We frequently see canine patients at our clinic with huge fluid filled cyst located either under their jaw or within their mouth. When we say huge, we really mean what we say because some of those found below the lower jaw are larger than grapefruits. There are many other causes of swelling in this area such as puncture wounds, abscesses, infections of the teeth, and tumors, but most common relate to the salivary glands. The salivary glands, as their name implies, are responsible for the production of saliva. Several sets of them lie in the tissue area beneath the skin in the upper and lower jaw.
Saliva production goes on constantly.
It continuously makes its way into the mouth through small ducts that originate within the salivary glands and course under the skin, opening directly into the oral cavity. The purpose of saliva is to lubricate the mouth, moisten the food, and begin the digestive process. Saliva breaks down starch into individual sugar molecules, both within the mouth and during chewing and later on in the stomach and small intestine. Salivary cysts occur when saliva leaks from the salivary ducts into the tissues near or within the mouth. This may be caused simply by trauma to the ducts.