Your cat has a bone sticking out of his chest – How bad is that?

What does a cat's chest look like?

On this page we explain which rib protrusions are normal and which are abnormal. Does your cat have a bump on his ribs that doesn’t feel like a piece of bone? Then you are not in the right place on this page. Here we just discuss a bone sticking out of your cat’s chest.

You can see a cat’s chest in the x-ray at the top of this page. The chest cavity is formed by the vertebrae at his back, the breastbone, also called sternum, at the bottom and the ribs form the arch at the side. The sternum has a protrusion in the front. We call this the Manubrium. And there also is a protrusion at the back of the sternum. We call this the Xyphoid. The ribs are made of bone tissue on the vertebral side, but where they run to the sternum they are cartilaginous. The older a cat becomes, the smaller the cartilaginous part becomes. Protrusions can therefore be felt throughout the chest. Sometimes they should be there, but sometimes it is also an abnormal formation or development of bone tissue.

Normal bone sticking out of his chest

You can sometimes feel a bone-like bump at the transition from the bone part of the rib to the cartilage part of the rib. This bump is not painful when you touch it and can also change shape during the next few years. This mainly occurs in young cats. The bump is then approximately 1/3 of the way up the chest cavity seen from the sternum. In the x-ray at the top of this page you can see that the ribs bend at the transition from bone to cartilage. Since the cat in the photo is a little older, the kink is already a bit lower than 1/3rd of his chest cavity. A bone sticking out at this part of his chest is nothing to worry about as long as it is painless by the touch. 

Normal bone sticking out on your cat's sternum

The Manubrium is located at the front of the sternum. This can become quite large and protrude in some cats. The Xiphoid is located at the back of the sternum and can also become quite large in some cats. With both protrusions, your cat does not experience any pain when you press on them. As long as it doesn’t hurt, there is no cause for concern about this lump on your cat’s sternum.

A normal bone sticking out on your cat's vertebrae

As you can see in the photo at the top of this page, the vertebrae have some protrusions on top at the level of the chest cavity. However, you should hardly feel these because they are surrounded by muscles and tendons. You can feel small bumps on skinny cats, but they are approximately equally noticeable on each vertebra. And they don’t hurt when you press on them.

A bone sticking out on a cat's ribs can easily develop if a cat like this is between cars.

An abnormal bone sticking out on your cat's ribs

It happens quite regularly that a cat has an accident. An accident involving a vehicle is especially hard. Unfortunately, in many cases this is fatal for your cat. But fortunately a lot of cats survive. If the blow was significant and hit the chest, your cat may have broken a rib or ribs. A bone sticking out on his chest may be felt on your cat’s ribs in that case. Immediately after the accident, this is of course very painful when you touch it. But if the fracture healed, it can be in the wrong position, causing a hard bump to remain in that spot for life. But it will no longer feel painful when you push on that area.

Is the is bone sticking out of your cat’s chest painful? Then it is wise to take him to your vet. After all, a problem may also have arisen in your cat’s lungs. Or a tear may have developed in his diaphragm. It is important that this is checked by your vet. This probably suggests taking an x-ray of your cat’s chest to check what’s broken. If it only concerns one or more ribs, this does not need to be treated. Your cat will heal this itself. With the possible development of a bony bump on his ribs for the rest of his life. However, he will receive a painkiller from your vet to lower the pain that the bone sticking out of his chest is causing him.

A protruding sternum in your cat

So, under normal circumstances, cats can have a bony protrusion at both ends of the sternum. In that case, the Manubrium or Xiphoid is somewhat larger than you would expect. This is nothing to be bothered about. But it is also possible that your cat sufferes from a broken sternum as a result of an accident or a kick from an angry neighbour. In this case too, there is a chance that more damage occurred internally than you suspect. So it is wise to have your cat examined by your veterinarian, if you suddenly feel a bone sticking out of his chest that hurts him. In some cases, the sternum will have to be surgically repaired with metal plates.

A protuding spine in your cat

This is always abnormal and especially when it is painful. In this case, your cat’s back is probably broken. Try to pick him up very calmly without bending his back. And take him to your vet. A broken back can lead to paralysis and in many cases this leads to euthanasia in your cat.

A protuding rib in your cat

Cats can sometimes also have a congenital defect in a rib. In that case it may protrude. We mainly see this in the rear three ribs. These are not attached to the sternum and can therefore sometimes protrude considerably. As long as it is not painful for your cat when you touch this spot, you don’t have to worry about it.

Schematic drawing of a cat skeleton so you can clearly see where the bone might be sticking out on a cat's chest.

A protruding bone under the ribcage

Below the rib cage, at the level of the sternum, are the bony protrusions called manubrium and xiphoid at the ends of this sternum. In many cats, this protrusion feels quite large. Again, as long as this bump on the bottom of the rib cage is not painful, then there is no problem that needs to be solved.

When should you go to the vet with an abnormal bone sticking out on your cat's ribs, sternum or vertebrae?

If your cat reacts very painfully when touching the bone that is sticking out, it is wise to take him to your vet and have him checked. This is certainly the case when he has difficulty breathing or when he has difficulty eating or pooping and urinating.

Do you really not want to go to your vet? Then keep your cat indoors for a few days and keep a close eye on his breathing. He should also eat well and poop and urinate normally. For example, if there is a tear in the diaphragm as a result of the accident, the liver and stomach may have ended up in the chest cavity. Your cat will then have difficulty breathing, but will also not be able to digest its food properly. So do you notice abnormal breathing or abnormalities in eating and pooping? Then you do need to visit your vet. Is he otherwise behaving normally, but a little painfully? Then you can give him half a child’s aspirin (=81mg) once every 2 days (not 2x a day!!!). NO PARACETAMOL, IBUPROFEN OR OTHER PAIN KILLS FOR PEOPLE!!! These are deadly for cats! Only Aspirin is suitable.

Good luck!

Hopefully you have come to the conclusion that there is nothing wrong with dat bone sticking out of your cat’s chest. If it does seem to be abnormal we wish you and your cat good luck!