From the Guidelines
The ureters enter the bladder at the posterior wall through two openings called the ureteric orifices, located at the upper corners of the trigone. This anatomical arrangement is crucial for maintaining the unidirectional flow of urine from the kidneys to the bladder, thus preventing potential infections or pressure damage to the kidneys. The ureters approach the bladder obliquely, creating a natural valve mechanism that prevents urine from flowing backward into the ureters when the bladder contracts during urination, as described in general urological principles 1. Key aspects of this anatomy include:
- The location of the ureteric orifices at the upper corners of the trigone
- The oblique entry of the ureters through the bladder wall
- The role of this anatomy in preventing urine reflux and protecting the kidneys Given the importance of this anatomy in urological health, understanding the precise point of entry of the ureters into the bladder is essential for both diagnostic and therapeutic purposes, including surgical interventions like those discussed in the context of ureteral injuries and repairs 1.
From the Research
Ureteral Entrance to the Bladder
- The ureters enter the bladder at the trigone, a key area for bladder function that allows one-way passage of urine into the bladder without obstruction 2.
- The trigone is formed by the interaction between the Wolffian duct and the bladder, with the ureteric bud arising from the Wolffian duct and being incorporated into the developing bladder at the trigone 2.
- The ureters emerge from the Wolffian ducts and undergo extensive epithelial remodeling to reach their final trigonal positions via vitamin A-induced apoptosis 2.
- Perturbation of this process can lead to clinical obstruction or urine reflux, and congenital malformations such as ureteric duplication and bladder exstrophy 2.
Clinical Relevance
- Malignant ureteral obstruction can cause significant morbidity and mortality, and management options include tandem stents, metallic stents, percutaneous nephrostomies, and extra-anatomic stents 3, 4, 5.
- The choice of management option depends on individual patient factors, and there is a need for prospective, randomized clinical trials to provide evidence-based guidelines for patients with malignant ureteral obstruction 3.
- Ureteral stenting may increase the risk of metachronous upper tract urothelial carcinoma in patients with bladder tumors, and should be avoided as a preventive measure after resection of tumors involving the orifice when possible 6.