With expanding blades
![](/_userfiles/pages/images/Museum/Instruments/IMG_1158-Kollmann%20Dilators%20_640x312_.jpg)
According to Wyndham Powell, writing in 1909, Kollmann dialtors should be used with rubber covers or sheaths.
See "Wyndham Powell BMJ 1909 A point in the use of Kollmanns Urethral Dilator".
The dilators could be either curved or straight, but both had four blades which expanded to a calibre determined by winding the dial (bottom image).
![](/_userfiles/pages/images/Museum/Instruments/IMG_7397%20-%20Kollmann%20urethral%20dilator%20_curved_%20_800x600_.jpg)
![](/_userfiles/pages/images/Museum/Instruments/IMG_7396%20-%20Kollmann%20urethral%20dilator%20_curved_%20_800x600_.jpg)
← Back to Urethrotomes & Dilators