Floating Ribs in Dogs Develop Other Conditions?
Yes, on top of fractures, a dog's floating ribs can be prone to inflammation, arthritis and dislocation, explains veterinarian Dr. Jeff.
A part of the floating rib is composed of cartilage. Right where the bony part and the cartilaginous part meet, the area can be subjected to injuries.
Floating ribs are more prone to injuries because they are shorter and less protected as they are not attached to the sternum as the other ribs.
Floating Ribs Showing in Young Puppies
In young puppies such as those around 8-16 weeks old, the ribs may show up more, but their position should firm up as they develop.
The process is known as "mineralization of the costal cartilages" and may result in enlargements of the costochondral and costosternal joints with some temporary irregular shapes and distributions.
This process is progressive, meaning that as the pup develops, there should be decreased mobility of that last rib, explains veterinarian Dr. Salkin.
It's therefore something that they tend to grow out of. In other words, with time, the ribs will no longer appear to be poking out as during puppyhood.
References:
- Gilbert, E. M. (2017). K-9 Structure Terminology. United Kingdom: Dogwise Publishing.
- Veterian Key: The Thoracic Wall
- Denbow, D. M., Akers, R. M. (2013). Anatomy and Physiology of Domestic Animals. United States: Wiley
Disclaimer: this article is not meant to be used as a substitute for professional veterinary advice or behavioral advice. If your dog is acting sick or aggressive please consult with a qualified professional for proper diagnosis and treatment.
