Ureteric constriction is seen at all the following positions, EXCEPT:

Ureteric constriction is seen at all the following positions, EXCEPT:

A. Ureteropelvic junction
B. Ureterovesicle junction
C. Crossing of iliac artery
D. Ischial spine

Answer is D. Ischial spine

The normal ureter is not of uniform caliber, with three distinct narrowings classically described: the ureteropelvic junction, crossing of the iliac vessels, and the ureterovesical junction.

Sites of narrowing of the normal ureter are:

1. Ureteropelvic junction: At the ureteropelvic junction, the renal pelvis tapers into the proximal ureter. In many cases, this perceived narrowing may be more apparent than real, with no evidence of obstruction evident on radiographic or endoscopic investigation.
2. Crossing of the iliac vessels: Due to a combination of extrinsic compression of the ureter by the iliac vessels and the necessary anterior angulation of the ureter as it crosses the iliac vessels to enter into the pelvis. There is also no intrinsic change in the ureteral caliber at this location.
3. Ureterovesical junction: A true physical restriction of the ureter as it makes the intramural passage through the bladder wall to the ureteral orifice.
4. Juxtaposition of the vas deferens or broad ligament
5. Ureteric orifice