Organ
Trigone of the bladder
The smooth floor between ureteral and urethral openings
High-yield
The old description of an entirely mesonephric-derived trigone is incomplete. Its urothelium is endodermal, while developmental studies show that trigonal muscle mainly joins the bladder's muscular framework with ureteric contributions.
Overview
The trigone is the triangular bladder-base region connecting the two ureteric openings with the internal urethral opening. Firm mucosal attachment gives it a relatively smooth surface while much of the empty bladder forms folds. Its tissues participate in outlet and ureterovesical coordination.
Reference facts
- Location
- On the internal posterior bladder base, immediately proximal to the bladder neck.
- Parts
- Ureteric orifices mark the upper corners and the urethral orifice the lower corner; an interureteric ridge joins the ureteric openings.
- Blood supply
- Communicating vesical branches of the internal iliac circulation, with vaginal arterial contributions in females.
- Innervation
- Pelvic autonomic and sensory pathways regulate the trigonal and adjacent bladder tissues.
- Venous/Lymphatic drainage
- Vesical veins reach internal iliac channels; lymph follows pelvic node groups, including internal and external iliac routes.
- Relations
- Related posteriorly to seminal-vesicle and rectal regions in males or anterior vaginal and cervical regions in females, with intervening tissue planes.
- Function
- Helps organize the ureteral entries and bladder outlet and participates in coordinated storage and emptying.
Clinical correlation
Inflammation or a distal ureteric stone near this region can contribute to urgency and discomfort. Filling sensation involves urothelium, nerves and muscle throughout the bladder rather than a single isolated sensory triangle.
Frequently asked questions
Where is the trigone of the bladder located?
On the internal posterior bladder base, immediately proximal to the bladder neck.
What does the trigone of the bladder do?
Helps organize the ureteral entries and bladder outlet and participates in coordinated storage and emptying.
What are the parts of the trigone of the bladder?
Ureteric orifices mark the upper corners and the urethral orifice the lower corner; an interureteric ridge joins the ureteric openings.
What is the blood supply of the trigone of the bladder?
The trigone of the bladder is supplied by the communicating vesical branches of the internal iliac circulation, with vaginal arterial contributions in females.