Where do the ureters enter the urinary bladder?

Where do the ureters enter the urinary bladder?

• A. Bladder dome
• B. Lateral walls
• C. Superior aspects of the trigone
• D. Bladder posterior wall

Answer: (C)

Ureters enter the bladder at the superior corners of the trigone, along the base of the bladder on the posterior wall. The trigone is the triangular area formed by the two ureteric orifices and the internal urethral orifice, and the openings lie in those superior, posterolateral aspects. The ureters pass through the detrusor muscle obliquely, creating a valve-like mechanism that helps prevent vesicoureteral reflux as the bladder fills and contracts. Therefore, the other sites like the bladder dome, lateral walls, or the posterior wall away from the trigone do not describe the actual entry points.

Ureters enter the bladder at the superior corners of the trigone, along the base of the bladder on the posterior wall. The trigone is the triangular area formed by the two ureteric orifices and the internal urethral orifice, and the openings lie in those superior, posterolateral aspects. The ureters pass through the detrusor muscle obliquely, creating a valve-like mechanism that helps prevent vesicoureteral reflux as the bladder fills and contracts. Therefore, the other sites like the bladder dome, lateral walls, or the posterior wall away from the trigone do not describe the actual entry points.