DIAMETERS OF THE MAIN EXCRETORY DUCTS OF THE ADULT HUMAN SUBMANDIBULAR AND PAROTID-GLAND - A HISTOLOGIC-STUDY

In assessing new minimally invasive diagnostic techniques (duct endosc opy) and therapy (lithotripsy), it is of importance to know the true d imensions of the excretory ducts. Twenty-five ducts of the parotid gla nd and 20 ducts of the submandibular gland were examined histologicall y at different points of their anatomic course, and their in vivo diam eters were evaluated with the use of a previously determined formalin- induced shrinking-factor. The mean diameter of Stensen's duct ai four different points along its length ranged between 1.4 mm and 0.5 mm, wi th a maximum of 2.3 mm and a minimum of 0.1 mm, depending on the site. A narrowing at the middle of the duct was striking. in all preparatio ns examined, the minimum width of the excretory duct was located at th e ostium. In Wharton's duct the narrowest duct diameter was also ident ified at the ostium. The mean values for the duct diameters ranged bet ween 1.5 mm and 0.5 mm. The largest duct diameter reached 2.2 mm; the smallest one, 0.2 mm. Far diagnostic and therapeutic purposes, endosco pes, balloon catheters, and stone-extraction-baskets probably should, despite the extensibility of the duct, conform as much as possible to the physiologic duct widths. A diameter of 1.2 mm should be aimed at a s an upper limit for these instruments. Our findings also suggest that , in the case of salivary stone lithotripsy, the best results will be achieved when the maximum size of stone fragments does not exceed 1.2 mm.