Ranula is a cyst of the salivary gland. A cyst is a localized buildup of fluid (i.e. pus, blood, saliva) inside the glandular duct.
Depending on its location, the ranula, which is a special variety of cyst, can develop on the outside skin along the angle of the lower jaw or inside the mouth beside the tongue. If the cyst develops inside of the mouth, movement of the tongue and swallowing may be impaired. As a complication, the cyst may become injured, and as a result, become infected. In severe cases, a dangerous septicemia may develop.
Salivary glands are located along the base of the ear and the angle of the jawbone. Glandular ducts discharge saliva generated by the salivary glands into the mouth. If a blockage of these ducts occurs, (i.e. after inflammation or the introduction of a foreign body) the duct becomes enlarged and forms a bulging cyst, which is referred to as a ranula.
Clinical examination of the salivary gland and the content of the ranula may reveal the cause of the blockage. Surgical excision of the whole cyst is curative if the blockage cannot be relieved by other means.
Consult a veterinary clinic if you suspect that your dog is suffering from a ranula.