The presence of calculi in the salivary glands or their ducts is apparently of rather infrequent occurrence, if one considers only the reported cases. Proetz,1 writing on the subject in 1923, states that about 300 cases had been reported up to that time; while Harrison,2 writing on the same subject in 1926, found 375 cases in a review of the literature from 1825 to the date of his writing. To these he adds twenty-seven cases of his own. Undoubtedly there are many cases which have not been reported.
Calculi may form in all of the salivary glands or their ducts, but the larger proportion, about 60 per cent, are found in the submaxillary gland. The parotid and sublingual glands each furnish about 20 per cent.
As to origin, Brophy3 states: "There seems to be no question that calculus formation in the salivary apparatus, as elsewhere, is