by Angie Pollock

Created on: May 19, 2008   Last Updated: September 22, 2008

Canines have four pairs of salivary glands that are used to produce saliva. The parotid, mandibular, sublingual and zygomatic glands each have their own duct that carries saliva into the mouth. The salivary glands are in the tissue beneath the skin in both the upper and lower jaw.

The salivary glands have many important functions. The saliva is used to turn food into soft pieces to slide through the esophagus, to aid in mouth lubrication, to flush away food debris in the oral cavity and to aid in cooling.

Viral and bacterial infections of the salivary glands can be common. Dogs with salivary gland infections can develop some key symptoms. Excessive drooling, swollen jaws and inability or difficulty eating are just a few of these symptoms.

Many times infections are caused by an obstruction of the salivary gland duct or from a puncture wound. The zygomatic salivary gland is located at the floor of the orbit beneath the eye. If this gland becomes enlarged from an infection or cyst, the gland can push the eye forward.

Some canines will contract a fluid-filled cyst under the jaw or within the mouth. These cysts transpire when the saliva leaks from the salivary ducts into the tissues around or within the mouth. This can be caused by trauma or when the fluid is too thick to travel through the small ducts. Surgery is usually required in cases where the saliva leaks into the surrounding tissues.

A tumor of the salivary gland can spread to other parts of the body. The most common tumors of the salivary glands are adenocarcinomas and carcinomas. They are usually located in the parotid or mandibular salivary glands. While tumors of the salivary gland are uncommon in canines, it does occur. Treatments range from surgical removal of the tumor to radiation therapy or chemotherapy.

While salivary gland infections can be common, salivary gland diseases are uncommon in dogs. Most conditions that affect the salivary glands include ruptures, swelling, autoimmune diseases and obstructions. Salivary "mucoceles" are painless bulges located under the tongue that are filled with liquid. This condition is also known as sialocele, cervical sialocele, cervical mucocele, ranula, and salivary cyst. The most common cause of mucocele is thought to be trauma to the duct or gland. Symptoms include swelling under the rear portion of the jaw.

A ranula is a mucocle located under the tongue which can cause difficulty in chewing or cause blood to be present in the saliva. Mucoceles, if not treated, can become infected but with proper treatment can be cured. Even though trauma is thought to be the cause for mucoceles, it is recommended to avoid choke collars and prevent your dog from chewing on sticks.

Our dogs rely on us to keep them in good health. A proper diet and exercise isn't always enough to keep them healthy. It is recommended to check your dog's mouth for obstructions in the curves and creases of the mouth and in between the teeth. Properly clean any injuries your pet may incur and always seek veterinarian care for your pet if problems persist.

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