Sialo - related to the salivary glands
Lith - stone-mass
A third name for salivary stones is salivary calculi (in the plural, of course).
Salivary stones are generally composed of calcium carbonate and calcium phosphate. Uric acid stones may
form in patients with gout. Stone formation occurs via the deposition of calcium phosphate and an organic matrix of carbohydrates and amino acids about a nidus of debris or other material.
The majority form in the submandibular gland and it's duct, Wharton's duct. Approximately
10% occur in the parotid gland and it's duct, Stensen's duct, and 5% in the minor salivary glands. Stone formation is thought to be more common in the submandibular gland secondary to the higher mucin content of its saliva and
the anti-gravity flow of saliva within the duct. Its saliva is also more alkaline and has a higher calcium and phosphorous content. Submandibular stones are usually also larger in size. Serum calcium and phosphorous levels have no known correlation with the formation of calculi.
The calculi may be found within the ductal system itself or within the salivary gland parenchyma. For the major
glands, in 75 % of cases there is a single calculus, with multiple gland involvement occurring in only 3 %.
Recurrent pain and swelling of the salivary glands and ducts during salivation (eg meal times) are common initial presenting features - sialolithiasis. Symptoms vary depending on the size and location of the stone.