Final answer:
The three most common sites where a ureteric calculus can be lodged are the ureteropelvic junction, the point where the ureter crosses the pelvic brim, and the ureterovesical junction.
Step-by-step explanation:
The three most common locations for a ureteric calculus, commonly known as a kidney stone, to be lodged are as follows: the junction where the ureter exits the kidney, the point where the ureter crosses over the pelvic brim, and the junction where the ureter enters into the urinary bladder.
These locations are narrow points that can become sites of obstruction if a stone is unable to pass through them easily. Ureters are retroperitoneal organs that propel urine from the kidneys to the urinary bladder through peristalsis.
The ureters enter the pelvis laterally, then turn medially and enter the bladder wall obliquely, creating a one-way valve to prevent urine reflux. This anatomical structure significantly contributes to where a ureteric calculus might lodge.