<prompt> French in Foleys Catheter refers toOuter circumference measurementInner circumference measurementDiameter of catheterLumen size  <response>: Ans. c Diameter of catheterRef Internet Sources, Wikipedia The French scale or French gauge system most correctly abbreviated as Fr, but also often abbreviated as FR or F is commonly used to measure the size diameter of a catheter. 1Fr0.33mm, and therefore, the diameter of the catheter in millimeters can be determined by dividing the French size by 3: DmmFr3 or Fr D mm x3For example, if the French size is 9, the diameter is 3mm.Note that the French scale is a measurement of the diameter, not the circumference diameter xp. An increasing French size corresponds to a larger diameter catheter. This is contrary to needle-gauge size, where the diameter is 1gauge, and where the larger the gauge the narrower the bore of the needle. 