 We are going to demonstrate the bladder in the lower urinary system. So this structure which is being held up by my assistant, these are the two ureters, which are descending down into the pelvis. And this structure which is being held up by my other assistant, this is the bladder. So this is the apex of the bladder, to which we can see attached is a ligament, median umbilical ligament, which is the vibrous remnant of the urecus, which in turn is derived from the fetal allen toy. This portion of the bladder that we see here, this is the dome of the bladder, or the superior surface of the bladder, which is covered by visceral pleurotronium, but it has been removed. This portion that we see here, this is the vesico-utrient pouch, in this case, the uterus is highly atrophied. And behind that, this is the recto-utrient pouch. The ureters open onto the trigon in the floor of the bladder, which we shall show when we open the bladder. Now let's take a look at some other ligaments of the bladder. This structure that we see here, on the right side, this is the distal portion of the umbilical artery. And this forms the medial umbilical ligament. And this, as we can see, this is giving rise to one of the superior vesicle arteries. There will be many other superior vesicle arteries given off. Now let's take a look at the relations and the spaces around the bladder. The portion in front of the bladder, where my hand has gone in, between the pubic bone, pubic symphysis and the anterior surface of the bladder, this is known as the pre-vesicle space or the retropubic space. It is also referred to as the cave of red Zeus. And this is filled with endopelvic fascia. And in the case of females, there's a condensation of the fascia which is known as pubo-vesicle ligament. In the case of males, it is called the pubo-prostitic ligament. On either side of the bladder, there are again condensation of the endopelvic fascia, which have been removed, which allow passage to these blood vessels. These are the vesicle arteries and veins. These are known as the lateral ligaments of the bladder. One on this side and one on this side. A space behind the bladder. In the case of females, as I have told you, it is the vesico-utrient pouch. In the case of the males, it will be the recto-vesicle pouch. Now let's take a look at the interior of the bladder. We have opened up the anterior surface of the bladder to show the interior. Most of the bladder is derived from the endodermal of the urogenital sinus. However, this region that we see here, this is the region of the trigone. And this is derived from the misodermal wolfian duct. Squamous non-charitonizing metaphysia of the trigonal mucosa is common in females. The rest of the bladder is transitioned into the epithelium. Now let's take a look at the three openings in the trigone. On either side, we can see this is the ureter coming. This is the opening of the ureteric orifice. On the other side, this is the ureter. And this is the opening of the ureteric orifice. And finally, at the apex of the trigone where my finger has gone in, that is the urethral orifice. So the structure, which is demarcated by these three openings, this is referred to as a trigone. When we are doing a scistoscopy, normally we can see only two ureteric orifices and the region between the two, which is known as the inter ureteric bar. In the same view, we cannot see the urethral orifice. And if we were to be able to see the urethral orifice also, then that is known as marioncine positive, which is the feature of benign prostrate hypertrophy in males. But that is not the case in this particular patient. A quick word about the ureteric orifices in the bladder. The ureters do not enter the bladder straight away. They enter in a bevel fashion through the musculature of the bladder. And here they constitute a sphincteric mechanism, which prevents vesicouretric reflux of urine when the patient is passing urine. Because if the sphincteric mechanism were not there, then urine will reflux up and then it will lead to ascending urinary tract infection. Coming to the blood supply of the bladder. The bladder in the case of the males is supplied by two sets of arteries. One of the superior vesicle arteries, which come from the umbilical artery. This is the proximal part of the umbilical artery, which is patent. And we can see one branch here. This is the superior vesicle artery. There are many other branches. We can see them on the left side here. And we can see the other branches on the right side here. These are all branches of the superior vesicle artery. In the case of males, we also have an inferior vesicle artery, which arises as a separate branch from the anterior division of the internal iliac. But in the case of females in this cadaver, there is no inferior vesicle artery. Instead, there are vaginal arteries. Incidentally, in this cadaver, the uterus is very atrophied and therefore the structures pertaining to the uterus are almost non-existent. Now, let's come to some important clinical correlations pertaining to the bladder. Bladder calculus is quite common. And when there is calculus, there is a stylus, which is the inflammation of the bladder. And when a patient has got an infection or inflammation of the bladder mucosa, then he has urgency. That is, sudden desire to pass urine. In addition, there is dysuria, where the patient complains of pain in the suprapubic region and pain during passing urine. The mucosa of the trigon is very sensitive. And whenever there is an irritation due to calculus or infection that is known as trigonitis, the patient has severe urgency and frequency and dysuria. The patient wants to pass urine repeatedly. Now, let's come to the problem which is not so in this particular cadaver, but in males. And that is benign prostatic hypertrophy. When there is an enlargement of the prostate, the median lobe of the prostate pushes into the neck of the bladder through the region of the sphincter urethrae. And that projection is referred to as the uvula. And then it gives rise to what is known as the marioncine positive. In such cases, this musculature of the bladder that we see here, in this particular cadaver, this is very thin, but the musculature becomes hypertrophied. And it can also become trabiculated and there can be sacculations and even diverticulate may develop in such patients. Another is cancer of the mucosa of the bladder. It is usually transitional cell carcinoma. And finally, we have this entity which I've already mentioned that is the vesicoeurotric reflux, which happens when the sphincter mechanism of the ureters are deficient and that can lead to ascending urinary tract infection. So these are some common abnormalities pertaining to the bladder. If there are any questions or comments, please put them in the comment section below. Dr. Sanjay Sanyal signing out. Have a nice day. Make sure you like this video and make sure you subscribe. Thanks for watching.