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Why Do Dogs Have a Bump on the Roof of Their Mouth?

Dogs have a bump on the roof of their mouth and not many dog owners are aware of it, until one day, they accidentally stumble upon it when perhaps their dogs are yawning while lying down belly-up. What's that bump doing there? Interestingly, that bump on the roof of your dog's mouth is there for a reason and it's closely connected to your dog's sense of smell.

Why Do Dogs Have a Bump on the Roof of Their Mouth? It could happen one day that, out of the blue, your dog is lying down with his head on your lap and you notice a bump on the roof of your dog's mouth. Who ever saw that before? What it that? 

You may therefore start worrying as wild thoughts of cancer and surgery to remove the growth cross your mind. You might have heard of how growths in a dog's mouth can be cancerous and perhaps you know of a friend whose dog had a malignant melanoma in the mouth. While it's always best to have any suspicious lumps or bumps on a dog's mouth checked by a vet, there is one little hard lump in the roof of a dog's mouth that is actually perfectly normal.

Introducing Your Dog's Incisive Papilla

In a normal, healthy dog, there's a little lump that's located on the roof of the dog's mouth right behind the top two upper middle teeth which, by the way, are known as the incisors. 

Some describe this little lump as being diamond-shaped and hard to the touch. This bump goes by the name of "incisive papilla," and it ranks as one of the top reasons dog owners make a panic appointment to their vet, explains veterinarian Dr. Truli on his website VirtuaVet. 

As the name implies, the term incisive in this case refers to the fact that it's located right behind the dog's top central incisor teeth; whereas, the term "papilla" is just a simple name for a little lump. Below, you can see the incisive papilla right behind my dog's front incisors. 

Picture of the incisive papilla in the roof of my dog's mouth. Notice the black bump right behind the top middle incisor teeth. 

Picture of the incisive papilla in the roof of my dog's mouth. Notice the black bump right behind the top middle incisor teeth. 

An intriguing Purpose

So why does a dog need an incisive papilla? Turns out, this little bump has a small cavity leading to the incisive duct which connects the mouth with the nose.

 The incisive papilla therefore communicates with the dog's vomeronasal organ which is responsible for detecting pheromones. Pheromones are naturally occurring substances that impact the behavior of the receiver. 

Once pheromones are detected, the information is sent to the brain where it can trigger an emotional reaction or other physiological response.

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For sake of an example, a dog kicking dirt after pooping or peeing, does so because in between the dog's toes there are special glands which are capable of emitting pheromones. These pheromones are therefore left behind for other dogs to detect, courtesy of their incisive papilla which has a hole that leads to a duct that communicates with the dog's Jacobson organ (also known as vomeronasal organ).

 Once pheromones reach the Jacobson organ, this information reaches  the dog's amygdala, an important part of the brain that plays a big role in emotional reactions. So put all these puzzle pieces together you can get a clear picture of how the incisive papilla plays a primary role in canine emotions and behaviors. 

Upon detecting these pheromones, the dog may therefore decide to steer clear of the area or perhaps pee and poop nearby, or maybe just walk away and ignore it. 

Now That You Know...

Now that you know why dogs have a bump on the roof of their mouth, there are some things to be aware of. 

While the incisive papilla normally just sits there and rarely causes any problems, there are some cases that may require veterinary attention.

 For instance, according to Animal Dentistry and Oral Surgery Specialists LLC, should a dog have a malocclusion where the lower teeth end up puncturing the roof of the mouth, the incisive papilla may swell. 

Therefore, it's not a bad idea to routinely inspect your dog's mouth and get familiar with its normal appearance. This way, you can promptly report to your vet any unusual findings. 

A good way to do this is when you brush your dog's teeth. And obviously, have your dog see your vet if there appears to be any odd looking lumps or bumps in your dog's mouth.

Did you know? While dogs do not exhibit the typical lip curl ("flehem") as seen often in horses, deer and goats, they have their own modified version. According to the book "Behavior Problems of the Dog and Cat by Gary M. Landsberg, Wayne L. Hunthausen and Lowell J. Ackerman, in dogs, flicking the tongue against the incisive papilla, (tonguing) along with panting, are behaviors that may likely help them detect pheromones. Tonguing may be accompanied by teeth chattering and production of foam.

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