The ureter has three natural constrictions where renal stones commonly lodge. At which of the following is the ureter narrowest?
- A Ureteropelvic junction
- B Intramural part (through the bladder wall) ✓
- C At the pelvic brim crossing the common iliac vessels
- D At the level of the ischial spine
Correct answer: B. Intramural part (through the bladder wall)
Explanation
The intramural part of the ureter as it passes obliquely through the bladder wall is the narrowest segment. The three constrictions are the ureteropelvic junction, the pelvic brim crossing, and the intramural portion. The intramural segment's narrow diameter (about 1-2 mm) makes it the most common site for stone impaction.
Reference: Gray's Anatomy for Students, 4th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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