Longitudinal ultrasound image of the urinary bladder in a cat, showing the presence of a small (<1 cm diameter), well-defined, fluid-filled, anechoic structure, protruding beyond the serosal surface of the cranioventral bladder wall, consistent with extramural vesicourachal diverticulum. The bladder presents a moderate, diffuse, thickening of the wall, with an irregular mucosal surface. A moderate amount of echogenic sediment is present in the lumen. Shadowing hyperechoic material adhered to the ventral bladder wall mucosa is also observed, which may represent congealed mineralized sediment.