Urine good hands here at Osmosis, because we care about each other and our learners! Bad puns aside, urine is an important way for us to eliminate waste and it takes quite the journey from the kidneys to the outside world! Let’s look at the path of urine after it leaves the kidneys, and the structures it passes through along its journey.

After exiting the kidney, urine travels through 3 main structures before leaving the body; the ureters, the urinary bladder and the urethra.

Let’s start with the ureters, which are paired muscular tubes sitting retroperitoneally that transport urine from the kidneys to the urinary bladder. The ureters are roughly 30 centimeters long, and have two parts; an upper abdominal part and a lower pelvic part.

The abdominal part starts at the kidneys, and descends in the abdomen posterior to the peritoneum to reach the pelvic brim. Here, the ureters cross near the bifurcation of the common iliac arteries - where the external and internal iliac arteries begin - and are now referred to as the pelvic ureters.

The pelvic ureters run on the lateral walls of the pelvis reaching the ischial spines. Then, each pelvic ureter passes anteromedially to enter the posterior wall of the urinary bladder. Now, the ureter is surrounded by many structures that differ between biologically male individuals and biologically female individuals.

In males, the ureters enter the posterior wall of the bladder superior to the seminal vesicles, which are paired glands that secrete parts of the seminal fluid. Also, the ureters run posterior to the ductus deferens, which are paired tubes that carry sperm from the scrotum to the pelvic cavity.

The ductus deferens emerges from the inguinal canal and travels to the posterolateral angle of the bladder, where it passes superior to the ureter. In females, the ureters pass medial to the origin of the uterine artery. Then, at the level of the ischial spine, the uterine artery crosses the ureter. Finally, the ureters run near the lateral part of the upper vagina and enter the bladder.