The diameters of Stensen's and Wharton's ducts and their importance in diagnosis and therapy

In assessing new minimally invasive diagnostic techniques (duct endoscopy) and therapy (lithotripsy) of salivary gland disease, it is of importance to know the true dimensions of the secretory ducts. Twenty-five ducts of the parotid gland and 20 ducts of the submandibular gland were examined histolo gically at different points of their anatomic course and their in vivo diam eters were evaluated using a previously determined formalin-induced shrinki ng factor. The mean diameter of Stensen's duct at four different points alo ng its length ranged between 0.5 mm and 1.4 mm, depending on the site. A na rrowing at the middle of the duct was striking. In all preparations examine d, the minimum width of the secretory duct was located at the ostium. In Wh arton's duct the narrowest duct diameter was also identified at the ostium. The mean values for the duct diameters ranged between 0.5 mm and 1.5 mm. F or diagnostic and therapeutic purposes, endoscopes, balloon catheters and s tone-extraction baskets should conform as much as possible to physiological duct widths. A diameter of 1.2 mm should be considered the upper limit for duct instruments. Our findings also suggest that in the case of salivary s tone lithotripsy the best results will be achieved when the maximum size of a stone fragment does not exceed 1.2 mm.