Bladder & Urethra

 When empty, the bladder lies on the pelvic floor surrounded by extraperiotoneal fatty tissue, posterior to the pubic bones. As it fills, it ascends in the extraperitoneal fatty tissue and enters the greater pelvis, reaching as high as the level of the umbilicus when full. In males, it is situated anterior to the rectum and superior to the prostate gland. In females, it is anterior to the vagina and anteroinferior to the uterus.

The anterior portion of the bladder, the apex, is connected to the medial umbilical ligament (vestigal urachus). The superior surface is covered with peritoneum. There are two inferolateral surfaces, a base, and a neck.

The body of the bladder extends from the apex to the posterior end, the fundus. The ureters enter the bladder through the internal ureteric orifices at the posterolateral angles of the trigone, which is located at the posterior base of the bladder and extends inferiorly to its anteroinferior angle at the neck of the bladder and the internal urethral orifice.