lateral wall of urinary bladder

The lateral wall of the urinary bladder refers to either of the two side walls of the bladder, situated on the flanks of the organ. Together, the right and left lateral walls form the sides of the bladder, bridging the anterior and posterior walls.

The lateral walls of the urinary bladder are bordered by the obturator internus muscles and fascia, the pelvic sidewall vessels and nerves (obturator nerve and vessels), and the ureters as they course toward the bladder. In males, the lateral walls are also near the seminal vesicles and vasa deferentia posterolaterally.

The peritoneum covers only the superior and part of the posterosuperior surface of the bladder. The lateral walls of the bladder are primarily extraperitoneal, covered by the pelvic fascia and surrounded by perivesical fat. This extraperitoneal location of the lateral walls allows perivesical fluid (urine or blood) to accumulate without entering the peritoneal cavity.

The paravesical space (lateral vesical space) is a potential space lateral to the bladder wall, bounded laterally by the obturator internus fascia and medially by the bladder wall. It contains loose connective tissue and is important in pelvic surgery as it can be developed as a surgical plane to approach the lateral bladder wall, ureters, and pelvic lymph nodes during cystectomy or hysterectomy.

Urothelial carcinomas can arise on the lateral walls of the bladder, and tumors here may invade adjacent structures including the obturator nerve, internal iliac vessels, or pelvic sidewall. Advanced bladder cancers on the lateral wall may be unresectable if they fix to the pelvic sidewall. Lateral wall tumors near the ureteral orifices may cause ureteral obstruction and hydronephrosis.