Female Urinary Bladder Trigone in Sagittal Section, Gross Anatomy

Description

Oriented in a midsagittal section through the adult female pelvis, the urinary bladder is opened to emphasize the trigone, a smooth triangular field on the posteroinferior bladder wall. The internal urethral orifice sits at the inferior apex of the triangle, while the right and left ureteric orifices form the superolateral corners, connected by the interureteric ridge (plica interureterica). Superior to the trigone lies the bladder body and dome, and inferiorly the bladder neck continues as the female urethra, positioned anterior to the vagina and inferior to the uterus and cervix when those relationships are included in the section. Smooth mucosa. No rugae here. Clinically, the trigone matters because it behaves differently from the rest of the bladder mucosa: it remains relatively fixed as the bladder fills, and the close packing of ureteric orifices and bladder neck makes it a frequent site where pathology declares itself. Cystitis pain commonly localizes to the trigonal region, and trigonal inflammation can produce irritative voiding symptoms out of proportion to findings elsewhere. For procedural teaching, this is the key surface anatomy used during cystoscopy to identify the ureteric jets, avoid iatrogenic injury to the ureteric orifices, and orient the endoscopist to the bladder neck during evaluation of vesicoureteral reflux or postoperative ureteral obstruction. Use this sagittal trigone view for urology and gynecology teaching blocks, pelvic anatomy labs, and medical textbooks covering lower urinary tract endoscopy, continence mechanisms, and common bladder pain syndromes. It also fits patient-facing surgical consent materials when explaining ureteral stenting, cystoscopy landmarks, or bladder neck procedures in women. Anatomical accuracy verified by SciePro's Medical Advisory Board.