<prompt> Ureteric constriction is seen at all the following positions, exceptUreteropelvic junctionUreterovesical junctionCrossing of iliac aeryIschial spine  <response>: Ureter has three constrictions, which are the most common sites of renal calculus obstruction: at the pelvi-ureteric junction PUJ of the renal pelvis and the ureter as the ureter enters the pelvis and crosses over the common iliac aery bifurcation at the vesicoureteric junction VUJ as the ureter obliquely enters the bladder wall Ref - BDC vol2 6e , researchgate.net 