The interureteral crease is a fold in the inner wall of the bladder between the two ureteral openings. The interureteral folds are usually located on the posterior lower wall of the bladder and appear as a pale band on cystoscopy and are clinically important in finding the ureteral orifices. Another important structure associated with the interureteral fold is the bladder triangle, which refers to the triangular area between the ureteral orifices and the internal urethral orifice on either side. The tissue in this area lacks a submucosal component, resulting in the mucosa being directly attached to the muscularis mucosae in close proximity and thus remaining smooth, making it a good area for bladder tumors, bladder tuberculosis, and inflammation, and is a key focus when performing a cystoscopy. Drinking plenty of water, urinating regularly, not holding urine, and keeping the external urethral opening and perineum clean are good ways to prevent bladder diseases. If symptoms such as hematuria, painful urination, or difficulty urinating occur, seek medical attention promptly.