Ureteral function. III. The catheter and the geometry of the ureter

The geometry of a canine ureter with and without the presence of an indwelling catheter has been studied after in vivo freezing and sectioning. Changes in ureteral cross-section were observed as catheter size was increased from about 2 Fr. through 6 Fr. using a new microphotographic procedure. These preliminary results indicate direct contact between the ureteral wall and catheter during ureteral contraction, relaxation, and inactivity. In the region of a urine bolus, an open lumen could be clearly observed. The shape of the lumen appears to depend on the bolus volume, the size of the catheter, and local muscular characteristics of the ureteral wall. In the absence of a catheter, the lumen appears to vary between a totally collapsed configuration and an almost circular shape.