 Sanju Sanal, Professor, Department Chair. Let's quickly mention a few clinical aspects about the ureters. Ureters that are about 25 to 30 centimeters long, they start from the pelvic ureteric junction and they end in the urotropicycle junction in the pelvis. So therefore the ureters have got two segments. One is the abdominal portion and then we have the pelvic portion. The ureters, as they run down in the abdominal portion, they are in relation to the tips of the transverse process of the lumbar vertebra. And as they come further down, they are in relation to the posterior lumbar spine. And then they cross over at the pelvic brim over the archaic line over the common iliac arteries. And then they enter the pelvis in relation to the ischial spine. And then they enter the floor of the bladder in the trigon at the urotropicycle junction. So this is the course of the ureter and these are the landmarks. As the ureter is descending down, there are three constant constrictions, which are normal constrictions. The first constriction is at the pelvic ureteric junction. The second constriction is when the ureter crosses in front of the common iliac. And we can see the same thing on this side also, when the ureter crosses in front. And the third normal constriction is at the urotropicycle junction. These three sides of constriction are the sides of calculus impaction. And it is generally said that if a calculus is more than 5 millimeters, it is likely to be impacted and it may not come out on its own. There are some other inconstant or gender variation places of constriction. In the abdomen, we can see that these are the gonadal vessels. This is the right gonadal vessel. In this case is ovarian and the ovarian artery. The crossing of the gonadal vessel is also another inconstant side of constriction. In the case of the male, it is a testicular vessel. Crossing of the broad ligament and ductus difference in the pelvis are also sides of constriction in the pelvis in males and females. Now let's come to a very important surgical concept. If you take a look at the ureter, you notice that I purposely retained the fascia here. Because running within the fascia, we have the peri-urotric plexus. And this peri-urotric plexus is the blood supply to the ureter. In the abdomen, the blood supply comes from the abdominal aorta, from the renal arteries, and from the gonadal arteries. In the pelvis, the blood supply comes from the common iliac, internal iliac, the vesicle arteries and the uterine arteries. In the abdomen, the blood supply comes from the medial aspect. And they form a plexus in the peri-urotric fascia and the supply. In the pelvis, the blood supply, because the ureter is going antromedially, the blood supply comes from the lateral aspect. In abdominal surgery, if to retract the ureter too far laterally, we are likely to rupture the blood vessels because they're coming from the medial side. And similarly, when we are doing surgery in the pelvis, if you were to retract the ureter too far medially, we are likely to rupture the blood vessels because they're coming from the lateral side. In which case, we will deprive the ureter of its blood supply and will produce a delayed ischemic necrosis, which usually occurs 7 to 10 days later. And it needs to delay rupture of the ureter. For the same reason, if we were to strip off the ureteric fascia during surgery, then we are also removing the blood supply because the blood supply goes through the peri-urotric plexus. Then also we can produce the same situation, namely delayed ureteric rupture, which occurs 7 to 10 days after surgery. The ureter can be imaged by the following techniques. Intravenous spilogram, where we inject intravenously radiopic dye and as it is excreted out through the kidneys, we visualize both the ureters. In a normal person, we should not be able to visualize the entire length of the ureter in one film because if we were to visualize it, that means there is an abnormality and obstruction. There's yet another method of visualizing the ureter and that is by injecting a dye in a retrograde fashion from the urethra and that is known as retrograde pylogram. So these are the two methods of visualizing the ureter. The left side, the ureter has a unique relationship with the root of the mesosigmoid. The forceps is holding the left ureter and the probe is binding at the root of the mesosigmoid. And therefore, when we are doing a sigmoidectomy, we have to be careful while accessing the middle mesosigmoid because we are likely to injure the left ureter. The pelvic helices system is an intricate division of the renal pelvis, which is here is the renal pelvis. It divides into two or three major calisthenes and each major calisthenes divides into two or three minor calisthenes. The whole thing is referred to as the pelvic calisthenes system. There is something called the staghorn calculus. It is nothing but a calculus which fills up the pelvis and branches up into the mesos, looking like the horns of a stag and therefore it is called a staghorn calculus. This is a still shot picture of the cut section of the kidney showing the structures clearly labeled. The congenital abnormalities where we have bifurcations of the renal pelvis, bifurcations of the ureter either complete or partial and there is a vigoured mirror rule which is applicable to complete bifid renal pelvis and ureter. The vigoured mirror rule states that the upper pole ureter is the topic ureter and it inserts into the bladder inframedially in relation to the normal lower pole ureter.