Trigone of bladder
Trigonum vesicae
Definition
The trigone of the bladder is a triangular area located at the most caudal aspect of the urinary bladder. The apex of the triangle is the internal urethral orifice, and the base is the line connecting the two ureteral orifices.
The trigone of the bladder is composed primarily of smooth muscle and is distinct from the rest of the urinary bladder due to its embryological origin and structural characteristics. This area is free from the characteristic mucosal folds of the urinary bladder, but poorly developed ridges, converging toward the urethral crest, denote the boundaries of the trigone.
References
Constantinescu GM, Schaller O. Illustrated veterinary anatomical nomenclature, 3rd Edition, Enke Verlag, Stuttgart, 2012.
Evans HE, de Lahunta A. Miller’s anatomy of the dog, 4th edition, Elsevier Saunders, St Louis, 2012.
