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Trigone of urinary bladder: anatomy, location and function

The trigone is the smooth triangular area on the inner surface of the bladder base. It funnels urine towards the urethra, and its stretch-sensitive lining signals bladder filling.

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Highlighted in the model: Trigone of urinary bladder. Click any part to read about it, or switch off “Highlight topic” to see the whole body. Use Male / Female to switch bodies. 3D data: BodyParts3D, © The Database Center for Life Science; knee ligaments, menisci, tonsils, palate and parotid glands from the Human Reference Atlas Visible Human Male model and female parts from its Visible Human Female model (HuBMAP / NIH); lung lobes built from the BodyParts3D chest; all CC BY 4.0; meshes simplified and recoloured. The female body shares the male skeleton, muscles and organs except its pelvis, reproductive organs, breasts, bladder, urethra and skin.

Trigone of urinary bladder at a glance

What it is
The trigone is the smooth triangular area on the inner surface of the bladder base.
Location
Its corners are the two ureteric openings above and the internal urethral orifice below.
Function
It funnels urine towards the urethra, and its stretch-sensitive lining signals bladder filling.
Body system
Urinary · single, midline structure · female body
FMA ID
FMA15910 (Foundational Model of Anatomy)

Key facts

  • It stays smooth because its lining is firmly attached to the underlying muscle, while the rest of the empty bladder is folded into rugae.
  • It develops from the lower ends of the mesonephric ducts.
  • In the female body it rests on the anterior vaginal wall.

Clinical relevance

Irritation of the trigone, for example by infection or a catheter, causes urgency and frequent urination.

Structures next to the trigone of urinary bladder

The nearest named structures in the 3D model, measured from the centre of each part:

References

  1. Foundational Model of Anatomy: Trigone of urinary bladder (FMA15910). EMBL-EBI Ontology Lookup Service.
  2. OpenStax. Anatomy and Physiology 2e, §25.2 Gross Anatomy of Urine Transport. Rice University, 2022.
  3. Mitsuhashi N. et al. (2009). BodyParts3D: 3D structure database for anatomical concepts. Nucleic Acids Research 37, D782–D785. Data © The Database Center for Life Science, CC BY 4.0.
  4. Browne K., Schlehlein H. 3D Reference Organ Set for United, Female (Visible Human Female). Human Reference Atlas 3D Reference Object Library, HuBMAP / NIH. Data from the NLM Visible Human Project. CC BY 4.0.

Related anatomy

Explore the whole body in the interactive 3D human anatomy model, or browse the A–Z list of human structures.